Effect of injecting 2- and 3-year-old ewes with calcium and magnesium on reproduction and rearing of lambs

Abstract The investigations were conducted on 75 ewes before first lambing and 75 ewes after first lambing, and covered the effect of i.m. injections of Ca and Mg on fertility, prolificacy, number of lambs reared and the live weight of lambs at birth and at the age of 28 days. The blood plasma was sampled twice before injections and the mean Ca concentrations in 2-year-old animals were 2.27 and 2.02 mmol l −1 , and in 3-year-old animals were 2.17 and 1.99 mmol l −1 . The corresponding values for Mg were 0.52 and 0.69 mmol l −1 , and 0.49 and 0.69 mmol l −1 . In 2-year-old sheep fertility was higher only in the group which received an Mg injection (96%; controls 72%). Three-year-old ewes had higher fertility after Ca (92%) and Mg (92%) injections (68% for controls). Twenty-six and 23 lambs were reared in the groups which received Mg (compared with 19 and 15 for controls). In the case of 3-year-old ewes the Ca injection also increased the number of lambs reared (21). Mean body live weight of lambs on Day 28 of life (10.6 kg) and their daily live weight gains between birth and Day 28 of life (226.5 g) were significantly higher ( P