Predicting ovulation rate from liveweight in ewes

Morley, F. H. W.; White, DH; Kenney, PA; Davis, IF

doi:10.1016/0308-521x(78)90004-5

Cited by 72 publications

(26 citation statements)

References 20 publications

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“…The linear response is consistent with Lindsay et al (1975) and Morley et al (1978). The average increase in reproductive rate was about two extra fetuses per 100 ewes per kg of liveweight, which is at the high end but consistent with previous work (Kelly and Croker 1990).…”

Section: Discussionsupporting

confidence: 78%

“…It follows that knowledge of ewe liveweight at key points during the reproductive cycle could be a useful predictor of fleece wool characteristics. In addition, both liveweight at joining and changes in liveweight before joining influence the fertility and fecundity of breeding ewes (Morley et al 1978;Kelly et al 1983; Thompson et al 1985). The nature of the relationships between wool production and reproduction with the change in liveweight of ewes throughout a breeding cycle (liveweight profile) remain largely unknown.…”

Section: Introductionmentioning

confidence: 99%

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The wool production and reproduction of Merino ewes can be predicted from changes in liveweight during pregnancy and lactation

Ferguson

Thompson

Gordon³

et al. 2011

Anim. Prod. Sci.

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Abstract. Defining the nature of the relationship between change in liveweight throughout a breeding cycle and ewe wool production and reproduction would be useful for developing management guidelines for Merino ewes. In this paper we tested the hypotheses that (1) feed on offer has variable effects on liveweight profiles of individual ewes; and (2) liveweight profiles of individual ewes can be used to predict their fleece wool production and reproductive performance. At sites in Victoria and Western Australia in 2001 and 2002, pregnant Merino ewes were exposed to 10 nutritional treatments. In each of the four experiments, ewes in average condition score 3 at artificial insemination were fed to achieve either maintenance or loss of a condition score over the first 100 days of pregnancy before grazing one of five levels of feed on offer between Day 100 and lamb weaning. Across all four experiments, the average difference in ewe liveweight between extreme treatments was: 7.0 kg (range 4.7-8.7 kg) at Day 100 of pregnancy; 11.9 kg (range 4.9-17.8 kg) at lambing; and by weaning was 13.9 kg (range 8.8-22.7 kg). Liveweight at joining and liveweight change during pregnancy and lactation of individual Merino ewes were significantly related to their clean fleece weight, fibre diameter and staple length and thus the second hypothesis was supported. Heavier ewes at joining produced more wool that was longer and broader and this effect was consistent across both sites and years. A 10-kg loss in ewe liveweight between joining and mid pregnancy, mid pregnancy and lambing or during lactation reduced clean fleece weight by 0.4-0.7 kg and fibre diameter by 0.5-1.4 um. At the Victorian site, where ewes were shorn in summer, a loss of 10 kg in liveweight between joining and Day 100 of pregnancy reduced staple strength by 5 N/ktex. As expected the influence of food on offer on changes in ewe liveweight was different between years and sites and between late pregnancy and lactation due to a complex group of pasture and animal factors. Therefore, managing changes in ewe liveweight itself rather than feed on offer will achieve more predictable outcomes. A higher liveweight at joining resulted in a predictable improvement in ewe reproductive rate and liveweight at joining was more important than the liveweight profile leading up to joining. This paper has shown that it is possible to predict the differences in wool production and reproductive rate of flocks of Merino ewes if ewe liveweight records at key times are known.

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Section: Discussionsupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

The wool production and reproduction of Merino ewes can be predicted from changes in liveweight during pregnancy and lactation

Ferguson

Thompson

Gordon³

et al. 2011

Anim. Prod. Sci.

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show abstract

“…Subsequently, a third phenomenon, the 'immediate effect', was defined by Smith & Stewart (1990) to cover increases in ovulation rate following nutritional supplements that are provided for only 4-6 days and do not lead to detectable increases in body mass. Some authors suggested that ewes in low body condition (BC) respond better to the immediate effect of nutrition, while others found a better response in heavier ewes (Morley et al 1978, Leury et al 1990). This issue is yet to be resolved and, to date, there are no reports describing the effect of BC score on the response to a 6-day period of supplementation.…”

Section: Introductionmentioning

confidence: 99%

The use of a ‘first-wave’ model to study the effect of nutrition on ovarian follicular dynamics and ovulation rate in the sheep

Viñoles

Paganoni²,

Glover³

et al. 2010

Reproduction

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We have developed an experimental model in which groups of ewes are simultaneously experiencing the first ovarian follicular wave of their oestrous cycle. We used this 'first-wave model' in a 2!2 factorial experiment (ten ewes per group) to study the effect of body condition (BC) and a short-term supplement on follicular dynamics and ovulation rate. The 'first-wave' was established by giving ewes three injections of prostaglandin (PG), 7 days apart. The 6-day supplement (lupin grain) began 2 days after the second PG injection and continued until the third. Follicles were studied by ultrasound, and blood was sampled to measure glucose and hormones. The supplement increased (P!0.01) the concentrations of glucose, insulin and leptin, decreased FSH concentrations (P!0.01) and tended to increase oestradiol concentrations (PZ0.06). The supplement tended to increase the number of 3 mm follicles (PZ0.06). Compared with low-BC ewes, high-BC ewes had more follicular waves (P!0.05), higher concentrations of insulin, leptin and IGF1 (P!0.05) and tended to have higher FSH concentrations (PZ0.09). Leptin and insulin concentrations remained high until the end of supplementation in high-BC ewes, whereas they decreased after the third day of supplementation in low-BC ewes. In conclusion, high concentrations of metabolic hormones in fat ewes are associated with the development of more follicular waves. When a supplement is superimposed on this situation, changes in glucose and metabolic hormones allow more follicles to be selected to ovulate.

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“…De acordo com Morley et al(1978), há um aumento de 2% na prolificidade a cada quilograma de peso ganho até o momento da estação de monta.…”

Section: Flushing X Condição Corporalunclassified

Fontes de energia oriundas de carboidratos e lipídios no flushing de ovelhas

Rodrigues¹,

Cruz²,

Macedo³

2016

Pubvet

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ResumoFlushing é a denominação dada à prática nutricional de suplementação às fêmeas nos períodos que precedem a estação de monta e algumas semanas após, visando à melhora nas taxas de ovulação e diminuição das perdas embrionárias. O presente trabalho teve como objetivo desenvolver uma revisão de literatura sobre as fontes de energia oriundas de carboidratos e lipídios no flushing de ovelhas, através da utilização de alimentos como o milho, polpa cítrica, caroço de algodão e grão de soja.Palavras-chave: alimentos, foliculogênese, produtividade, suplementação Sources of energy from carbohydrate and lipids in flushing of sheep AbstractFlushing is the name given to the practice of nutritional supplementation to RODRIGUES, V.J.C., CRUZ, W.F.G. e MACEDO JUNIOR, G.L. Fontes de energia oriundas de carboidratos e lipídios no flushing de ovelhas. PUBVET, Londrina, V. 6, N. 19, Ed. 206, Art. 1376, 2012 females in the periods preceding the breeding season and a few weeks, aiming at the improvement in ovulation rates and embryonic loss reduction. This study aimed to develop a literature review on the sources of energy derived from carbohydrates and lipids in the flushing of sheep, through the use of foods like corn, citrus pulp, cottonseed and soybean.

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Predicting ovulation rate from liveweight in ewes

Cited by 72 publications

References 20 publications

The wool production and reproduction of Merino ewes can be predicted from changes in liveweight during pregnancy and lactation

The wool production and reproduction of Merino ewes can be predicted from changes in liveweight during pregnancy and lactation

The use of a ‘first-wave’ model to study the effect of nutrition on ovarian follicular dynamics and ovulation rate in the sheep

Fontes de energia oriundas de carboidratos e lipídios no flushing de ovelhas

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