Replacing toxic, wild-type Neotyphodium coenophialum-infected tall fescue (E+) with nontoxic, N. coenophialum-infected tall fescue (NE+) has improved cow performance, but producer acceptance of NE+ has been slow. The objective was to compare performance by spring- and fall-calving cows grazing either E+ or NE+ at different percentages of the total pasture area. Gelbvieh×Angus crossbred cows (n=...

The propensity of migratory waders to remain on the non-breeding grounds during the arctic breeding season (‘‘oversummer’’) in their first biological year of life (‘‘juveniles’’) may be latitude, and thus migratory distance dependent. We compared the extent of preparation for northward migration of western sandpipers Calidris mauri spending the non-breeding season in México and Panamá during 19...

BACKGROUND In species with biparental care both members of the breeding pair cooperate to raise the offspring either by assisting each other in every reproductive task or by specializing in different ones. The latter case is known as reproductive role specialization. Raptors are considered one of the most role-specialized groups, but little is known about parental behavior away from the nest. U...

Longevity and lifetime productivity are important factors influencing profitability for the cow-calf producer. Heifers that conceive earlier in the breeding season will calve earlier in the calving season and have a longer interval to rebreeding. Calves born earlier in the calving season will also be older and heavier at weaning. Longevity data were collected on 2,195 heifers from producers in ...

Supplementary feeding stations, or "vulture restaurants", are common conservation management tools. While a number of studies have investigated the consequences of surplus food on the population dynamics of scavengers, relatively little is known about the effects of such practices at the individual level. Within the long-term monitored breeding population of Canarian Egyptian vultures (Neophron...

Effects of body condition score (BCS) at parturition and postpartum weight gain on luteal activity and concentrations of glucose, insulin, and NEFA in plasma were evaluated during the breeding season in 242 primiparous beef cows over 3 yr (Y) at three locations (L). At approximately 90 d prepartum, cows were blocked by breed, expected calving date, and BCS and randomly assigned to diets so that...

In many seabird studies, single annual proxies of prey abundance have been used to explain variability in breeding performance, but much more important is probably the timing of prey availability relative to the breeding season when energy demand is at a maximum. Until now, intraseasonal variation in prey availability has been difficult to quantify in seabirds. Using a state-of-the-art ocean dr...

Th e energetically challenging periods of molting and breeding are usually temporally separated in temperate birds, but can occur simultaneously in tropical birds, a condition known as molt – breeding overlap. Here, we document great variation in the timing and duration of molting and breeding, and in the extent of molt – breeding overlap, among 87 species of understory passerines in central Am...

Year-class differences in reproductive function were investigated in a free-living population of adult male Dark-eyed Juncos, Junco hyemalis, breeding in interior Alaska. Second-year males (SY, entering their first breeding season) were compared with after-second-year males (ASY, entering at least their second breeding season). We measured body mass, size of the cloacal protuberance (CP), testi...