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Results for “Estrus Synchronization”

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At least 1,135 records · Page 63Linked to original sources
PubMed1978

Heat and conception rate after synchronisation of oestrus with cloprostenol.

The intensity of induced oestrus in heifers on high and low nutritional planes was graded according to the degree of uterine contraction and cervical relaxation and the volume of oestrous mucus, and correlated with the pregnancy rates after insemination. In the heifers on a high nutritional plane, the heat was more intensely expressed and the conception rates were greater than in the poorly fed animals. In both groups the conception rate was lower in treated heifers than in untreated controls but this difference was minimal on a high plane of nutrition.

Animals↗
PubMed1979

Fertility in buffaloes after oestrus synchronisation with cloprostenol and fixed time insemination.

Fifty-seven cycling buffalo cows of the river type were treated with two doses of 0.5 mg cloprostenol intramuscularly given 11 days apart. Each animal was inseminated twice at 72 and 96 hours after the second injection of cloprostenol. The first service conception rate diagnosed by rectal palpation at 90 days was 38.6 per cent. At the time of insemination the cervix was easily penetrable on both days in only 39 (68.4 per cent) of the animals. They were inseminated at or beyond the internal cervical os, while the others were inseminated in the cervical canal. There was a marked difference in conception rate between those receiving deep inseminations (48.7 per cent) and the others (16.7 per cent). In relation to the interval from calving to insemination the conception rates for those which had calved 60 to 90, 90 to 120 and 120 to 150 days earlier were 16.6, 36.4 and 55.5 per cent respectively. The use of cloprostenol treatment and fixed-time insemination is a useful method of overcoming the problem of oestrus detection in buffaloes. Acceptable levels of fertility can be obtained in those animals which have a sufficiently relaxed cervix to permit semen deposition at the internal os, provided the interval from calving to insemination is more than 90 days.

Animals↗
PubMed1979

Plasma progesterone and luteinising hormone levels in cattle after synchronisation of oestrus with dinoprost.

The plasma levels of progesterone and luteinising hormone (LH) were monitored in a group of cattle after pretreatment with two injections of 25 mg dinoprost. Close groupings of preovulatory LH peaks were observed and the possible significance of this is discussed. Based on the findings of this study, supporting evidence is provided for the timing of insemination after injection of cattle which have been synchronised for oestrus with dinoprost.

Animals↗
PubMed1980

Effect of gonadotrophin releasing hormone on levels of luteinising hormone in cattle synchronised with dinoprost.

Synchronisation of oestrus was achieved in a group of three cows and two heifers with dinoprost. Sixty-six hours after the second injection of dinoprost, 0.125 mg synthetic gonadotrophin releasing hormone (GnRH) was given intramuscularly. Concentrations of luteinising hormone (LH) were monitored in peripheral blood and close grouping of preovulatory LH peaks was seen around 2.5 hours after injection of GnRH.

Animals↗
PubMed1981

Induction of twin-calving by non-surgical embryo transfer: a field trial.

Non-surgical embryo transfers were carried out on nine farms to 84 previously inseminated recipient cows. Insemination and transfers were at a fixed time after synchronisation. Forty-nine (58 pr cent) of the 84 cows calved to the fixed insemination and transfer, producing a total of 69 calves or 1.4 calves per cow calving. The twinning rate was 41 per cent in cows calving. Transferred embryo survival was high (59 per cent) in pregnant cows. Data on calf and calving performance are given.

Animals↗
PubMed1982

Effect of repeated horse anterior pituitary extract treatment on ovulatory response in the ewe.

Twenty-five oestrus synchronised ewes were subjected to superovulation treatment with horse anterior pituitary extract, and 23 of these were similarly treated between two and six months later. Seven of these 23 ewes were treated a third time, approximately four months after the second treatment. Ovulatory response was low after the second treatment within two months, but it was satisfactory if a longer period of time was allowed to elapse. Recovery rates of eggs decreased with successive treatments, but fertilisation rates were high. Results of the present experiment demonstrate that ewes can be successfully superovulated three times within a six month period; if a period greater than two months is allowed between successive treatments, high ovulatory responses can be obtained.

Animals↗
PubMed1984

Tail painting technique as an aid to oestrus detection in cattle.

The value of heat detection by tail painting was assessed by simultaneous visual observation and regular plasma progesterone assay in grazing animals; 88.1 per cent of all heats were accompanied by a positive tail paint record and 30.1 per cent of positive tail paint records occurred in dioestrous animals. Conception rates to the first insemination were 57.6 per cent and 57.9 per cent for heifers and cows, respectively. Of seven animals which showed behavioural oestrus but had intact tail paint, three conceived following insemination. These results suggest that tail paint may be a useful aid in heat detection.

Animals↗
PubMed1984

Plasma progesterone and gonadotrophin concentrations following norgestomet treatment with and without cloprostenol in beef cows.

Twelve Hereford cross Friesian cows received subcutaneous implants containing 6 mg norgestomet and intramuscular injections of 5 mg oestradiol valerate and 3 mg norgestomet. Six of the cows also received 0.5 mg cloprostenol eight days later and all implants were removed on day 9. When treatment was commenced between days 3 and 5 of the ovarian cycle, luteal function was not prevented although the luteal phase was shortened in some cases. When treatment was commenced between days 8 and 14 of the cycle progesterone concentrations remained above basal levels for five to seven days. Cows with corpora lutea that were given cloprostenol underwent rapid luteolysis. It is concluded that oestradiol valerate does not control luteal function adequately, particularly if administered early in the cycle, and this may explain failure of oestrus synchronisation in some cases. Administration of prostaglandin 24 hours before norgestomet implant removal may improve the degree of oestrus synchronisation in groups of cyclic cows.

Animals↗
PubMed1985

Embryo transfer in sheep under practice conditions.

Embryo transfer was carried out on nine Texel donor ewes, one of them on two occasions, over two breeding seasons (1980 and 1981). The donors were prepared for superovulation on the farm by two different regimens and the recipients were also synchronised on the farm of origin. Surgery was carried out on donors and recipients at a veterinary practice and the techniques of anaesthesia, surgery and embryo transfer are described. Superovulation was variable and more than two ovulations were seen in only four of the 10 ewes. Forty-one corpora lutea were produced by the 10 ewes and 27 embryos were recovered. Twenty-one embryos were transferred to recipients and 14 lambs were produced. All the 10 donors except one produced lambs themselves. The value, economics and welfare aspects of the technique of embryo transfer under practice conditions are discussed and it is concluded that the procedure should not be carried out routinely but reserved for special circumstances.

Animals↗
PubMed1985

Matching of embryo stages and grades with recipient oestrous synchrony in bovine embryo transfer.

The efficacy of matching embryos with recipients on the basis of embryo stage and grade and donor-recipient oestrous synchrony was investigated using the records of 13,663 embryos that were collected and transferred at a commercial embryo transfer centre. The selection of early blastocysts for exact oestrous synchrony cows was effective and resulted in the highest pregnancy rates. Selection of early morulae was effective for recipients in oestrus after the donor but not when transferred into exact and negative recipients. The matching of late morulae with recipients in oestrus after the donor was not effective and had no influence on pregnancy rates. The selection of late, hatched and collapsed blastocysts for transfer into recipients in oestrus before the donor was ineffective and pregnancy rates were higher in exact and +12 hour recipients. Pregnancy rates declined 23.6 per cent in quality grades 1 to 4 whereas the range between stages was 13.3 per cent. Higher quality embryos of all stages gave the highest pregnancy rates. Examination of pregnancy rates of grades within stages suggested that the more developed the embryo the more difficult it is to grade. The difference in pregnancy rates between exact and -24 (6.9 per cent) and +24 (4.8 per cent) hour recipients was small and declined a further 4.7 per cent and 9.8 per cent in -36 and +36 hour recipients. Grade 3 and 4 embryos tolerated asynchrony better than grade 1 and 2, and early morulae tolerated asynchrony better than the other stages. It was concluded that the matching of certain embryo stages with the donor-recipient oestrous synchrony is advantageous but not always possible.

Animals↗