Food availability is an important limiting factor for avian reproduction. In altricial birds, food limitation is assumed to be more severe during the nestling stage than during laying or incubation, but this has yet to be adequately tested. Using food-supplementation experiments over a 5-year period, we determined the degree and timing of food limitation for burrowing owls (Athene cunicularia) ...

Use of GnRH in AI protocols results in ovulation of a wide range of follicle sizes. Our objective was to determine the effect of ovulatory follicle size at GnRH-induced ovulation or standing estrus on pregnancy rates and embryonic/fetal mortality. Lactating beef cows (n = 273) received the CO-Synch protocol (100 μg GnRH, i.m. on d -9; 25 mg PG, i.m. on d -2; and 100 μg GnRH, i.m. on d 0 with ti...