Utilization of Zizyphus nummularia leaves by three breeds of sheep

Abstract

The chemical composition of Zizyphus nummularia leaves was determined, and their nutritive value studied by feeding them to 8-month-old ram lambs, three each of the Rambouillet, Rambouillet x Chokla, and Malpura breeds. Z. nummularia leaves contained 14% crude protein, 3% ether extract, 17% crude fibre, 56% nitrogen-free extract, 73% total carbohydrates, 10% total ash, 2.8% calcium, and 0.14% phosphorus.

The dry matter intake of the lambs was 2.05 kg per 100 kg body weight. The palatability of the leaves was low and the animals lost weight. The average digestion coefficients of dry matter, organic matter, crude protein, ether extract, crude fibre, nitrogen-free extract, and total carbohydrates were 44, 54, 40, 28, 35, 64, and 57% respectively. The digestion coefficients of the nutrients did not differ between breeds except that for crude protein, which was higher in the Rambouillet (P < 0.05). The leaves contained 5.56 kg digestible crude protein and 49.7 kg total digestible nutrients per 100 kg dry matter. The nutritive ratio was 1 : 7.9.

The leaves were quite nutritious, but palatability was low. Digestibility of protein was poor and urinary nitrogen excretion was low. Animals were in positive nitrogen balance, yet lost weight; possible causes for this are discussed. It is considered that Z. nummuluria leaves fed to growing lambs should be supplemented with other fodder. Protein and phosphorus supplements also seem desirable.

Results indicate that wider investigations on factors limiting food intake, the role of supplements in improving the nutritional inadequacy of the diet, and ecological aspects of Zizyphus are necessary.