אסיף מאגר המחקר החקלאי

Characterization of short luteal cycles in the early post-partum period and their relation to reproductive performance of dairy cows

Year:

1988

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Volume :

16

Co-Authors:

Eger, S., Advisory Service, Ministry of Agriculture, Israel
Shemesh, M., The Kimrom Veterinary Institute, Israel
Schindler, H., Institute of Animal Science, Agricultural Research Organization, Bet Dagan, 50250, Israel
Amir, S., Institute of Animal Science, Agricultural Research Organization, Bet Dagan, 50250, Israel
Foote, R.H., Department of Animal Science, Cornell University, Ithaca, NY, United States

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Abstract:

The ovarian activity of primiparous and multiparous Israeli-Friesian dairy cows was monitored by progesterone (P4) determination in fat-free milk twice weekly, beginning at calving and continuing until pregnancy was confirmed by palpation, but not later than 150 days post partum. The cows were observed for standing oestrus, thrice daily. Based on the distribution of progesterone concentrations concurrent with inseminations at behavioral oestrus resulting in conceptions or not, 0.5 ng/ml was taken as the dividing value between luteal and non-luteal origins of progesterone. Resumption of luteal activity occurred by 35 days post partum in 99% and 93% of the primiparous and multiparous cows, respectively. The rate of short luteal cycles (≤ 11 days) was about 54% in the first, 24% in the second and 20% in the third-fifth luteal cycles post partum. The duration of first luteal cycles was associated with post partum interval. Neither length nor maximum progesterone concentration of the cycle preceding insemination was associated with conception rate. The results indicate that short luteal cycles (≤ 11 days), whenever they occur, can be attributed to a functional corpus luteum and not to ovary malfunction. © 1988.

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