Abstract. Experimental material consisted of 20 piglets from litters of 2 sows of wbp x pbz breed, crossed with the Pietrain x Duroc hybrid breed boar. The piglets were divided into two experimental groups of 10 animals. The experiment lasted 84 days, during which experimental group I received the feed in the form of a mash and group II in a pelleted form adapted to each of the rearing period. Analyzing ADFI rate between 5 and 28 days, a low, statistically significant (P ≤ 0.01) daily intake of feed was noticeable and amounted to 54.3 g for MS − 1 mixed feed and 63.6 for MG − 1 mixed feed. Daily gains were also statistically significant (P ≤ 0.05), favoring mash diet. Between days 29 and 50 no significant differences were observed in any of the tested parameters but the results speak in favor of pelleted mixed feed. A significant difference (P ≤ 0.05) was noted in average daily feed intake in the MS − 3 ration between days 51 and 84, compared to the MG − 3 mix, while the value of ADG did not show significant differences. Analyzing the whole testing period, i.e. from day 1 to 84 days after weaning, there was no significant difference in daily gains between mash and pelleted diets, feed consumption or final body weight.
Abstract. The aim of the study was to evaluate the effect of age and milk production capacity of cows in standard lactation on the frequency of lactations with noted cases of mastitis. The effect of occurrence of mastitis on somatic cell count in milk and on the course of lactation was also determined. The study was carried out in a herd of Polish Holstein-Friesian cows with production capacity > 8000 kg milk. The study included 496 lactations and 5405 results from test-day milking. Both lactation number and milk production level were found to affect the frequency of mastitis. Lactations in which mastitis occurred at least once between calving and the dry period were noted more frequently in multiparous cows than in primiparous cows. Udder health status significantly affected the somatic cell count in milk. Occurrence of mastitis did not affect the course of lactation of cows with low or average milk production capacity. Higher daily milk yield over the course of lactations with mastitis in cows with the highest production potential suggests that highly productive cows are most susceptible to mastitis.
Abstract. The aim of the study was to analyse the effect of non-genetic factors on fertility in high-yielding Montbéliarde cows. The length of the rearing period for the Montbéliarde heifers in the herd analysed was found to depend on their origin and on the season in which they were born. Their average age at first calving was 908 days, with imported heifers calving for the first time on average 168 days later than native heifers. Heifers born in autumn months gave birth earliest, while those born from March to May calved latest. The acclimatization process may have negatively affected reproductive performance, as longer calving-to-first-service intervals (CFSI), service periods (SP), calving-to-conception intervals (CCI), and calving intervals (CI) were noted in the imported cows. Delayed first calving in heifers significantly increased the calving-to-first-service interval. In successive lactations a general downward trend was observed in the length of CFSI, SP, CCI and CI. Reproductive efficiency was significantly reduced by 305-day milk yield exceeding 10~000 kg FPCM. Hence, in the case of record productivity in the Montbéliarde breed, as in Holstein-Friesians, reduced fertility must be expected.
Abstract. The aim of this study was to examine the relationship between genotype two SNPs located in the promoter region of CYP19 gene and milk production traits. The study included 181 Jersey cows. The genotypes were identified by the PCR-RFLP method. The frequencies of the most common alleles were as follows: A − 0.98 (CYP19/PvuII) and A − 0.94 (CYP19/Cfr13I). The results showed that there were no statistically significant associations between the individual genotypes of both SNPs and milk traits; however, the animals with heterozygous genotypes achieved the lowest milk yield and the highest protein and fat content in milk.
Abstract. The aim of this study was to investigate associations between SCD1 polymorphism and the estimated breeding value of milk production traits (milk, fat and protein yield, kg; fat and protein content, %) in the Polish Holstein-Friesian cows’ herd. The genotype and allele frequencies for g.10329C>T SNP in exon 5 of SCD1 gene were estimated in the examined herd. Statistical analysis revealed that studied polymorphism significantly affected the breeding value of protein content in milk (P ≤ 0.05). The results indicated that selection for the SCD1-TT individuals might contribute to increased protein content in milk in the Polish Holstein-Friesian cows. Further studies are needed to confirm these results.