Long breeding seasons result in long calving seasons. This results in calvings distributed through a range of environmental and nutritional conditions and a disparity in calf maturity at any planned weaning time. It also results in cows entering their period of maximal nutritional requirements over the same range of environmental conditions. Attempts to increase cow and calf productivity often ...

The response to melatonin expression is one way that circadian rhythms of many biological processes are regulated. To evaluate the relationship between the melatonin receptor 1A (MTNR1A) gene and reproductive performance, records were compared in Dorset and 3/4-Dorset x 1/4-East Friesian ewes expressing different genotypes at the MTNR1A gene in the Cornell University sheep flock. There were 116...

The BLRI Cattle Breed 1(BCB-1) is a native cattle breed developed by Bangladesh Livestock Research Institute (BLRI) through selective breeding among indigenous cattle of Bangladesh. Data asserted from record sheets of 529 animals maintained during 1992 to 2006 were analyzed to evaluate the reproductive efficiency of BCB-1 cattle in different generations, seasons and parities. The highest percen...

Environmental conditions experienced during foetal and neonatal life influence early development with potential long-term consequences for later life events. In many parts of the world, the external environment varies with the season. This includes factors such as photoperiod, climatic factors, nutrition or prevalence of infectious agents. Birth season is one surrogate for the environmental con...

Forty six Holstein Friesian repeat breeding cows (the average AI/conception was 5.2 ± 0.2) were investigated using the progesterone assay after AI to determine possible differences in plasma progesterone profiles between summer and winter seasons. Twenty eight (60.9%) and 18 (39.1%) cows were followed in summer (June–August) and winter (December–February), respectively. In the summer season, th...

The reproductive performance of a dairy herd has a significant effect on the profitability of that herd. Common measures of reproductive performance are days to first service, days to conception, calving interval, services per conception, conception rate, estrus detection rate, and pregnancy rate. Most cow operations would benefit economically by reducing the number of operational days, decreas...

The reproductive performance of a dairy herd has a significant effect on the profitability of that herd. Common measures of reproductive performance are days to first service, days to conception, calving interval, services per conception, conception rate, estrus detection rate, and pregnancy rate. Most cow operations would benefit economically by reducing the number of operational days, decreas...