Effect of feeding calcium salts on performance of nursing Awassi ewes

Twenty nursing Awassi ewes (BW = 50 ± 2.35 kg, age = 4.5 ± 1.2 years) with their lambs were used to evaluate the effects of feeding calcium salts in lactation diets on performance and pre-weaning growth of their lambs. Treatments were 0% calcium salts (CON) or 5% calcium salts (FAT). At the end of the study, a digestibility experiment was performed. Milk yield was greater ( P < 0.05) for ewes fed the FAT diet than the CON diet. Milk composition was similar ( P > 0.05) between diets. However, milk energy value (kcal/day) tended to be greater ( P = 0.07) for the FAT diet than the CON diet. Concentrations of milk C18:1c9 and C20:0 were greater ( P < 0.05) in ewes fed the FAT diet than the CON diet. However, concentration of trans -10, cis -12 CLA was lower ( P = 0.05) in the FAT diet than in the CON diet. No differences in feed intake and body weight change were detected between diets. Digestibility of dry matter, organic matter, crude protein, ether extract, neutral detergent fiber, and acid detergent fiber were similar ( P > 0.05) for diets. For lambs, weaning weight was not affected by treatments. However, average daily gain and total gain were greater ( P = 0.053) for the FAT diet than the CON diet. Results suggest that supplementing lactating ewes with calcium salts at the beginning of lactation phase improves daily milk yield of ewes and pre-weaning growth of their lambs with no major negative impact on feed intake and digestibility.