Efecto sobre el comportamiento productivo, reproductivo y la respuesta al desafío parasitario en corderas cuyas madres fueron esquiladas a los 50 días de gestación.

ABSTRACTThis study evaluated the effect of shearing ewes at 50 day of gestation on the growth, reproductive behavior and response to a gastrointestinal parasite challenge in thefemale offspring from weaning (104 d) to 18 months old. Fifty-seven Polwarth female lambs were used, 22 single (S) and 35 twin (T) born to ewes either shorn at 50 days of pregnancy (PS, n = 23) or shorn at 62 days post-partum (U, control, n = 34) resulting in four sub-groups: SPS: single female lambs born to ewes shorn at 50 days of pregnancy (n = 8), SU: single female lambs born to ewes shorn postpartum (n = 14), TPS: twin females lambs born to ewes shorn at 50 days of pregnancy (n = 15) or TU: twin female lambs born to ewes shorn postpartum (n = 20). All progeny was managed together under improved pasture with a minimum forage allowance of 6% live weight on dry matter basis. Body weight, body condition score (BCS) and fecal eggs count was recorded every 14 d from weaning to 18 months ofage. Concentrations of progesterone were measured weekly (from 4 to 10 months of age and from 14 to 18 months of age) to establish the onset of puberty. Ovulation rate (545 ± 1.0 d old) was recorded. Prepartum shearing did not affect the age at puberty or the ovulation rate, but those female lambs born as singles were more precocious (P = 0.03) and heavier (P = 0.02) at puberty than twin born female lambs. Both the average value of parasite egg count (P = 0.07) and the Famacha index (P = 0.02) for the entire study period were lower in female lambs born to prepartum shorn ewes than those born to postpartum shorn ewes. In conclusion, shearing at 50 days of gestation did not affect the growth or the reproductive behavior of female offspring. However, female lambs born from ewe shorn during gestation showed a better response to the parasite challenge, but further research is required to confirm this