Despite increased emphasis in recent years on declining dairy cow reproductive performance, there has been very little focus on the management of the periparturient dairy heifer and cow at calving time. Perhaps as a result, US producers are now reporting increasing perinatal calf losses at calving. A critical determinant in reducing periparturient losses is good calving management. The tenets o...

Polymorphisms in μ-calpain (CAPN1) that beneficially associate with beef tenderness are reported to antagonistically calving day heifers and post-partum interval estrus cows. We, therefore, hypothesized a molecular breeding value for slice shear force, calculated based on CAPN1 calpastatin (CAST) genotypes, would demonstrate an antagonistic relationship between genomically predicted force ordin...

A total number of 1243 records of calving cases of 585 dairy Friesian cows during 8 consecutive years from 1997 to 2004 collected from Sakha Animal Production Research Station belonging to Animal Production Research Institute, Agriculture Research Center were used to study the effect of sire, live body weight (LBW) and age of dam and calving season on twinning rate and its consequent effects on...

Calving and weaning data from crossbred calves sired by five Bos indicus breeds and one Bos taurus breed were evaluated. Data included calving and weaning records of F1 calves out of multiparous Hereford cows and sired by Angus, Gray Brahman, Gir, Indu-Brazil, Nellore, and Red Brahman bulls. At calving, Angus-sired calves had shorter gestations and lower (more desirable) calving ease scores and...

introduction: age at first calving (afc) has an important effect on profitability and reproductive management of dairy cattle. every month increase in afc beyond 24 months increases the cost of production. the time between birth and first calving represents a period in which replacement heifers are not generating income. instead this rearing period requires considerable capital expenditures inc...

The effect of growth rate from birth through 30 months of age on the reproductive performance of Polled Hereford heifers calving as 2-year-olds was examined. Heifers with high gains during the first winter as weanlings had higher breeding efficiency when bred as yearlings, had larger pelvic areas as 2-year-olds, gave birth to larger calves, had less calving difficulty at first parturition and h...

The objective of the present study was to estimate genetic trends for lactation milk yield, persistency of milk yield, somatic cell count and interval between first and second calving in Holstein dairy cows of Iran. The dataset consisted of 210,625 test day and 25,883 first parity cows with milk yield recorded from July 2002 to September 2007 comprising 97 herds in Iran. Breeding values of anim...