We previously reported that ovulation rate, but not pregnancy rate or litter size at d 30 after mating, was enhanced by treatment with P.G. 600 (400 IU of PMSG and 200 IU of hCG, Intervet America, Inc., Millsboro, DE) in gilts fed the orally active progestin, altrenogest (Matrix, Intervet America, Inc.) to synchronize estrus. We hypothesized that in addition to increasing ovulation rate, P.G. 6...

to investigate uterine and serum ca++ and mg++ variations during the estrous cycle in the bovine, 66 genital tracts and blood samples were collected from urmia abattoir, urmia, iran. the phase of the estrous cycle was determined by examination of the structures present on ovaries and uterine tonicity. of the collected samples, 17 were pro-estrus, 12 estrus, 14 metestrus and 23 diestrus. the ute...

An estrus synchronization protocol (7-11 Synch) was developed to synchronize the first follicular wave and timing of ovulation in postpartum beef cows. In Exp. 1, follicular development and timing of ovulation in response to the following protocol were evaluated. Beef heifers (n = 12) and cows (n = 6), at random stages of the estrous cycle, were fed melengestrol acetate (MGA; .5 mg x animal(-1)...

An attempt was made to determine the cyclicity in yak through plasma progesterone estimation during breeding season as well as non-breeding season because silent or non-detected estrus is very common in this species. Blood samples were collected from yak (n = 8) during peak breeding season (July to November) and from the same animals in non-breeding season (February to March) at a two-day inter...

Puberty: For the gilt and filly, the first corpus luteum (CL) appears to have a normal lifespan. For both species, first CL usually is associated with estrus but can form in the absence of estrus. For the ewe and cow, a transient (1 to 4 d, ewe; 3 to 10 d, cow) rise and fall of ovarian derived progesterone (P4) is detected in peripheral blood (80% of ewes; 50% of heifers) prior to first "normal...

The objective was to evaluate the effect of estrus occurrence (based on removal of tail-head marks) on ovarian responses and pregnancy per AI (P/AI; 30 d after AI) in suckled Bos indicus beef cows submitted to timed AI (TAI) protocols. Cows received an intravaginal device containing 1.0 g progesterone, and 2.0 mg estradiol benzoate im; 8 d later, the intravaginal device was removed, and they we...

Boar exposure has been used for estrus induction of prepubertal gilts, but has limited effect on estrus synchronization within 7 d of introduction. In contrast, PG600 (400 IU of PMSG and 200 IU of hCG; Intervet, Millsboro, DE) is effective for induction of synchronized estrus, but the response is often variable. It is unknown whether boar exposure before PG600 administration might improve the e...

Effects of monoamines or its precursors on the induction of persistent estrus by testosterone propionate (T.P.) were studied in Wistar strain female rats. Daily treatment with 5-hydroxytryptophane (5-HTP) for the first 10 days of life delayed the occurrence of persistent estrus in rats given T.P. at 4 days of age. The onset of persistent estrus occurred in this group of animals at 67.1+/-2.5 da...

Cows not conceiving will return to estrus again beginning about 18 to 25 days after the synchronization period. The females will still be synchronized to a slight degree, which gives a second chance to artificially inseminate each female in the early part of the breeding season. Without synchronization, the herd manager is faced with a 21-day period of continual estrus detection and only one op...

Aim: The study was undertaken to find out the estrus induction and fertility response in delayed pubertal Kankrej heifers treated with norgestomet ear implant. Materials and methods: Total eighteen anoestrus Kankrej heifers of delayed puberty weighed above 250 kg and attained between 30 to 36 months of age were selected and divided in to three groups of six animals each at random to conduct the...