1856
Altering ewe nutrition in late gestation; the impact on lamb performance
Exposing the foetus to adverse conditions in-utero may result in developmental adaptations to the postnatal, structural and physiological growth of the animal. Maternal nutritional status is one of the primary extrinsic factors, contributing to the programming of foetal nutrient availability and nutrient partitioning throughout gestation. Altering the level of nutrition received by the ewe has been shown to affect foetal growth, influencing birth weight, postnatal growth and metabolism, and reproductive function.
The objective of this study was to examine the effects of offering ewes 80% (R), 100% (M), or 120% (E) of recommended metabolisable energy (ME) requirements from d 105 of gestation to parturition on subsequent ewe and lamb performance. In a randomised complete block design study, sixty twin bearing ewes were allocated to one of three dietary treatments (n=20). Energy requirements were calculated individually for each ewe and amended according to specific treatment allocation. Ewe liveweight and body condition score (BCS) were recorded throughout the study. Within one hour of birth, the birth weight, lambing difficulty and skeletal measurements were recorded from all lambs. Ewes were hand milked at 1, 10, and 18 h post˗partum and lamb colostrum intake recorded. Lamb live weight was recorded intermittently from birth to slaughter and subsequent average daily gain (ADG) calculated.
Restricting the metabolisable energy offered (R) to the ewe in late gestation resulted in a decline in ewe body weight (P<0.05) and BCS (P<0.01) at 24 h post-partum when compared to ewes offered the excess energy diet (E). Combined litter weight, colostrum yield at 1 h post-partum and total yield up to 18 h post-partum were greater for ewes offered the E diet than either of the other treatment groups (P<0.01). While there was no difference in individual lamb birth weight (P>0.05), lambs born to ewes offered the R diet had a lower ADG (P<0.01) up to 21 d of age and remained lighter (P<0.05) than those born to ewes offered the E diet up to weaning (d 98 post-partum). In conclusion, offering ewes a restricted level of ME for the final 6 wk of gestation negatively impacted ewe performance to parturition and compromised lamb growth to weaning.
Keywords: foetal programming, late pregnancy nutrition, lamb performance