Performance of crossbred progeny of Trangie Fertility Merino and Booroola Merino rams and Poll Dorset ewes. 1. Lamb birth weight, survival and growth

Hall, D. D.; Fogarty, NM; Gilmour, AR

doi:10.1071/ea9951069

Cited by 28 publications

(15 citation statements)

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“…In the same way, a higher proportion of the lightest lambs at birth was born as triplets compared with the proportion of triplets in the flocks. Similar results were found by Hall et al (1995), Holst et al (2002) and Christley et al (2003). They showed that birth weight had a non-linear relationship with hazard of mortality, with both lighter and heavier lambs at greater risk.…”

Section: Discussionsupporting

confidence: 80%

Analyses of lamb survival of Scottish Blackface sheep

Conington

Brotherstone

et al. 2007

Animal

128

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Scottish Blackface lamb viability records at birth, and postnatal survival from 1 day to 14 days, from 15 days to 120 days and from 121 days to 180 days were used to determine influential factors and to estimate variance components of lamb survival traits. The binary trait viability at birth was analysed using a linear model whereas the postnatal survival traits were analysed as continuous traits using a Weibull model. The data consisted of about 15 000 survival records of lambs born from 1996 to 2005 on two farms in Scotland. The models included fixed factors that had significant effects and random direct and maternal additive genetic effects and maternal litter effects for viability at birth, and sire and maternal litter effects for the postnatal survival traits. The possible effect of maternal behaviour measured around lambing on lamb survival was investigated in separate analyses. Male lambs were found to be at a higher risk of mortality than females during all periods considered. The effect of type of birth and age of dam was more important during the preweaning period than at later ages. The postnatal hazard rate was not significantly affected by the behaviour score of the dams. The genetic merit of dams had more influence on viability at birth than the genetic merit of lambs themselves. Estimates of heritability for postnatal survival traits were in the range of 0.18 to 0.33 and were significantly greater than zero. These results indicate that lamb survival can be improved through farm management practices and genetic selection. Both animal and maternal genetic effects should be considered in breeding programmes for improving viability at birth.

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Section: Discussionsupporting

confidence: 80%

Analyses of lamb survival of Scottish Blackface sheep

Conington

Brotherstone

et al. 2007

Animal

128

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“…A significant h² estimate was computed in the present study. This estimate accorded with a value of 0.11 reported for crossbred lambs by Hall et al (1995). It was, however, higher than corresponding estimates of 0.01 recently reported by Lopez-Villalobos and Garrick (1999) and that of 0.01 to 0.03 reported by Morris et al (2000).…”

Section: Discussioncontrasting

confidence: 51%

“…It was, however, higher than corresponding estimates of 0.01 recently reported by Lopez-Villalobos and Garrick (1999) and that of 0.01 to 0.03 reported by Morris et al (2000). Hall et al (1995) reported a litter variance -this could also be expressed as a maternal temporary environmental effect (Lewis & Beatson 1999) -amounting to 19% of the total phenotypic variance. This estimate differs from the c² estimate in the present study in the sense that it involved lambs born in the same litter in fecund Booroola crossbred ewes.…”

Section: Discussioncontrasting

confidence: 50%

Environmental and genetic aspects of survival and early liveweight in Western Australian Merino sheep

Cloete¹,

Greeff²,

Lewer³

2001

SA J. An. Sci.

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Abstract(Co)variance estimates for birth weight, pre-weaning lamb survival and weaning weight were obtained for Merino lambs derived from 16 bloodlines. Between bloodline variance ratios (± s.e.) amounted to 0.10 ± 0.04 for lamb birth weight, 0.053 ± 0.036 for lamb survival (logit scale) and 0.18 ± 0.07 for lamb weaning weight. Direct additive genetic variances for weaning weight -expressed as a ratio of the total phenotypic variance within bloodlines (h², direct heritability) -were estimated at 0.18 ± 0.02 for birth weight, 0.094 ± 0.020 (logit scale) for pre-weaning survival and 0.30 ± 0.02 for weaning weight. Corresponding maternal genetic variance ratios (m²) were estimated at 0.15 ± 0.02 for birth weight and 0.08 ± 0.02 for weaning weight. It was not significant in the case of lamb survival. Maternal permanent environmental variance ratios (c²) amounted to 0.08 ± 0.02 for birth weight, 0.044 ± 0.018 for lamb survival (logit scale) and 0.07 ± 0.02 for weaning weight. These results were discussed with reference to sheep production.

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“…When dystocia occurred, the risk of lamb loss increases more in ewes with single lambs than in ewes with larger litters (Holmøy et al, 2014). Dystocia is reported as a more frequent cause of death in single lambs than in lambs in larger litters (Dalton et al, 1980;Hall et al, 1995). In cases of dystocia associated with litters of multiples, often due to malpresentation of lambs (Speijers et al, 2010), successful obstetric delivery may be achieved with less trauma because of the smaller foetuses.…”

Section: Discussionmentioning

confidence: 99%

Early neonatal lamb mortality: postmortem findings

Holmøy

Waage

Granquist

et al. 2017

Animal

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An investigation of stillbirth and early neonatal lamb mortality was conducted in sheep flocks in Norway. Knowledge of actual causes of death are important to aid the interpretation of results obtained during studies assessing the risk factors for lamb mortality, and when tailoring preventive measures at the flock, ewe and individual lamb level. This paper reports on the postmortem findings in 270 liveborn lambs that died during the first 5 days after birth. The lambs were from 17 flocks in six counties. A total of 27% died within 3 h after birth, 41% within 24 h and 80% within 2 days. Most lambs (62%) were from triplet or higher order litters. In 81% of twin and larger litters, only one lamb died. The most frequently identified cause of neonatal death was infectious disease (n = 97, 36%); 48% (n = 47) of these died from septicaemia, 25% (n = 24) from pneumonia, 22% (n = 21) from gastrointestinal infections and 5% (n = 5) from other infections. Escherichia coli accounted for 65% of the septicaemic cases, and were the most common causal agent obtained from all cases of infection (41%). In total, 14% of neonatal deaths resulted from infection by this bacterium. Traumatic lesions were the primary cause of death in 20% (n = 53) of the lambs. A total of 46% of these died within 3 h after birth and 66% within 24 h. Severe congenital malformations were found in 10% (n = 27) of the lambs, whereas starvation with no concurrent lesions was the cause of death in 6% (n = 17). In 16% (n = 43) of the lambs, no specific cause of death was identified, lambs from triplet and higher order litters being overrepresented among these cases. In this study, the main causes of neonatal lamb mortality were infection and traumatic lesions. Most neonatal deaths occurred shortly after birth, suggesting that events related to lambing and the immediate post-lambing period are critical for lamb survival.

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Performance of crossbred progeny of Trangie Fertility Merino and Booroola Merino rams and Poll Dorset ewes. 1. Lamb birth weight, survival and growth

Cited by 28 publications

References 0 publications

Analyses of lamb survival of Scottish Blackface sheep

Analyses of lamb survival of Scottish Blackface sheep

Environmental and genetic aspects of survival and early liveweight in Western Australian Merino sheep

Early neonatal lamb mortality: postmortem findings

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