Corpus luteum (CL) function following spontaneous or prostaglandin F2 alpha-induced estrus was studied in 27 Brahman cows and 16 Brahman heifers. Females received one injection of 0, .38, .75 or 2.25 mg alfaprostol (PGF)/100 kg body weight at 12 +/- .1 d post-estrus. Serum progesterone (P4) during CL formation, following the subsequent estrus, increased over time (P less than .001, 1 to 13 d po...

Several managerial and pharmacological methods are available for porcine estrus synchronization. Before implementing a method, producers must have a clear idea of the goal of estrus synchronization and a realistic expectation of the outcome. Induction of precocious puberty in gilts is perhaps the most economically favored estrus synchronization technique available to swine producers. Appropriat...

Embryos from Bos indicus are more resistant to elevated culture temperature (i.e. heat shock) than embryos from some Bos taurus breeds. The present experiment was designed to determine if Brahman embryos have greater resistance to heat shock than Holstein embryos at a stage in development before the embryonic genome was fully activated. A second objective was to test breed effects on estrus syn...

To investigate uterine and serum copper (Cu) and zinc (Zn) concentrations variation during the bovine estrus cycle , 232 blood and genital tract samples were collected from the abattoir in Urmia. The phase of the estrous cycle was determined by the examination of the ovaries and the uterine tonicity. Of the 46 samples selected for use in the study, 13 were pro-estrus, 10 estrus, 8 metestrus, an...

The aim of this study was to investigate the period of estrus cycle in aceh cattle, Indonesia, based on vaginal cytology techniques. Four healthy females of aceh cattle with average weight of 250-300 kg, age of 5-7 years, and body condition score of 3-4 were used. All cattle were subjected to ultrasonography analysis for the occurrence of corpus luteum before being synchronized using intramuscu...

We determined whether a fixed-time AI (TAI) protocol could yield pregnancy rates similar to a protocol requiring detection of estrus, or estrous detection plus TAI, and whether adding a controlled internal device release (CIDR) to GnRH-based protocols would enhance fertility. Estrus was synchronized in 2,598 suckled beef cows at 14 locations, and AI was preceded by 1 of 5 treatments: 1) a CIDR ...

Two experiments were conducted to assess the effect of buck exposure to synchronize estrus in mature and pre-pubertal norgestomet-treated crossbred (criolloxdairy breeds) goats. In experiment 1, 100 mature goats (25 per group) under range conditions were either teased at 48 or 24h before Sincromate-B (SMB; 9 days treatment of 2mg norgestomet) implant withdrawal. A third group was exposed to buc...

The rat uterus receives an innervation from the lumbosacral and thoracolumbar segments of the spinal cord. These segments receive descending oxytocinergic projections from the paraventricular nucleus of the hypothalamus. We tested the hypothesis that oxytocin regulates uterine motility through a spinal site of action. Oxytocin was administered in anesthetized female rats either intrathecally at...

Production systems with group housing of sows during a part of the lactation are used in certified organic production and can increase the occurrence of lactational estrus thus making batch-wise breeding difficult. The aim of this study was to investigate the occurrence of lactational estrus and time at return to estrus after weaning by following the performance of the sow (change in body weigh...

Three hundred and five Large White (LW, 93), Landrace (L, 92), Yorkshire (Y, 69) and Chester White (CW, 51) gilts produced at the Roman L. Hruska U.S. Meat Animal Research Center over 3 yr with 15 to 41 gilts per breed group per year were housed in total confinement and mated to farrow at 1 yr of age. After 28 to 30 d lactation, piglets were weaned and all females were observed for estrus daily...