Ninety-nine multiparous Brahman-influenced (1/4 to 3/8 Brahman) cows were managed to achieve low (BCS = 4.3 +/- 0.1; n = 50) or moderate (BCS = 6.1 +/- 0.1; n = 49) body condition (BC) to determine the influence of bovine somatotropin (bST) on estrous characteristics, reproductive performance, and concentrations of serum GH and plasma NEFA. Beginning 32 d postpartum, cows within each BC were as...

Spring-calving, crossbred (1/4 to 3/8 Brahman) primiparous (n = 56) and multiparous (n = 102) beef cows were used to evaluate the effects of progesterone, delivered via a controlled internal drug-releasing (CIDR) device, and prostaglandin F(2alpha) (PGF(2alpha)) on estrous behavior, synchronization rate, initiation of estrous cycles, and pregnancy rate during a 2-yr period. To determine luteal ...

The freezability of semen collected during the low (May-July) and the peak (September-November) breeding seasons from 18 Nili-Ravi buffalo bulls of young (3-4 years), adult (6-8 years) and old ( 1215 years) age groups was studied. After extension in lactose.:..fructose-egg-yolk-glycerol extender, semen samples were frozen and stored in liquid nitrogen. Post-thaw motili�y and liveability of sper...

The coyote is a seasonally breeding mammal, with most copulations occurring between December and April (depending on location). The objective of this study was to characterize seasonal changes in serum testosterone concentrations, testicular volume, and ejaculate quantity and quality in captive male coyotes. There were seasonal differences in testicular volume, with the greatest volume (20.2+/-...

Knowledge of the basic reproductive physiology of snow leopards is required urgently in order to develop a suitable management conditions under captivity. In this study, the long-term monitoring of concentrations of three steroid hormones in fecal matter of three female snow leopards was performed using enzyme immunoassays: (1) estradiol-17β, (2) progesterone and (3) cortisol metabolite. Two of...

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=...

With the goal of characterizing the type and degree of injuries and blemishes incurred by horses living under natural social conditions, all members of a semi-feral herd of ponies were inspected on 4 occasions over a period of 28 months. Two occasions were during breeding/foaling season and 2 during non–breeding/foaling season months. On each occasion, each animal was examined (N = 47–65) and a...

Background Gonadotropin-inhibitory hormone (GnIH), initially discovered in birds as a hypothalamic neuropeptide, inhibits the synthesis and release of gonadotropins via affecting GnRH neurons and gonadotropes. Therefore, it could be a key neuropeptide in regulating seasonal breeding in birds. The aim of the present study was to investigate the expression of GnIH in the hypothalamus of male and ...

St. Croix White hair sheep ewes were used to evaluate the effect of supplemental nutrition prior to breeding during the dry and wet seasons on St. Croix. Beginning 21 d prior to breeding ewes were fed supplement in addition to grazing guineagrass pasture (FEED). Other ewes in the flock grazed pasture only (CONTROL). This study was conducted during the dry (June and July) and wet seasons (Octobe...

A 3-yr study was conducted with heifers (n = 170) whose dams were used in a 2 x 2 factorial arrangement of treatments to determine the effects of late gestation (LG) or early lactation (EL) dam nutrition on subsequent heifer growth and reproduction. In LG, cows received 0.45 kg/d of a 42% CP supplement (PS) or no supplement (NS) while grazing dormant Sandhills range. During EL, cows from each l...