Associations between polymorphism localised in the third exon of the prolactin gene (PRL-RsaI) and milk production traits of Black-and-White and Jersey cattle were analysed. A total of 427 cows were included in the study. PCR-RFLP method was used. The frequencies of genotypes and alleles were as follows: 0.7107 -AA, 0.2851 -AB, 0.0042 -BB; 0.8533 -PRL A and 0.1467 -PRL B for Black-and-White cattle and 0.0919 -AA, 0.4324 -AB, 0.4757 -BB; 0.3081 -PRL A and 0.6919 -PRL B for Jersey cattle. Statistically significant differences between the breeds were observed in the frequencies of genotypes and alleles. Associations between PRL-RsaI polymorphism and milk production traits of Jersey cows and lack of associations with these traits in Black-andWhite cows were observed.
Abstract. Associations between polymorphism of the bovine growth hormone releasing hormone (GHRH) and pituitary transcription factor 1 (PIT1) genes and production traits of Limousine cattle were analysed. A total of 130 calves were included in the study. PCR-RFLP method was used for genotyping. The frequencies of genotypes and alleles of PIT1 and GHRH were as follows: 0.0692 – AA, 0.4077 – AB, 0.5231 – BB, and 0.2731 for PIT1A, 0.7269 for PIT1B; 0.0154 – AA, 0.1692 – AB, 0.8154 – BB, and 0.1 for GHRHA, 0.9 for GHRHB. Associations between polymorphism and production traits of Limousine calves were found. Statistically significant differences (P ≤ 0.01) between individuals of different GHRH genotypes were found in relation to height at sacrum (cm) and height at withers (cm) at 210th day of age. The calves with AA genotype of GHRH were shorter (−8,14 and −8,33 cm) than AB and BB individuals (P ≤ 0.01). The small number of calves with the AA genotype did not enable important conclusions.
Polyunsaturated fatty acids (PUFAs) play a role in a wide
variety of physiological processes. They are produced by a series of
desaturation and elongation reactions. normalΔ-6-desaturase is a
membrane-bound enzyme that catalyzes the conversion of italicα-linolenic acid
(C18:3n-3) and linoleic acid (C18:2n-6) to stearidonic acid (18:4n-3) and
italicγ-linolenic acid (18:3n-6). It is encoded by the FADS2 gene located on bovine
chromosome 29. The aim of this study was to identify a single nucleotide
polymorphism in the FADS2 gene and to determine possible associations with milk
fatty acid composition in two breeds of dairy cattle, i.e., Jersey and Polish
Holstein-Friesian. Direct DNA sequencing revealed the presence of an A-to-G
substitution in intron 3 of the FADS2 gene (rs209202414). Both populations were
genotyped with an appropriate PCR-RFLP assay. The following genotype
distributions were observed: for Jerseys, AA = 0.24, AG = 0.63, and GG = 0.13; for
Polish Holstein-Friesians, AA = 0.17, AG = 0.40, and GG = 0.43. In Jerseys,
statistically significant relationships were found between the FASD2 genotypes
and the following milk fatty acids: lauric (P=0.0486), behenic (P=0.0199),
lignoceric (P=0.0209), oleic (P=0.0386), eicosatrienoic (P=0.0113), and
docosadienoic (P=0.0181). In Polish Holstein-Friesian cows, significant
associations were observed for erucic (P=0.0460) and docosahexaenoic (P=0.0469)
acids. The study indicated the A-to-G substitution (rs209202414) in the bovine
FADS2 gene as a potential genetic marker for fatty acid composition in cattle
milk.
Milk yield in goats was infl uenced by environmental conditions connected with the calendar year. Daily milk production was observed to decrease with progressing lactation, while an increase was observed in SCC, as well as percentage fat and protein contents, while the lactose content in milk decreased. No signifi cant infl uence was found of birth type, number of kids born or reared on the qualitative and quantitative parameters of milk yield and lactation duration. Goats in their fi fth and further lactations produced over 15% milk less compared with fi gures recorded in a mediumsized fl ock (248.9 and 2942.3 ml, respectively). Goat milk contained almost 67% more somatic cells (log 6.099 and log 5.877, i.e. 1260 × 10 3 and 755 × 10 3 cells/ml).
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