Parturition difficulties in sheep

Grommers, F.J.; Elving, L.; Eldik, P. van

doi:10.1016/0378-4320(85)90065-x

Cited by 30 publications

(11 citation statements)

References 12 publications

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“…In this study, the differences in the proportion of ewe dystocia caused by oversized lambs between the sire breeds was in line with their respective differences in lamb birth weight. However, this study also found a significant effect of sire breed on ewe dystocia caused by lamb malpresentation, independent of birth weight, which is in agreement with Grommers et al (1985). The slightly higher incidence of malpresentations in ewes mated to Swaledale sires could be explained by a larger litter size.…”

Section: Discussionsupporting

confidence: 86%

“…The age of ewe also had a small effect on the incidence of ewe dystocia, with younger ewes having higher risk of dystocia. This is consistent with the inexperience at lambing of young (primiparous) ewes and their disadvantage when delivering lambs that are too large for them (Woolliams et al, 1983;Grommers et al, 1985). Ewe dystocia, as expected (e.g.…”

Section: Discussionsupporting

confidence: 83%

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Effects of sire breed on ewe dystocia, lamb survival and weaned lamb output in hill sheep systems

Speijers

Carson

Dawson

et al. 2010

Animal

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A study was carried out on six hill farms, located in the main hill regions of Northern Ireland, over three breeding seasons to investigate the effect of sire breed on ewe dystocia, lamb survival and weaned lamb output. On each farm, groups of 26 to 40 purebred Scottish Blackface ewes (n 5 3174) were crossed with Blackface, Swaledale, North Country Cheviot, Lleyn and Texel sires by natural service (year 1) and artificial insemination (years 2 and 3). Each of the mating groups was initially balanced for ewe age, live weight and condition score, and a total of 15 sires of each breed were used over the 3 years. In total, 2272 ewes were recorded at lambing, producing 3451 lambs, over the 3 years. Sire breed had a significant effect (P , 0.001) on lamb birth weight with Blackface and Swaledale the lowest and Texel the highest. The proportion of ewes with dystocia was higher with Texel sires compared with Lleyn, Swaledale and Blackface sires (P , 0.05). Ewes mated to Cheviot sires had more dystocia than those mated to Blackface and Swaledale sires (P , 0.05), while ewes mated to Lleyn sire breed had more dystocia (P , 0.05) than those mated to Blackface sire breed. Most of the incidence of dystocia was attributable to increased lamb birth weight (P , 0.001), and some to litter size (P , 0.05). Swaledale, Cheviot, Lleyn and Texel sire breeds increased the incidence of malpresentations (P , 0.05). Lamb live weight at weaning was higher with Texel-and Cheviot-and Lleyn-sired lambs compared with Blackface-and Swaledale-sired lambs (P , 0.01). The level of lamb mortality at birth was not affected by sire breed. However, lamb mortality at weaning was lower for Lleyn-sired lambs compared with the other lamb genotypes (P , 0.05). These results indicate that the use of sires from larger breeds, such as Lleyn and Texel, within the Blackface ewe flocks can increase lamb output, with no apparent detrimental effects on lamb mortality or ewe survival, but increased assistance at lambing will be required.

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Section: Discussionsupporting

confidence: 86%

Section: Discussionsupporting

confidence: 83%

Effects of sire breed on ewe dystocia, lamb survival and weaned lamb output in hill sheep systems

Speijers

Carson

Dawson

et al. 2010

Animal

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“…This is the first study to report the effect of EP and MP nutrition on the incidence of dystocia. There is a well-established link between birth weight and the incidence of dystocia in ewes (Grommers et al, 1985;Dwyer et al, 1996). However, dystocia is not related simply to birth weight.…”

Section: Discussionmentioning

confidence: 99%

“…However, dystocia is not related simply to birth weight. Grommers et al (1985) identified birth presentation as the most significant factor influencing the incidence of parturition difficulty. Normal birth presentations in the current study most certainly influenced the amount of assistance required at lambing, but were not directly affected by plane of nutrition in EP.…”

Section: Discussionmentioning

confidence: 99%

Effect of plane of nutrition of 1- and 2-year-old ewes in early and mid-pregnancy on ewe reproduction and offspring performance up to weaning

Muñoz

Carson

McCoy

et al. 2009

Animal

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The objective of the present study was to determine the effect of plane of nutrition in early pregnancy (EP) and mid-pregnancy (MP), on the productive performance of 1-and 2-year-old ewes and their offspring. Over 2 successive years, between days 0 and 39 after synchronized mating (EP), 1-(n 5 117) and 2-(n 5 52) year-old ewes were allowed 60% (low, L-EP), 100% (medium, M-EP) or 200% (high, H-EP) of requirements for maintenance (M). Between days 40 and 90 (MP), 1-year-old ewes were allowed 140% (M-MP) or 200% (H-MP), while 2-year-old ewes were allowed 80% (M-MP) or 140% (H-MP) of their M requirement. After day 90, all ewes were fed to meet requirements for late pregnancy. Increasing the plane of nutrition between days 0 and 39 resulted in increases in live weight (LW) ( P , 0.001) and body condition score (BCS) ( P , 0.001) during the EP period (H-EP . M-EP . L-EP), differences that in 1-year-old ewes were sustained to lambing ( P , 0.05). On day 42 of gestation H-EP ewes had lower plasma progesterone concentrations than L-EP or M-EP ewes in 1-( P , 0.01) and 2-( P , 0.001) year olds. This was concomitant with diet H-EP tending to reduce the number of lambs born per ewe in both age groups ( P 5 0.06 and 0.07, respectively). Foetuses from 1-year-old L-EP ewes had smaller cranial ( P , 0.01) and abdominal ( P , 0.05) diameters at day 53 of gestation, with H-EP lambs tending to be heaviest at birth ( P 5 0.07). Similar findings were recorded for 2-year-old ewes. One-year-old ewes offered diet L-EP presented negative maternal behaviours more frequently ( P , 0.05), while the incidence of lamb mortality at 6 weeks tended to be greater for L-EP lambs ( P 5 0.07). In MP, 1-year-old ewes offered diet M-MP were associated with foetuses with bigger abdominal diameters at day 78 ( P , 0.05). However, there were no differences in lamb weight or size at term ( P . 0.05). These ewes exhibited more positive maternal behaviours (e.g. increased grooming frequency and duration; P , 0.05) than ewes offered diet H-MP, and their offspring were more successful in suckling ( P , 0.05). Results suggest that in young ewes, a temporary nutrient restriction in EP resulted in increased prolificacy. However, ewes and their offspring were lighter at birth and ewe maternal behaviour was poorer, resulting in increased lamb mortality. In MP, a medium plane of nutrition offered to 1-year-old ewes led to improved maternal and offspring behaviour.

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“…Lamb birth weight is related to litter size, with singletons more likely to be too heavy, and lambs born in multiple litters more likely to be too light, to meet this optimum. The genetic basis to lambing ease was realised when breed differences in the occurrence of lambing difficulties were first reported (Grommers, 1985). The aim of this study was to evaluate the genetic component of lambing difficulty in Scottish Blackface sheep and to explore key environmental components affecting the occurrence of dystocia in this population.…”

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confidence: 99%