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Results for “Estrus Synchronization”

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At least 1,297 records · Page 72Linked to original sources
PubMed1987

[The sexual cycle in the bitch: recent insights and impact on therapy and reproduction control].

Present knowledge about the estrous cycle of the bitch has been reviewed from a morphological, endocrinological and clinical point of view. This cycle is truly biphasic, characterized by its slow motion. It includes pregnancy or pseudopregnancy, and lactation. Corpus luteum function and regression as well as endometrial recovery, following endometrial desquamation at about day 100 of the cycle, are finalized at about days 140 to 150. Soon thereafter, subclinical preparations for the next proestrus can be recognized. Prolactin seems to play an important role as a luteotrophic agent, beginning at about day 30 to 35 of the cycle. Inhibition of prolactin secretion can be used to induce abortion, or to inhibit lactation and to shorten the cycle, or to treat clinical anestrus. Late metestrus and subclinical proestrus, i.e. days 120 to 170 of the cycle, is the most suitable period of the cycle to initiate suppression of the cycle, i.e. prevention of the next estrus, by using progestins with the least tendency for side effects.

Animals↗
PubMed1985

[Outlook for the programmed insemination of sheep in the anestrual season].

Studied were certain methods for programming the estrus and fixing the optimal term for the insemination of sheep. A record was kept of the changes taking place in the genital apparatus in various periods of time following the use of hormonal preparations during the anestral period. The fertility of sheep was also taken into consideration both after the first treatment with serum gonadotropin and after the two-fold programmed insemination at a 16-day interval with regard to the total fertility. It was shown that the optimal time for programmed insemination of sheep was between the 36th and the 56th hour after the three-fold injection with Prolosan at 12-hour intervals so far as periods other than the breeding season were concerned. Fertility at two-fold injection rated at 121 per cent, and conception--at 78.2 per cent.

Anestrus↗
PubMed1977

Influence of a progestogen on the cytophysiologic character of the bovine adenohypophysis.

The objective in the present experiment was to study the effects of melengestrol acetate (0.5 mg for 14 days starting at day 15 of the estrous cycle) on the cytophysiologic character of the bovine adenohypophysis. Twelve Hereford and Angus heifers were used. A combination of thick-thin sectioning of resin-embedded material was used to aid in specific identification of individual hypophyseal cells. Alterations were not observed in the cytophysiologic activity of the presumptive prolactin-, somatotropin-, thyrotropin- or corticotropin-secreting cells. A marked increase in chromophobes was observed in animals given melengestrol acetate. Evidence indicated that these chromophobes originated from gonadotropin-secreting cells.

Animals↗
PubMed1977

Adrenocortical involution in rats during oestrus synchronisation with medroxyprogesterone.

Daily treatment of female rats with medroxyprogesterone acetate in aqueous suspension resulted in adrenocortical atrophy. The doses given were those used for oestrus synchronisation. Intramuscular injections of 2-0 mg medroxyprogesterone acetate were used to investigate the atrophic process. Adrenocortical involution was associated with extensive single cell deletion (apoptosis). It is suggested that theses changes were due to suppression of pituitary ACTH secretion. The cytological changes support the concept that single cell death plays an important role in organ remodelling. Biochemical determinations of DNA, RNA, protein and dry matter, and histological examination, did not reveal significant changes in the liver.

Adrenal Cortex↗
PubMed1977

Synchronisation of oestrus in buffaloes (Bubalus bubalis) using prostaglandin F2alpha.

Prostaglandin F2alpha (PGF2alpha) was used intramuscularly in two preliminary trials to determine its effect in cycling buffalo cows. In the first trial, animals with corpora lutea in their ovaries responded to either two doses of 15 mg on two consecutive days, or to a single dose of 30 mg, by showing signs of oestrus commencing 31 to 55h after the initial injection. In the second trial two doses of 30 mg PGF2alpha given 11 days apart resulted in oestrus on the third day after the second injection.

Animals↗
PubMed1977

[The effect of Suisynchron on the glucose tolerance and the plasma insulin in bitches].

Suisynchron, a derivative of bisthio-urea commonly used for oestric synchronisation, was applied to nine female Alsatians over 21 days. All animals received intravenous glucose injections before ten, and 21 days from the beginning of treatment as well as 21, and 84 days after the end of treatment. The glucose-stimulated plasma insulin levels were significantly reduced during Suisynchron treatment and 21 days after the end of treatment. Both glucose tolerance and response of free fatty acids remained unaffected. This phenomenon might be attributable to a stimulated hepatic insulin degradation, to a biguanid-like effect on "peripheral" glucose turnover, or to an inhibited secretion of hormonal insulin antagonists of the anterior lobe of the pituitary gland. However, the long persistence of the Suisynchron action after interruption of treatment, could not be explained by any of these effects.

Animals↗
PubMed1977

[Conclusions on the use of Suisychron in the USSR].

Suisynchron was applied to 2,258 gilts, including 850 from breeding farms. Forty-four pigs were checked to elucidate the influence of sexual maturity on the success of oestrus synchronisation. Suisynchron-Prämix was fed to the animals over 20 days, the daily dose for each pig having been 5 g. Twenty-four hours were allowed to elapse from the last administration before 1,500 I.U. PMSG were injected. Synchronised oestrus occurred in 81.2 per cent of all pigs between four and six days from serum injection. Fertilisation in response to first insemination was recorded from 72.9 percent of the pigs, their fertility rate being 9.7 piglets from each farrowing sow. The results of oestrus synchronisation obtained from fattening pigs were somewhat inferior to those recorded from pigs of breeding units. Suisynchron and serum of pregnant mares can synchronise oestrus in 91 per cent of all mateable sows with no previous cycle. The fertility rates recorded from such pigs did not exceed 59 per cent or were between 28.9 and 31.9 per cent lower than those recordable from pigs with a cycle history prior to the use of Suisynchron.

Animals↗
PubMed1977

[Studies of the high toxicity of zinc-metallibur].

The high toxicity of Zine-Metallibur was tested in gilts aged eight months and weighing between 78 and 96 kg. Zinc-Metallibur, either 1 g/kg live weight or a quantity 1,000 times that used for synchronisation, was admixed to feed rations and introduced directly into the stomach through and intra-oesophageal tube. Fodder with the entire dose admixed is rejected by the pig. Direct intragastric administration of the same amount, however, is possible and does not cause death.

Animals↗