Bumble bee workers (Bombus bifarius, Hymenoptera: Apidae) exhibit aggression toward one another after the colony begins producing female reproductive offspring (the competition phase). Workers in competition phase colonies must continue to perform in-nest tasks, such as nest thermoregulation, and to forage for food, to rear the reproductives to maturity. Therefore, competition phase workers are...

Has the reproductive performance in your herd improved, remained the same or declined over time? If your herd is typical for the Southeast, reproductive performance has declined over time. A study that evaluated reproductive performance from 1976 to 2002, in Florida and Georgia dairy herds, showed that days to first service, days to conception, and calving interval increased significantly over ...

Complex organismal traits such as body size are influenced by innumerable selective pressures, making the prediction of evolutionary trajectories for those traits difficult. A potentially powerful way to predict fitness in natural systems is to study the composite response of individuals in terms of performance measures, such as foraging or reproductive performance. Once key performance measure...

The objective of this study was to evaluate relationships between rebreeding performance and growth performance (n = 3,777 gilts) and rebreeding performance and reproductive performance (n = 2,242 sows). Our data were from a selection experiment for shorter intervals from weaning to estrus after the first parity (IWE), involving Dutch Landrace pigs, in which a selection line and a control line ...

Retrospective data from Sebele Dairy Farm were analysed for reproductive performance of Friesian/Holstein cows. Three hundred records from 1989 to 1995 were used. The herd was zero grazed and the data was analysed for age at first calving (AFC), calf birth weights (BW), calving interval (CI), days open (DO), calving rate (CR), reproductive wastage (RW) and calving difficulty (CD); dystocia, aft...

retrospective data from sebele dairy farm were analysed for reproductive performance of friesian/holstein cows. three hundred records from 1989 to 1995 were used. the herd was zero grazed and the data was analysed for age at first calving (afc), calf birth weights (bw), calving interval (ci), days open (do), calving rate (cr), reproductive wastage (rw) and calving difficulty (cd); dystocia, aft...

Sixty Ghezel ewes (age 3.5 years) were used to study the effect of different nitrogenous supplements in flushing ration on reproductive performance. Experimental treatments were divided in five groups: group A: urea; group B: soybean meal (SBM); group C: corn gluten meal (CGM); group D: barley grain and group E: control or basal diet (no flushing). The four flushing rations had nearly the same ...

There has been a significant decline in the reproductive performance of dairy cattle in recent decades. Cows, take longer time to return to the oestrus after calving, have poorer conception rates, and show fewer signs of oestrus. Achieving good reproductive performance is an increasing challenge for the dairy producer. In this study we focus on understanding the overall biological phenomena ass...

The reproductive behavior of semi-wild and feral horses is described briefly in order to provide a background on the reproductive patterns and the specific behavioral elements comprising courtship and mating in the horse. The reproductive behavior of the domestic stallion is discussed at length as are various breeding conditions and normal breeding performance. Finally, sexual behavior problems...