The effect of mid-pregnancy shearing or yarding stress on ewe post-natal behaviour and the birth weight and post-natal behaviour of their lambs

Corner, R.A.; Kenyon, P. R.; Stafford, Jackeline; West, D.M.; Oliver, Mark

doi:10.1016/j.livprodsci.2005.12.001

Cited by 25 publications

(21 citation statements)

References 29 publications

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“…However, it is important to first exclude other potential mechanisms. Gestation length, as reported in previous studies Corner et al, 2006), did not differ between ewe groups. Means within columns with different superscripts are significantly different (P , 0.05).…”

Section: Discussionsupporting

confidence: 80%

“…A single exposure to stressors that are commonly associated with shearing, for example, handling, fasting, crutching and sham-shearing, has been shown not to induce an increase in birth weight (Corner et al, 2006 and2007a). Similarly, in this study, repeated sham-shearing and isolation failed to increase lamb birth weights.…”

Section: Discussionsupporting

confidence: 47%

“…Mid-pregnancy shearing in winter and under outdoor pastoral grazing systems results in an increase in the birth weight of both singleton (Morris et al, 2000;Sherlock et al, 2003;Corner et al, 2006 and2007b) and multiple-born lambs (Morris and McCutcheon, 1997;Smeaton et al, 2000;Kenyon et al, 2004;Corner et al, 2006 and2007a) and has been shown to increase lamb survival rates (Morris et al, 1999;Kenyon et al, 2006). The birth weight response to mid-pregnancy shearing has also been observed in winterhoused ewes (Dyrmundsson 1991, Cam andKuran, 2004) and summer-shorn, autumn-lambing ewes grazed on pasture (de Nicolo et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Repeated stressors result in elevated maternal stress hormones such as cortisol (Niezgoda et al, 1987;Coppringer et al, 1991;Roussel et al, 2004). Similarly, shearing of pregnant ewes increases cortisol concentrations (Corner et al, 2006). This increase in maternal cortisol may increase ewe metabolism by stimulating gluconeogenesis and increasing glycogen in the liver, which in turn can increase circulating glucose concentrations (Cunningham, 2002).…”

Section: Introductionmentioning

confidence: 99%

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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: 80%

Section: Discussionsupporting

confidence: 47%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…An increase in the birth weight of light-weight lambs has the potential to increase survival rates to weaning (Morris et al, 1999). Mid-pregnancy shearing has consistently increased lamb birth weights (Morris and McCutcheon, 1997;Morris et al, 2000;Smeaton et al, 2000;Kenyon et al, 2002a,b,c;Revell et al, 2002;Kenyon et al, 2004;Corner et al, 2006). However, in New Zealand, mid-pregnancy shearing takes place in the winter when conditions can be cold, wet and windy and may result in hypothermia (Morris et al, 1962) with ewe mortality rates of 3-14% (Dabiri et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

The effect of mid-pregnancy stressors on twin-lamb live weight and body dimensions at birth

et al. 2007

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Reproductive management (including impacts of prenatal stress on offspring development)

Dwyer

2017

Advances in Sheep Welfare

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The effect of mid-pregnancy shearing or yarding stress on ewe post-natal behaviour and the birth weight and post-natal behaviour of their lambs

Cited by 25 publications

References 29 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

The effect of mid-pregnancy stressors on twin-lamb live weight and body dimensions at birth

Reproductive management (including impacts of prenatal stress on offspring development)

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