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

Abstract

The present study investigated the effect of age at first lambing (AFL) on the performance of Lacaune sheep under intensive management conditions. Records from 3088 maiden sheep from one farm, for the period 2005-2010, were classified into four experimental groups: group E (early) ewes with AFL ⩽390 d; group M (middle) with AFL of 391-450 d; group L (late) with AFL of 451-510 d; and group A (aged) with AFL ⩾511 d. The higher the number of lactations, the lower were the yield/lactation and yield/Day in Milk. Ewes from group M up to 450 days old lambed 0.2 times more often and had 0.25 more lactations than the ewes from group L; in addition, the former group lambed 0.5 times more often and had 0.49 more lactations than ewes from group A. Group A had the lowest yield per lifetime; the yield followed the sequence: group E (1032 l) >group M (1051 l) >group L (989 l) > group A (859 l) (P<0.0001). Yield/lactation was affected by AFL during the first three lactations (P<0.05). Group E produced significantly less milk in the first lactation than ewes from groups M, L and A. AFL correlated negatively with the number of lactations in life (r= -0.26; P<0.0001) and with total milk yield (r= -209; P<0.0001). The productive performance between the ewes that reached puberty early (n=404) or late (n=2684) in life were different (P<0.0001) with the early sheep having a lower total milk yield (591 v. 1073 l, P<0.0001). In conclusion, the current study indicates that the optimal AFL for the Lacaune breed under an intensive dairy system is between 390 and 450 d. Ewes with AFL earlier than 390 d or later than 450 d are likely to have a shorter productive life and a lower lifetime milk production.

Reproductive Performances of Indigenous Ewes in Bangladesh

“…There is good evidence that in most domestic species, nutrition is an important factor for the age and body weight of puberty [21]. The energy deficiency delays puberty and decreases animal fertility, body weight gain, and other productive parameters [22]. The present data showed that the ewes in supplemented group reached puberty at significantly earlier age than ewes of traditional feeding system of farmers.…”

Comparison between linear and proportional hazard models for the analysis of age at first lambing in the Ripollesa breed

“…Nevertheless, less than 200 ewes were removed from the data set because they were culled at an age of two or more years and without lambing records. Other populations provided similar performances such as the Rasa Aragonesa (528 days to 688 days; Gabiña, 1989) Hernandez et al, 2011). Smaller ages at first lambing were also reported in Finnish Landrace × Targhee (377 days) and Romanov × Targhee (365 days) flocks (Gallivan et al, 1993).…”

Accurate mathematical models to describe the lactation curve of Lacaune dairy sheep under intensive management

“…Descriptive study of the Lacaune lactation curve and biological interpretation As previously reported in Lacaune sheep (Hernandez et al, 2011) and Asaff sheep (Pollott and Gootwine, 2004), the mean milk yield per lactation and the length of lactation decreased with lactation number, that is, with the age of the sheep. The decrease between lactations 1 and 2 was slight, but it increased from lactation 2 onward.…”

“…This breed has become one of the world's high-yielding milk ovine breeds, with average daily milk yields of 1.59 l and a total milk yield of 270 l over a 165-day lactation period (Barillet et al, 2001). In Spain, our group has observed mean milk yields of 448 l/ewe in an intensively managed flock, with a mean lactation length of 238 days (Hernandez et al, 2011). Production of Roquefort cheese is strictly regulated by legislation of the European scheme of geographical indication named 'protected designation of origin'.…”

“…The original flock had been imported from the French Lacaune Association (Upra Lacaune Region of Aveiron) between 2005 and 2006. Its management has previously been described by Hernandez et al (2011) and is summarized as follows. At the Cerromonte Farm, animals are housed indoors.…”