Association of milk production level and milk urea content with date and efficiency of the first insemination service in cows.

GIL, ZYGMUNT; ADAMCZYK, KRZYSZTOF; ŻYCHLIŃSKA-BUCZEK, JUSTYNA; POKORSKA, JOANNA

Association of milk production level and milk urea content with date and efficiency of first insemination service in cows. The aim of the study was to analyse the association between milk yield, first insemination date and efficiency of the first insemination service in cows. The experiment involved 391 Polish Holstein-Friesian cows (Black-and-White type), which were used in the years 2011-2016 on a farm located in the Małopolska region. Cows that had completed their first three lactations were selected for the study. Animals were kept in a loose-housing system and fed total mixed rations (TMR). For each cow, data on whole lactation and 305-day lactation milk yields were obtained from milk recording reports. Milk urea content was also observed for the first three test-day yields of the cows in each lactation. Furthermore, the number of days from calving to first insemination as well as efficiency of the first insemination were noted. Whole milk yield of lactation averaged 11,900 kg and milk urea content ranged from 161 mg/l in the first lactation to 198 mg/l in the third. The number of days from calving to first insemination was 75, 81 and 80 in the first, second and third lactation, respectively. Efficiency of the first insemination service averaged 19.83% and showed a downward trend. It was highest (22.13%) in the first and lowest (15.17%) in the third lactation. Positive correlations were observed between milk yield level and number of days from calving to first insemination; the highest coefficient of correlation (r = 0.16) was calculated for the first lactation and it was highly significant. The correlation coefficients between milk yield and efficiency of the first insemination service were generally very low (from - 0.06 to 0.06) and statistically insignificant. Likewise, the coefficients of correlation between the cows' milk urea content and first insemination date and success were very low and statistically insignificant. In summary, it is concluded that the increasing milk yield of the cows delayed the date of first insemination. Efficiency of the first insemination service was very low, but one of the possible reasons were estrus detection errors.

MILK yield; ARTIFICIAL insemination; COWS; UREA content of milk; CATTLE parturition

Annals of Warsaw University of Life Sciences-SGGW, Animal Science, 2019, Vol 58, Issue 1, p13

1898-8830

Academic Journal

10.22630/AAS.2019.58.1.2