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

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

doi:10.1016/j.livsci.2006.09.007

Cited by 3 publications

(6 citation statements)

References 22 publications

(28 reference statements)

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“…The dose administered in this study was based on the study of Jobe et al (2003), which observed that hydrocortisone administration on day 124 of pregnancy did Effect of pregnancy stressors on the lamb not alter foetal weight on day P131. The rise in plasma cortisol reported by Jobe et al (2003) was similar to the rise in plasma cortisol observed in response to mid-pregnancy shearing (Corner et al, 2007a). However, in this study, the cortisol response observed in the cortisol-administered ewes was far greater than that observed in mid-pregnancy shorn ewes.…”

Section: Discussionsupporting

confidence: 79%

“…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%

“…The absence of an increase in birth weight in response to the isolation, sham-shearing and cortisol suggests that repeated stress was not the mechanism for the increase in lamb birth weight resulting from midpregnancy shearing. This observation is further supported by reported plasma cortisol responses to shearing, which show that cortisol returns to baseline concentrations within 60 min of shearing (Hargreaves and Hutson, 1990;Corner et al, 2007a) or 3 days after shearing when sheep were kept at 28C to 138C (Pierzchala et al, 1983). Therefore, it appears that the repeated stressors employed did not adequately simulate the physiological changes associated with shearing.…”

Section: Discussionmentioning

confidence: 82%

“…The dose rate of cortisol was selected based on the report of Jobe et al (2003), which showed that the in vivo cortisol response to a dose of 6 mg/kg produced a plasma cortisol response that was similar to that observed in response to mid-pregnancy shearing (Corner et al, 2007a).…”

Section: Methodsmentioning

confidence: 99%

“…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%

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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: 79%

Section: Discussionsupporting

confidence: 47%

Section: Discussionmentioning

confidence: 82%

Section: Methodsmentioning

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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Natural variation in gestational cortisol is associated with patterns of growth in marmoset monkeys (Callithrix geoffroyi)

Mustoe

Birnie

Korgan

et al. 2012

General and Comparative Endocrinology

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High levels of prenatal cortisol have been previously reported to retard fetal growth. Although cortisol plays a pivotal role in prenatal maturation, heightened exposure to cortisol can result in lower body weights at birth, which have been shown to be associated with adult diseases like hypertension and cardiovascular disease. This study examines the relationship between natural variation in gestational cortisol and fetal and postnatal growth in marmoset monkeys. Urinary samples obtained during the mother’s gestation were analyzed for cortisol. Marmoset body mass index (BMI) was measured from birth through 540 days in 30- or 60-day intervals. Multi-level modeling was used to test if marmoset growth over time was predicted by changes in gestational cortisol controlling for time, sex, litter, and litter size. The results show that offspring exposed to intra-uterine environments with elevated levels of cortisol had lower linear BMI rates of change shortly after birth than did offspring exposed to lower levels of cortisol, but exhibited a higher curvilinear growth rate during adolescence. Average daily change in gestational cortisol during the first trimester had a stronger relationship with postnatal growth than change during the third trimester. Higher exposure to cortisol during gestation does alter developmental trajectories, however there appears to be a catch-up period during later post-natal growth. These observations contribute to a larger discussion about the relationship of maternal glucocorticoids on offspring development and the possibility of an earlier vulnerable developmental window.

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Implications of intensification of pastoral animal production on animal welfare

Stafford¹,

2008

New Zealand Veterinary Journal

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The intensification of pastoral animal production results from several major developments including increased forage production and utilisation, diet supplementation, breeding animals to increase milk, meat or wool production, and changes in management. The impact of increased intensification on welfare will differ across species and systems. More intensive-grazing systems and the feeding of novel forages will underpin all moves to intensification. More intensive grazing generally reduces opportunities for shade and shelter. Improved nutrition will generally benefit welfare but competition for available feed may cause increased social pressure. Increased flock and herd size will be associated with a reduction in the human:animal ratio and less time to observe individual animals. Remote monitoring of activity and health might counter this impact. Intensification of dairy production will result in larger herds, more year-round milking, robotic milking, use of housing and yards year round, and total mixed-ration feeding. Larger herds mean longer distances to walk to and from the dairy shed, and more lameness and less time to spend on self-maintenance activities such as grooming. Holding and feeding dairy cows on yards will cause an increase in lameness and mastitis and perhaps an increase in agonistic behaviour but will reduce time spent walking. Intensification of sheep production will involve increased flock size, increased fecundity, breeding from hoggets, and breeding ewes all year round. Housing during lambing might be considered appropriate, as would feeding to lift milk yields. Increased fecundity with an increase in triplets will increase lamb mortality rates, but housing ewes, when managed well, will result in reduced lamb mortality. Intensification of lamb finishing will be by improved nutrition. Intensification of beef production will include more breeding of heifers at 15 months, and more problems with dystocia. Intensification of pastoral production will have positive and negative effects on animal welfare. The balance will be determined by the quality of management and stockmanship, and the pressure on businesses to be profitable.

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

Cited by 3 publications

References 22 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

Natural variation in gestational cortisol is associated with patterns of growth in marmoset monkeys (Callithrix geoffroyi)

Implications of intensification of pastoral animal production on animal welfare

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