Effects of shearing at housing, grass silage feed value and extended grazing herbage allowance on ewe and subsequent lamb performance

Keady, T.W.J.; Hanrahan, J. P.

doi:10.1017/s1751731108003303

Cited by 21 publications

(26 citation statements)

References 28 publications

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“…The results of this study add to the growing body of evidence that links mid-pregnancy shearing with increases in lamb birth weight (Keady and Hanrahan, 2009). The birth weight response from shearing observed in this study allows the role of chronic stress, as a potential mechanism for the birth weight response, to be tested.…”

Section: Discussionsupporting

confidence: 62%

The effect of different types of stressors during mid- and late pregnancy on lamb weight and body size at birth

Corner

Kenyon

Stafford

et al. 2010

Animal

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Mid-pregnancy shearing has consistently been shown to increase lamb birth weight, which can lead to an increase in lamb survival rates. However, shearing ewes during the winter months and under outdoor pastoral farming conditions can expose the recently shorn ewe to a greater risk of hypothermia. The aim of this study was to determine if exposure of ewes to repeated stressors, in mid-and late pregnancy, would result in an increase in lamb birth weight. This information may assist in the elucidation of the mechanism for the birth weight response to mid-pregnancy shearing, which in turn could assist in the design of management options to increase lamb birth weight without placing the ewe at risk. One hundred and forty-four twin-bearing Romney ewes were allocated to one of six mid-pregnancy treatments: control, isolation on 2 or 10 occasions, sham-shearing on 10 occasions, intramuscular cortisol injection on 10 occasions or shearing. Isolation, sham-shearing and cortisol treatments were conducted twice a week beginning, on average, day 74 of pregnancy and shearing occurred on day 76. During pregnancy, ewe treatment had no effect on ewe live weight. However, average ewe body condition scores were higher in the shorn group than in the sham-shorn or cortisol groups ( P , 0.05). Intramuscular injections of cortisol had a greater effect on ewe plasma cortisol concentrations than all other treatments ( P , 0.05). Shearing produced a greater plasma cortisol response than isolation 3 10 and sham-shearing ( P , 0.05). Ewe plasma cortisol responses decreased during the 5 weeks of isolation and sham-shearing but cortisol injections produced a greater response during the fifth treatment than the first or ninth treatments ( P , 0.05). Lambs born to shorn ewes were heavier and had a longer crown rump, forelimb and hind limb lengths than all other lambs ( P , 0.05). In addition, lambs born to ewes in the cortisol treatment were lighter than lambs born to control, isolation 3 2, isolation 3 10 and shorn ewes ( P , 0.05). The plasma cortisol concentrations observed for ewes injected with cortisol were far greater than those observed in all other groups, which is likely to explain the low birth weights of lambs born to ewes in that group. These results indicate that the mechanism by which mid-pregnancy shearing increases lamb birth weight is unlikely to be repeated stressors.

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Section: Discussionsupporting

confidence: 62%

The effect of different types of stressors during mid- and late pregnancy on lamb weight and body size at birth

Corner

Kenyon

Stafford

et al. 2010

Animal

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“…Shearing pregnant ewes has consistently been reported to increase lamb birthweight, particularly if conducted during early to mid-gestation ( Figure S3). Associated with this response are increases in maternal feed intake, gestation length and maternal plasma glucose concentrations (Symonds et al 1988;Morris et al 2000;Keady and Hanrahan 2009;Banchero et al 2010). Although shearing is associated with a robust stress response in the ewe, these data suggest that its primary effect on birthweight is through increased feed intake, and hence nutrition of the developing lamb.…”

Section: Animal Behaviour and Welfarementioning

confidence: 94%

Epigenetics and developmental programming of welfare and production traits in farm animals

Sinclair

Rutherford

Wallace

et al. 2016

Reprod. Fertil. Dev.

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Abstract. The concept that postnatal health and development can be influenced by events that occur in utero originated from epidemiological studies in humans supported by numerous mechanistic (including epigenetic) studies in a variety of model species. Referred to as the 'developmental origins of health and disease' or 'DOHaD' hypothesis, the primary focus of large-animal studies until quite recently had been biomedical. Attention has since turned towards traits of commercial importance in farm animals. Herein we review the evidence that prenatal risk factors, including suboptimal parental nutrition, gestational stress, exposure to environmental chemicals and advanced breeding technologies, can determine traits such as postnatal growth, feed efficiency, milk yield, carcass composition, animal welfare and reproductive potential. We consider the role of epigenetic and cytoplasmic mechanisms of inheritance, and discuss implications for livestock production and future research endeavours. We conclude that although the concept is proven for several traits, issues relating to effect size, and hence commercial importance, remain. Studies have also invariably been conducted under controlled experimental conditions, frequently assessing single risk factors, thereby limiting their translational value for livestock production. We propose concerted international research efforts that consider multiple, concurrent stressors to better represent effects of contemporary animal production systems.

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“…, 2007) or throughout (Keady et al. , 2007; Keady and Hanrahan, 2009a) pregnancy increased lamb birth and weaning weights relative to progeny from ewes that were housed unshorn. Furthermore, extended grazing, while reducing financial margins per hectare because of reduced stock‐carrying capacity (Keady and Hanrahan, 2007a), reduced fixed costs because of absence of requirements for ewe housing and storage facilities for conserved forage.…”

Section: Introductionmentioning

confidence: 99%

“…Herbage yield and allowance, and concentrate supplementation, are the major factors that determine stock‐carrying capacity during extended grazing. While the impact of AEGH to ewes during mid and late pregnancy on ewe and subsequent lamb performance have been evaluated in previous studies (Keady and Hanrahan, 2009a,b,c), there is a paucity of data on the effects of herbage allowance on the performance of ewe lambs.…”

Section: Introductionmentioning

confidence: 99%

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The effects of allowance of deferred herbage and concentrate supplementation when offered to ewe lambs, and system of allocation when offered to ewes in late gestation, on animal performance

Keady

Hanrahan

2010

Grass and Forage Science

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The effects of allowance of extended (deferred) grazed herbage (AEGH) and herbage allocation management (HAM) were studied in ewe lambs (248) and late-gestation ewes (152), respectively, on commercial farms in south-east Ireland in 2005-06. In Experiment 1, which consisted of four treatments, the effects of AEGH (0AE75, 1AE25 and 1AE75 kg DM per head daily) and concentrate supplementation (0AE5 kg per head daily with the 0AE75 kg DM herbage allowance) on lamb performance during the extended grazing (16 December to 3 March) and subsequent grazing (4 March to 11 August) seasons were evaluated. Increasing AEGH increased herbage intake linearly (P < 0AE001) and live weight (P < 0AE001) at the end of extended grazing and the subsequent grazing season. In Experiment 2, single-and twinbearing ewes were allocated to either a conventional (single-and twin-bearing ewes grazed separately) or leader-follower system (twin-and single-bearing ewes, as leaders and followers respectively) of HAM from 30 January to 24 March. The same quantities of herbage were offered daily for each system. System of HAM affected ewe condition score at lambing but did not alter (P > 0AE05) subsequent lamb birth or weaning weights. It is concluded that increasing AEGH to ewe lambs increased liveweight gain during extended grazing and resulted in heavier animals in mid August of the subsequent grazing season. For ewe lambs each 1 kg concentrate DM had the same feed value as 2AE4 kg DM AEGH. Use of a leader-follower system for ewes in late pregnancy did not alter lamb birth weight or subsequent performance.

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Effects of shearing at housing, grass silage feed value and extended grazing herbage allowance on ewe and subsequent lamb performance

Cited by 21 publications

References 28 publications

The effect of different types of stressors during mid- and late pregnancy on lamb weight and body size at birth

The effect of different types of stressors during mid- and late pregnancy on lamb weight and body size at birth

Epigenetics and developmental programming of welfare and production traits in farm animals

The effects of allowance of deferred herbage and concentrate supplementation when offered to ewe lambs, and system of allocation when offered to ewes in late gestation, on animal performance

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