Some factors affecting first service conception rate in holstein dairy cows under Egyptian conditions [electronic resource].

Includes references.

The objective of this study was to investigate the effect of some fac-tors on first service conception rate in Holstein dairy cows under Egyptian conditions. These factors are parity, days to first insemination, body con-dition score at calving and at first insemination time and its changes from calving to first insemination, peak and 305-d milk yield, season of insemi-nation, temperature humidity index and progesterone level at the time of insemination. The study was carried out on 670 dairy cows and 190 heif-ers which were loosely housed in fenced partially shaded yards and milked three times daily in a milking parlour. Cows were fed on a total mixed ration (TMR) based on com silage, yellow com, soya bean and cot-ton seed meal. Estrus was detected by the use of electronic activity tag and cows were inseminated artificially. First service conception rate was sig¬nificantly affected by body condition score at insemination time and its changes from parturition till insemination, 305-d milk yield, season of in¬semination, temperature humidity index and progesterone level at the time of insemination, while there was no significant effect for parity, days to first insemination, body condition score at calving and peak milk yield.

Summary in Arabic.

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