Effect of time of weaning on the reproductive performance of Barbados Blackbelly ewes and lamb growth reared in the tropics

Knights, M.; Siew, Narendra; Ramgattie, R.; Singh-Knights, Doolarie; Bourne, Gregory A.

doi:10.1016/j.smallrumres.2011.09.042

Cited by 20 publications

(26 citation statements)

References 20 publications

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“…Mortality of lambs in the present study is much higher than that observed with other well-fed hair lambs (Macías-Cruz et al, 2012;Knights et al, 2012) but close to the findings by Cloete et al (2007) with Dorper ewes crossbred to meat sheep. The extent of pre-weaning mortality is a complex issue.…”

Section: Discussionsupporting

confidence: 84%

Growth and pre-weaning mortality of Katahdin lamb crosses

Mellado

Macías

Avendaño

et al. 2016

Rev Colomb Cienc Pecu

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SummaryBackground: Katahdin breed sheep is highly disseminated in Mexico. This breed and its crosses have recently gained attention among sheep producers. However, research with crosses between Katahdin and other meat breeds is limited. Objective: to evaluate the genetic and non-genetic factors affecting growth and mortality rate of crossbred lambs from Katahdin ewes fecundated with breeds specialized for meat production. Methods: crossbred lambs (n = 152) from Katahdin ewes sired with Hampshire (KH; n = 43), Texel (KT; n = 53) or Charolais (KCH; n = 56) were evaluated under intensive management conditions. The effects of genotype and non-genetic factors on birth weight, weaning weight, pre-weaning daily weight gain, and mortality rate were determined. Results: breed differences were not detected for birth weight (4 ± 1.1, 4.3 ± 0.9 and 4 ± 1.1 Kg for KCH, KH, KT, respectively), nor for the 60-d weaning weight (20.2 ± 4.3, 20.9 ± 4.3, 18.2 ± 4.2 Kg for KCH, KH, KT, respectively). Weight of lambs did not differ significantly between sexes, but it decreased (p<0.05) with increased litter size (weaning weight at 60 days for single, twins and triplets was 24.5 ± 2.6, 19.2 ± 3.5, and 14.3 ± 3.8 Kg, respectively). Pre-weaning mortality of KH lambs was 13.3% and it was significantly lower than that of the other genotypes (24.5 and 39.3% for KT and KCH, respectively). Conclusion: inclusion of Charolais, Hampshire or Texel rams in Katahdin flocks results in similar lamb weaning weight, but Hampshire-sired progeny excels regarding pre-weaning survival.

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Section: Discussionsupporting

confidence: 84%

Growth and pre-weaning mortality of Katahdin lamb crosses

Mellado

Macías

Avendaño

et al. 2016

Rev Colomb Cienc Pecu

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“…The lower quality of pasture during dry/wet transition period could lead to a decreasing in reproductive efficiency rates. Knights et al (2012) and Hatcher et al (2010) observed significantly higher mortalities in lambs that were lighter at weaning. Thus, the understanding of these seasonal variations is of uttermost importance for the selection of strategies and methods aimed at improving reproductive efficiency.…”

Section: Discussionmentioning

confidence: 88%

“…It is known that females that have lambed underweight have longer postpartum anoestrus and higher lambing interval, therefore impaired reproductive efficiency. In this way, Knights et al (2012) showed that ewes, and in particular aseasonal breeds, when provided with an optimum nutritional and a favorable photoperiodic environment do not require weaning to resume cyclicity and show high levels of fertility when bred after day 70 postpartum.…”

Section: Discussionmentioning

confidence: 99%

Reproductive and productive performances of Santa Inês ewes submitted to breeding in different periods of the Amazonian humid tropical climate

Soares

Oliveira

Padilha-Nakaghi

et al. 2015

Trop Anim Health Prod

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The objective of this study was to evaluate the reproductive and productive performance of Santa Inês ewes bred at different times of the year in humid tropical climate. One hundred and forty-eight Santa Inês ewes were grouped according to the time of the year of their breeding season (i.e., mating period) (dry/wet, wet, wet/dry, and dry season). The service type was natural mating and the ewes and rams were kept together every night for 45 days. Reproductive efficiency was assessed by service, pregnancy, lambing, prolificacy, twinning, pregnancy loss, weaning, and lamb mortality rates. Ewes were weighed at the beginning and at the end of the breeding season and before and after parturition, and sequential weighing of the lambs was performed (at birth, 15, 30, 60, and 90 days). Reproductive efficiency index (number of lambs weaned/total of served ewes) and productive efficiency (kg of weaned lamb/kg of served or lambed ewes) were calculated. All ewes expressed estrus early in the breeding season; however, a higher percentage (53.5 and 7.1 % at 30 and 45 days, respectively) of ewes returned to estrus during the wet/dry period. The lower rates (13.9 %) of return to estrus at 30 days were during the wet season (P < 0.05). There were no (P > 0.05) effects of breeding seasons on the remaining reproductive rates. Ewes that lambed during the wet/dry transition period weighted less, before (40.5 ± 2.5 kg) and after (38.6 ± 1.6 kg) parturition, than those of other groups (P < 0.05). Lamb weight at birth did not vary between groups, however, weight at weaning was higher (15.6 ± 2.1 kg) in lambs born during the wet season (P < 0.05). The reproductive efficiency index was lower (0.66) when the breeding season took place during the dry/wet period (P < 0.05). Productive rates were significantly higher (0.29 and 0.33 for kg of weaned lamb/kg of served and lambed ewes, respectively; P < 0.05) in ewes served in the dry season. The reproductive performance of Santa Inês ewes was not significantly influenced by the period of the year in which the breeding seasons took place, allowing for four breeding seasons a year in the Amazon region. Variations between periods in return to estrus rates, weight of ewes close to parturition and lamb weight at weaning indicate that climate changes can also affect reproductive rates.

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“…Early weaning between 7 -8 weeks caused about 25% reduction in the live-weight gain of the lambs compared to weaning at 14-16 weeks which grew 30% faster (Dynes et al, 2006). Lambs that were weaned early showed a continuous reduction in their growth rate which persists for the duration of about 2 months while an increased growth rate has been reported in lambs that were suckled continuously or un-weaned as compared to lambs weaned early (Simpson-Rastle et al,2012;Knights et al, 2012).…”

Section: Effect Of Weaning On Lamb Growth and Survivalmentioning

confidence: 99%

“…In a study conducted by Vecihi et al (2009) to investigate the effect of 45, 60 and 75 days of weaning on growth and survival rates in Awassi lambs, it was reported that survival rate was significantly lower in the group of lambs weaned at 45 days old when calculated on days 120 and 210 compared to the other 2 groups, and also the live weight gain was lower in lambs weaned at 45 days when calculated on day 210. According to Knights et al, (2012) higher levels of mortality observed in lambs that were weaned early may be partly due to reduced immune function.…”

Section: Effect Of Weaning On Lamb Growth and Survivalmentioning

confidence: 99%

Effect of Nutrition, Lactation and Gonadotropin Stimulation on Ram-Induced LH Surge and Subsequent Fertility in Early Post-Partum Ewes during Seasonal Anestrous

Adebiyi¹

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Effect of time of weaning on the reproductive performance of Barbados Blackbelly ewes and lamb growth reared in the tropics

Cited by 20 publications

References 20 publications

Growth and pre-weaning mortality of Katahdin lamb crosses

Growth and pre-weaning mortality of Katahdin lamb crosses

Reproductive and productive performances of Santa Inês ewes submitted to breeding in different periods of the Amazonian humid tropical climate

Effect of Nutrition, Lactation and Gonadotropin Stimulation on Ram-Induced LH Surge and Subsequent Fertility in Early Post-Partum Ewes during Seasonal Anestrous

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