Effect of supplemental rumen-protected methionine on reproduction and production of Awassi ewes

Abstract

The effect of rumen-protected methionine (RPM) was investigated in Awassi ewes (0, 3 or 5 g/head/d, n = 20) on reproductive and productive performance (initial body weight [BW] = 70.9 − 71.8 kg, 3 − 5 years). Supplementation started with the flushing feeding regime (at the breeding time) and lasted for 42 d. RPM was reused during the last 60 d of pregnancy and the first 60 d of lactation. RPM increased (p < .05) progesterone concentration with a higher lambing rate at the 5RPM level. The number of lambs born for each ewe exposed to the ram was also higher (p < .05) with 3RPM and 5RPM. Methionine levels in the plasma were greater (p < .05) with RPM mainly at 5RPM level. Birth weights of the lambs were higher (p < .05) with RPM regardless of the level. Contrary to this, weaning weights and rate of gain for lambs were reduced (p < .05) with RPM addition. RPM did not affect milk production of ewes during the first 60 d of lactation or on energy corrected milk and feed to milk ratio. However, milk protein content was increased (p < .05) at the 5RPM level while milk fat content was decreased. Regardless of the level of RPM addition, milk casein content increased (p < .05). At all levels, the effect of RPM on milk fatty acid profile was minor. It can be concluded that supplementing RPM might be a valuable tool to enhance the reproductive and productive performance of ewes during their breeding season.

Keywords

• awassi ewes
• milk production
• pregnancy
• birth weight
• rpm