Growth rates of Romane ewe lambs and correlated effects of being mated as hoggets or two-tooth ewes on first offspring performance

García, Eliel González; Hazard, Dominique

doi:10.1016/j.livsci.2016.04.022

Cited by 11 publications

(13 citation statements)

References 17 publications

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“…This finding is agreement with the findings of many researchers (Kenyon and Blair, 2014;González-García et al, 2015;González-García and Hazard, 2016;Griffiths et al, 2016). The lighter birth weights of lambs born to primiparous ewes compared to multiparous ewes can be explained by the fact that the uterus environment of primiparous dams was not fully developed, especially with regard to size (González-García et al, 2015).…”

Section: Discussionsupporting

confidence: 92%

“…Additionally, there are many reports that ovulation rate and litter size were influenced by ewe BW, parity and BCS (Michels et al, 2000). It was reported in some studies (Michels et al, 2000;Yilmaz et al, 2011;González-García and Hazard, 2016) that parity has a strong effect on fecundity and prolificacy or litter size in sheep farming. The present study showed that animal body fat reserves can affect the return rate and fecundity of ewes.…”

Section: Discussionmentioning

confidence: 99%

“…The lighter birth weights of lambs born to primiparous ewes compared to multiparous ewes can be explained by the fact that the uterus environment of primiparous dams was not fully developed, especially with regard to size (González-García et al, 2015). As a matter of fact, there are many reports about the birth weight differences favoring lambs born to multiparous ewes, and this continues to weaning time (Corner et al, 2013;González-García and Hazard, 2016). On the other hand, it is known that the birth weights of lambs affect BWs and BCSs of ewes at postpartum.…”

Section: Discussionmentioning

confidence: 99%

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Body condition status at mating affects gestation length, offspring yield and return rate in ewes

2018

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Abstract. The present study was planned to determine the effect of ewe body condition score (BCS) and parities on fertility, return rate, gestation length, fecundity, litter size and lamb birth weight. Data were collected from 284 heads of ewes with first to fifth parity and raised at a state farm for three consecutive (2002)(2003)(2004) years. Teaser rams were used to monitor estrus twice daily in the morning and in the evening from September to October. BCSs and body weights (BWs) were recorded at mating and postpartum. The ewes, at mating time in breeding season and within first 6 h after the expulsion of fetal membranes, were divided into four groups on the basis of their BCS: thin (BCS = ≤ 2.0; n = 70; 38), medium (BCS = 2.5-3.0; n = 122; 142), fat (BCS = 3.5-4.0; n = 72; 59) and very fat (BCS = ≥ 4.5; n = 20;17). BCSs and BWs of ewes at postpartum were highly correlated with lamb birth weight (R = 0.486, P < 0.01, and R = 0.130, P < 0.05, respectively). BCSs and BWs of ewes at postpartum had positive effects on lamb birth weight (Y = 3.43 ± 0.10 + 0.130 + 0.047 ewe body condition score (EBCS), P < 0.01; Y = 2.92 ± 0.42 + 0.018 ± 0.009 ewe body weight (EBW), P < 0.05 kg of lamb birth weight per BCS and kilogram of ewe live weight, respectively). The fertility rate, litter size and fecundity were higher in the medium and fat groups than thin and very fat groups (χ 2 = 10.607, P < 0.01). The BW and BCS at postpartum affected gestation length positively (P < 0.05). Return rate or number of coitus for conception were higher (P < 0.05) in thin and very fat groups than medium and fat groups. The data revealed that the ewes with medium and fat body condition (BCS = 2.5-4.0) scores were profitable.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Body condition status at mating affects gestation length, offspring yield and return rate in ewes

2018

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“…The study analyzed data from a Romane meat sheep flock that was reared extensively on 280 ha of rangeland at the INRA Experimental Farm of La Fage (Causses du Larzac, 43°54′54.52″N; 3°05′38.11″E; altitude approximately 800 m, Roquefort-Sur-Soulzon, Aveyron, France). The overall characteristics of the experimental farm, the animals, and the management have been previously described by Molénat et al (2005), González-García et al (2014), and Macé et al (2018). For the period examined in this study (from 2002 to 2015), the average annual temperature and rainfall were 9.8 °C and 910 mm, respectively.…”

Section: Animals and Experimental Farming Systemmentioning

confidence: 99%

“…Animal models were used to estimate heritabilities and repeatabilities for each PERF trait from univariate analyses and to estimate phenotypic and genetic correlations between PERF traits and BR from bivariate analyses. The analyses were performed with the ASREML software (Gilmour et al, 2006) assuming a repeatability model with measurements across productive cycles considered to be the same traits with constant variances. Fixed effects included AGE, PAR, YR, SEX, and LS at birth for Wlamb-B and Wlitter-B, LS at weaning for Wlamb-W, Wlitter-W, and litterSurv, and LS during the suckling period for litterADG1m, litterADG2m, and litterADG3m.…”

Section: Genetic Analysesmentioning

confidence: 99%

Relationships between body reserve dynamics and rearing performances in meat ewes1

Macé

Hazard

Carriere³

et al. 2019

Journal of Animal Science

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The main objective of this work was to study the relationships between body reserve (BR) dynamics and rearing performance (PERF) traits in ewes from a Romane meat sheep flock managed extensively on “Causse” rangelands in the south of France. Flock records were used to generate data sets covering 14 lambing years (YR). The data set included 1,146 ewes with 2 ages of first lambing (AGE), 3 parities (PAR), and 4 litter sizes (LS). Repeated measurements of the BW and BCS were used as indicators of BR. The ewe PERF traits recorded were indirect measurements for maternal abilities and included prolificacy, litter weight and lamb BW at lambing and weaning, ADG at 1, 2, and 3 mo after lambing, and litter survival from lambing to weaning. The effects of different BW and BCS trajectories (e.g., changes in BW and BCS across the production cycle), previously been characterized in the same animals, on PERF traits were investigated. Such trajectories reflected different profiles at the intraflock level in the dynamics of BR mobilization–accretion cycles. Genetic relationships between BR and PERF traits were assessed. All the fixed variables considered (i.e., YR, AGE, PAR, LS, and SEX ratio of the litter) have significant effects on the PERF traits. Similarly, BW trajectories had an effect on the PERF traits across the 3 PARs studied, particularly during the first cycle (PAR 1). The BCS trajectories only affected prolificacy, lamb BW at birth, and litter survival. Most of the PERF traits considered here showed moderate heritabilities (0.17–0.23) except for prolificacy, the lamb growth rate during the third month and litter survival which showed very low heritabilities. With exception of litter survival and prolificacy, ewe PERF traits were genetically, strongly, and positively correlated with BW whatever the physiological stage. A few weak genetic correlations were found between BCS and PERF traits. As illustrated by BW and BCS changes over time, favorable genetic correlations were found, even if few and moderate, between BR accretion or mobilization and PERF traits, particularly for prolificacy and litter weight at birth. In conclusion, our results show significant relationships between BR dynamics and PERF traits in ewes, which could be considered in future sheep selection programs aiming to improve robustness.

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Intra-flock variability in the body reserve dynamics of meat sheep by analyzing BW and body condition score variations over multiple production cycles

Macé

García

Carriere³

et al. 2019

Animal

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Breeding for resilience requires a better understanding of intra-flock variability and the related mechanisms responsible for robustness traits. Among such traits, the animals’ ability to cope with feed fluctuations by mobilizing or restoring body reserves (BR) is a key mechanism in ruminants. The objective of this work was to characterize individual variability in BR dynamics in productive Romane ewes reared in extensive conditions. The BR dynamics profiles were characterized by combining individual longitudinal measurements of BW and body condition scores (BCS) over several production cycles. Historical data, including up to 2628 records per trait distributed in 1146 ewes, underwent cluster analysis. Two to four trajectories were observed for BW depending on the cycle, while three trajectories were found for BCS, whatever the cycle. Most trajectories suggested that BR dynamics were similar but the level of BR may differ between ewes. Nevertheless, some trajectories suggested that both BR dynamics and levels were different for a proportion of ewes. Clustering on BW and BCS profiles adjusted for individual level trends, resulted in differences only in the level of BW or BCS, rather than differences in trajectories. Thus, the overall shape of trajectories was not changed considering or not the individual level trend across cycles. In addition to individual variability, the ewe’s age at first lambing and litter size contributed to the distribution of the ewes between the trajectories. Regarding the entire productive life, three trajectories were observed for BW and BCS changes over three productive cycles. Increase in BW at each cycle suggested that ewes kept growing up until 3 to 4 years old in our conditions. Similar alternation of BCS gains and losses across cycles suggested BR dynamics might be repeatable. Many individual trajectories remained the same throughout a ewe’s life, whatever the age at first lambing, parity or litter size. Our results demonstrate the relevance of using BW and BCS changes for characterizing the diversity of BR mobilization–accretion profiles in sheep in a long timespan perspective.

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Growth rates of Romane ewe lambs and correlated effects of being mated as hoggets or two-tooth ewes on first offspring performance

Cited by 11 publications

References 17 publications

Body condition status at mating affects gestation length, offspring yield and return rate in ewes

Body condition status at mating affects gestation length, offspring yield and return rate in ewes

Relationships between body reserve dynamics and rearing performances in meat ewes1

Intra-flock variability in the body reserve dynamics of meat sheep by analyzing BW and body condition score variations over multiple production cycles

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