Differences in productive robustness in rabbits selected for reproductive longevity or litter size

Differences in productive robustness in rabbits selected for reproductive longevity or litter size.

The aim of this work was to evaluate the ability of a line selected for reproductive longevity (LP) to confront productive challenges compared to a line selected during 31 generations for litter size at weaning (V). A total of 133 reproductive rabbit does were used (72 and 61 from LP and V lines, respectively). Within each line, three groups with different levels of productive effort were plann...

Candidate Reproductive Genes Do Not Explain Responses in Lines Selected for Ovulation Rate and Litter Size

Ovulation rate in sheep selected for weaning weight or litter size.

Ovulation rate was measured by laparoscopy at two consecutive cycles on 366 ewes 2 yr old and over and 85 yearling ewes of five lines of Targhees from the base base population; 53 yearling linecross ewes were also included. The lines were two unselected controls (HCl and DC), two selected for 21 yr for increased 120-d weight (HW and DH) and one selected for 19 yr for multiple births (T). Ewes w...

Productive Longevity in Beef Cows

Introduction. Cow longevity is one of the most economically important traits in the beef cow. Longevity is inter-related to other important traits, and, therefore, it is difficult to separate the importance of longevity, itself, from the importance of traits that are related to longevity. For example, reproductive performance is usually part of the culling criteria. It is often stated that repr...

Behavioural differences in non-reproductive adult females in a long-term selection experiment for litter size in mice

In a previous study, it has been shown that adult, non-reproductive female mice from a line Ž . Ž . selected for high litter size at birth S-line have higher residual feed intake RFI than females of Ž . a non-selected control line C-line . Several studies have indicated that a higher RFI is related to a higher activity level. Differences in activity may suggest underlying differences in coping ...