Physiological impact on fertility in cattle, with special emphasis on assessment of the reproductive function by progesterone assay

Karg, H.

doi:10.1016/0301-6226(81)90004-x

Cited by 27 publications

(13 citation statements)

References 22 publications

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“…Concentrations fluctuate over the next few days but remain in excess of 6 nmol/ in plasma, until about 48 hours before the next oestrus. A precipitous decrease to the typical oestrus level then occurs 14,19,20 . There is a high correlation between blood and milk progesterone concentrations (MPC) throughout the bovine oestrous cycle, with the milk concentration being consistently higher than in plasma 10,19,27 .…”

Section: Introductionmentioning

confidence: 99%

“…Compared to natural breeding, low success rates have been achieved, with the extensive nature of beef herd management complicating oestrus observation 8,14,23 . Also, the period of standing oestrus is short and poorly defined, with cows often showing oestrus for only a few hours, very often only at night 8,14,16,23 . Oestrus detection has often been cited as a major factor limiting the widespread use of artificial breeding in beef herds.…”

Section: Introductionmentioning

confidence: 99%

“…Since the average calving rate to a given insemination is usually only 0.5 to 0.6, the earlier a cow is correctly observed in oestrus and inseminated the easier it is to achieve the target 365-day inter-calving period 21 . Major difficulties may exist in oestrus detection, with at least 10 % and possibly up to 36 % of cows in problem herds failing to conceive because of insemination at the wrong time due to faulty observation 3,10,13,14,16,19 . Artificial insemination is widely practised in dairy cattle.…”

Section: Introductionmentioning

confidence: 99%

“…The key period of the reproductive cycle that determines overall reproductive efficiency is the calving to conception interval. The length of this interval is influenced by the post partum onset of oestrous cycles and oestrus detection efficiency 5,7,14,15,17,21,24 . Accuracy of oestrus detection is commonly defined as the percentage of oestrus events observed that are true oestrus.…”

Section: Introductionmentioning

confidence: 99%

“…There is a high correlation between blood and milk progesterone concentrations (MPC) throughout the bovine oestrous cycle, with the milk concentration being consistently higher than in plasma 10,19,27 . Measurement of either blood, skim milk, whole milk or milk fat progesterone concentrations can be used to confirm or monitor post partum ovarian activity and oestrus, as well as pregnancy diagnosis, early embryonic mortality and ovarian pathology 3,4,9,11,[13][14][15][16][19][20][21]23,25,27 . In cattle, MPC has been used in various ways to evaluate oestrus detection.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of oestrus observation and conception rates in suckling beef cows using whole milk progesterone concentration

Lourens¹,

Thompson²,

Bertschinger³

et al. 2002

J. S. Afr. Vet. Assoc.

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A 2-sample regime was used to measure whole milk progesterone concentration on the day of oestrus and insemination (Day 0) and 6 days later (Day 6) in a sample of 50 primiparous and 100 multiparous suckling beef cows. Exposure to teaser bulls and observation by cattlemen identified the occurrence of oestrus. Three sets of criteria used to define ovulatory oestrus were compared : a) milk progesterone concentration less than 6 nmol / l on Day 0 ; b) milk progesterone less than 6 nmol / l on Day 0 and rising to greater than 6 nmol / l on Day 6; c) milk progesterone less than 6 nmol / l on Day 0 and rising to greater than 6 nmol / l on Day 6, or cow diagnosed pregnant to 1st insemination. Using only a single milk sample on Day 0 (criterion a) would have resulted in the positive predictive value of heat detection being estimated at 98.7%. Using a paired measurement (criterion b) resulted in a significantly lower estimate of 84.7%. The inclusion of cows that conceived despite not showing a marked rise in milk progesterone concentration (criterion c) resulted in a more accurate estimate of 89.3%. Use of a 2-sample regime also allowed calculation of conception rates while eliminating the effect of heat detection errors. In the cows sampled, of those in ovulatory oestrus that were inseminated, 73.1% conceived to the 1st insemination. These results demonstrate that artificial insemination within a limited breeding season can be successful if nutrition is optimal and management is intensive. The use of a 2-sample milk progesterone test may be a valuable tool in investigating heat detection and conception problems in beef herds in which artificial insemination is used

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Section: Introductionmentioning

confidence: 99%