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This paper reports a new method for synchronizing the time of ovulation in cattle using GnRH and PGF(2alpha). In Experiments 1 and 2, lactating dairy cows (n=20) ranging from 36 to 280 d postpartum and dairy heifers (n=24) 14 to 16 mo old were treated with an intramuscular injection of 100 mug GnRH at a random stage of the estrous cycle. Seven d later the(More)
OBJECTIVES CODOX-M/IVAC (cyclophosphamide, vincristine, doxorubicin-methatrexate/ifusamide, etoposide, cytarabine) chemotherapy is commonly used to treat Burkitt lymphoma and in the HIV-negative population. Rituximab is often added with suggested survival benefits. Concerns over increased toxicity in an already immunocompromized population have prevented(More)
Four experiments were conducted to examine effects of GnRH administered at estrus on various reproductive characteristics in repeat-breeding dairy cows (eligible for third service). In Exp. 1, cows (n = 8 per group) received (i.m.) either saline or 50, 100, or 250 micrograms of GnRH at 12 h after onset of estrus. There was a positive linear (P < .05) effect(More)
Our objective was to determine whether pregnancy rates following first services would be improved by supplementing lactating dairy cows with exogenous progesterone via a progesterone-releasing intravaginal device. Estrus was induced in cows with PGF2 alpha (3-wk clusters of cows ranging from 42 to 63 d postpartum) following a positive milk test for high(More)
The objective was to determine the effects of progestogen treatment on the lifespan of the first corpus luteum induced by GnRH in periparturient-milked cows. Dairy cows (n = 55) were assigned randomly following normal parturitions to receive either a progestogen implant (6 mg of norgestomet) or a blank implant (control) for 6 d beginning 2 to 5 d after(More)
The objective was to determine the influence of gonadotropin-releasing hormone on pregnancy rates of dairy cattle at first services, when both the timing of hormone injection and insemination were altered relative to the onset of estrus. Cows (n = 325) were assigned randomly to six groups making up a 2 X 2 X 2 incomplete factorial experiment; dose of GnRH(More)
Two experiments were performed in two different herds to determine if utilizing prostaglandin F 2 alpha to induce estrus for first services would be effective in reducing the duration and variability of calving intervals. In Experiment 1, cows were assigned randomly as controls (n = 217) to be inseminated as they were detected in estrus (beginning d 42 to(More)
Hypothyroidism reportedly decreased sexual behavior in several species. To confirm the role of hypothyroidism in the expression of estrus in cattle, our objective was to determine whether estrus could be induced in ovariectomized cows without intact thyroid glands using estradiol benzoate and progesterone. Eight nonlactating, nonpregnant Holstein cows were(More)
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