Influence of protein supplementation on reproductive traits of Awassi sheep grazing cereal stubble

Sheep in the dry areas of Iraq are heavily dependent on stubble grazing as their sale source of feed during mating season. However, as the grazing season progresses, both ewes and rams, exhaust the supply of nutritious parts and consequently the quality of the stubble and their nutritive value declines. To overcome this problem, urea feed blocks (UFB) were supplemented to sheep grazing stubble. This study was conducted to evaluate supplementation of UFB enriched with cotton seed meal as a source of undegradable protein on lambing, twinning and fertility of ewes as well as semen quality, sexual activity and some blood characteristics of rams. Fifty four mature ewes and eight rams were randomly divided into supplementated ewes (SE) and rams (SR) and control, non-supplemented ewes (NSE) and rams (NSR). Both SE and NSE animals were stubble grazed and SE offered UFB enriched with undegradable protein and AD(3)E after their return from stubble. The NSR and SR were offered barley grain and straw and SR and SR fed in addition to UFB. Lambing and twinning rates were slightly higher and the percentage of barren ewes significantly lower in SE compared to NSE. Pen test parameters were not different between SR and NSR. On the other hand, sperm motility and concentration and percentage of dead and abnormal sperms were lower in SR. Supplementation had no effect on hemoglobin concentration, packed cell volume, red blood cells count but increased white blood cell count. The UFB enriched with undegradable protein had a positive effect on ewe fertility. In contrast, UFB reduced semen quality but did not influence sexual activity and most blood characteristics in rams. Published by Elsevier Science Ireland Ltd.