Changes in brain peptides associated with reproduction and energy homeostasis: Putative roles of gonadotrophin‐releasing hormone‐II and tyrosine hydroxylase in determining reproductive performance in response to daily food availability times in diurnal zebra finches

2020 ◽  
Vol 32 (2) ◽  
Author(s):  
Ila Mishra ◽  
Neha Agarwal ◽  
Abhilash Prabhat ◽  
Twinkle Batra ◽  
Sanjay Kumar Bhardwaj ◽  
...  
Author(s):  
B.V.E. Segwagwe ◽  
J. Malmo ◽  
K.L. Macmillan ◽  
P.D. Mansell

This experiment compared the reproductive performance of synchronised anoestrous dairy cows that were treated initially with a combination of progesterone and oestradiol benzoate and then with either gonadotrophin-releasing hormone (GnRH) or oestradiol benzoate to resynchronise returns to service. It was hypothesised that injecting anoestrous dairy cows with GnRH 12-15 days after insemination and coinciding with the time of insertion of a controlled intravaginal progesterone-releasing (CIDR) device would increase conception rates to the preceding 1st insemination compared with oestradiol benzoate treated cows; both GnRH and oestradiol benzoate would resynchronising the returns to service of those cows that did not conceive to the preceding insemination. Groups of cows in 11 herds were presented for a veterinary examination after they had not been seen in oestrus postpartum. Those cows diagnosed with anovulatory anoestrus (n = 1112) by manual rectal palpation and / or ultrasonography were enrolled in the trial. Each enrolled cow was injected with 2mg oestradiol benzoate i.m. on Day -10, (where Day 0 was the 1st day of the planned insemination) concurrently with vaginal insertion of a CIDR device. The device inserted was withdrawn on Day -2 and then each cow injected i.m. with 1 mg of oestradiol benzoate on Day -1 unless it was in oestrus. Observation for oestrus preceded each insemination. Every cow that had been inseminated on Days -1,0,1 or 2 was presented for treatment for resynchrony on Day 14 (n=891). They were divided into 2 groups; those with an even number were each injected i.m. with 250 µg of a GnRH agonist (Treatment group n = 477); each of the cows with an odd number injected i.m. with 1mg of oestradiol benzoate (control group, n = 414). Each GnRH or oestradiol benzoate injection preceded reinsertion of a CIDR device previously inserted from Days -10 to -2. It was withdrawn on Day 22, 24 hours before injecting 1mg oestradiol benzoate. Cows observed in oestrus were submitted for a 2nd insemination. Every enrolled cow still present in the herd was pregnancy tested by palpation of uterine contents per rectum about 6 weeks later and again at the end of a herd's seasonal breeding programme. The alternative use of GnRH instead of oestradiol benzoate did not affect the percentage of cows conceiving within 3 days of the mating start date (MSD) (35.6 %vs 35.3 %, P=0.90), resubmission rates for a 2nd insemination among cows not pregnant to the 1st insemination (81.6 % vs 83.5 %, P=0.41), 6-week pregnancy rate (59.3 % vs 60.6 %, P=0.65), 21-week pregnancy rate (86.6 vs 85.0, P=0.36), mean interval from MSD to conception (32.5 + 1.8 days vs 29.9 + 1.8 days, P = 0.26) or conception rate of cows reinseminated by Day 28 (43.3 % vs 38.8 %, P=0.39). When GnRH conception rate of cows reinseminated by Day 28 (43.3% vs was compared with oestradiol benzoate, it did not increase conception rates to the 1st service; it was as effective as oestradiol benzoate in synchronising returns to service in previously treated anoestrous cows that did not conceive to the 1st service. Its use affected neither conception rates to the preceding 1st inseminations nor to the following 2nd inseminations.


1987 ◽  
Vol 67 (3) ◽  
pp. 715-719 ◽  
Author(s):  
R. N. KIRKWOOD ◽  
E. S. LYTHGOE ◽  
F. X. AHERNE

Twenty-four first parity and 48 multiparity crossbred sows (Yorkshire × Landrace) were used in a 2 × 2 factorial design involving high (H) or low (L) lactation feed intakes and the intramuscular injection, or not, of 50 μg of gonadotrophin-releasing hormone (GnRH) at the onset of the first postweaning estrus. All sows were weighed at farrowing and weaning. The H feed intake entailed feeding sows at levels of 10, 13, and 14% of each sow's immediate postfarrowing metabolic weight during weeks 1, 2, and 3–4 of lactation, respectively. Low-fed sows received 50% of the H feed level. The diet contained 12.5 MJ DE kg−1 and 16% crude protein. Between weaning and mating, and following mating, all sows were fed 2.25 kg daily of the lactation diet. After weaning, sows were exposed to a boar twice daily to facilitate estrus detection. GnRH was administered at the onset of standing heat. All sows were slaughtered 25 d after mating at which time the reproductive tracts were removed and examined to determine the number of ovulations and the number of viable embryos. Low-level feeding resulted in an extension of the remating interval (5.9 ± 0.3 vs. 4.5 ± 0.2 d; P < 0.05), an increased incidence of anestrus (16.7 vs. 3.6%; P > 0.1) and a reduction in pregnancy rates (69.7 vs. 81.6%; P > 0.1). Interactions were noted between lactation feeding level and GnRH injection (P < 0.05) and between parity and GnRH injection (P < 0.05) for number of viable embryos. The data obtained suggest that both low level of feeding during lactation and a young age are associated with decreased embryo numbers, but this situation is alleviated by the administration of GnRH. Key words: Sows, feed intake, estrus, GnRH


2020 ◽  
Vol 382 ◽  
pp. 112497 ◽  
Author(s):  
Ila Mishra ◽  
Twinkle Batra ◽  
Abhilash Prabhat ◽  
Neha Agarwal ◽  
Sanjay Kumar Bhardwaj ◽  
...  

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