Endocrine Changes during Restoration of Estrous Cycles Following Induction of Anestrus by Restricted Nutrient Intake in Beef Heifers1
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چکیده
منابع مشابه
Endocrine changes during restoration of estrous cycles following induction of anestrus by restricted nutrient intake in beef heifers.
The working hypotheses in this experiment were: that ovarian estradiol would inhibit luteinizing hormone (LH) secretion in heifers that were anestrus as a result of restricted dietary energy intake and the responsiveness of LH secretion to estradiol negative feedback would decrease during the period when restoration of estrous cycles occurred following feeding of diets adequate in energy. Fifte...
متن کاملEndocrine changes and ultrasonography of ovaries in suckled beef cows during resumption of postpartum estrous cycles.
Changes in follicular and luteal structures were assessed and concentrations of estradiol and progesterone were measured in 13 Hereford X Angus suckled beef cows during resumption of estrous cycles. Transrectal ultrasonography was used to monitor follicular size, ovulation, and formation and regression of the corpus luteum (CL). The interval from parturition to first postpartum ovulation (FO) w...
متن کاملEvaluation of Three Estrous Synchronization Protocols in Beef Heifers1
Objectives of this study were to evaluate synchronization, conception, and pregnancy rates of heifers synchronized with melengestrol acetate (MGA)-prostaglandin F2α (PGF2α,), Select Synch, or Select Synch preceded by MGA (MGA-Select Synch). Heifers in the MGA-PGF2α group (n = 209; BW = 378 kg) received MGA (0.5 mg/ d per heifer) for 14 d and PGF2α (25 mg) 19 d later. Select Synch heifers (n = 2...
متن کاملQuantification of naloxone binding sites in brains from suckled beef cows during postpartum anestrus and resumption of estrous cycles.
Thirty beef cows, approximately 3 yr of age, were randomly assigned to be slaughtered on d 7, 14, 28, 42 or 56 postpartum. Each cow suckled one calf until slaughter. Data from cows slaughtered on d 42 and 56 were pooled and further classified as anestrous or cyclic based on the presence of a corpus luteum and elevated serum concentrations of progesterone at slaughter. Specific binding of [3H]na...
متن کاملInfluence of exposure to bulls on resumption of estrous cycles following parturition in beef cows.
The effect of bull exposure on the resumption of estrous activity following parturition was studied in an experiment using mature Hereford and Hereford X Angus beef cows. In the spring of 1981 and 1982, cows were assigned by breed and calving date to one of two treatment groups. Cows were exposed to bulls either from 3 to 85 d postpartum (BE; n = 45, 1981; n = 35, 1982) or from 53 to 85 d postp...
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ژورنال
عنوان ژورنال: Journal of Animal Science
سال: 1986
ISSN: 0021-8812,1525-3163
DOI: 10.2527/jas1986.632565x