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At least 667 records · Page 37Linked to original sources
PubMed1984

Evaluation of fluctuations in milk yield and parlour behaviour as indicators of oestrus in dairy cows.

A herd of 73 dairy cows was observed at pasture and during parlour milking for three weeks during the breeding season. Thirty-nine cows were seen in oestrus, which occurred either naturally or following prostaglandin induction. Readiness to enter the parlour, restlessness and elimination in the parlour were not found to be significantly affected by oestrus. However, cows in oestrus were more likely to be two or more batches away from their normally preferred parlour entry batch, and were more often early than late. Much more reliably indicative of oestrus, however, were large fluctuations in milk yield. Many cows showed a suppression at oestrus onset, with a rebound enhancement at the next milking. If a cow produced less than 75 per cent of its usual yield, there was a 50 per cent chance that it was in oestrus, and the rare occasions on which it gave 25 per cent more milk than normal only occurred during oestrus. Of seven cows induced but giving no behavioural indication of oestrus, six showed fluctuations in yield of this magnitude during the two days in which oestrus was expected.

Animals↗
PubMed1984

Relationship between oestrous behaviour and frequency of visits made by dairy cows to out-of-parlour concentrate dispensers.

Sixty-five oestruses in 38 cows were confirmed either by using progesterone concentration determined in milk or by conception to a service on the same day. The cows were fed concentrates through variable-time out-of-parlour dispensers and the number of visits made by each cow to the dispensers was automatically recorded daily and a 10-day running mean calculated. A significant increase or decrease in visits was recorded when the number of visits on one day differed from the mean number of visits during the previous 10 days by at least two standard deviations. Ninety-three increases and 40 decreases in visits occurred within +/- 10 days of the 65 confirmed oestruses. There were significantly more (16) than the expected number of increases on the day before oestrus (P less than 0.001) but at no other time. Recording increased visits to out-of-parlour concentrate dispensers may help to identify oestrus in dairy cows.

Animals↗
PubMed1987

Comparison of radioimmunoassay and enzyme-linked immunoassay for the measurement of progestogen in equine plasma and milk.

Milk and plasma samples were obtained every 48 hours from eight pony mares for 40 days after foaling. Progestogen concentrations in milk and plasma were measured using an enzyme-linked immunoassay (ELISA) and compared with radioimmunoassay of the plasma. In general the three assays showed similar trends in progestogen concentration changes but absolute values varied considerably. Difficulty could occur in interpreting the results from single samples taken at times when progestogen concentrations were either rising (ie, after ovulation) or falling. ELISA could be used on plasma obtained by allowing the erythrocytes to settle for 30 minutes at room temperature or for two days at 4 degrees C.

Animals↗
PubMed1989

Oestrus during pregnancy in the cow.

Forty-three oestruses were observed in 35 pregnant cows in one beef suckler herd and 17 dairy herds; at each oestrus the pregnant cow stood willingly to be mounted by another cow or bull. Such oestruses were observed at all stages of pregnancy, although more often between 121 and 240 days, occurred more than once per pregnancy and were also seen in successive pregnancies. On one farm where the dairy cows were observed for four 30 minute periods daily, oestrus was recorded in 5.7 per cent of pregnant cows. The behavioural signs associated with oestrus during pregnancy were indistinguishable from those of true oestrus in non-pregnant animals and although its duration was shorter (mean 5.6 hours), its intensity was comparable to that of the true oestrus. Pregnant cows showing oestrus were usually seen interacting with other oestrous cows in the sexually active group. Pregnant cows showing oestrus had a higher mean condition score (3.9 +/- 0.64) than control pregnant cows (3.0 +/- 0.36). Physiological changes in the genital tract normally associated with true oestrus were not observed in pregnant cows showing oestrus. There was no ovulation or metoestrous bleeding. The characteristics of cervical mucus, including ferning patterns, were similar to those of pregnant cows at the same stage of pregnancy. Hormonal changes associated with oestrus in non-pregnant cows were not observed in the pregnant cows exhibiting oestrus. Seven of nine pregnant cows at oestrus stood willingly to be mounted by a bull. On seven occasions, bulls exposed only to cervical mucus from pregnant cows showing oestrus did not display flehmen.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Piglets born after transcervical transfer of embryos into recipient gilts.

A method is described for the non-surgical transfer of embryos in pigs. Embryos at the 8-cell to the hatched blastocyst stage, recovered on days 4 to 7 of the oestrous cycle by flushing the oviducts and uteri of superovulated donors, were transferred transcervically into the uterine body of anaesthetised recipient gilts using a sterile disposable plastic spiral catheter and an embryo transfer cannula. Fifty-eight non-surgical transfers have been performed and six pregnancies were established. Eight and three normal fetuses were recovered from two recipients slaughtered between 35 and 45 days after embryo transfer. Three recipients came to term and gave birth to litters of two, six and seven living piglets. One recipient aborted between 45 and 60 days of gestation.

Animals↗
PubMed1995

Serum prolactin concentration in pseudopregnant and normally reproducing goats.

Previous experiments with bromocriptine suggested that prolactin plays a role in the aetiology of pseudopregnancy in goats. Serum prolactin concentration was measured in a herd of white Dutch dairy (Saanen) goats when hydrometra (a typical characteristic of pseudopregnancy) was diagnosed by ultrasound, during the spontaneous development of pseudopregnancy, and in normally reproducing goats during the breeding season. In the normally reproducing does the prolactin concentration decreased at the beginning of the breeding season. In 12 of 14 pseudopregnant goats the prolactin concentration was within the range observed in the normally reproducing goats on the day that hydrometra was diagnosed. In two goats the prolactin concentration was low during the first few weeks of pseudopregnancy and in a third it fluctuated. There was no correlation found between the concentration of prolactin and the development or the presence of a persistent corpus luteum. These results suggest that prolactin does not play a crucial role in the aetiology of pseudopregnancy in the goat.

Anestrus↗