Maize silage was exposed to doses of y radiation varying from 0 to 6 Mrad inclusive and the effects of this treatment on the microflora and possible changes it might impose on the chemical composition were monitored. The highest dose was required to reduce the native population of micro-organisms to an insignificant level and only minor losses of lactic acid and ethanol were sustained. In addition, the irradiated silage was inoculated with representatives of groups of micro-organisms implicated in the aerobic deterioration of silage and the subsequent changes upon exposure to air observed. The inoculum proliferated and induced losses of fermentation acids, water-soluble carbohydrates, dry matter and, to a minor degree, neutral detergent fibre, and resulted in an increase in temperature and total nitrogen, the factors most likely to change during aerobic deterioration. Only the 6 Mrad dose yielded material suitable for investigations into the identification of those organisms primarily responsible for aerobic deterioration.

Data from three dairy-cow nutrition experiments have been analysed in terms of the yields of milk, lactose, fat and protein. Yields of the three constituents varied linearly with milk yield. However, yields of fat from individual cows were much more variable at high milk yields than were the other two constituents. Patterns of feeding had relatively little effect on the pattern of protein yield in cows fed to their production potential but could be important in influencing yields of fat.

Predicted responses of protein and fat yields to increments of feed were generally small in cows being fed according to their predicted yield potential and the conversion of metabolizable energy to milk constituents was of a low biological efficiency.

Field experiments made for 4 years between 1976–7 and 1979–80 in a semi-arid environment of north-west India showed that the productivity of dryland unirrigated wheat can be increased considerably by adjusting the date of sowing to conducive atmospheric temperatures. Sowing in the middle of November when daily mean temperatures ranged between 19 and 21 °C produced yields ranging between 2·6and 3·5t/ha (averaged over the 4 years) compared with 1·4–3·3 t/ha obtained from the crop sown by mid-October when the daily mean temperature ranged between 24 and 26 °C. The tall cultivar C 306, a derivative of winter x spring wheat cross, could withstand sowing at higher temperatures (mid-October) more than the spring wheats. High temperatures prevailing during the seedling stage of spring wheats shortened their vegetative growth and initiated early differentiation. Night temperatures above 13 °C coupled with day temperatures of 33–35 °C in the last fortnight of October adversely affected the tillering of spring wheats sown on 15 October and produced smaller spikes with few fertile spikelets.

Studies were conducted to evaluate the effect of 50% restriction of normal daily water intake on nitrogen balance, plasma urea concentration and excretion of different urinary nitrogenous constituents (ammonia, creatine, creatinine, urea and undetermined nitrogen) in the Marwari breed of sheep of the Rajasthan desert, India. The results indicated that the reduction in feed intake in water-restricted sheep leads to a reduction in intake and excretion of nitrogen through faeces (P < 0·01) and urine (P < 0·01) of these animals. No sigficant differences in the excretion of most urinary nitrogenous constituents between ad libitum watered and water-restricted animals were observed, except for creatine which was excreted in significantly higher concentrations in the urine of the water-restricted animals. On offering water ad libitum for 3 days to the restricted animals, the plasma urea in these animals dropped from 33·0 to 20·7 mg/100 ml, i.e. almost to the level in the animals watered ad libitum (18·7 mg/ 100 ml). The daily dry-matter intakes of the ad libitum watered and restricted animals were 790 and 488 g, respectively. The digestibility coefficients for dry matter and crude protein of the feed were 47·1 and 27·2%, respectively in ad libitum watered and 56·6 and 39·5%, respectively, in restricted animals. This improvement in the efficiency of digestion in water-restricted sheep may not be due to any enhanced microbial activity in the rumen, but may possibly be due to an increased absorption of feed nutrients in the hind gut of these animals.

The effects of N, P, K and Na silicate fertilizers, and drought on the concentrations of K in the dry matter and tissue water of field-grown spring barley crops have been investigated. Percentage K in dry matter depended on the amounts of N, P, K or water received by the crops and was linearly related to fresh weight to dry weight ratio, but the slope of this relationship depended on whether or not the crops received K. Expressing K concentrations on the basis of tissue water eliminated differences between crops, except for those given insufficient K. Barley crops given fertilizer K maintained K concentrations in their tissue water of about 200 mmol/kg tissue water for most of the growth period but crops grown without K had only 50–70 mmol/kg tissue water. The results indicate that K concentrations in the tissue water are a more reliable indicator of tissue K status than % K in dry matter.

Decreases in crop K content resulting from poor K supply were balanced by increases in Na and Ca (but not Mg) contents so that total cation concentrations in the tissue water were similar in low and high K crops. The extra Na and Ca are probably primarily involved in maintaining charge balance for anion absorption but once in the plant they may also substitute for K in its osmotic role.

A variety of factors influence the voluntary intake of ruminants including reticulo-rumen fill or distension (Campling & Balch, 1961; Welch, 1967; Grovum, 1979) and rate of passage of digesta through the gastrointestinal tract (Bines & Davey, 1970). The exit point of the reticulo-rumen, the reticulo-omasal orifice, potentially serves as a control site in regulation of particle movement from the rumen.

However, little definitive information on the functional behaviour of this anatomical location is available. Therefore, a fibre-optic endoscopic technique was designed to allow visual observation of the reticulo-omasal orifice in conscious, fed cattle.

America, New Hyde Park, NY) and a 35 mm camera (Olympus 0M-2N with 1–9 focusing screen) was attached. Photographs were taken at a shutter speed of 1/30 or 1/60 sec. The film used was Kodak (ASA 160) tungsten balanced slide film. Prints were generated from slides using the Cibachrome P30 process. An Olympus CLK-3 cold light source, having a colour temperature of 3200 °K, provided the illumination for projection through the endoscope. Opening and closing of the reticuloomasal orifice were photographed using this procedure.

Singh & Taneja (1978a, 6, 1981) have reported on several aspects of salinity tolerance in Indian desert sheep breeds, for example, maintenance of body weight, feed and water intake, body water compartments and blood characteristics. No report is available in the literature on the effect of varying levels of salt intake from drinking water on reproductive performance in these animals. The earlier reports on salinity tolerance in sheep have been almost wholly based on the animals' response to different levels of sodium chloride in synthesized drinking waters. It is, however, generally agreed that the upper limit of total salt tolerance in sheep depends not only on the concentration of the most abundant salt constituent in the drinking water (usually sodium chloride), but also on the concentrations of the other constituents. Divalent cations (calcium and magnesium) and anions (sulphates and carbonates) in the water are believed to be more toxic than the monovalent cations and anions (sodium and chloride).

Increased demand for steroidal drugs in recent years has prompted a worldwide search for sources of diosgenin other than from species of Dioscorea (Singh et al. 1980). Costus speciosus (Koen.) Sims, an erect perennial herb found growing wild throughout India, has been suggested as one possible alternative source of diosgenin (Dasgupta & Pandey, 1970; Sarin, Bedi & Atal, 1974; Kapahi et al. 1978). Efforts have been made at the Central Institute of Medicinal and Aromatic Plants to increase the diosgenin yield of Costus speciosus by improved agronomic methods. This note is a result of such experiments, in which the effect of different rates of application of N, P and K was studied.

It was observed in a recently concluded study (O. O. BalogunandB. L. Fetuga, unpublished data) that methionine and palm-oil supplementation to a cassava flour-soya-bean meal diet encouraged satisfactory growth, efficiency of live-weight gain, nitrogen retention and carcass quality of weanling pigs. Our earlier reports (Balogun & Fetuga, 1981; Balogun, Fetuga & Oyenuga, 1982) also indicated that the muscles of pigs responded differently to dietary methionine and lysine and that the quantitative requirements of these amino acids for maximum development of the muscles were at variance with the methionine or lysine requirements for maximum growth performance and nitrogen retention.

Vascular injection or infusion of isotopically labelled fatty acids into both ruminant and nonruminant species has been used as a method for determining the entry rate of non-esterified fatty acids (NEFA) into blood (Bickerstaffe, Annison & Linzell, 1974; Vranic, 1975). Results obtained in this way represent the release of fatty acids from several sources, principally adipose tissue. The predominant labelled end-products from [3H]– and [14C]fatty acid metabolism are water and carbon dioxide respectively. Both these metabolites enter extensive body pools and the label is unlikely to be reincorporated into plasma NEFA during the time course of conventional short-term experiments (2–4 h). During isotope dilution experiments, however, some labelled fatty acid could be incorporated into adipose tissue triacyglycerol (TAG) following synthesis of low-density lipoprotein in the liver. In addition, the contribution of NEFA carbon to endogenous acetate production could result in transfer of 14C in any C, or 8H attached to the C8 position in acetate, from the infused fatty acid to fatty acids synthesized by liver and adipose tissue.

The main source of skin surface protein is sweat glands. Studies on skin surface proteins of domestic animals have been made by Joshi etal. (1968), Jenkinson, Lloyd & Mabon (1976, 1979), Lloyd, Mabon & Jenkinson (1977) and Rai, More & Singh (1982). However, information on sweat proteins (skin surface proteins) of goats is lacking. The present study is an effort to characterize sweat proteins of goats and to compare them with those of sheep.