Animal welfare in dairy cows: selection of health- and
production-related indicators
Martínez, G. M.1*; Suárez, V. H.2; Ghezzi, M. D.3
1
INTA EEA Salta (RN 68 km 172 – Cerrillos – Salta – Argentina). 2 INTA CIAP - IIACS – AISA, sede EEA
Salta. 3UNICEN, Facultad de Cs. Veterinarias.
*e-mail: martinez.gabriela@inta.gob.ar
Abstract
Animal welfare has been defined by the World Organization for Animal Health (WOAH)
as the broad term used to describe how an individual is coping with the conditions in which
it lives. An animal is in a good state of welfare if it is healthy, comfortable, well nourished,
safe, able to express innate behaviour and not suffering from unpleasant states such as pain,
fear and distress. For many years, genetic improvement programs of dairy herds were
aimed at increasing milk production per individual. Later, efforts were focused on making
those yield increases compatible with enhanced efficiency in food conversion. Throughout
that period, the productive system was transformed to provide those animals of high genetic
merit with the necessary environment to express their potential. However, this increase in
production had negative effects related to intensification. The health equilibrium of animals
with high genetic merit seems fragile. Accordingly, several authors have reported that these
individuals have increased risks of suffering from mastitis, foot lesions, reproduction
disorders and other events known as production-related diseases (e.g., hypomagnesemia,
hypocalcemia) with respect to animals with low or medium genetic merit. All these factors
affecting high-production cows cause a reduction in their productive life. The challenge in
current milk production has taken a clear direction: establishing management programs
associated with animals of high genetic merit so as to combine high production under the
best possible animal welfare conditions. The study of useful variables for evaluating animal
welfare in dairy herds has increased considerably in the last 15 years, and a number of
indicators are now available which are well documented and being included in animal
welfare protocols. However, the protocols that have been proposed and applied until now
are costly and difficult to implement, and are starting to be evaluated. There is consensus in
the reliability of measurements based directly on the animal as useful indicators, such as
body condition, foot disorders, mastitis and other more general indicators, such as infertility
and mortality rates, obtained from records of dairy farms that can be studied under our
production conditions. The aim of the present review is to show producers and technicians
the importance of early detection of some health problems of dairy cows closely associated
with production and welfare as well as to report the current situation of animal welfare in
milk production at the global level.
Introduction
Animal welfare (AW) has been defined by the World Organization for Animal Health
(WOAH) as the broad term used to describe how an individual is coping with the
conditions in which it lives. An animal is in a good state of welfare if it is healthy,
comfortable, well nourished, safe, able to express innate behaviour, and if is not suffering
from unpleasant states such as pain, fear and distress. While AW science is a quite modern
field of knowledge, the concept and concern are not. Concern for AW is as old as livestock,
possibly because since ancient times, men needed to avoid feeding on diseased animals and
having the animal die before being used as food. It has even been stated that AW was the
basis for domestication, because without this condition, animals would not have remained
alongside men (Price, 1984). Several authors agree in associating AW with ethics, with
ethics being understood as the decision of doing good and knowing the difference between
good and bad. Blasco (2006) considers that ethics seems to vary over time, since sensitivity
to animals has changed throughout history; the author also suggests that ethics can be
influenced by geographical location, since establishing ethical rules in a developed country
would not be the same as doing so in a developing country, where concerns regarding
human welfare may be a priority.
Different studies conducted worldwide have demonstrated that not only ethics but also
economic benefits obtained by producers that apply AW protocols have contributed to a
growing interest for this topic. In dairy herds, body condition (used as a tool for monitoring
nutrition and health of animals), control and prevention of foot lesions, and mastitis are the
key issues in the different protocols currently used in dairy farms to qualify AW (FIL-IDF,
2009; WelfareQuality, 2009).
In Argentina, AW awareness is just starting, and in fact consumers are still not sensitized.
Interested parties in that topic are producers that perceive welfare as either a way to avoid
reduction in incomes due to production losses or as a future requirement of international
markets that they must comply with in order to add value to their products. Accordingly,
Argentina has endorsed the Universal Declaration of Animal Rights and in 2002, SENASA
(National Service for Agrifood Health and Quality) created the National Commission of
Animal Welfare and has already begun to elaborate documents related to AW. In addition,
INTA (National Institute of Agricultural Technology) and several universities have already
begun to include AW in research projects, with some results already being achieved in milk
production (Ghiano et al., 2011; Suarez et al., 2013; Suarez and Martínez, 2014). However,
to date, there is no general project involving science and technology with producers,
industry and consumers.
Given the background mentioned, and because the general society will continue to increase
their demands with the aim of obtaining safely produced foods, via an "ideal treatment " to
animals (Croney and Botheras, 2010), this review aims at showing the current status of AW
in milk production worldwide, as well as at raising awareness of producers and technicians
about the importance of early detection of certain health disorders of milk cows closely
associated with production and AW.
Animal welfare: productivity and profitability.
In the last years, the main objectives for selection and genetic breeding programs associated
with milk production have been to pursue an increase in individual milk production. While
most of the implemented programs have attained important achievements regarding
production, they have put at risk other important aspects involved in AW and farm
profitability. Oltenacu and Algers (2005) reported that dairy cows that have been selected
for their high production are particularly susceptible to stress and are at risk of suffering
metabolic, physiological and immunological disorders. However, Trevisi et al. (2006)
concluded that under suitable management programs of animals of high genetic merit, high
productions combined with good welfare conditions can be obtained. As suggested in the
FAO’s Guide to Good Dairy Farming Practices (2004), all dairy farms should be capable of
combining profitability and responsibility of protection of human health, AW and
environment.
Animal welfare: the five freedoms.
In 1992, the UK’s FAWC (Farm Animal Welfare Council) determined general rules
associated with AW based on the five privileges proposed in 1965. They are grouped into
what is currently known as the “five freedoms”. These freedoms or animal needs that
should be met to attain biological control are currently the pillars of the European Union
and the rest of the world in terms of welfare of production animals.
According to the “Five freedoms”, the following conditions should be provided to the
animal to ensure its welfare in a production system:
1) Free from hunger and thirst: animals should receive a suitable diet in amount and
quality; they should not be exposed to prolonged hunger and they should have ready
access to sufficient water quality and quantity for their needs, with no prolonged
thirst.
2) Free from physical and thermal discomfort: animals should have access to
suitable environments for summer and/or winter seasons, and comfortable resting
areas.
3) Free from pain and diseases: animals should be free from lesions, diseases and
pain induced by management procedures. Preventive schemes and timely diagnosis
and treatment should be established to avoid disorders.
These three freedoms or needs are technical problems to be solved related to animal
production and are easily quantified by using appropriate indicators.
4) Free to express normal behaviour: animals should be housed in a conformable
manner and with a positive human/animal relationship; they should be allowed to
express their social and other behaviours. Animals should be provided with
sufficient space, suitable infrastructure and company of animals of the same species
to facilitate their interaction.
5) Free from negative emotions or harmful stress (distress): animals must be
managed so as to avoid negative emotions such as suffering, pain, fear, anxiety,
discomfort, boredom, frustration and harmful stress or distress, i.e. functional
response of an organism in which several defence mechanisms act to face a
situation perceived as threatening or demanding of increased energy.
These last two freedoms or needs are ethical problems to be resolved, because they are
related to subjective aspects that have technical difficulties for their evaluation and of
recent technical-scientific interest.
Animal welfare: evaluation.
Fraser et al. (1997), Duncan and Fraser (1997), and Von Keyserlingk et al. (2009) agree
that three important aspects should be considered in evaluating AW: biological functioning
(health), natural living (behaviour), and emotional state (mental state). These authors
suggest that the overlap of these functions leads to the ideal welfare state, since the success
of a single one does not ensure that a welfare state has been reached.
There are a number of valid indicators that can be surveyed in the field for each aspect of
AW to be assessed. These indicators can all be measured scientifically and are independent
of any moral assessment. Indicators to be considered for milk production systems can be
grouped into two categories: animal-based and environment-based indicators (see some
examples in Table 1).
Table 1. Example of animal- and environment-based indicators and their association with
principles and criteria used for their assessment.
Animal-based
Indicator
Principle
Criterion
Body condition
Feeding
Health
Absence of prolonged hunger
Cleanliness of animals
Housing
Comfort regarding resting and hygiene
Coughing
Integument alterations
Nasal and/or ocular and/or
vulvar discharge
Hampered breathing
Movement (lameness)
Mastitis
Mortality
Avoidance distance
Health
Health
Health
Absence of disease
Absence of disease
Absence of disease
Health
Health
Health
Health
Behaviour
Absence of disease
Absence of disease
Absence of disease
Absence of disease
Water provision
Feeding
Absence of prolonged thirst
Feeding
Feeding
Housing
Absence of prolonged thirst
Absence of prolonged hunger
Comfort regarding resting
Environment- Cleanliness of water points
based
Feeding troughs
Housing ventilation
Positive human-animal interaction
Bedding
Animal density
Facilities
Housing
Housing
Behaviour
Access to pasture
Behaviour
Comfort regarding resting
Space allowance
Absence of pain or injuries caused by
management practices
Expression of other behaviours
WelfareQuality, 2009
Practical animal welfare indicators and animal-based measures
The study of useful variables for assessing AW at the herd level has increased considerably
in the last 15 years, and the number of indicators available at present are sufficiently
documented as to be included in AW protocols (Whay et al., 2003; Winckler et al., 2003;
2007). There is strong consensus in using animal-based measures, such as foot lesions and
body condition, despite the wide variations in a number of factors among dairy farms
(Veissier and Evans, 2007; Whay et al., 2003). However, the protocols for assessing AW in
the dairy farm are time-consuming, costly and difficult to implement over time, especially
in regions with a large number of dairy farms. The general real situation shows that WA
qualification protocols should tend to be less costly and time-consuming as well as safe and
easy to evaluate (Winckler et al., 2003; de Vries et al., 2013). This could be conducted
based on:
a) the study and validation of only a few animal indicators or parameters in our dairy farms
(easy and safe to evaluate);
b) the use of some animal-based AW indicators that can be taken from management
program databases (production, reproduction, health, mortality, among others) used in
Argentine dairy farms to keep records of their activities (PRO Tambo Master; Dirsa;
INTAmbo).
Although it is known that absence of disease does not necessarily indicate an optimal
animal welfare state, it is clear that the presence of one or some diseases generally leads to
an insufficient welfare state (Webster, 2005). Among the health indicators most relevant to
AW, relatively easy to measure in the field and that can be taken from databases from dairy
farms are body condition, foot lesions, mastitis, indices and causes of culling and/or
mortality, fertility problems and production indices.
Body condition
Animal malnutrition favours the appearance of diseases, especially those related to
metabolic disorders and calving problems; it also has a negative influence on ovulation and
fertility rate (Roche et al., 2009). The purpose of including body condition in a rapid
evaluation of AW in the field is to identify animals that are too fat or too thin, since level of
body reserves in both cases is associated with increased risk of disease (Leach et al., 2009).
Body condition and AW make up a complex relationship that is influenced by diverse
factors, such as genetic merit, feeding and, especially, production system (Fisher and
Mellor, 2008). Accordingly, Roche et al., (2009) and Matthews et al. (2012) suggest that
subjective estimation of body reserves in dairy cattle can contribute to the establishment of
an individual’s welfare, provided that the score assigned to each animal is interpreted
within a broader context that considers production, health and management aspects. Hence,
Matthews et al. (2012) proposed body condition as a field monitoring tool for the detection
of problems associated with a possible reduction of the degree of animal welfare.
Foot lesions
This type of lesions is widely recognised as of greatest incidence on welfare of dairy cattle
due to the pain they produce and the consequent alterations at the production, reproduction
and animal behaviour levels (Von Keyserlingk et al., 2009).
Most (90%) affections involve cattle feet and include diseases such as lameness, sole
ulcers, white line disease and digital dermatitis (Shearer, 1998; Tadich, et al., 2005;
Olechnowicz and Jaskowski, 2011). Foot diseases can be the consequence of an
individual’s disorders, such as nutritional deficiency, as well as of poor dairy farm
infrastructure, such as pathways, pens or milking parlours (Olechnowicz and Jaskowski,
2011). A survey conducted in dairy farms in Valle de Lerma (Salta) recorded on average a
12 to 18% prevalence of foot lesions in dairy cows. This is well above the maximum
prevalence of 8%, which is usually considered to determine a dairy farm as of low lameness
prevalence, with positive cows being those with a lameness score of 3, 4 and 5, following
Sprecher et al. (1997).
A retrospective cohort study involving more than 900 dairy farms with high lameness
prevalence (≥ 16%) found that probabilities of dairy cow mortality were 2.9 higher than in
dairy farms with low lameness prevalence (McConnel et al., 2008). Dairy cows with severe
lameness were usually culled.
Prolonged lameness generally affects productive and reproductive performance in dairy
cows. Indeed, lame cows spend most of the time lying down compared to nonlame cows;
consequently, they lose weight due to lower food consumption, and produce between 20
and 50% less milk (Rehbun et al., 1980; Enting et al., 1997; Warnick et al., 2001;
Hernández et al., 2005). Data obtained from the CLAVES (2009) program for transition
cows (transition period spans 21 days before calving and 21 days after calving) from central
Argentina revealed that milk losses due to foot problems during the 90-day period after
calving can reach 562 L/animal, with this condition being the one of greatest impact on
dairy cows during their reproductive cycle. Regarding reproductive problems, lame cows
represent a problem during oestrus detection, since chronic stress produced by lameness
causes a reduction in progesterone concentration before oestrus, with a consequent weak
sexual behaviour (Collick et al., 1989; Walker et al., 2008a; Walker et al., 2008b).
Furthermore, Whay et al., (1997) demonstrated that lameness caused by sole ulcers and
white line disease produced hyperalgesia, with lame animals exhibiting a lower pain
threshold than healthy animals.
Mastitis
Clinical and subclinical mastitis are the most frequent conditions affecting dairy cows
worldwide, with negative effects on cow welfare, and on milk production and composition
(De Graves and Fetrow, 1993; Hortet and Seegers, 1998). Some of the adverse effects of
mastitis include dairy farms being penalised for increased SCCs and economic losses due to
withdrawal time during and after treatment with antibiotics, costs of treatments and extra
labour needed. A survey conducted in dairy farms located in Valle de Lerma (Salta), by the
authors of the present review, showed that on average 67% of cows had subclinical
mastitis. This survey was conducted in the frame of CLAVES program and revealed
clinical mastitis affecting transition cows produces a reduction in milk yield of about 435
L/animal during the first three lactation months.
Inflammation caused by mastitis is painful and therefore associated with animal welfare.
This issue is very severe and, although it has not been deeply studied, its negative effects
may affect cow longevity. Some studies have reported an association between mastitis and
clinical wounds and swelling at the tarsus (Sogstad et al., 2006) or with certain
management conditions (Nyman et al., 2009).
Bartlett et al. (1992) found that the index of environmental sanitation based on the amount
of manure on the cow and its environment was a predictor of the occurrence of coliform
mastitis. Furthermore, in a study conducted in four dairy farms, Ward et al. (2002) observed
that the lowest incidence of mastitis occurred in the farms with the cleanest cows and most
satisfactory bedding condition.
The presence of mud is a serious animal welfare issue affecting animal hygiene and causing
stress. Thus, muddy conditions become a predisposing factor for increased incidence of
clinical mastitis, and therefore, a higher number of cows need to be treated. Inappropriately
designed pathways used by cows generally become muddy after prolonged rain seasons,
making cows prone to foot lesions and mastitis (Lagger, 2006).
Infertility
Although infertility is a complex and multi-causal issue that is not always associated with
cows welfare, it can be used as an indirect indicator of poor welfare, since it is one of the
first reasons for early culling (Lucy, 2001). Fertility can be influenced by body condition,
metabolic disorders and negative energy balances, diseases, inefficient general and
reproductive management of heifers and dry and lactating cows, water stress and high
genetic level. Many of these causes are related to good nutrition as well as sanitary and
general management of the herd, and cow welfare.
Reproductive problems, such as cows with multiple services, in permanent or recurrent
anoestrus are the main reasons for culling in England (Esslemont and Kossaibati, 1997;
Whitaker et al., 2000). These problems lead to prolonged lactation in cows, affecting total
dairy farm production, since daily production does not increase with any feeding
management strategy. Recording days in milk in a dairy farm would be a good indirect
measure of animal welfare; a herd with mean lactations above 250 days in milk is
inefficient (Nebel and McGilliard, 1993).
Mortality
Despite the great importance of mortality or culling in dairy herd economy, literature on the
subject is relatively scarce. Thomsen and Houe (2006) mentioned that mortality ranges
between 1% and 6% yearly or per lactation. A mean annual mortality rate of 13% was
recorded in dairy farms during the survey conducted in Valle de Lerma. The most common
reasons for mortality or culling include traumatic accidents, calving disorders, digestive
disorders, locomotion disorders, metabolic and udder disorders (Stevenson and Lean, 1998;
Thomsen et al., 2004; Thomsen and Houe, 2006).
The importance of using mortality as a measure of animal welfare in a dairy farm has been
even less studied. A few works reported data of the association between mortality and other
adverse effects in milk production. A study involving 55 dairy farms in Sweden showed
that mortality, along with two fertility measures, stillbirth rate, mastitis incidence and
incidence of feed-related diseases, had 96% sensitivity and 56% specificity for their correct
classification as dairy farms with welfare problems (Nyman et al., 2011). A study
conducted in 40 herds in Denmark evaluated the performance of the record of predictive
data from dairy herds with high prevalence of foot lesions and identified mortality rate as a
significant predictor (Otten et al., personal communication, 2012).
Conclusion
The concern for AW is increasing worldwide and specifically in cattle milk production, the
main global producers have made outstanding efforts in studying how to most properly
qualify milk herd treatment and the benefits inherent to the activity. Argentina is one of the
most important producers of milk and dairy products; however, the study of AW and
especially welfare of dairy herds is just beginning. The information provided in the present
review, as well as the importance of AW worldwide and the implications of AW in future
exports show the need to study these issues at the local level. Efforts should include
research and validation of indicators and practical, low-cost and safe methods to classify
AW, as well as involvement of the industry in working towards consolidation of a strategy
in order to make progress in AW in Argentine dairy farms.
References
BARTLETT, P. C.; MILLER, G. Y.; LANC, S. E.; HEIDER, L. E. 1992.Managerial determinants
of intramammary coliform and environmental Streptococci infections in Ohio dairy herds.
J.DairySci. 75:1241-1252.
BLASCO, A. 2006. Ética y bienestar animal. 8th World Congress on Genetics Applied to the
Livestock Production, Belo Horizonte, Brazil.
CLAVES. 2009. Organización y Análisis de un Sistema de Registros de Enfermedades del
Periparto en Vacas Lecheras: su Incidencia e Impacto Económico sobre las Empresas. Convenio de
Asistencia Técnica Institucional INTA – Elanco – AACREA. pp 1-25.
COLLICK, D. W.; WARD, W. R.; DOBSON, H. 1989. Associations between types of lameness
and fertility. Veterinary Record, 125: 103–106.
CRONEY C.C.; BOTHERAS N.A. 2010.Animal Welfare, Ethics and the U.S. Dairy
IndustryMaintaining a Social License to Operate.Tri-StateDairyNutritionConference. [En línea]
http://tristatedairy.osu.edu/Proceedings %202010/Croney% 20paper.pdf [Consulta 16 de noviembre
de 2014].
DE GRAVES, F.J.; FETROW, J. 1993. Economics of mastitis and mastitis control, Vet. Clin.North
Am. Food Anim. Pract.9, 21–34.
DE VRIES, M.; ENGEL, B.; DEN UIJL, I.; VAN SCHAIK, G.; DIJKSTRA, T.; DE BOER, I. J.
M.; BOKKERS, E. A. M. 2013. Assessment time of the Welfare Quality® protocol for dairy cattle.
Anim. Welf., 22: 85-93.
DUNCAN, I. J. H.; FRASER, D. 1997. Understanding animal welfare. Animal Welfare, M.C.
Appleby, y B.O. Hughes, eds., CABI Publising, Wallingfor, pp 19-31.
ENTING, H.; KOOIJ, D.; DIJKHUIZEN, A. A.; HUIRNE, R. B. M.; NOORDHUIZENSTASSEN, E.N. 1997. Economic losses due to clinical lameness in dairy cattle. Livestock
Production Science 49, 259–267.
ESSLEMONT, R. J.; KOSSAIBATI, M. A. 1997.Culling in 50 dairy herds in England.Veterinary
Record, 140: 36-39.
FAO. 2004. Manual de buenas prácticas en explotaciones lecheras. [En
ftp://ftp.fao.org/docrep/fao/008/y5224s/y5224s00.pdf [Consulta 15 de diciembre de 2014].
línea]
FAWC. 1992. Updates the five freedoms Veterinary Record 17: 357.
FIL-IDF. 2009. Guía para el bienestar animal en la producción lechera de la Federación
Internacional de Lechería – 2008. Rev. Sci. Tech. Off. int. Epiz. 28 (3): 1183-1191.
FISHER, M. W.; MELLOR, D. J. 2008.Developing a systematic strategy incorporating ethical,
animal welfare and practical principles to guide the genetic improvement of dairy cattle. N. Z. Vet.
J. 56: 100-106.
FRASER, D.; WEARY, D. M..; PAJOR, E. A.; MILLIGAN, B. N. 1997.A Scientific conception of
animal welfare that reflects ethical concerns.Anim. Welf. 6: 187–205.
GHIANO, J. E .J.;GARCIA K. E.; GASTALDI, L. B.; DOMINGUEZ , J.; SOSA N.; MASSONI,
F.; FERREIRA, M.; TAVERNA, M. A. 2011. Manejo del estrés calórico en el tambo. Alternativas
de sombras. Ficha técnica 17, www.inta.gov.ar/lechería[Consulta 9 de enero de 2015].
HERNÁNDEZ, J. A.; GARBARINO, E. J.; SHEARER, J. K.; RISCO, C. A.; THATCHER, W. W.
2005. Comparison of milk yield in dairy cows with different degrees of lameness. J. American
Veterinary Medical Association 227, 1292–1296
HORTET, P.; SEEGERS, H. 1998. Calculated milk production losses associated with elevated
somatic cell counts in dairy cows: review and critical discussion, Vet. Res. 29, 497–510.
LAGGER, J. R. 2006. Animal Welfare Strategies to prevent lameness. Scottish Agriculture
College-Bush State Edinburgh-Scotland-GB.
LEACH, K. A.; KNIERIM, U.; WHAY, H.R. 2009. Condition Scoring for dairy and beef cattle and
veal calves. Welfare quality report nº11.Edited by Forkman and Keeling.
LUCY, M. C. 2001. Reproductive loss in high-producing dairy cattle: Where will it end?. J. Dairy
Sci. 84:1277-1293.
MATTHEWS, L. R.; CAMERON, C.; SHEAHAN, A.J.; KOLVER, E.S.; ROCHE, J.R. 2012.
Associations among dairy cow body condition and welfare-associated behavioral traits. J. Dairy Sci.
95: 2595-4889.
MCCONNEL, C. S.; LOMBARD, J. E.; WAGNER, B. A.; GARRY, F. B. 2008. Evaluation of
factors associated with increased dairy cow mortality on United States dairy operations. J. Dairy
Sci. 91:1423-1432.
NEBEL, R. L.; MCGILLIARD, M. L. 1993.Interactions of high milk yield and reproductive
performance in dairy cows. J. Dairy Sci.; 76:3257-68.
NYMAN, A.K.; EMANUELSON, U.; GUSTAFSSON, A.H.; PERSSON WALLER, K. 2009.
Management practices associated with udder health of first-parity dairy cows in early lactation.
Preventive veterinary medicine 88, 138–49.
NYMAN, A. K.; LINBERG, A.; SANDGREN, C. H. 2011. Can pre-collected register data be used
toidentify dairy herds with good cattle welfare? ActaVeterinaria Scandinavica, 53(Suppl 1):S8.
OIE. The OIE´s achievements and objectives in animal welfare.[En
http://www.oie.int/eng/bien_etre/en_introduction.htm. [Consulta 3 de diciembre de 2014].
línea]
OLECHNOWICZ, J.; JASKOWSKI, J. M. 2011. Behaviour of lame cows: a review. Veterinarni
Medicina 56: 581-588.
OLTENACU, P.A.; ALGERS, B. 2005. Selection for increased production and the welfare of dairy
cows: are new breeding goals needed? Ambio 34: 4–5.
PRICE, E.O. 1984. Behavioural aspects of animal domestication. Quarterly Review of Biology 59:
1-32.
REHBUN W. C.; PAYNE, R. M.; KING, J. M.; WOLFE, M.; BEGG, S. N. 1980.Interdigital
papillomatosis in dairy cattle. JAVMA 177, 437-440.
ROCHE, J. R.; FRIGGENS, N. C.; KAY, J. K.; FISHER, M. W.; STAFFORD, K. J.; BERRY,
D. P.. 2009. Body condition score and its association with dairy cow productivity, health, and
welfare. J. Dairy Sci.92: 5769 – 5801.
SHEARER, J. K. 1998. Lameness in dairy cattle: consequences and causes. The Bovine
Practitioner 32, 79-84.
SOGSTAD, Å. M.; OSTERÅS, O.; FJELDAAS, T. 2006. Bovine Claw and Limb Disorders
Related to Reproductive Performance and Production Diseases. J. Dairy Sci.89, 2519–2528.
SPRECHER, D. J.; HOSTETLER, D. E.; KANEENE, J. B. 1997.A lameness scoring system that
uses posture and gait to predict dairy cattle reproductive performance. Theriogenology 47:1179.
STEVENSON, M. A.; LEAN, I. J. 1998.Descriptive epidemiological study on culling and deaths in
eight dairy herds. Australian Veterinary Journal 76, 482–488.
SUÁREZ, V. H.; BUSETTI, M. R.; GAVELLA, J, 2013. Propuesta para calificar bienestar animal
en lechería ovina. VetArg. www.veterinariargentina.com, Nº 302 / June, 1-19. [Consulta 15 de
enero de 2015].
SUÁREZ, V. H.; MARTÍNEZ G. M. 2014. Observaciones preliminares para calificar bienestar
animal en lechería bovina. Resúmenes 37° Congreso Argentino de Prod. Animal (AAPA), 20-22oct-2014, CABA. SA 25, p. 31.
TADICH, N.; HETTICH, E.; VAN SCHAIK, G. 2005. Prevalencia de cojera en vacas de 50
rebaños lecheros del sur de Chile. Arch Med Vet 37, 29-36.
THOMSEN, P. T.; KJELDSEN, A. M.; SØRENSEN, J. T.; HOUE, H. 2004. Mortality (including
euthanasia) among Danish dairy cows (1990-2001).Preventive veterinary medicine 62, 19–33.
THOMSEN, P. T.; HOUE, H. 2006.Dairy cow mortality.A review.The Veterinary quarterly 28,
122–9.
TREVISI, E.; BIONAZ, M.; PICCIOLI-CAPPELLI, F.; BERTONI, G. 2006. The management of
intensive dairy farms can be improved for better welfare and milk yield. Livest.Prod.Sci., 103: 231236.
VEISSIER, I.; EVANS, A. 2007.Rationale behind the welfare quality assessment of animal welfare.
Assuring Animal Welfare: From Societal Concerns to Implementation, Second Welfare Quality
Conference Stakeholder Conference pp 9-12. 2-3 May, 2002, Berlin, Germany.
VON KEYSERLINGK, M. A. G.; RUSHEN, J.; DE PASILLE, A.M.; WEARY, D. M. 2009.The
welfare of dairy cattle - Key Concepts and the role of science. J. Dairy Sci. 94: 4101-4111.
WALKER, S. L.; SMITH, R. F.; JONES, D. N.; ROUTLY, J. E.; DOBSON, H. 2008a. Chronic
stress, hormone profiles and estrus intensity in dairy cattle. Hormones and Behavior 53, 493–501.
WALKER, S. L.; SMITH, R. F.; ROUTLY, J. E.; JONES, D. N.; MORRIS, M. J.; DOBSON, H.
2008b. Lameness, activity time-budgets and estrus expression in dairy cattle. J. Dairy Sci. 91,
4552–4559.
WARD, W.R., HUGHES, J.W., FAULL, W.B., CRIPPS, P.J., SUTHERLAND, J.P., SUTHERST,
J.E. 2002. Observational study of temperature, moisture, pH and bacteria in straw bedding, and
fecal consistency, cleanliness and mastitis in cows in four dairy herds. Veterinary Record, 151:199206.
WARNICK, L. D.; JANSSEN, D.; GUARD, C. L.; GROHN, Y. T. 2001.The effect of lameness on
milk production in dairy cows. J. Dairy Sci. 84, 1988–1997.
WEBSTER J. 2005. Animal Welfare: Limping Towards Eden. Blackwell Publishing.
WELFARE QUALITY. 2009. Welfare Quality assessment protocol for cattle. Welfare quality
consortium, Lelystad, the Netherlands. http://www.welfarequality.net/ [Consulta 10 de diciembre de
2014].
WHAY, H. R.; WATERMAN, A. E.; WEBSTER, A. J. F. 1997.Association between locomotion,
claw lesions and nociceptive threshold in dairy heifers during the peri-partum period. Veterinary
Journal 154, 155–161.
WHAY, H. R.; MAIN, D.; GREEN, L.; WEBSTER, A. J. F. 2003. Assessment of the welfare of
dairy cattle using animal-based measurements: direct observations and investigation of farm
records. Veterinary Record,153: 197-202.
WHITAKER, D. A.; KELLY, J. M.; SMITH, S. 2000.Disposal and disease rates in 340 British
dairy herds. Veterinary Record, 146: 363-367.
WINCKLER, C.; CAPDEVILLE, J.; GEBRESENBET, G.; HØRNING B.; ROIHA U.; TOSI, M.;
WAIBLINGER, S. 2003. Selection of parameters for on-farm welfare assessment protocols in cattle
and buffalo. Anim. Welf.2003, 12:619-624.
WINCKLER, C.; BAUMGARTNER, J.; WAIBLINGER, S. 2007. Proceedings of the 3rd
International Workshop on the Assessment of Animal Welfare at Farm and Group Level. Anim.
Welf. 16(2).