Postpartum Reproductive Activity of Indigenous Zebu and Friesian x Zebu Crossbred Cows in the Ethiopian Central Highlands.
1990
Tesfu Kasa (Addis Abeba University, Debre Zeity (Ethiopia). Faculty of Veterinary Medicine, Department of Clinical Studies)
Postpartum reproductive activity of 72 cows, 41 indigenous zebu and 31 Friesian x zebu crossbred, from 14 smallholder farms was investigated using plasma progesterone profiles determined by solid-phase radioimmunoassay. Mean plus or minus S.D. Postpartum intervals for both anestrus and calving to conception were 110.4 plus or minus 23.5 and 199.8 plus or minus 61.8 d for zebu and 97.5 plus or minus 25.1 and 157.8 plus or minus 55.5 d for crossbred cows. These values were significantly (p less than 0.05) affected by nutritional status in both genotypes. The pregnancy rates were 48.8 percent in zebu and 54.8 percent in crossbred cows. Body condition scores and progesterone profiles of the cows had significant (p less than 0.01) effects on pregnancy rate. The findings indicate that the Friesian blood as well as better nutritional status considerably reduce the interval for resumption of postpartum ovarian cycles and the interval between calving to conception.
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