38 Lactating dairy cows (n=1,538) were enrolled in a randomized complete block 39 design study to evaluate protocols to synchronize estrus and ovulation. Within each 40 herd (n=8), cows were divided into three calving groups: EARLY, MID and LATE 41 based on days in milk (DIM) at mating start date (MSD). EARLY calving cows 42 (n=1,244) were  42 DIM at MSD, MID calving cows (n=179) were 21 to 41...

We hypothesized that 50mg of prostaglandin F2α (PG) on d 6 would induce luteolysis in a traditional 5-d Ovsynch-72 program [GnRH 5 d before (d 0) and 72 h after (d 8) 25-mg PG doses (d 5 and 6 after GnRH); timed artificial insemination (AI) on d 8]. Experiment 1 monitored luteal regression of original and GnRH-induced luteal tissue (corpus luteum, CL) by transrectal ultrasonography and blood se...

AIM To evaluate estrus induction response and fertility including plasma progesterone and biochemical profile following use of three standard hormonal protocols in anestrus crossbred cows. MATERIALS AND METHODS The study was carried out on 40 true anestrus and 10 normal cyclic cows. 10 anestrus cows each were treated with standard intravaginal controlled internal drug release (CIDR) device, O...

The goal of this experiment was to compare the effectiveness three popular synchronization protocols, viz. ovsynch, double prostaglandin (PGF2? /PG) injections, and MAP (Medroxyprogesterone acetate) sponges, in anestrous goats. Twenty one non pregnant multiparous goats with an average body condition score (BCS = 2.5) were selected. After last PG injection, all exposed fertile bucks. They observ...

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The objective was to determine the effects of bovine somatotropin (bST) and two artificial insemination (AI) protocols on reproductive performance of Holstein cows. Lactating cows (n = 840) were assigned at 37 d in milk (DIM) to one of four treatments in a 2 x 2 factorial arrangement. Treatments consisted of either bST (500 mg/14 d) starting at 63 +/- 3 DIM or no bST (control), with cows either...

this study was carried out at sakha animal production research station, during the period from oct., 2009 to sept., 2010. forty rahmani ewes were divided into three treatment groups: the 1st, 2nd and 3rd treatment groups were intramuscularly injected (day 0) with 1 ml gnrh analogue followed by an intramuscular injection with 0.7 ml pgf2α5 (g1), 6 (g2) or 7 (g3) days later. a second dose of 1 ml...

Our objective was to compare the effect of treatment with GnRH at first (G1) Breeding-Ovsynch portion a Double-Ovsynch (DO) protocol human chorionic gonadotropin (hCG) on pregnancies per artificial insemination (P/AI) in lactating dairy cows. In experiment 1, cows (n = 1,932) submitted DO for timed (TAI) 2 commercial farms were blocked by parity (primiparous vs. multiparous) and randomly assign...