Uploaded by Hakan Şener

Case study (3)

Animal model
1. Read through scientific papers A and B and identify the following information and write
your answers below:
Paper A
Material of the study
Methods used in the study
Identify a dependable variable
Identify an independent variable
What factors were controlled
What was the control group
the evaluation of change in the traditional milking system
using automatic milking system
Animal material consisted of 2,818 cows (heifers,
primiparous and multiparous cows) of the Polish Holstein–
Friesian breed used on nine farms equipped with the
automatic milking system (AMS Astronaut A4 made by
The animals were kept in free stalls; before the introduction
of the AMS, they had been fed using the total mixed ra‐ tion
(TMR) system, and after the installation of the robot the
system was changed to partly mixed ration (PMR).
Method used in the study was multifactorial analysis of
variance. The following linear models were used,
differentiated by the types of traits:
Model 1—services per 1st conception, 1st service period,
length of 1st pregnancy
Model 2—services per 2nd conception, 2nd service period,
length of 2nd pregnancy
Model 3—calving interval, calving to conception, milk yield,
fat content, protein content
Polish Holstein–Friesian breed
Age of cows
Year of study
No of cows
Fat and proteın conct.
The cows were controlled in the scope of selected
reproduction features and milk production utility, that is,
services per conception (number of services per 1st and
2nd conception), service periods (1st service period—days
the second group was formed from animals which
analogous production periods started during the operation
of the AMS. age at first calving (AFC; 931 days),
insemination season and calving season (IS; CS; spring,
summer, autumn, winter). milk yield, protein and fat
Was the experiment planned
correctly? Was it unbiased? If yes,
explain what steps researchers did to
make sure that the experiment is
successful. If no, explain why you
think so.
The method used by the researchers was statically proceed,
that shows that the production and reproduction traits in
the two different milking system. The experiments shows
that the replacement of cms system with ams system has a
significant effect on the dairy cows that is milk yield quality
and quantity, fat and protein concentration.
Paper B
Material of the study
Methods used in the study
Identify a dependable variable
Identify an independent variable
What factors were controlled
What was the control group
The Frequency of the Myostatin Genotypes Would
Vary Among Breeds And Would Associate With Body
The studied material consisted of 200 individuals of two
tested sheep breeds (Kamieniec and Pomeranian), 100
individuals each. Animals varied in terms of type of birth.
Each tested population was composed of equal number of
males and females. Sheep of Pomeranian breed were kept
in Pomeranian voivodeship (Poland).
Data collection; the body weight of a lamb in the second
day of life (BW2, kg), the body weight at 56th day of life
(BW56, kg), daily gains (ADG) between the 2nd and 56th
day [g]. Animals varied in terms of sex and type of birth
Identification of polymorphisms in MSTN gene;
Statistical analysis;
Traits within each breed were statistically characterized by
calculating arithmetic mean and coefficient of variation. To
investigate effect of myostatin genotypes on growth traits
the multi-factor analysis of variance using the least squares
method was applied (GLM procedure in SAS software
Allele and genotypes frequencies
Body weight
Polymorphism in intron
the mutation as well as its impact
Polymorphism c.*1232G >
different polymorphisms in myostatin
c.*1232 genotypes
Growth traits
Birth weight
c.*1232 genotypes and
meat performance traits
Growth trait
myostatin polymorphisms,
that the effect of different polymorphisms in myostatin
gene may be breed dependent, showing that the
Was the experiment planned prevalence of the mutation as well as its impact and even
correctly? Was it unbiased? If yes, its level vary depending on the tested breed.
explain what steps researchers did to
make sure that the experiment is
successful. If no, explain why you
think so.
1) Read a scientific paper C and search for the information corresponding to steps 1-8 and write
your answers down below:
Intestinal mucosa is the interface between the microbial content of the gut and the
host’s milieu.
The goal of this study was to modulate chicken intestinal microflora by in ovo stimulation with galactooligosaccharides (GOS) prebiotic and to demonstrate the molecular
responses of the host.
Drive beneficial effects of GOS stimulation in ovo in chicken. It focuses on both sides
of microbiota-host interaction,selected microbial populations and intestinal mucosa
effects of GOS delivered in ovo analyzed was analysed:
(1) Abundance of Bifidobacterium and Lactobacillus in the intestinal chyme as well as
(2) the immune and physiological parameters of the intestinal mucosa measured by
gene expression.
The trial was conducted on Ross 308 broiler chickens. Fertilized eggs (400 eggs) were
incu-bated in standard conditions. On day 12 of incubation, the eggs were candled
and viable embryos received an in ovo injection that contained either a biologically
active compound (prebiotic) or physiological saline (mock injection). Experimental
eggs (200 eggs) were injected in ovo with GOS. Control eggs (200 eggs) were mockinjected in ovo with 0.2 ml of physiological saline. RNA and DNA isolationTotal
bacterial DNA was isolated from the intestinal content. Approximately 100 mg of
material was lysed and purified using a Genomic Mini AX Stool. The relative
abundances of Bifidobacterium spp.
The significance of the effects and their interaction was analysed with two-way
ANOVA. The effects were: in ovo injected group (GOS vs. C) and intestinal segment
(duodenum, jejunum,ileum, and caecum). An HSD Tukey post hoc test was used to
determine differences in gene expression. Significance thresholds P < 0.05, 0.01 and
0.001 were used.
Intestinal segment (P < 0.001) and prebiotic treatment in ovo (P < 0.01) had a
significant effect on the relative abundance of microbial communities
(Bifidobacterium and Lactobacillus) in the chyme.
the beneficial effects of the in ovo stimulation with GOS prebiotic in chickens. The
effects were analysed on microbial and mucosal sites of the chicken GIT. Microbial
stimulation with GOS delivered in ovo was manifested by increased abundance of
Bifidobacterium spp. in caecum,