Livestock production is a major consumer of fresh water, and the influence of livestock production on global fresh water resources is increasing because of the growing demand for livestock products. Increasing water use efficiency of livestock production, therefore, can contribute to the overall water use efficiency of agriculture. Previous studies have reported significant variation in livestock water productivity (LWP) within and among farming systems. Underlying causes of this variation in LWP require further investigation. The objective of this paper was to identify the factors that explain the variation in LWP within and among farming systems in Ethiopia. We quantified LWP for various farms in mixed-crop livestock systems and explored the effect of household demographic characteristics and farm assets on LWP using ANOVA and multilevel mixed-effect linear regression. We focused on water used to cultivate feeds on privately owned agricultural lands. There was a difference in LWP among farming systems and wealth categories. Better-off households followed by medium households had the highest LWP, whereas poor households had the lowest LWP. The variation in LWP among wealth categories could be explained by the differences in the ownership of livestock and availability of family labor. Regression results showed that the age of the household head, the size of the livestock holding and availability of family labor affected LWP positively. The results suggest that water use efficiency could be improved by alleviating resource constraints such as access to farm labor and livestock assets, oxen in particular.

The purpose of this research is to show that the vegetable wastes produced by the greenhouses of the Poniente region of Almería, which grow eight main horticultural crops, can be defined as vegetable subproducts and used for animal feed. These vegetable subproducts from greenhouses (VSG) meet existing legal maximum limits of waste from phytosanitary products at the European level, and they are free of other solid wastes. For this purpose, a farm must show that subproducts are traceable. The use of such VSG by sheep and goats would allow considerable reduction in biomass generated by vegetable greenhouses along with sustainable profit. At the same time, the cost of food for livestock would be reduced at a time when prices of fodder and concentrates are increasing. Finally, new traceability for vegetable wastes is proposed that would be compatible with and complementary to that existing nowadays, and would reduce the environmental impact of these wastes.

Increased amino acid content in high-oil maize (Zea mays L.) grain may add further value to its use in livestock rations, especially if this enhanced amino acid content is consistent across varying growing conditions. Most high-oil maize (HOM) grown in the USA utilizes the TopCross system which involves planting a blend (TC Blend) of two types of maize. Field experiments and on-farm studies were conducted in 1997 and 1998 to compare the amino acid profile of grain from HOM TC Blends with that of their normal-oil maize (NOM) counterparts across a range of production environments in Ohio. In 1997, the composition of four amino acids (lysine, methionine, glycine and arginine) was significantly higher in HOM compared to NOM grain. In 1998, nine amino acids (lysine, methionine, glycine, arginine, asparagine, threonine, serine, cysteine and tryptophan) were greater in HOM than in NOM grain. Lysine and methionine content in HOM grain averaged 12 and 13% higher than in NOM grain in both years. The number of amino acids significantly affected by the grain parent was greater than that for maize type each year. A significant maize type × grain parent interaction for a limited number of amino acids suggest that TC Blend grain parents may affect the consistency of amino acid composition in HOM grain. Results of this study demonstrate that the levels of several amino acids, including economically important lysine and methionine, were consistently greater in HOM than in NOM grain across a range of production environments. Modelling with livestock ration balancing software showed that the additional amino acids and oil in HOM added 12–20% to its value as livestock feed.

Differences in the nutritive value of four grades of stackburned yellow maize, obtained from a single storage unit in Mozambique, were examined. Samples were analysed for chemical composition, and subjected to the following in vitro assays for estimating digestibility: total dietary fibre and pancreatin for non-ruminants, and gas production using sheep rumen fluid for ruminant livestock. Samples were also fed to broiler chicks at 600 g/kg diet in a growth trial. There were no significant differences in crude protein contents of the maize samples, but there was evidence for the development of Maillard reaction products. Detectable amino acids were lower in discoloured maize, with decreases of 52% in lysine, 35% in arginine, and 15% in glycine concentration in the most severely discoloured sample compared with control. Total starch, reducing sugar, acid-detergent fibre a d amylase-neutral-detergent fibre values increased, while total non-reducing sugar content decreased with increased discolouration. Total dietary fibre and pancreatin assays indicated a lowering in digestibility of maize with increasing discolouration. Weight gain of chicks (P=0·0228), efficiency of feed utilization (P=0·0009) and the metabolizable energy value of diets decreased (P<0·0001) with increasing stackburn discolouration. There were no significant effects on N retention of diets. In vitro fermentation using sheep rumen fluid showed a linear decrease in gas production with increasing maize discolouration, indicating a reduction in rumen degradability with stackburn