Abstract :
Reproductive performance of 3137 ewe records of 957 purebred and crossbred D’man ewes
and 4094 growth and survival performance of their purebred and terminal-sired progeny
produced under three lambings in two years were analyzed. D’man ewes were joined to
D’man (D) or Meat-Lacaune (L) rams, whereas crossbred L
×
D ewes were joined to Mérinos
Précoce (M) rams. Data were collected from 2003 to 2007 in a private flock. As expected,
D’man ewes gave birth to 0.28 lambs and weaned 0.22 lambs more than 1/2-D’man ewes,
but when weight of lamb born and weaned per ewe lambed was considered, there was
a tendency towards higher lamb outputs for purebred D’man ewes mated to L sires and
1/2-D’man ewes mated to M sires. Moreover, the number of lambs born and weaned from
purebred D’man ewes was independent of the breed of the service sire (D or L). Lambing
interval was not significantly affected by the mating type. Weight at birth and 70 days,
as well as pre weaning average daily gain were influenced by the breed group of lamb,
but lamb survival prior to weaning was not. Purebred D’man lambs had the lowest and
M
×
LD crossbred lambs had the highest growth performance. Except lamb survival that
was unaffected by sex, all ewe traits were influenced by season and year of lambing, and
lamb growth and survival were affected by type of birth, sex, season and year of birth. It
was concluded that in a terminal sire production system, using 1/2-D’man crossbred ewes
would take advantage of increased reproductive capacity in the ewe without compromising
lamb performance to market weight and/or product quality.
