Age of First Calving and Subsequent Fertility and Survival in Holstein Friesian Cattle
2014
constantin Gavan
The aim of the study was to investigate the relationship between age at first calving (AFC) and subsequent fertility and survival up to third calving in Holstein Friesian heifers. Study comprised 116 consecutively born female calves from the same herd. The animals were divided in four AFC groups for analysis: <24 months, 25-27 months, 28-30 months, > 30 months. Fertility before first calving was recorded as age at first breeding (AFB), services per conception (S/C), age at conception, first service conception rate (FSCR) and actual AFC. After first calving, fertility was recorded as days to first service (DFC), days to conception (DTC), S/C and FSCR. Survival rate up to third calving also was recorded. The proportion of heifers conceiving to first service, before calving, was highest (100%) for the youngest AFC group (<24 mounth) and worst (33,33%) for the oldest AFC gropu (>30 mounth). Fertility in the first lactation was best in primiparous cows calving at 25-27 months. Survival rate up to third calving was 42,85% for <24 months group, 75,55% for 25-27 months group, 68,42% for 28-30 months group and 44,44% for >30 mounth group. In conclusion, performance in Holstein Friesian cows was achieved with an AFC of 25-27 months. These animals performed well in terms of fertility and survival.
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