Factors associated with lamb mortalities in Muzaffarnagari sheep

Mandal, Ajoy; Prasad, H; Kumar, Ashok; Roy, R.; Sharma, Nagendra Kumar

doi:10.1016/j.smallrumres.2006.07.010

Cited by 57 publications

(57 citation statements)

References 19 publications

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“…The overall rate of lamb mortality obtained in the present study (5.2%) was lower than that reported in the literature for other breeds of sheep (Southey et al 2001;Mandal et al 2007;Riggio et al 2008;Cloete et al 2009;Vatankhah and Talebi 2009;Chniter et al 2011). The lamb losses from birth to 7 days of age (1.8%) were lower than those reported for Muzaffarnagari and Lori-Bakhtiari breeds (Mandal et al 2007;Vatankhah and Talebi 2009).…”

Section: Discussioncontrasting

confidence: 85%

Lamb survival analysis from birth to weaning in Iranian Kermani sheep

Barazandeh

Moghbeli

Vatankhah³

et al. 2011

Trop Anim Health Prod

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Survival records from 1,763 Kermani lambs born between 1996 and 2004 from 294 ewes and 81 rams were used to determine genetic and non-genetic factors affecting lamb survival. Traits included were lamb survival across five periods from birth to 7, 14, 56, 70, and 90 days of age. Traits were analyzed under Weibull proportional hazard sire models. Several binary analyses were also conducted using animal models. Statistical models included the fixed class effects of sex of lamb, month and year of birth, a covariate effect of birth weight, and random genetic effects of both sire (in survival analyses) and animal (in binary analyses). The average survival to 90 days of age was 94.8%. Hazard rates ranged from 1.00 (birth to 90 days of age) to 1.73 (birth to 7 days of age) between the two sexes indicating that male lambs were at higher risk of mortality than females (P < 0.01). This study also revealed a curvilinear relationship between lamb survival and lamb birth weight, suggesting that viability and birth weight could be considered simultaneously in the selection programs to obtain optimal birth weight in Kermani lambs. Estimates of heritabilities from survival analyses were medium and ranged from 0.23 to 0.29. In addition, heritability estimates obtained from binary analyses were low and varied from 0.04 to 0.09. The results of this study suggest that progress in survival traits could be possible through managerial strategies and genetic selection.

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Section: Discussioncontrasting

confidence: 85%

Lamb survival analysis from birth to weaning in Iranian Kermani sheep

Barazandeh

Moghbeli

Vatankhah³

et al. 2011

Trop Anim Health Prod

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“…NLAW, as a criterion of mortality of lambs from birth to weaning, was affected significantly (p < 0.05) by the sex of the lamb. In accordance with Southey et al (2001) and Mandal et al (2007), lamb mortality was greater among males than females in the period of birth to weaning.…”

Section: Fixed Effectssupporting

confidence: 53%

Genetic parameters of live body weight, body measurements, greasy fleece weight, and reproduction traits in Makuie sheep breed

Jafari¹,

Hashemi²,

Darvishzadeh³

et al. 2014

Span. j. agric. res.

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Genetic parameters of production and reproduction traits were estimated using 39,926 records from 5,860 individual progenies of 163 sires and 1,558 dams. The data were collected at Makuie Sheep Breeding and Raising Station (Maku, Iran) from 1989 through 2013. Nineteen traits were classified in four main groups: a) live body weight traits, b) body measurement traits, c) greasy fleece weight traits, and d) reproduction traits. Year of birth, lamb sex, age of dam, and birth type were considered as fixed effects in the animal model. Four different animal models that are differentiated by including or excluding maternal effects were fitted for each trait. The Akaike information criterion was used to determine the most appropriate model for each trait. Parameters were overestimated substantially when maternal effects, either genetic or environmental, were ignored from the models. By ignoring the maternal effects, the traits could be classified into three main groups: body live weight traits with high heritability (0.34-0.46), body measurement and greasy fleece weight traits with medium heritability (0.11-0.27) and reproduction traits with low heritability (0.03-0.20). The genetic correlations among the traits ranged from-0.41 to 0.99. The estimated genetic parameters may be used to set up short/long term breeding program for the selection purpose of Makuie sheep breed.

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“…Lambs having light birth weight had lowest survival rates. The birth weight affect the lamb's ability to ingest colostrum and receive proper mothering shortly after birth and thus develop an ability to combat infections [57]. Improving lamb birth weight using different management interventions such as improving prepartum feeding of ewes especially animals with poor body condition carrying twins may partially solve the problem [56].…”

Section: Discussionmentioning

confidence: 99%