Maize silage with a non-protein nitrogen additive as feed for autumn-calving cows

Maize silages made in October were fed to forty-three autumn-calving cows during a 20-week winter feeding trial. The control silage received no additive whereas a non-protein nitrogen (NPN) additive was applied to the other silage at harvest time. The four experimental feeding treatments were: A, maize silage + 6 kg d^?1 barley; B, maize silage with NPN + 6 kg d^?1 barley; C, maize silage + 5 kg d^?1’barley + 1 kg d^?1 extracted decorticated groundnut cake; D, maize silage with NPN. The mean daily milk yields of cows on the treatments were 14.7, 15.1, 15.3 and 15.0 kg respectively. All cows received maize silage ad libitum. There were no significant differences in milk yield but the milk produced by the cows on treatment D had significantly lower concentrations of milk fat, protein and solids-not-fat when compared to the other three treatments. The cows on treatment D had a negative liveweight change which was significantly different (P < 0.05) from those of the cows on treatments B and C.     

The influence of the herbicide methabenzthiazuron on the synthesis of plastidic lipids in Hordeum vulgare seedlings

The herbicide methabenzthiazuron, and inhibitor of the Hill reaction, was applied to Hordeum seeds at the time of sowing, and the greening process under continuous Fluora light was investigated to the age of 13 days. Chlorophyll and xanthophyll contents were increased by methabenzthiazuron relative to the controls, with degrading ratios of chlorophyll a/chlorophyll b and rising xanthophyll/carotene values. The enhanced ratios of chlorophyll a to lipoquinones, like the absolute values, indicate an inhibition of the lipoquinones. These metabolic alterations are similar to those found in shade-adapted leaves. It is suggested, therefore, that inhibition of the photosynthetic electron transport, like deficiency in light of shade leaves, is compensated by metabolic reactions leading to a greater amount of photosystem II with an enhanced accumulation of the light-trapping chlorophylls and carotenoids.     

Grass production studies in the uplands of north-east Scotland 1. The effects of soil parent material, altitude and soil major group

Sites were established on good quality grass swards in areas representative of three of the most extensive soil parent materials in north-east Scotland and covering an altitudinal range of 260–460 m. Overall yields of herbage dry matter in 1975 were high, ranging from 6280 kg ha^-1 with no fertilizer to 9190 kg ha^-1 with an application of 100, 26 and 50 kg ha^-1 N, P and K respectively. Differences in production between parent material and altitude groupings were found to be associated with differences in major soils group and past land use, with long-enclosed brown earths outyielding podzols recently reclaimed from heather moorland by about 30% overall. Increasing inputs of fertilizer appeared to reduce the effects of soil and climatic conditions. Brown earths showed higher apparent recoveries of N fertilizer than did podzols.     

NUTRITIONAL PROBLEMS OF LIVESTOCK PRODUCTION FROM SEMI-ARID GRASSLANDS IN THE TROPICS*

Herbage of very low quality forms the main diet of ruminants on the semi-arid grasslands in the tropics for several months of the year. The grasses available have a high content of dry matter and crude fibre, a low digestibility and a very low crudeprotein content. Ruminants are unable to eat enough herbage to supply the nutrients required for their body functions and it is this inadequacy which is the major factor limiting animal production from semi-arid grasslands in the tropics.     

BEEF PRODUCTION FROM PASTURE LEYS IN UGANDA*

The potential for producing beef in savanna grassland areas is discussed in relation to the results obtained from grazing trials on sown pastures at Serere Research Station, Uganda. Liveweight gains from small East African Zebu stock are used to illustrate the progress that has been made in the selection of improved pasture species and mixtures grown at various levels of fertilizer application. The utilization of herbage from selected pastures is shown to vary under different grazing management systems, grazing pressure having the greatest effect upon animal production. The need for further investigations and the integration of existing research findings into farming practice is stressed.