Estrous behavior and initiation of estrous cycles in postpartum Brahman-influenced cows after treatment with progesterone and prostaglandin F2α1,2

2006 ◽  
Vol 84 (7) ◽  
pp. 1916-1925 ◽  
Author(s):  
R. Flores ◽  
M. L. Looper ◽  
D. L. Kreider ◽  
N. M. Post ◽  
C. F. Rosenkrans
Keyword(s):  
Estrous Cycles ◽  
Estrous Behavior

Interactive effects of food deprivation and exercise on reproductive function in female hamsters

1994 ◽  
Vol 267 (1) ◽  
pp. R185-R190 ◽  
Author(s):  
J. B. Powers ◽  
A. E. Jetton ◽  
G. N. Wade
Keyword(s):  
Food Deprivation ◽  
Reproductive Function ◽  
Hormonal Treatment ◽  
Estradiol Benzoate ◽  
Interactive Effects ◽  
Combined Effects ◽  
Inhibitory Effects ◽  
Estrous Cycles ◽  
Running Wheels ◽  
Estrous Behavior

Two experiments evaluated the combined effects of food deprivation and runningwheel access on estrous cycles and estrous behavior of female hamsters. In experiment 1, food deprivation on days 1 and 2 of the estrous cycle disrupted the next expected ovulation, and this effect was more, rather than less, robust in females allowed to exercise in running wheels while they were deprived. In experiment 2, a similar protocol was used except the females were ovariectomized and received sequential injections of estradiol benzoate (EB; 5 micrograms) and progesterone (P; 200 micrograms) separated by 48 h to induce lordosis, which was tested 4-5 after P. Food deprivation concomitant with hormonal treatment diminished lordosis durations, but this effect was significant only among the females that were permitted to run in activity wheels. Previous findings demonstrated that access to running wheels attenuated the inhibitory effects of short photoperiod exposure on hamster estrous cycles. In contrast, the present results indicate that this same manipulation exaggerates rather than diminishes the inhibitory effects of food deprivation on estrous cycles and hormone-induced behavioral estrus.

Decreased availability of metabolic fuels induces anestrus in golden hamsters

1990 ◽  
Vol 258 (3) ◽  
pp. R750-R755 ◽  
Author(s):  
J. E. Schneider ◽  
G. N. Wade
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Food Deprivation ◽  
Follicular Development ◽  
Acid Oxidation ◽  
Estradiol Treatment ◽  
Estrous Cycles ◽  
Golden Hamsters ◽  
Body Weights ◽  
Estrous Behavior

Food deprivation inhibits ovulation and estrous behavior in golden hamsters. In experiment 1, the effects of phasic starvation (food deprivation on days 1 and 2 of the 4-day estrous cycle) depended on prior body weight and fat content. Starvation-induced anestrus, which occurs after only one cycle of phasic starvation in lean hamsters, did not occur until after three or more cycles in fat hamsters. None of the fat hamsters became anestrous until their body weights had declined to the level of lean hamsters. However, in experiment 2, we found evidence that changes in reproductive status were not signaled by any dimension of body size per se but instead by the general availability of metabolic fuels. Estrous cycles of thin hamsters were not significantly affected by food deprivation and weight loss when the hamsters were provided with either a 25% glucose solution or with vegetable shortening. In experiment 3, simultaneous pharmacological reduction of both fatty acid oxidation and glycolysis inhibited estrous cycles in hamsters fed ad libitum. Estradiol treatment restored estrous behavior, but not ovulation, in food-deprived, lean hamsters and in hamsters in which both fatty acid oxidation and glycolysis were reduced. Decreased availability of utilizable metabolic fuels may inhibit follicular development, which may in turn lead to circulating estradiol levels that are insufficient to stimulate estrous behavior.

THE INFLUENCE OF ALLYL TRENBOLONE ON THE OCCURRENCE OF NORMAL ESTROUS CYCLES FOLLOWING A GONADOTROPHIN-INDUCED OVULATION IN PREPUBERTAL GILTS

1989 ◽  
Vol 69 (4) ◽  
pp. 1091-1093 ◽  
Author(s):  
T. A. VAN LUNEN ◽  
R. N. KIRKWOOD ◽  
P. A. THACKER
Keyword(s):  
Key Words ◽  
Estrous Cycles ◽  
Induced Ovulation ◽  
Effect Of Treatment ◽  
Estrous Behavior

Sixty prepubertal Yorkshire × Landrace gilts were either injected with PMSG and hCG (n = 40) or acted as controls. Of the hormone-injected gilts, 20 were fed 15 mg d−1 of allyl trenbolone from 7 to 21 d after the PMSG injection. Gilts were mated at their second estrus. There was no effect of treatment on the incidence of cyclic estrous behavior or on subsequent ovulation rates and numbers of embryos. Key words: Allyl trenbolone, gonadotrophins, puberty, gilts

Estrous Cycles of Nine Species of Muroid Rodents

1977 ◽  
Vol 58 (1) ◽  
pp. 89-92 ◽  
Author(s):  
D. A. Dewsbury ◽  
D. Q. Estep ◽  
D. L. Lanier
Keyword(s):  
Estrous Cycles ◽  
Muroid Rodents

THE DURATION OF THE BREEDING SEASON OF FOUR BREEDS OF SHEEP

1974 ◽  
Vol 54 (3) ◽  
pp. 389-392 ◽  
Author(s):  
J. J. DUFOUR
Keyword(s):  
Sexual Activity ◽  
Breeding Season ◽  
Estrous Cycles ◽  
Progressive Decline ◽  
Daily Exposure ◽  
Almost All

Three breeds of sheep (Dorset, Leicester, and Suffolk) and a crossbred line from these breeds (DLS) were observed throughout 1 yr to determine their sexual activity by daily exposure of the ewes to vasectomized rams. The DLS and Dorset ewes exhibited their first estrus earlier in the year (P < 0.01) and stopped cycling later than the Leicester and Suffolk ewes (P < 0.01). The duration of the breeding season in the DLS ewes was 20 days (P > 0.05) longer than in the Dorsets and 70 and 115 days (P < 0.01) longer than in the Leicester and Suffolk ewes, respectively. The percentage of Dorset and DLS ewes showing one or more estrous periods increased progressively from June to reach 100% in September for both breeds. The Suffolk and Leicester ewes commenced to cycle in late August and by September almost all ewes had shown an estrous period. The progressive decline in estrous activity became evident first with the Suffolk in January, then with the Dorset and Leicester in February and with the DLS in March. The Dorset, DLS and Leicester ewes had longer estrous cycles than the Suffolk ewes. Within ewes, length of estrous cycles was highly repeatable for all breeds. False estrus and silent estrus occurred in 1.0 and 3.9% of the estrous periods, respectively. Over successive estrous cycles, length of estrous cycles increased significantly.

Rejuvenating effects of 10-week underfeeding period on estrous cycles in young and old rats

1987 ◽  
Vol 8 (3) ◽  
pp. 225-232 ◽  
Author(s):  
K. Quigley ◽  
R. Goya ◽  
J. Meites
Keyword(s):  
Estrous Cycles ◽  
Old Rats
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