MINISTRY OF EDUCATION AND TRAINNING MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT NATIONAL INSTITUTE OF ANIMAL SCIENCES HONG SON TRINH PERFORMANCE AND ESTIMATED BREEDING VALUE OF VCN03 SIRE LINE MAJOR: ANIMAL GENETICS AND BREEDING CODE NUMBER: 62.62.01.08 SUMMARY OF PhD THESIS HANOI, 2014 PhD thesis was conducted at: National institute of animal sciences Supervisor: Dr. Que Coi Nguyen Ass. Prof. Dr. Van Chinh Dinh Reviewer 1: …………………………………………………………. ……………………………………………………………………….. Reviewer 2: ………………………………………………………….. ………………………………………………………………………… Reviewer 3: …………………………………………………………... ……………………………………………………………………….... The PhD theses will be defended at PhD thesis examination Committee of National Institute of Animal Sciences on .… h … day …. Month …. , 2014. This PhD thesis can be found in: - National Library of Vietnam - Library of National Institute of Animal Sciences LIST OF PUBLICATIONS RELATED TO THE PHD THESIS 1. Hong Son Trinh, Que Coi Nguyen and Van Chinh Dinh (2013). Semen characteristics, heritability and factors affecting semen quality of boars of VCN03 sire line. Journal of Science and Development, Vol. 46: 6-12. 2. Hong Son Trinh, Que Coi Nguyen and Van Chinh Dinh (2013). Growth Performance, Carcass Characteristics and Meat Quality of Boars of VCN03 sire line. Journal of Science and Development, Vol. 11: 965-971. 3. Hong Son Trinh, Que Coi Nguyen and Van Chinh Dinh (2014). Heritability and estimated breeding value for some reproductive traits of sows of VCN03 sire line. Journal of Science and Development, Vol. 10: 9-18. 1 Chapter I INTRODUCTION 1.1. Rational Two methods used for improvement of productivity and product quality in pig industry are selection, pure breeding and crossbreeding. VCN03 sire line (L19 - White Duroc) plays a key role in the breeding program of the PIC and is used to produce parental pig in breeding systems of Vietnamese PIC, and meanwhile it plays an important role in promoting lean pig programs in Vietnam. However, so far some production traits and meat quality of VCN03 sire line have not been yet properly and systematically studied to identify genetic parameters and estimate breeding values. For a higher efficiency of VCN03 sire line selection in particular and contributing to enhancement of productivity, quality, and efficiency of pig production in PIC pig breeding systems at Vietnam in general, it is necessary to investigate “performance and estimated breeding value of VCN03 sire line” at Tamdiep pig research and development station. 1.2. 1.3. Objectives of the study Evaluation of the reproductive performance of VCN03 dam line; quantity and quality of semen VCN03 sire line; growth potential, performance and meat potential of the VCN03 sire line Determination of heritability and estimated breeding value of some reproductive traits of VCN03 dam line; and growth and meat potential traits of VCN03 sire line. The novelty of thesis It was the first time in Vietnam, one systematic and scientific work on reproductive performance of VCN03 dam line; quantity and quality of boar semen of VCN03 sire line; growth, yield and quality of meat of VCN03 sire line was published. It also was the first time in Vietnam, heritability and estimated breeding value of reproductive traits of sows of VCN03 dam line, growth and the meat potential traits of boars of VCN03 sire line were determined. Estimated breeding value of some production traits was applied in a selection program to improve productivity and quality of VCN03 sire line. 1.4. Scientific and practical meaning of the thesis The thesis provided the additional technical information on productivity, heritability and estimated breeding value of reproductive traits of sows, growth and meat potential traits of VCN03 sire line. Estimated breeding value of some reproductive and production traits was applied in a selection program to improve productivity and quality of VCN03 sire line. One group of sows with high reproductive performance of VCN03 dam line and one group of boars with high growth and meat potential of VCN03 sire line have been selected. VCN03 sire line with high productivity and quality have been created to produce parental sows and to contribute to improving economic efficiency in the pig industry. Chapter II LITERATURE REVIEW Selection of high-yield lines in pigs and crossbreeding programs to find out the crosses complexes, which give more newborn piglet/litter, higher lean meat percentage, lower feed consumption and lower back fat thickness, were successful in developed countries with advanced animal production levels such as America, Germany, Canada, Britain, the Netherlands, Denmark and Australia (Hermesch et al., 1995; Alfonso et al., 1997). 2 On Yorkshire and Landrace, estimated heritability for newborn piglet/litter and weight at 21 day old/litter traits have been reported from 0.03 to 0.20 (Hermesch et al., 2000; Hanenberg et al., 2001; Chen et al., 2003; Hamann et al., 2004; Arango et al., 2005; Rho et al., 2006; Imboonta et al., 2007). For the average body weight gain/day, reported heritability was significantly different among studies and ranged from 0.13 to 0.42 (Chen et al., 2003; van Wijk et al., 2005; Roh et al., 2006; Imboonta et al., 2007). Similarly, heritability of back fat thickness trait was reported from 0.50 to 0.71 (Hicks et al., 1998; Chen et al., 2003; Rho et al., 2006; Imboonta and et al., 2007). The reason for significant difference among studies was due to the different populations of gene frequency, differences in data sources as well as different calculated methods. Genetic progress for newborn piglet/litter trait in the United States was increased from 0.36 to 0.63 piglets (Mabry et al., 2001; Holl and Robinson, 2003; Boyette et al., 2005). Pig productivity was reported to be affected by breed, halothane genotype factors (Phung Thi Van et al., 2001; Phan Xuan Hao, 2002; Phan Van Hung and Dang Vu Binh, 2008; Do Duc Luc et al., 2008 ; Phan Xuan Hao and Nguyen Van Chi, 2010; Doan Van Viet and Dang Vu Binh, 2010; Ha Xuan Bo et al., 2013a). BLUP method had been applied in Vietnam to determine the estimated breeding value in pigs for a while in Vietnam (Ta Thi Bich Duyen and Nguyen Van Duc, 2001; Nguyen Ngoc Tuan and Tran Thi Dan, 2001; Ta Thi Bich Duyen 2003; Tran Van Chinh, 2004; Nguyen Thi Vien, 2005; Nguyen Van Hung and Trinh Cong Thanh, 2006; Pham Thi Kim Dung and Ta Thi Bich Duyen, 2009; Ta Thi Bich Duyen et al., 2009). PigBLUP was also used to assess the genetic value through herds (Willi Funchs, 1991; Tony Henzell, 1993; Tom Long, 1995; 5:20 PigBLUP version of user's manual, 2006). Selective index based on phenotypic values of production traits of pig was established (Cleveland et al., 1983; McPhee, 1981; Ellis et al., 1988; Tran The Thong, Le Thanh Hai, 1982 ; Dang Vu Binh, 1992; Le Thanh Hai et al., 1998; Nguyen Hong Hanh, Nguyen Que Coi, 2000; Che Radiology et al., 2001; Vu Dinh Ton et al, 2004). However, so far the productivity of VCN03 line has not been yet comprehensively and systematically studied and evaluated. The determination of heritability and estimated breeding value of reproductive traits of sows, growth and the meat potential traits of boars and application of estimated breeding value of some production traits in selection to improve productivity and quality of VCN03 sire line have not been studied in Vietnam. Chapter III PRODUCTIVITY OF VCN03 BOAR LINE 3.1. Reproductive potential of VCN03 dam line 3.1.1. Introduction L19 pig line (White Duroc) or VCN03 (new name) has been received and reared by Thuy Phuong Pig Research Center since 2001. However, over a period of exploitation and utilization, breeding pigs has not been fully examined their reproductive potential. It is essential to create a basis for selection, breeding improvement in subsequent generations, an assessment of factors affecting productivity and productivity of VCN03 line is very critical. The purpose of this study was to evaluate the production potential and the influence of some factors on the production potential of VCN03 line. 3.1.2. Materials and methods 3.1.2.1. Subjects of study - VCN03 line: 362 pigs with 1129 litters. 3.1.2.2. Methods 3 - The study was conducted at Tamdiep pig research and development station belonging to Thuy Phuong Pig Research Centre - National Institute of Animal Sciences. Data on reproductive performance of VCN03 dam line were collected from data base stored in Computers using PPM management software from 2002 to 6/2010 and collected directly in the station from 7/2010 to 4/2013. - Piglet number was determined by counting at the time of delivery, weaning, and after weaning. Body weight was determined by a scale at the time of delivery, weaning. - The data were analyzed using SAS 9.1 software (2002). The statistical parameters were: sample size (n), Mean, maximum value (Max), minimum value (Min). GLM procedure was used to calculate least square mean (LSM), standard error (SE) and to assess impacts of some factors on studied parameters. The mathematical model for a statistical analysis was as follow: Yijk = μ + THi + Lj + Nk + εijk Where: Yijk: reproductive performance; μ: the population mean; TH: effect of the ith generation (i = 1, 2, 3, 4); Lj: effect of jth parity (j = 1, 2, 3, 4, 5, 6, 7); Nk : effect of kth year (k = 2002, 2003 ... .., 2013); εijk: random error. Pair comparison among LSM values was done using Turkey comparisons. 3.1.3. Results and Discussion 3.1.3.1. Factors affecting the reproductive performance of sows of VCN03 line Reproductive performance of VCN03 dam line was not affected by generations (P> 0.05). Litters affected alive newborn/litter and weaning weight/piglet (P <0.01). Years affected weaned number/litter, weaned weight/litter, newborn weight, weaning weight/piglet and weaning weight/litter (P <0.001). These results were consistent with findings of some authors such as Tran Thi Minh Hoang et al. (2006; 2008b); Dang Vu Binh et al. (2008); Pham Thi Kim Dung and Tran Thi Minh Hoang (2009); Doan Van Soan and Dang Vu Binh (2010). 3.1.3.2. Reproductive performance of sows of VCN03 line Sows of VCN03 line had a low number of alive newborn number/litter (8.85 piglets/litter), a high newborn weight (1.56 kg/piglet) and high growth potential (weaning weight: 6.72 kg/piglet). Imboonta et al. (2007) reported that alive newborn number/litter of Landrace pigs in Thailand was 10.03 piglets. According to Nguyen Huu Tinh (2009), newborn number/litter, weaned weight/ litter at 21 days of age of Landrace and Yorshire sows in the southern provinces in the period from 1995 to 2005 were 9.60 and 9.57litter, and 58.79 and 57.26 kg/litter; respectively. This author also reported that newborn number/litter, weaned weight/ litter at 21 days of age of Landrace and Yorshire sows in the southern provinces in the period from 2000 to 2007 were 9.70 and 9.80 piglets/litter, and 54.10 and 54.09 kg/litter, respectively. Thus, sows from VCN03 line were from "sire line '', which were characterized by lower reproductive performance compared to reproductive performance of sows from dam lines. Sows from dam lines, for example: Meishan, had a higher reproductive performance. On average, number of newborn alive/litter of Meishan was 14-16. Reproductive performance of sows, which were born from mating between boars of sire line and crossbred sows was also higher. Phan Van Hung and Dang Vu Binh (2008) reported that newborn number, weaned number/litter of F1 hybrid sows (LxY), Du x F1(YxL), L19 x F1(LxY) and L19 x F1(YxL) were 10.00; 10.43; 10.27 and 10.61 piglets/litter; 9.60; 9.89; 9.72 and 10.00 piglets/litter, respectively. Doan Van Soan and Dang Vu Binh (2010) reported that number of born alive and weaned number of F1 hybrid sows (L x Y) with Duroc boars and L19 (or VCN03) were 11.26 and 11.44 piglets/litter, and 10.37 and 10.46 piglets/litter respectively. However, newborn weight/piglet was 1.49 and 1.47 kg/piglet, respectively. 4 3.1.3.3. Reproductive performance of sows of VCN03 line over generations Newborn number/litter was decreased from one generation to another, being the highest in the first generation and the lowest in the fourth generation. Newborn number /litter of the first generation was 9.29 piglets and decreased by 0.49 piglets/litter in the second generation. This decreased trend also occurred in the thirst and the fourth generations at lower rate. The main reason for that was VCN03 sire line was only kept in Thuy Phuong Pig research center in our country and has not been improved for a long time. To enhance genetic value, stabilize performance and quality, Center has already imported a new genetic resource from abroad since 2005. Newborn weight/litter was the highest in the first generation, decreased in the next generation (2, 3 and 4). Newborn weight/litter of the first generation was higher due to higher newborn number/litter. In contrast, weaned weight/litter was the lowest in the first generation. Weaned weight/litter increased in the second and thirst generations then decreased in the fourth generation. Lower weaned weight/litter of the first generation may be due to the inappropriate feeding of sows with piglets of VCN03 line. However, newborn weight/litter and weaned weight/litter of sows of VCN03 line over generations were not significantly different (P≥0.05). Alive newborn weight/piglet over 4 generations was high, from 1.55 to 1.57 kg/piglet, and no significant difference over generations was found. Weaned weight/piglet was negatively correlated with weaned number/litter. In the first generation, while weaned number/litter was the highest, weaned weight /piglet was the lowest. Weaned weight /piglet was the lowest in the first generation then increased in the next generation and seemed to be stable later. Similar to alive newborn weight/litter, weaned weight/piglets over generation was not statistically significantly different (P≥0.05). Thus, alive newborn number/litter, weaned number/litter, and alive newborn weight/litter decreased from the first generation to the fourth generation. Alive newborn weight/piglet was relatively stable over generations. Weaned weight/litter slightly increased in the second generation and was relatively stable in the thirst and fourth generations. For exotic pigs, after more than 10 years raising, fertility was in stability and positive result. 3.1.3.4. Reproductive performance of sows of VCN03 line over parities Newborn number/litter, weaned number/litter of sows of VCN03 line over parities was presented in Table 4. The results showed that newborn number/litter was the lowest in the first parity, increased in the second parity, was the highest in the thirst parity, decreased in the fourth parity, increased in the fifth and sixth parities and decreased again in the other late parities. The variation in alive newborn number/litter and weaned number/litter of sows of VCN03 line over parities was not similar with the report of Yen et al. (1987). Table 4: Newborn number/litter, weaned number/litter of sows of VCN03 line over parities Parities Newborn number/litter (piglet) Weaned number/litter (piglet) n LSM SE n LSM SE 1 229 8,50a 0,16 218 7,89 0,14 2 204 8,78ab 0,17 194 8,00 0,14 3 185 b 9,19 0,17 176 8,35 0,14 4 151 8,61a 0,19 143 8,04 0,15 5 133 9,16b 0,20 125 8,21 0,17 6 100 9,23b 0,23 93 8,35 0,19 5 ≥7 8,69ab 127 0,21 117 7,97 0,18 * Within column, LSM values bearing different superscripts differ (P<0, 05) Newborn number/litter, weaned number/litter of sows of VCN03 line tended to increase from the first parity to the thirst parity. However, alive newborn number/litter of the fourth parity was markedly reduced compared to that of the thirst parity. The cause of this situation may be due to the biological cycle characteristics of VCN03 line, it was different from other breeds. It was found out that culling rate of sows of VCN03 line after the thirst parity was the highest (18.38% ). The high culling rate of sows may affect alive newborn number/litter. However, at the fifth parity, newborn number/litter recovered and was the highest in the sixth parity. The reason for the highest newborn number/litter in the sixth parity was that in this parity, sows with a poor performance were culled. Culling rate from the first parity to sixth parity was 56.33%. Similar to sows from other exotic breeds, newborn number/litter was remarkably reduced in the sixth parity. Along with the breed factor, environmental factors affected reproductive performance including newborn number/litter of sows. Alive newborn weight/litter over parities varied in a similar trend of alive newborn number/litter. Newborn weight/litter in the fourth parity was lower than that of other parities. It may be due to the fact that number born alive/litter was low. However, no significant difference in alive newborn weight/litter, weaned weight/litter over parities was found. This finding indicated that parity did not affect newborn weight/litter and weaned weight/litter. It appeared that variation of weaned weight/piglet were greater than that of weaned weight/litter. Weaned weight/litter was low in the first parity (6.46 to 6.88 kg/piglet), increased in the second parity, then was stable in the thirst, fourth and fifth parities, significantly reduced in the sixth parity 6 and increased again at seventh parity. Differences in weaned weight/piglet over parity were statistically significant (P <0.05). 3.1.3.5. Reproductive performance of sows of VCN03 line over the years Alive newborn number/litter and weaned number/litter of sows of VCN03 line over the years were presented in Table 6. Table 6: Alive newborn number/litter and weaned number/litter of sows of VCN03 line over the years Alive newborn number/litter (piglets) weaned number/litter (piglets) Year n LSM SE n LSM SE 2002 123 8,55 0,28 116 7,70ac 0,23 abc 0,22 2003 109 8,60 0,25 93 7,87 2004 89 8,53 0,26 80 7,98abcd 0,22 2005 106 8,68 0,25 102 7,86ac 0,21 ac 0,20 2006 99 8,67 0,25 97 7,81 2007 119 9,16 0,22 112 8,32abd 0,18 2008 113 9,29 0,22 113 8,34abd 0,18 d 0,19 2009 99 9,17 0,23 94 8,52 2010 62 9,16 0,29 61 8,52bd 0,24 2011 86 9,19 0,26 83 8,58d 0,22 2012 101 9,07 0,27 94 8,39abd 0,23 2013 23 8,47 0,50 * Within column, LSM values bearing different superscripts differ (P<0,05) 21 7,50 c 0,42 6 The results in Table 6 showed that the alive newborn number/litter in the period of 2002 to 2006 (8.53 to 8.68 piglets/litter) was lower than that in the period of 2007 to 2012 (9.07 to 9, 29 piglets/litter). In 2013, only 23 litters were monitored so that data were not reflected the true reproductive potential of sows of VCN03 line. Differences in alive newborn number/litter over the years of 2007 to 2012 was significant (P> 0.05). Weaned number/litter of each year depended on alive newborn number/litter and survival rate before weaning. Variation in weaned number/litter of sows of VCN03 line over years was similar to variation in alive newborn number/litter over years. Thus, weaned number/litter was depended on alive newborn number/litter. The external factors may also had a great influence on weaned number/litter. Alive newborn weight/litter, alive newborn weight/piglet, weaned weight/litter and weaned weight/piglet of sows of VCN03 line by years were presented in table 7. Table 7: Alive newborn weight/litter, alive newborn weight/piglet, weaned weight/litter and weaned weight/piglet over years Alive newborn Alive newborn Weaned weight/litter weaned weight/piglet weight/litter (kg) weight/piglet (kg) (kg) (kg) Year n LSM SE n LSM SE n LSM SE n LSM SE 2002 28 13,22 0,63 28 1,57ab 0,03 28 64,53a 2,63 28 6,91adc 0,19 2003 44 15,10 0,48 44 1,64b 0,02 43 55,96b 2,04 43 6,25b 0,15 ab a cde 0,17 2004 33 15,14 0,54 33 1,58 0,02 32 63,32 2,30 32 6,79 2005 50 14,71 0,46 50 1,55ab 0,02 50 55,78b 1,94 50 6,57bde 0,14 2006 53 13,58 0,44 53 1,56ab 0,02 54 56,03b 1,82 54 6,74cde 0,13 eb 0,09 ab b 1,22 119 6,46 2007 111 14,48 0,30 111 1,55 0,01 119 55,60 2008 112 14,08 0,30 112 1,52a 0,01 111 57,81b 1,24 111 6,79cd 0,09 2009 94 14,23 0,32 94 1,54a 0,01 94 62,34a 1,33 94 7,98ac 0,10 ab b 1,61 64 6,48 bde 0,12 2010 61 14,32 0,39 61 1,57 0,02 64 57,45 2011 83 14,62 0,36 83 1,58ab 0,01 89 59,17b 1,45 89 6,60bde 0,11 2012 94 14,03 0,38 94 1,53a 0,02 93 59,19b 1,57 93 6,67de 0,12 21 ab 21 b 21 a 0,21 2013 21 13,06 0,69 1,56 0,03 56,30 2,90 7,28 * Within column, LSM values bearing different superscripts differ (P<0, 05) Alive newborn weight/litter was the lowest in 2002 and 2006, and was the highest in 2003 and 2004 then was relatively stable in later years. Alive newborn weight/litter over the years was not statistically different indicating that the year factor did not affect alive newborn weight/litter. Weaned weight/litter was higher in 2002, 2004 and 2009 (64.53, 63.32 and 62.34 kg/litter) and significantly differed from weaned weight/litter in later years (P <0.05). Weaned weight/litter in the later years ranged from 55.60 to 59.19 kg/litter. However, no difference among years was found for most of the parameters measured. Weaned weight/litter and weaned weight/piglet considerably varied over years. Breed factor and also external factors during 12 years were the main reason for the variation. 3.1.3.6. Conclusions and recommendations a. Conclusions Sows of VCN03 line were from "sire line '', which were characterized by lower reproductive performance. Alive newborn number/ litter and weaned number/litter of sows of VCN03 line were graduately decreased from the first generation to the fourth generation (P> 0.05). 7 Alive newborn weight/piglet and weaned weight/piglet were relatively stable over generations. Weaned weight/litter in the second, thirst and fourth generations was improved (P> 0.05). Alive newborn number/litter, weaned number/litter, alive newborn weight/litter were lower in the first parity and increased in the second and thirst parities. From thirst parity to the sixth parity, alive newborn number/litter, weaned number/litter, alive newborn weight/litter were fluctuated and decreased in the seventh parity. Alive newborn number/litter and weaned number/litter in the period of 2007 to 2012 were higher than these of the period of 2002 to 2006 (P <0.05) due to genetic improvement in this period.. b. Recommendations For improvement of reproductive performance of sows of VCN03 line, selection with a higher pressure, a combination of good feeding, herd management with periodical introduction of new exotic genes would be necessary. It would be very critical that heritability and breeding value of reproductive traits of sows need to be estimated for application in breeding programs 3.2. The semen quantity and quality of boars of VCN03 sire line 3.2.1. Introduction Evaluation of semen quantity and quality of boar is important in the use of sire line. Many boars with a nice looking have a poor reproductive performance and some can not work as a boar. Therefore, evaluation of semen quality will help us to indentify some boars with reproductive problems, especially boars used in artificial insemination and to have any intervention measure for a higher breeding efficiency. Selection for improvement of quantity and quality of semen of boars in the field has been considered as an important key factor, and is paid attention by researchers and farmers over the world. The objective of this study was to determine how and in what extents main factors such as age, generation, individuals, season and year, affect semen quality and quantity. Semen quantity and quality of boars of VCN03 sire line was evaluated through two generations in this study. 3.2.2. Materials and methods 3.2.2.1. Subjects of study - 22 boars of VCN03 sire line of 2 generations (generation 0: 11 boars in 2006, the generation of 1: 11 boars selected from generation 0). 3.2.2.2. Methods The study was conducted at Tamdiep pig research and development and research station belonging to Thuy Phuong Pig Research Centre - National Institute of Animal Science. Data on quantity and quality of semen of boars from VCN03 sire line was collected from data stored at the station from 2006 to June, 2010 and collected directly from April, 2013 to July, 2010. Boar semen was collected when boars were 12 months of age and finished when boars was 36 months of age. Semen boar was collected in the morning using a bar. Semen volume (V)(ml/collection) was determined using a syringe with a ruler. Sperm motility (A) was as percentage of sperms moving straight/total sperms observed in the microscope with a magnification of 100-300 times. A could range from 0 to 1 (or from 0% to 100%). Sperm concentration (C) (millions/ml) were measured using a machine (SDM5 Minitube, Germany). Total of semen of straight movement (VAC) was V multiplied by A and by C. Abnormally shaped sperm percentage (K) was determined by staining and counting with a microscopic detector with a magnification of 400-600 times. pH value of semen was measured by pH meter (Metter Toledo MP 220). 8 The data were analyzed in a similar way as described in Section 3.1.2.2 with the following mathematical model: Yijklm = μ + THi + Dj + Kk + Ml + Nm+ T + εijklm Where: Yijklm: quantity and quality of semen; μ: population mean; THi: effect of generations (0, 1); Dj: effect of individual sires (1, 2, ..., 22); Kk: effect of interval between two semen collection (1, 2, 3, 4, 5, 6 days); Ml: effect of seasons (Spring, Summer, Fall, Winter); Nm: effect of the year (2006, 2007, ... .., 2013); Tijklm: effect (covariance) of age (months); εijklm: random error. 3.2.3. Results and discussion 3.2.3.1. Factors affecting semen quantity and quality of boars of VCN03 sire line All factors such as age of semen collection, generation, individuals, breed, season and year affected semen quality and quantity of boars of VCN03 sire line (P <0.001). However, A, C and K were not influenced by intervals of two semen collection. Sperm concentration was also not influenced by seasons. Results of this study were slightly similar to works of Ha Xuan et al. (2013a); Smital, (2009); Wysokinska et al. (2009); Banaszewska et al. (2007); Milewska et al. (2004). 3.2.3.2. Semen quantity and quality of boars of VCN03 sire line Semen volume (V), sperm motility (A), sperm concentration (C), abnormally shaped sperm percentage (K) and VAC of boar semen of VCN03 sire line were 266.49 ml; 84.11%; 282.05 million/ml; 6.28% and 63.72 billion, respectively. Figures of this study were higher than these published by Phan Van Hung and Dang Vu Binh (2008); Do Duc Luc et al. (2013b) and lower than these published by Ha Xuan Bo et al (2011); Do Duc Duc et al. (2013a). These figures were similar to the results reported by Ciereszko et al. (2000); Smital (2009); Wolf and Smital (2009); Wysokinska et al. (2009); Wierzbicki et al. (2010). Semen quality and quantity of boars of VCN03 sire line rearing at Tamdiep were rather good and met the temporary national standard for exotic boars in AI programs issued by Ministry of Agriculture and Rural Development (Decision N01712 QD-BNN, 2008). 3.2.3.3. Semen quantity and quality of boars of VCN03 sire line over seasons Semen volume (V), sperm motility (A), sperm concentration (C), abnormally shaped sperm percentage (K) and VAC of boar semen of VCN03 sire line in the season (spring, summer, autumn, winter) were presented in Table 10. V, A of semen were higher in spring and summer, lower in autumn and winter. VAC was higher in spring and summer, lower in the fall and winter. Abnormally shaped sperm percentage was the lowest in spring and winter, the highest in the fall and summer. Table 10: Semen population and quality of boars of VCN03 sire line over seasons Spring (n = 809) LSM SE Indicators Semen volume (ml) Sperm motility (%) Sperm concentration (millions/ml) VAC (billions/time) Abnormally percentage (%) shaped Summer (n = 788) LSM SE Autumn (n = 805) LSM SE Winter (n = 858) LSM SE 264,82a 85,79a 7,62 0,89 264,99a 85,23a 5,56 0,65 259,70b 83,60b 3,63 0,42 257,60b 84,08b 2,05 0,24 273,40 63,39a 7,10 2,69 274,09 63,37a 5,17 1,96 273,14 60,39b 3,38 1,28 275,56 61,34ab 1,91 0,73 6,21b 0,20 6,29ab 0,15 6,36a 0,10 6,21b 0,05 sperm * Within column, LSM values bearing different superscripts differ (P<0, 05) 9 According to Smital (2009), Ha Xuan Bo et al. (2011) semen quality of Pietrain boars was the best in the winter and next spring to autumn and the lowest in summer. Wierzbicki et al. (2010) also showed that C, A and VAC in the winter (642.02 million/ml, 72.68% and 94.14 billion/times) were higher than these in summer (590.87 million/ml, 72.51% and 92.72 billion/time) and that V was not affected by months of the year. According to Ha Xuan Bo et al. (2013a) Pietrain pigs had a better tolerance to stress in spring and their tolerance to stress was reduced in the summer. The research results of Do Duc Luc et al. (2013) also showed that C was the lowest in July (summer) and was the highest in October and November (winter). Thus, semen quantity and quality of boars of VCN03 sire lines kept in Tamdiep pig research and development station in four seasons (spring, summer, autumn and winter) were slightly different from semen quantity and quality of boars reported by several authors. This difference was partly due to the differences in breeds used and external conditions such as macro and micro climatic conditions...where boars were reared. 3.2.3.4. Semen quantity and quality of boars of VCN03 sire line over years Semen quantity and quality of boar of VCN03 sire line over years were presented in Table 11. Semen quantity and quality of boars of VCN03 sire line were greatly varied over years. Differences in semen quantity and quality of boars of VCN03 sire line over the years were statistically significant (P <0.001). Table 11: Sperm quantity and quality of boars of VCN03 sire line over years Year 2006 2007 2008 2009 2010 2011 2012 Semen volume (ml) LSM 264,57bc 258,79bc 248,20c 270,65ab 256,12bc 270,86a 263,24bc SE 30,37 21,69 13,14 5,23 5,49 13,63 22,20 Sperm motility (%) LSM 91,34a 90,79a 86,11b 86,45b 81,15c 79,24c 77,64c SE 3,55 2,54 1,54 0,61 0,64 1,59 2,60 Sperm concentration (millions/ml) LSM 247,21b 294,02a 278,26ab 280,47ab 264,45ab 276,93ab 276,98ab SE 28,29 20,20 12,24 4,87 5,11 12,70 20,68 VAC (billions/time) LSM 63,96ab 70,15a 60,50b 67,82a 55,68b 59,38b 57,37b SE 10,74 7,67 4,65 1,85 1,94 4,82 7,85 Abnormally shaped sperm percentage (%) LSM SE c 6,09 0,80 ab 6,43 0,57 c 6,13 0,34 bc 6,20 0,14 b 6,26 0,14 a 6,53 0,36 b 6,24 0,58 * Within column, LSM values bearing different superscripts differ (P<0, 05) 3.2.3.5. Semen quantity and quality of boars of VCN03 sire line over generations Semen quantity and quality of boars of VCN03 sire line over generations were presented 12. Table 12: Semen quantity and quality of boars of VCN03 sire line over generations Generation 0 Generation 1 (n = 1720) (n = 1540) Parameters P LSM SE LSM SE Semen volume (ml) 256,03a 11,71 267,52b 19,87 <0,0001 a b Semen motility (%) 78,23 1,37 91,12 2,32 <0,0001 a b Sperm concentration (millions/ml) 270,80 10,91 277,29 18,51 <0,0001 a b VAC (billions/time) 54,98 4,14 69,26 7,03 <0,0001 a b Abnormally shaped sperm percentage (%) 6,51 0,31 6,03 0,52 <0,0001 * Within column, LSM values bearing different superscripts differ (P<0, 05) Results showed semen volume, sperm motility and sperm concentration of boars of VCN03 sire line in the first generation were significantly improved compared to these in the zero generation. Therefore, VAC in the first generation was markedly improved and, increased by 14.28 billion/time (P <0.0001). Abnormally shaped sperm percentage in the first generation was also markedly decreased by 0.48% (P <0.0001). 10 Improvement of semen quantity and quality of boars of VCN03 sire line in the first generation was partly due to selection effort and improved rearing conditions. 3.2.3.6. Conclusions and recommendation a. Conclusions Semen quality and quantity of boars of VCN03 sire line were rather good and met the temporary national standard for exotic boars in AI programs issued by Ministry of Agriculture and Rural Development (Decision N01712 QD-BNN, 2008). Selection combined with improvement in environmental condition (nutrition, feeding, housing ...) increased semen quantity and quality of boars in the first generation. b. Recommendations Heritability and estimated breeding value of fertility traits of boars need to be regularly and continuously determinated. So that heritability and estimated breeding value of fertility traits of boars can be able to efficiently apply in breeding programs. 3.3. Growth, performance and meat quality of boar of VCN03 sire line 3.3.1. Introduction VCN03 sire line (White Duroc) plays a key role in the breeding program of the PIC Vietnam. This sire line was used for crossing with two grand parent pig lines (VCN11, VCN12) to produce parent line (VCN21, VCN22). This sire line has some advantages such as a high potential of growth, lower feed conversion ratio (FCR), higher marbling score and high reproductive performance. However, so far, growth, performance, quality of meat of pigs of VCN03 sire line have not been systematically investigated. Therefore, assessment of growth, performance, quality of meat of pigs of VCN03 sire line over generations is essential. Objectives of this study was to evaluate growth, performance, quality of meat of pigs of VCN03 sire line in two generations and to see the initial selection efficiency. 3.3.2. Materials and methods 3.3.2.1. Subjects of study 205 non-castrated boars (generation 0: 114 boars, generation 1: 91 boars) were used in this study. Carcass evaluation was conducted on 40 non-castrated boars (generation 0: 20 boars, generation 1: 20 boars) and meat quality evaluation was performed on 36 non-castrated boars (generation 0: 17 boars, generation 1: 19 boars). 3.3.2.2. Methods The study was conducted at Tamdiep pig research development station belonging to Thuy Phuong Pig Research Centre - National Institute of Animal Science. Data on growth, performance and meat quality of boars of VCN03 line was obtained from data base stored from 2002 to June, 2010 and collected directly from July, 2010 to April, 2013. Body weight of each animals was determined using Kelba electronic scales (Australia) at the start and at the end of the experiment. Average daily gain (g/day) (ADG) was calculated based on the difference between body weight at the end of experiments and body weight at the start of experiments. Back fat thickness and loin muscle thickness were measured at the end of the experiment using ultrasound equipment: Agroscan AL with the ultrasound probe Alal 350 (ECM, France) in position of thirst and fourth ribs, according to the method described in the study of Youssao et al. (2002). Back fat thickness and loin muscle thickness were used to estimate the proportion of lean meat using the regression equation recommended by Belgium Ministry of Agriculture in 1999. Y = 59,902386 - 1,060750 X1 + 0,229324 X2 11 Where: Y: estimated lean percentage (%); X1: back fat thickness including skin (mm); X2: loin muscle thickness (mm). Carcass weight was weighted using a scale (100 kg) after removing hair, blood and organ. Dressing percentage was calculated based on body weight before slaughter and carcass weight. Dressing percentage = (Carcass weight/slaughter weight) x 100. Meat quality was measured in Department of Animal Genetics and Breeding, Faculty of Animal Science and Aquaculture, Vietnam University of Agriculture. Parameters measured included: pH45 values (pH of loin muscle at 45 min after slaughter) and pH24 (pH of loin muscle preserved in 24 hours after slaughter), meat color, dehydration percentage in preservation. Meat processing was according to the method of Warner et al. (1997), meat toughness was measured by method of Channon et al. (2003). The pH value was measured using Testo 230 (Germany) at the time of 45 minutes (pH45) and 24 hours (pH24) after slaughter. The pH value was the mean of 5 measurements in 5 different points. Meat color was measured using a Minolta CR-410 (Japan) with indexes: L* (lightness) , a* (Redness) and b* (yellowness) at 24 hours (24 L*, a* 24, b* 24) after slaughter. Dehydration percentage in preservation and processing (%) were determined based on the sample volume before, after storage, processing at the time of 24 hours. Loin toughness (N) was determined using 2000D Warner Bratzler machine (USA) at 24 hours after slaughter preservation. Meat quality was classified on dehydration percentage in preservation, light meat (L*), pH45, pH24 values according to standards of Warner et al. (1997), Joo et al. (1999). Good quality pork would have dehydration percentage in preservation of 2-5%, light meat (L*) of 40-50, pH45 values of more than 5.8 and pH24 of less than 6.1 and of higher than 5.4. Data was analyzed as described in 3.1.2.2 section using mathematical model: yij = μ + ai + bxij + eij Where: yij: jth observation in the formula i, μ: population mean, ai: effect of generation i, bxij: covariance: effect of age at beginning of experiment (for weight of start experiment) or age at the end of the experiment (for growth, carcass and meat quality, except weight at the beginning of experiment). eij: random error. 3.3.3. 3.3.3.1. Results and discussion Growth and meat production of boars of VCN03 sire line Average body weight at 60 day old and average body weight at end of the experiment were 22.38 and 99.48 kg, respectively. ADG (g/day) from birth to end of the experiment, from 60 day old to the end of experiment, back fat thickness, loin muscle thickness, lean meat percentage of boars of VCN03 sire line were 621.04 g/day; 796.18 g/day; 9.88 mm; 47.71 mm and 60.37%, respectively. Body weight at 60 day old of boars of VCN03 sire line in this study was higher than that of Pietrain boars (Do Duc Luc et al. (2013). ADG (g/day) of boars of VCN03 sire line in individual tests (796.18 g/day) was higher than that reported by Pham Thi Dung (2005); Chen Weng Guang et al. (1997) in Duroc boars and higher than that reported by Do duc Luc et al. (2008); Zhang et al. (2011); Ha Xuan Bo et al. (2013a) in Pietrain. ADG (g/day) from birth to the end of experiment and ADG in individual tests of boars of VCN03 sire line were higher than these of reported by Phung Thi Van et al. (2001); Phan Xuan Hao (2002); Pham Thi Kim Dung (2005); Zhang et al. (2011). Back fat thickness of boars of VCN03 sire line (9.88 mm) was higher than that of stress resistance Pietrain boars (8.00 mm) (Ha Xuan Bo et al., 2013b; Do Duc Luc et al., 2013; Trinh Hong Son et al., 2012). Loin muscle thickness of boars of VCN03 sire line (47.71 mm) was similar to that Pietrain boars (Do Duc Luc et al., 2011) and lower than that of DuPi and PiDu hybrid boars (Trinh Hong Son et al., 2012). Lean meat percentage of boars of VCN03 sire line was higher than the published results of Phan Xuan Hao (2007); Nguyen Van Duc et al. (2010); but similar to the results reported by Bidanel et al. (1991); Marinus et 12 al. (2010); Werner et al. (2013) and lower than the published results of Werner et al. (2010); Ha Xuan Bo et al. (2013b). 3.3.3.2. a. Growth rate and meat production of boars of VCN03 over 2 generations Growth rate of VCN03 over 2 generations The first selected generation had a higher ADG in individual (60.09 g/day) than that of the zero generation and difference in ADG between two generations was statistically significant (P <0.001). A great improved ADG of the first generation was due to the first application of estimated breeding values of boars of VCN03 in a selection program and an improvement of feeding, housing... According to Kazuo Ishii et al. (2005), ADG of Shimofuri Red Boar line (Duroc) after 7 generations of selection was enhanced by 243 g/day. Giang Hong Tuyen (2008) showed that ADG of Mong Cai pigs was increased by 27.95 g/day (7.45%) after 4 generations of selection. b. Meat performance of boars of VCN03 sire line over 2 generations Dressing percentage of boars of VCN03 sire line (80.68 to 81.26%) was higher than that published by Werner et al. (2013); Phan Xuan Hao (2007); Phan Van Hung and Dang Vu Binh (2008). Back fat thickness of the first generation (9.38 mm) was lower than that of the zero generation (10.27 mm). Loin muscle thickness and lean meat percentage of the first generation was higher than that of the zero generation (48.80 vs. 46.84 mm and 61.14 vs. 59.74%. Thus, after one generation selection, back fat thickness and loin muscle thickness and lean meat percentage were improved. According to Kazuo Ishii et al. (2005), back fat thickness of Shimofuri Red boar line (Duroc) after 7 generations of selection was reduced by 0.8 mm. Lo et al. (2008) reported that carcass meat, lean meat percentage of Duroc and Landrace castrated boars raising in Taiwan were 84.18 and 83.39, 47.64 and 46.36%, respectively. Ha Xuan Bo et al. (2013b) reported that carcass meat, dressing percentage and lean meat percentage of Pietrain castrated boars were 80.21; 65.40 and 63.51%, respectively. It was showed that, after one generation selection, back fat thickness of boars of VCN03 sire line was reduced and lean meat percentage were improved. 3.3.3.3. Meat quality of boars of VCN03 sire line a. Meat quality of boars of VCN03 sire line pH45 and pH24 values of loin muscle of boars of VCN03 sire line in this study were 6.15 and 5.50, respectively. Value light (L*), red (a*) and yellow (b*) of meat were 54.06; 15.02 and 7.11, respectively; and were within the standard of good quality meat. Water loss percentage after 24 hours storage of meat of boars of VCN03 sire line was 1.86%. This finding was consistent with publications of Phan Xuan Hao (2007, 2009; Ruusunen et al., 2007; Kyla-Puhu et al., 2004; Channon et al., 2003; Nguyen Van Thang, Dang Vu Binh, 2006; Morlein et al., 2007; Alonso et al., 2009; Pas et al., 2010; Heyer et al., 2005; Phan Xuan Hao and Nguyen Van Chi, 2010; Edwards et al., 2003; Peinado et al., 2008; Phan Xuan Hao and Hoang Thi Thuy, 2009; Ha Xuan Bo et al., 2013b). Meat quality of boars of VCN03 sire line based on water loss percentage after 24 hour storage, meat light (L), pH45 and pH24 values of loin muscle and criteria of Warner et al. (1997), Joo et al. (1999), Van Laak and Kauffmanf (1999), was a good quality meat. b. Meat quality of boars of VCN03 sire line over generations pH45 value of loin muscle of boars of VCN03 sire line in the first generation was lower than that of the zero generation (P <0.05), but pH24 value of loin muscle of boars of VCN03 sire line in the first generation was lower than the zero generation (P> 0.05). It appeared that meat quality was negatively correlated with ADG of pigs. Increased ADG was associated with decreased meat quality (Latorre et al., 2003). In this study, higher ADG of boars in the first 13 generation may be a cause of lower pH value. However, pH45 and pH24 values of loin muscle of boars of VCN03 sire line in both generations were in a range of good quality meat. Meat quality of boars of VCN03 sire line over two generations in this study was good according to standards of Warner et al. (1997), Joo et al. (1999). 3.3.3.4. Conclusion and recommendation a. Conclusion Boars of VCN03 sire line had ADG of 796.18 g/day in the period of 22.48 to 96.30 kg, low back fat thickness (9.88 mm) and a high lean meat percentage (60.37%). Meat quality of boars of VCN03 sire line was in a range of good quality meat. After one generation selection, growth rate, meat production and quality were slightly improved. b. Recommendation Heritability and estimated breeding value of fertility traits of boars need to be regularly and continuously determinated. So that heritability and estimated breeding value of fertility traits of boars can be able to efficiently apply in breeding programs. Chapter IV HERITABILITY AND ESTIMATED BREEDING VALUE 4.1. Introduction Pig breeding was carried out mainly by the method of phenotypic selection of phenotypic traits and mating pairing to avoid inbreeding. For this reason, the genetic progress obtained was not as high as expected. In recent years, the use of breeding value has been started and applied in a limited number of pig breeding farms. So far there has been a few works publishing estimated breeding values of different traits of pigs in Vietnam (Kieu Minh Luc, 2001; Nguyen Ngoc Tuan and Tran Thi Dan, 2001; Ta Thi Bich Duyen, 2003; Tran Van Chinh, 2004; Nguyen Thi Xa, 2005; Nguyen Van Hung and Trinh Cong Thanh, 2006; Pham Thi Kim Dung and Ta Thi Bich Duyen, 2009; Ta Thi Bich Duyen et al., 2009). The objectives of this research was to calculate heritability and estimated breeding value of some reproductive traits of sows of VCN03 sire line and growth rate and meat quality traits of boars of VCN03 sire line. Estimated breeding value would be the basis for selection programs aiming at improving productivity and quality of VCN03 sire line. 4.2. Materials and methods 4.2.1. Subjects of study - 362 sows with the 1129 litters and non-castrated boars of VCN03 sire line, including 205 boars (The zero generation: 114 boars, the first generation: 91 boars) were used. 4.2.2. Methods Data collection was described in Section 3.1.2.2 and 3.3.2.2. Estimation of variance components, heritability and breeding value were done using REML method (Restricted Maximum Likelihood), MTDFREML software. The mathematical model was as follows: y = Xb + Za + e, V = Where: y: Observered vector of studied traits, b: Vector of fixed elements (generation, age, year), a: vector of additive genetic value, e: Vector of random error, X: Matrix of fixed elements, Z: Matrix of random element, A: Matrix of additive correlation among individuals, : additive genetic variance, : maternal 14 genetic variance, : external variance. For alive newborn weight /piglet and newborn weight/litter traits model was filled with b where b: number of weaned piglets/litter and weaned age. "Starting value" was estimated on previous studies. The estimated parameter included: genetic variance ( ), maternal genetic variance ( ), external variance ( ), phenotypic variance ( ), heritability ( ) and estimated breeding values (EBV) of the above studied traits. 4.3. Results and discussion 4.3.1. Heritability 4.3.1.1. Heritability of some reproductive performance traits of sows of VCN03 sire line Additive genetic variance, maternal genetic variance, external variance, phenotypic variance, heritability and maternal additive genetic coefficients for alive newborn number/litter, weaned number/litter, alive newborn weight/litter, alive newborn weight/piglet, weaned weight/litter and weaned weight/piglet of sows of VCN03 sire line were presented in Table 18. It was showed that additive genetic and maternal genetic heritabilities of sows of VCN03 sire line were low. Table 18: Additive genetic coefficient ( ), maternal genetic variance ( ), external variance ( ), phenotypic variance ( ), additive genetic coefficients ( ) and maternal genetic coefficients ( ) of some reproductive performance traits of sows of VCN03 sire line 2A 2M 2E 2P h2A h2M Alive newborn number 5,53197 0,19 ± 0,011 0,12 ± 0,051 Weaned number 2,31813 0,11 ± 0,035 0,01 ± 0,001 Alive newborn weight/piglet 0,00160 0,00095 0,01070 0,01325 0,12 ± 0,053 0,07 ± 0,004 Newborn weight/litter 0,10329 0,03643 0,92284 1,06256 0,10 ± 0,006 0,03 ± 0,049 Weaned weight /piglet 0,09573 0,14490 0,60192 0,84255 0,11 ± 0,008 0,17 ± 0,058 Weaned weight /litter 4,26662 0,733 44,67607 59,67581 0,24 ± 0,052 0,01 ± 0,001 Parameter Additive genetic coefficient ( ) of alive newborn number, weaned number, alive newborn weight/piglet, newborn weight/litter, weaned weight /piglet traits were low and they were 0.19; 0.11; 0.12; 0.10 and 0.11, respectively. Maternal genetic coefficient ( ) of alive newborn number, weaned number, alive newborn weight/piglet, newborn weight/litter, weaned weight /piglet and weaned weight/litter were also low and they were 0.12; 0.01; 0.07; 0.03; 0.17 and 0.01, respectively. Heritability values in this study were consistent with published works of Hermesch et al. (2000); Hanenberg et al. (2001); Chen et al. (2003); Hamann et al. (2004); Arango et al. (2005); Rho et al. (2006); Imboonta et al., (2007); Damgaard et al. (2003); Holm et al. (2004); Nguyen Huu Tinh (2009); Schneider et al. (2011) and were higher than these in reports of Smiltal et al. (2005) and Lundgren et al. (2010). Reproductive perfromance traits of sows of VCN03 sire line had a low and heritability. So that improved selection woud be inefficient. It would be important that selection needs to be combined with an improvement of environmental conditions. 4.3.1.2. Heritability of growth and meat productivity of boars of VCN03 sire line. Genetic variance ( ), external variance ( ), phenotypic variance ( ) and heritability ( ) of body weigh at 60 day old, body weight at the end of expriment, daily weight gain, back fat thickness, loin muscle thickness and lean meat percentage of boars of VCN03 sire lines were presented in Table 19. While heritability of body weight at 60 day old trait was low (0.17), heritability of loin muscle thickness (h2 = 0.58) and lean meat 15 percentage traits (0.56) were high. Heritability of traits such as ADG; back fat thickness and body weight at the end of the experiment were medium and they were 0.34; 0.34 and 0.22, respectively. The higher the heritability of traits was, the more efficient the selection was. Table 19. Genetic variance ( ), external variance ( ), phenotypic variance ( ) and heritability ( ) of body weigh at 60 day old, body weight at the end of expriment, daily weight gain, back fat thickness, loin muscle thickness and lean meat percentage of boars Parameter Body weight at 60 day old 0,324 1,580 1,904 0,17 ± 0,156 Body weight at the end of experiment 7,336 25,416 32,753 0,22 ± 0,172 418,946 829,388 1248,334 0,34 ± 0,199 Back fat thickness 0,834 1,633 2,467 0,34 ± 0,199 Loin muscle thickness 15,893 11,424 27,317 0,58 ± 0,239 Lean meat percentage 2,350 1,826 4,176 0,56 ± 0,209 Daily weight gain (ADG) Heritability of some traits in this study was in an agreement with works of Tomiyama et al. (2012); Gu et al. (1989) (cited by Clutter, 1998); Tran Thi Minh Hoang et al. (2008a); Kiszlinger et al. (2011); Saintilan et al. (2011); Tomka et al. (2010); Szyndler-Nedza et al. (2010); Radovic et al. (2013). Heritability of back fat thickness trait in our study (h2 = 0.34) was lower than that published by other authors. Tran Thi Minh Hoang et al. (2008a) reported that heritability of back fat thickness traits of Yorkshire and Landrace breeds was 0.45. According to Nguyen Huu Tinh (2009), heritability of back fat thickness traits of Landrace and Yorkshire pigs at 90 kg was 0.47 and 0.60 respectively. 4.3.2. Estimated breeding value-EBV 4.3.2.1. EBV for some reproductive performance traits of sows of VCN03 sire line 4.3.2.1.1. EBV for alive newborn number trait While EBV for the groups with 5 % of the best animals (18 animals) was 0.987, EBV for the groups with 10, 20, 30 and 50% of best animals was slightly lower and these groups had 32; 72; 109 and 181 animals, respectively. Average EBV was different from one group to another and from one individual to another. Therefore, the identification of individuals with a higher EBV for a selection program would be very necessary and meaningful. For example, EBV of five individuals with identification numbers of 3597, 3826, 3110, 3003 and 3001 were 1.551; 1.300; 1.223; 1.117 and 1.113, respectively. 4.3.2.1.2. EBV for weaned number trait Absolue value of EBV for weaned number trait ranged from -0.717 to +1.115 and overall mean of EBV for weaned number trait was -0.001. The average accuracy of estimation of this EBV was high (> 50%) and higher than that of EBV for newborn number trait. EBV for weaned number was not different so much from one group to another and from one individual to another. EBV for weaned number trait and accuracy of estimation of the best 5 individuals with indentification numbers of 3597, 3492, 3834, 3583 and 3829 were 1.115; 0.666; 0.645; 0.601; 0.590 and 0.68; 0.71; 0.63; 0.68; 0.64, respectively. 4.3.2.1.3. EBV for alive newborn weight/litter Absolute value of EBV for alive newborn weight/litter trait ranged from -0.260 to +0.415 and overall mean of EBV for alive newborn weight/litter was +0.009. EBV for newborn weight/litter trait and accuracy 16 of estimation of the best 5 individuals with indentification numbers of 3449, 3107, 4025, 3100 were 0.415 0.394; 0.393; 0.351; 0.317 and 0.51; 0.55; 0.55; 0.53 and 0.52, respectively. 4.3.2.1.4. EBV for alive newborn weight/piglet Absolute value of EBV for alive newborn weight/piglet trait ranged from -0.034 to +0.066 and overall mean of EBV for alive newborn weight/piglet trait was +0.001. EBV for alive newborn weight/piglet trait and accuracy of estimation of the best 5 individuals with indentification numbers of 3449, 3100, 3107, 4025 and 3538 were 0.066; 0.065; 0.050; 0.040; 0.035 and 0.53; 0.54; 0.56; 0.55; 0.61, respectively. It was found that among 5 individuals with higher EBV for alive newborn weight/piglet trait, 4 of 5 individuals also had a higher EBV for newborn weight/liter trait. It was indicated that EBV of two traits was close associated and positively correlated with each other. 4.3.2.1.5. EBV for weaned weight/litter EBV for weaned weight/litter trait and accuracy of estimation were the highest among EBV and accuracy of estimation for other reproductive perfomance traits in this study. Vaiation of average EBV of this trait was small from one group to another and from one individual to another. For example, group with 5% of best individual and group with 10% of best individual had EBV of 3.930 and 3.359. Difference in EBV between two groups was only below 8,55. EBV for weaned weight/liter trait ranged from -6.407 to +6.401 and overall mean of EBV for weaned weight/litter trait was +0.074. Accuracy of EBV estimation of groups with 5; 10; 20; 30% of the best individuals were over 60%. Accuracy of EBV estimation of the group with 50% of the best individuals was 55.8%. EBV for weaned weight/litter trait and accuracy of estimation of the best 5 individuals with indentification numbers of 4042, 3005, 3990, 3607; 3007 were 6.401; 5.272; 4.174; 4.087; 3.892 and 0.51; 0.57; 0.75; 0.73; 0.71, respectively. 4.3.2.1.6. EBV for weaned weight/piglet EBV for weaned weight/piglet trait was lower than that for weaned weight/litter trait. Difference in EBV among groups was not so high. For example, group with 5% of best individual and group with 10% of best individual had EBV of 0.219 and 0.186. Difference in EBV between two groups was only 8.49%. EBV for weaned weight/piglet ranged from -0.378 to +0.350 and was +0.004, on average. EBV for weaned weight/piglet trait and accuracy of estimation of the best 5 individuals with indentification numbers of 4042, 3005, 3607, 3665 and 4059 were 0.350, 0.301; 0.292; 0.226; 0.220 and 0.48; 0.39; 0.49; 0.45; 0.48, respectively. 4.3.2.2. Estimated breeding values for growth and meat productivity traits of boars of VCN03 sire line 4.3.2.2.1. EBV for body weight trait at 60 day old trait For body weight at 60 day old trait, it was prefered to chose individuals with a positive highest EBV. The range of EBV for body weight at 60 day old was the smallest (-0.579 to +0.774) and overall EBV was +0.102. However, accuracy of EBV estimation for this trait was low (approximately 0.50). The group with 1% of the best individuals including Y259 and Y232 boars had EBV of +0.774 and +0.747. 4.3.2.2.2. EBV for body weight at the end of experiment The range of EBV for the trait of body weight at the end of this experiment and accuracy of estimation were higher than these of body weight at 60 day old trait. EBV for the trait of body weight at the end of this experiment ranged from -2.824 to +5.096 and overall mean of EBV for the trait of body weight at the end of this experiment was +0.361. The accuracy of estimation of EBV for groups with 1% to 50% of the best individuals was above 0.50. The group with 1% of the best individuals including Y234 and Y277 boars had EBV of +5.096 and +3.457. 17 4.3.2.2.3. EBV for ADG trait While EBV for ADG trait of the group with 1% of best individuals was so much different form that of other groups, difference EBV for ADG trait among other group was not so large. The group with 1% of the best individuals including Y234 and Y232 boars had EBV of +43.759 and +37.294. There were a relatively large differences in EBV within groups, the more animal in the group was, the larger the difference in EBV was. Difference in EBV between individuals having the highest EBV and the lowest EBV in the group with 1% of the best individuals was 1.17 times. Similarly, these figures for groups with 5; 10; 20 and 50% of the best individuals were more than 1.93; 2.59; 3.95 and 15.31 times, respectively. The accuracy of EBV estimation was high. The accuracy of EBV estimation of the groups with 1 to 50% of the best individuals was 0.60. 4.3.2.2.4. EBV for back fat thickness trait Absolute value of EBV for back fat thickness trait of boars of VCN03 sire lines ranged from -1.331 to +1.563 and overall mean of EBV for back fat thickness trait of boars of VCN03 sire lines was +0.053. Y149 and Y147 boars in the group with 1% of the best individuals had the lowest negative EBV for this trait (-1.331 and -1.270) and average EBV of this group was -1.301 with an accuracy of 0.63. Similarly, EBVs of groups with 5, 10, 20 and 50% of the best individuals were -0.96; -0.801; -0.622; -0.341, respectively. Groups with 5, 10, 20 and 50% of the best individuals had 10, 21, 41 and 103 animals, respectively. Accuracy of EBV estimation for al above groups was 0.69. 4.3.2.2.5. EBV for loin muscle thickness trait EBVs for loin muscle thicness trait of Y234 and Y248 boars of VCN03 sire line in group with 1% of the best individuals was +10.368 and +8.553. EBVs for loin muscle thicness trait of boars of VCN03 sire line in group with 1 and 50% of the best individuals was similar. EBVs for loin muscle thicness trait of boars of VCN03 sire line were different from one group to another and were considerablly different from one animal to another wthin the same group. For example, differnce in EBVs between animals having the highest and lowest EBVs in the group with 10% of the best individuals was nearly 2 times. Differnce in EBVs between animals having the highest and lowest EBVs in the later groups was much higher. Differnce in EBVs between animals having the highest and lowest EBVs in the group with 50% of the best individuals was 12.93 times. Accuracy of EBV estimation for loin muscle thickness trait was the highest compared to that of other traits such as ADG, lean meat percentage, back fat thickness, body weight at 60 day old and body weight at the end of the experimenthighest. Accuracy of EBV estimation in the group with 1 to 50% of the best individuals was 0.70. 4.3.2.2.6. EBV for lean meat percentage trait EBV for lean meat percentage trait of the groups with 1 to 50% of the best individuals was positive. EBV for lean meat percentage trait of boars of VCN03 sire line ranged from -2.174 to +2.817 and overall mean of EBV for lean meat percentage trait of boars of VCN03 sire line was +0.178. EBVs of Y238 and Y151 boars in the group with 1% of the best individuals were +2.817 and +2.605; these individuals were in the nucleus herd. Accuracy of EBV estimation for lean meat percentage trait of the groups with 1% to 50% of the best individuals was high (over 0.72). The accuracy of EBV estimation for lean meat percentage trait was lower than that of for loin muscle thickness trait and lower than that for back fat thickness trait. 4.4. Conclusion 4.4.1. Heritability of reproductive performance trait, growth and meat productivity traits of sows and boars of VCN03 sire line. Heritability of reproductive performance traits including alive newborn number/litter, weaned number/litter, alive newborn weight/piglet, alive newborn weight/litter and weaned weight/piglet of sows of 18 VCN03 sire line was low and was 0.19; 0.11; 0.12; 0.10 and 0.11, respectively. Only heritability of weaned weight/litter trait was medium (0.24). Heritability of loin muscle thickness and lean meat percentage traits was high and was 0.58 and 0.56, respectively. While heritability of ADG, back fat thickness and weight gain in the end of the experiment traits was medium (0.34; 0.34 and 0.22), heritability of body weight at 60 day old trait was low (0.17). 4.4.2. Estimated breeding values on reproductive performance, growth and meat potential of VCN03 boar line. EBVs for reproductive performance traits of sows of VCN03 sire line in the group with 5% of the best individuals were the highest. Average accuracy of EBV estimation for traits such as alive newborn number/litter, weaned number/litter, and weaned weight/litter of sows of VCN03 sire line in the groups with 5% to 50% of the best individuals was higher than 0.50. Accuracy of EBV estimation for traits such as growth and meat productivity ranged from medium to high. Accuracy of EBV estimation for traits such as growth and meat productivity in the group with 1% of the best individuals was rather high and ranged from 0.45 to 0.79. Chapter V GENERAL DISCUSSION 5.1. Productivity of VCN03 sire line 5.1.1. Reproductive performance of sows of VCN03 sire line. Sows of VCN03 line was in the group of "sire line'' and their reproductive performance was lower than published results of Imboonta et al. (2007); Nguyen Huu Tinh, (2009); Phung Thi Van et al. (2001). Thus, reproductive performance of sows of VCN03 sire line was lower than most of Landrace and Yorkshire sows in Vietnam, and they were suitable for use as sows of "sire line'' to produce parental pigs. Two traits: alive newborn number/litter and weaned number/litter of sows VCN03 line appeared to be decreased over generations. However, differences in alive newborn number/litter and weaned number/litter of sows VCN03 line between two generations were not statistically significant indicating that reproductive performance sows of VCN03 sire line was relatively stable. As discussed some where, the efficiency of selection in past year was not as high as expected. For the above reason, the determination of heritability of some reproductive traits and EBV in sows were an urgent need for improving productivity of VCN03 sire line. 5.1.2. Semen quantity and quality of boars of VCN03 sire line While V, A, C and VAC of semen of boars of VCN03 sire line were higher than these of boars of L, Y, Du, Pi, and PiDu hybrids (25, 50 and 75% of Pietrain blood), abnormally shaped sperm percentage of semen of boars of VCN03 sire line was also higher than that of of boars of L, Y, Du, Pi, and PiDu hybrids (25, 50 and 75% of Pietrain blood) raised in Vietnam. However, quality and quantity of semen of boars of VCN03 sire line were lower than these of Pietrain boars raised in Vietnam (Ha Xuan Bo et al., 2011). Semen quantity and quality of boars of VCN03 sire line met the temporary national standard for exotic boars in AI programs issued by Ministry of Agriculture and Rural Development (Decision N01712 QD-BNN, 2008). Semen quantity and quality of VCN03 sire line after one generation selection were improved (P<0.0001) indicating that selection was the efficient way. However, variation in semen quality and quantity was still large and strongly influenced by seasonal factors, years. Therefore, in order to stabilize and improve 19 the productivity and semen quality of boars of VCN03 sire line, selection needs to go hand in hand with a external condition improvement 5.1.3. Growth, performance and meat quality of VCN03 sire line ADG of boars of VCN03 sire line was higher than published results of Do Duc Luc et al. (2008); Ha Xuan Bo et al. (2013a); Phung Thi Van et al. (2001); Phan Xuan Hao (2002). Dressing percentage of boars of VCN03 sire line was also higher than published results of Werner et al. (2013); Phan Xuan Hao (2007). Lean meat percentage of boars of VCN03 sire line was higher than published results of Nguyen Van Duc et al. (2010) and similar to works done by Bidanel et al. (1991); Marinus et al. (2010); Werner et al. (2010). Meat quality of boars of VCN03 sire line was good according to criteria of Warner et al. (1997), Joo et al. (1999), Van Laak and Kauffmanf (1999). 5.2. Heritability and estimated breeding value 5.2.1. Heritability and estimated breeding value of some reproductive performance traits of sows of VCN03 sire line Heritability of reproductive performance traits of sows of VN03 sire line was low and was from 0.10 to 0.19. This was normal, because reproductive performance traits was considerably affected by environmental factors. The low heritability of reproductive performance traits of sows explained why efficiency of selection for these traits was low in past years. The results also demonstrated thats selection approach in past years was not appropriate because the population was not large enough and the genetic evaluation was not conducted regularly. From this study, 5% of sows with best EBV for reproductive traits were selected and put in a nucleus herd as a source of genetic materials to improve productivity and quality of sows of VCN03 sire line. From these results, it could be concluded for enhancement of reproductive performance of sows of VCN03 sire line at Tamdiep pig research and development station, determined heritability and EBV for reproductive perfomance traits need to be involved in selection programs in a combination with new genetic materials introduction and external condition improvement. 5.2.2. Heritability and estimated breeding value for growth and meat productivity traits of boars of VCN03 sire line Heritability of growth traits and meat productivity for boars of VCN03 sire line was in a greement with most of publications of other authors (Gu et al., 1989; Tran Thi Minh Hoang et al., 2008a; Kiszlinger et al., 2011; Saintilan et al., 2011. However, there were few reports (Szyndler-Nedza et al.,2010; Radovic et al., 2013), in which heritability of ADG was lower (0.07 to 0.11). One generation selection improved ADG, back fat thicness, loin muscle thickness, lean meat percentage indicating that selection for these traits was very efficient and need to be focused more. Chapter VI CONCLUSION AND RECOMMENDAION 6.1. Conclusion Reproductive performance of sows of VCN03 sire line was low. Alive newborn number, weaned number/litter and weaned weight/litter was 8.85 piglets; 8.15 piglets and 58.56 kg, respectively 20 Semen quality of boars of VCN03 sire line was good and met the temporary national standard for exotic boars in AI programs issued by Ministry of Agriculture and Rural Development (Decision N01712 QD-BNN, 2008). While growth rate, lean meat percentage of boars of VCN03 line were high. back fat thickness of boars of VCN03 sire line was low. ADG (g/day), estimated leen meat percentage and back fat thickness were 796.18 g/day; 60.37%, and 9.88 mm, respectively. Heritability of most reproductive performance trait of sows of VCN03 sire line was low (0.10 to 0.19). Heritability of weaned weight/litter trait was medium (0.24). Heritability of growth and meat productivity traits of boars of VCN03 sire line was low or high depending on studied traits. Whie heritability of both ADG and back fat thickness traits was only 0.34, heritability of loin muscle thickness and and lean meat percentage was high (0.58 and 0.56). Reproductive performance was strongly influenced by external factors therefore phenotype based selection was not effective. After one generation selection using EBV, ADG, loin muscle thickness, lean meat percentage of boars of VCN03 sire line were increased by 60.09 g/day; 1.96mm; 1.4%, respectively. After one generation selction using EBV, backfat thickness of boars of VCN03 sire line were decreased by 0.89 mm. These progresses indicated that EBV based selection was very effective. Use of REML method and MTDFREML software, 5% of sows with the highest EBV per each selective traits (18 sows) and 1% of boars (9 boars) with the highest EBV for each selective trait were selected for next selection programs. The above sows and boars were good source of genetic materials in the nucleus herd for the genetic improvement of quality of herds of VCN03 sire line in Tamdiep pigs research and development station. 6.2. Recommendations The population of pigs of VCN03 sire line needs to increase to avoid inbreeding and to make sure that the selection and pure breeding would be done smoothly. Establishing selective indexes using EBV for better improvement of performance and meat quality of pigs of VCN03 sire line would be given a priority in selection programs. Estimated breeding values needs to be used in selection work for improvement of productivity and meat quality of VCN03 sire line and other pig lines in Vietnam. Periodical importation of new genetic resources and introduction of new genetic materials into VCN03 sire line to avoid inbreeding and improve productivity and quality would be an important step. Improvement of the external environment as such as feeding management, housing..to reduce any negative influence would be paid more attention.