Phenotypic study on total and partial lifetime traits for dairy ewes

Abstract

A data file on 36,396 lactations was used to determine the strength of the phenotypic relationship between productive, reproductive and lifespan traits for 7935 Spanish Churra ewes. These ewes first lambed between 1989 and 1997 and belonged to 23 flocks. The study took into account four lifespan traits (lifetime, productive life, useful life and lifetime score), three productive traits (total milk yield produced during lifetime, lambs weaned during ewe lifetime and total revenues from sold milk and weaned lambs during lifetime) and two reproductive traits (age at first lambing and mean interval between successive lambings). Moreover, milk yield and revenues from sold milk and weaned lambs were calculated per day of lifetime, productive life and useful life. Partial lifespan traits were considered for the first three parities. The model included flock, birth year within flock and season of birth of the ewe as fixed effects. The first two effects contributed significantly to variation in all traits, while season significantly affected lifespan traits, productive traits and age at first lambing. Milk production level was added to the model for lifespan traits only. It significantly contributed to explaining the variation in all lifespan traits with high percentage of variance explained averaging 14.91%. Lifetime averaged 2324 d. Productive life accounted for 57% of lifetime while useful life represented 50% of productive life. Age at first lambing averaged 622 d and average days dry during lifetime was 560. During lifetime, ewes gave an average of 4.6 parities, 6.5 weaned lambs and 636 l of milk. Average revenue from milk and lambs during lifetime was 673 euros. Milk/day of lifetime, productive life and useful life averaged 0.26, 0.51 and 0.93 l, respectively. The corresponding per-day revenues from sold milk and weaned lambs were, 0.27 euros, 0.55 euros and 1.01 euros, respectively. Lifespan and productive traits had strong relationships (rp among these traits ranged between 0.75 and 0.95). Two-parity and three-parity per-day milk yield had moderately high correlation (0.70-0.83) with total lifetime per-day milk yield traits. Therefore, good use of these traits would be helpful in determining best individuals early in life.

Impact of variation in production traits, inputs costs and product prices on profitability in multi-purpose sheep

“…Cheese Milk ted in our study (63 to 83% in all scenarios) was similar to the range from 53 to 81% reported for dairy sheep by other investigators (Ligda et al, 2000;El-Saied et al, 2006;Tolone et al, 2011). In dairy sheep breeding flocks, the proportional contribution of milk revenue to total revenues can drop substantially on 40% due to income from sale of young breeding animals (Ligda et al, 2000) or on 38 to 50% in an open flock, while the contribution from sale of breeding animals was nearly 20% (Vlácil, 2005).…”

Factors affecting the lactation curves of intensively managed sheep based on a clustering approach

“…However, this factor is unlikely to explain the observed influence in the present study, since no lactation was allowed. Other studies have suggested that lambing month influences productive and reproductive performance of Assaf, Awassi and Churra dairy sheep, both under intensive management (Gootwine & Pollott, 2000; Pollott & Gootwine, 2004) and non-intensive management (El-Saied et al 2006). The most productive lactations started in December, March and October, which is consistent with studies suggesting that lengthening photoperiod enhances productivity and persistency (Capuco et al 2003; Pollott & Gootwine, 2004).…”

“…Ewes born in September reach puberty during the next breeding season after birth, such that their AFL falls within the ideal range of 390 to 450 d (Hernandez et al 2011). Previous studies have attributed the influence of birth month on milk productivity to the influence of photoperiod on maternal milk yield and on prepubertal growth (Gootwine & Pollott, 2000; Pollott & Gootwine, 2004; El-Saied et al 2006). However, this factor is unlikely to explain the observed influence in the present study, since no lactation was allowed.…”

Influence of age at first lambing on reproductive and productive performance of Lacaune dairy sheep under an intensive management system

“…The animals' first lambing month did not seem to influence milk production. In contrast, this factor has been found to strongly affect productive and reproductive performance of other dairy breeds (Assaf, Awassi or Churra sheep), both under intensive management (Gootwine & Pollott, 2000;Pollott & Gootwine, 2004) and non-intensive management (El-Saied et al 2006). Influence of month-ofthe-year of birth and month-of-the-year of first lambing are mostly explained by the influence of the photoperiod on maternal milk yield and hence on prepubertal growth and peripubertal breeding activity (Gootwine & Pollott, 2000;Pollott & Gootwine, 2004;El-Saied et al 2006).…”