Five male animals of each of the following species, zebu, eland, small East African goat, fringe-eared oryx and Dorper sheep, were penned, and their water intake measured and metabolic water production estimated. The figures for water input were compared with simultaneous measurements of body-water turnover by liquid scintillation counting of tritiated water in plasma, following dioxane precipitation. It was found that the resultant regression was sufficiently linear with the intercept near zero to justify the use of a ratio to predict input from turnover. The tritiated water turnover overestimated the water input by an amount approximately equal to the overestimate of the body water pool by the tritiated water space. Although there was a considerable amount of variation in individual ratios which could not be explained, there was no significant difference in the mean ratios between species.

An experiment is desoribed which was conducted for 2 years under dryland conditions of north-west India to evaluate the optimum rate of application of N fertilizer and plant population density for a rapeseed crop. Stomata closing (phenyl mercuric acetate), film forming(Mobileaf) and reflective type (kaolinite) antitranspirants were used to examine their effectson conservation of stored moisture for a possible increased water use efficiency under drylandconditions.

The rapeseed crop responded to N fertilizer and it was profitable to use 53 kg N/ha xinder these conditions. In a drier year a wider row spacing of 60 cm (1·1 x 106 plants/ ha) was significantly better than narrower spacing of 30 cm (2·2 xlO5 plants/ha). Plants grown in wider row spacings utilized less water during the vegetative and flowering stages than those grown in closer spacings.

The relative water content of leaves sprayed with antitranspirants was greater than in the control plants. The leaf temperature of the kaolinite-treated canopy was 1·5 °C lower than the ambient air temperature. Averaged over 2 years, the film-forming antitranspirant Mobileaf increased the seed yield by 26% while spraying with phenyl mercuric acetate at 50 and 75 days and kaolin application at 50 days increased the rapeseed yield by 11, 18 and 17% over the no antitranspirant treatment.

The mixed buffer salts of artificial saliva were incorporated at three rates: 0 (diet 1), 5·7 (diet 2) and 11·4% (diet 3) (w/w) in pelleted diets prepared from60% ground flaked maize and 40% dried ground grass. The control and mineral-supplemented diets were fed to sheep hourly (Expt 1) or twice daily (Expt 2).

When the sheep were fed hourly or twice daily the pattern of fermentation in the rumen was altered from a predominantly propionate to mainly acetate fermentation. Dilution rate in the rumen increased from 0·036 to 0·053 to 0·064 when diets 1, 2 and 3 were fed hourly, and dilution rate was negatively related to the molar proportion of propionic acid (P < 0·05) and positively related (P < 0·05) to the molar proportion of acetic acid in rumen fluid, but these relationships were not apparent in Expt 2.

Nitrogen retention was higher for lambs fed diet 2 than for those fed diets 1 and 3 (P < 0·05) in Expt 1.

In sheep fed hourly, selenomonads and bacteroides were the predominant rumen bacteria associated with the control diet but the inclusion of mineral salts resulted in the bacteroides being replaced by large number of chain-forming cocci. Numbers of protozoa were variable. The relationship of these changes to the fermentation pattern is discussed. In sheep fed twice daily there was much variation between animals.

The increase in dry weight of field lettuce from sowings made between March and August in 1973 and 1974 started exponentially but this did not persist throughout growth. Departures from exponential growth were most marked in the 10 days of growth prior to maturity and a logistic rather than an exponential curve gave a better overall fit to the data. The rates of increase in plant dry weight were similar from all sowings made between mid-May and early to mid-July, when air temperatures and total radiation during the growth period of these crops exceeded 11–12 °C and 250 mWh/cm2, respectively. Sowings made earlier than mid-May took longer to mature and in 1973 gave crops with lighter heads. Quadratic regressions of harvest date on sowing date gave good fits to data obtained in different years at different sites but separate equations were required for each site.

Data are reported from three experiments from 1972 to 1974 in which the effects of two row widths (66 and 132 cm) and five planting densities on the growth of two maincrop potato varieties (Désirée and Maris Piper) were studied. The results were consistent over the 3 years and showed that the effects of widening the row width were to reduce the number of axillary branches and their leaves per plant, in Maris Piper L (leaf area index), and early in the season in both varieties dry weights of leaf, stem and underground parts per plant. Row width had no effect on tuber dry weight for most of the season but at the end of sampling, tuber dry weights were greater from 132cm than from 66 cm rows. Increasing planting density reduced number of axillary branches and their leaves per plant, dry weight of leaf, stem, underground parts and tubers per plant, but increased stem length and tuber dry weight per unit area.

Leaf growth of all treatments was rapid during May and high planting densities reached an Lof 3 before the end of this month. L was increased by increased planting density throughout growth, but the lower densities were able to maintain an L of 2–3 formuch of the season. The rapid early increase in L was not associated with any prematuredecline and high rates of tuber dry-matter accumulation were achieved and maintained throughout the season. It is suggested that as the pattern of leaf growth in this environment is coincident with changing light receipts, the environment is almost ideal for the growth of maincrop potatoes.

The joint scaling test of Cavalli (1952) and the six-parameter procedure of Jinks & Jones (1958) were applied to test the adequacy of the additive-dominance model and to estimate various main and interaction gene effects for five characters, namely, final plant height, ear length, number of spikelets per spike, number of grains per spike and yield per plant, in three wheat crosses (Kalyan Sona × Norteno 67, Norteno 67 × WL 212 and K. Sona × Moti). Goodness of fit of the model varied from cross to cross for the same character except for number of grains per spike and yield per plant for which the model was inadequate for all three crosses. The two methods were in complete agreement regarding the presence of epistasis in the material. Among the interaction parameters, the component [1] showed the greatest effect for most of the characters in all three crosses where there was evidence of epistasis.

Experiments were made to evaluate the feeding value of undecorticated (UCS) and decorticated (DCS) cottonseed cakes and defatted DCS for egg-type starter, broiler starter and finisher diets for chicks. The results showed that UCS on average contained 22% crude protein, 0·06% free- and 0·33% bound-gossypol and 4·9% available carbohydrate. The corresponding values for DCS were 38, 0·04, 0·63 and 9·5%, respectively. Average metabolizable energy (ME) content of UCS, DCS and defatted DCS was 7·94, 11·77 and 9·42 MJ/kg, respectively. Apparent protein digestibilities of UCS, DCS and defatted DCS were 42, 47 and 36%, respectively. Although UCS had no effect on growth rate of egg-type and meat-type chicks when fed as 15% of the diet, feed conversion was adversely affected. Feeding DCS to broiler starter and finisher chicks as 30% of the diet, replacing groundnut cake (GN) had no effect on growth rate and efficiency of protein utilization but feed conversion was affected. The chicks of either breed were able to tolerate 0·02% free-gossypol of the diet derived from UCS or DCS without any adverse effect on growth rate and internal organs.

A total of 225 herbage samples were taken from two areas with a history of bovine hypocupraemia and examined for their Cu, Mo, total S, Zn, Fe and Cd content.

In general, the concentrations of Cu and Mo (mean values 10·4 and 1·6 mg/kgD.M. respectively) were normal, as were those of Zn, Fe and Cd (mean values 43, 255 and 0–59 mg/kg D.M. respectively). The total S concentrations (mean value 3·5 g/kg D.M.) were, however, higher than found by some other workers.

The concentrations of available herbage Cu were calculated using the following relationship of Suttle & McLauchlan (1976):

logTA Cu = –0·0019 Mo–0·0755 S–0·0131 Mo × S–1·153,

where TA Cu is the true availability of Cu, and Mo and total sulphur (S) are dietary concentrations as mg/kg D.M. and g/kg D.M. respectively. Animal requirements for available Cu were derived from estimates of the factorial Cu requirements of various classes of livestock, and when these were compared with the calculated concentrations of available Cu in the herbage they provided a possible explanation for the widespread hypocupraemia experienced in these areas.

Data are reported from three experiments from 1972 to 1974 which examined the effects of two row widths (66 cm and 132 cm) and five planting densities on number of tubers, tuber yields and tuber saleability of two maincrop potato varieties (Désirée and Maris Piper). Fewer tubers were generally found in 132 cm rows than in 66 cm rows; in 1972 reductions were most marked at high densities in both varieties and in 1974 effects were most pronounced in Maris Piper. Row width had little effect on total tuber yield at any stage of growth in either variety. The use of 132 cm rows reduced tuber greening, so that yields of saleable ware tubers at final harvest were not reduced by 132 cm rows in any year and in 1973 were higher in Désirée from 132 cm rows than from 66 cm rows. These results suggest that wider rows than are currently used in practice should be considered for maincrop potatoes, especially where water is not limiting.

Increasing planting density increased total yields in both varieties although the responsesto the final increments in planting density were small. Yields > 38 and > 57 mm declinedat the higher planting densities in Maris Piper and the optimum above-ground stem densities for ware grades differed markedly in the two varieties. Good relationships between tuber yieldsand number of above-ground stems were found in all years and support the use of stems as thebasic unit of density in this crop.

Seventy-eight Finnish Landrace × Dorset Horn ewes in lamb to Suffolk rams were slaughtered serially between 50 and 145 days of gestation. The mean litter size was 2·7. The daily feeding regime aimed to provide each ewe with 15 MJ of metabolizable energy (ME) in the first month of gestation and 9·4 MJ in the second and third. Thereafter the ewes were provided with a basal intake of either 9·6 MJ (low plane, LP) or 13·4 MJ (high plane, HP) plus 1·3 MJ for each foetus.

For ewes with 2, 3 and 4 foetuses the mean percentage changes in maternal body weight over pregnancy were respectively — 5, — 10 and — 14 (LP) or + 3, — 2 and — 6 (HP). Changes in weights of blood, liver and the empty gastro-intestinal tract through gestation varied with the plane of nutrition but not with number of foetuses. In contrast, udder weight at parturition was dependent on number of foetuses but not on plane of nutrition.

Increased hydration of the maternal tissues in late pregnancy tended to mask concurrent losses of body fat. For example, over the last 2 months, HP ewes carrying quadruplets lost on average 1·0 kg in body weight but 5·5 kg of (chemically determined) fat. The latter was lost at a rate which increased up to an average of 170 g/day over the last 2 weeks of pregnancy. Net changes in body protein were estimated to be relatively small, but there was some redistribution, including loss from muscle and gain by the udder. There was no evidence of any demineralization of the maternal skeleton.

The practical significance of the changes in body composition is discussed, in particular that of the increasing rates of loss of body fat with increasing litter size. It is suggested that the dangers implicit in these rates of fat loss must be taken into consideration when deciding on dietary regimes and the timing of breeding cycles for highly prolific ewes, or indeed when embarking on a programme of increased prolificacy.

Cakes derived from Taramira (Eruca sativa), Raya (Brassica juncea), Toria (B. campestris var. toria) and yellow and brown sarson (B. campestris var. sarson) were evaluated for their contents of crude protein, true protein, essential amino acids, available carbohydrate and tannins. Feeding trials were also conducted to compare the suitability of these cakes with groundnut cake for broilers and White Leghorn chicks up to 4 weeks of age.

The crude protein content of Taramira cake was 33% whereas all the other cakes contained 37–38%. True protein accounted for 80–83% of crude protein in all the varieties and albumin and globulin constitutes the bulk of protein. The critical amino acid content of all the brassica seed proteins was found to be higher than that of other vegetable proteins although varietal differences were observed with respect to a few essential amino acids. The hulls accounted for 19% of whole Brassica seed and their removal raised the concentration of protein from 39 to 46% and reduced the crude fibre content from 15 to 6% in the defatted meal. Tannin content was higher in Taramira (1·74%) than in all other varieties (1·0–1·4%) and the major quantity of it was localized in the endosperm. The average metabolizable energy content of all the mustard cakes was 9·62 and 8·75 MJ/kg for meat-type and egg-type chicks, respectively. The nutritive value of Taramira cake was poorer than that of other Brassica cakes or groundnut cake for supporting growth rate of chicks of either breed.

Investigations of the reasons for the instability of emulsifiable concentrates (ECs) during storage and a study of reprocessing insecticide ECMs whose emulsification propertieshad deteriorated during storage is reported. Bioassay showed that very stable emulsions, although physically perfect, leave inadequate residues on the treated leaves. When a deteriorated EC was reprocessed, its emulsification properties were restored, resulting in better adherence of the insecticides on the leaves' surfaces; the residual toxicity was increased.

Comparative evaluation was made on the live weight and growth pattern of calves from Bunaji (White Fulani) cows sired by Charolais, three-quarters Friesian crossbreds (three quarters Friesian and one quarter Bunaji) and Bunaji bulls in 2 years. Twelve steers per breed were evaluated on carcass merit after 250 days postweaning feeding.

Results showed that the Charolais half-cross and the Friesian three-eighth calves were heavier by up to 7, 23, 57 and 51 kg respectively at birth, weaning, 112 and 250 days after weaning than the Bunaji calves. The carcass data indicated superior slaughter weight and loin eye area in favour of the cross - breds, but no differences were found for dressed weight, dressing percentage, carcass grade and hide weight percentage among the breed groups. Carcass retail cuts showed heavier sirloin steaks and round steaks in favour of the cross-breds also.

The results were indicative of the superior growth of the cross-breds and underlined their carcass potential which may be useful in upgrading the indigenous stock. In view of the small numbers of progeny per sire group, especially among the cross-breds, further work needs to be done to confirm the present trend.

The drying rate of fully exposed individual lucerne plants was substantially increased following brief immersion in 0·18 M potassium carbonate solution. The increase was maintained over a range of drying conditions, and at low moisture contents, but the use of more concentrated potassium carbonate solutions yielded no further increase. Changes in leaf:stem ratio had a smaller effect on the drying rate of potassium carbonate treated lucerne than on untreated lucerne.

Tests with diffusive resistance and viscous flow porometers support the hypothesis that potassium carbonate solution changes the water transmitting properties of the cuticular waxes.

In three experiments, ryegrass and lucerne were ensiled for 100 days in test-tube silos containing about 100 g of crop either without additive or after the addition of paraformaldehyde or formalin to provide 0·1–0.4% of the fresh crop weight as formaldehyde (HCHO). When applied as prills containing 82% HCHO, paraformaldehyde was as effective as formalin in restricting fermentation and preventing extensive protein breakdown at comparable HCHO application rates. The lower solubility of paraformaldehyde containing 98 % HCHO as powder or prills made these forms less effective than formalin in restricting fermentation. Paraformaldehydecontaining 98% HCHO was, however, effective even at the lowest rate of application, in preventing clostridial-type fermentations when these were present in silages made from untreated crops.This was in contrast to formalin which promoted such fermentation at low rates of application.

Eight amounts of nitrogen ranging from 0 to 210 kg N/ha were applied to two tall and one semi-dwarf variety of winter wheat in the spring of 1975 and 1976. The tall varieties were Cappelle-Desprez and Maris Huntsman; the semi-dwarf variety was Maris Fundin in 1975 and Hobbit in 1976. Interactions between varieties and nitrogen were few and small compared with the main effects. All varieties produced their maximum grain yields with 180 kg N/ha. The yield of the semi-dwarf varieties, but not the others, decreased slightly with more nitrogen.

Cappelle-Desprez yielded less grain than the other varieties in both years. In 1975 the yields of Maris Fundin and Maris Huntsman were similar and in 1976 Hobbit yielded more than Maris Huntsman. The varieties had similar numbers of ears at maturity and similar patterns of tillering. The semi-dwarf varieties had most grains per spikelet, and hence grains per ear, and Cappelle-Desprez had least. The semi-dwarf varieties had the smallest grains. The semi-dwarf varieties had less straw than the other varieties and hence the largest ratios of grain to total above-ground dry weight. The decrease in dry weight of stem and leaves between anthesis and maturity was similar for all varieties. In 1975 the efficiency of the top two leaves plus top internode in producing grain was the same for all varieties, but in 1976 Hobbit was more efficient than the other two. There were some small differences between varieties in nutrient uptake that were not related to differences in growth. Maris Fundin tended to have a greater phosphorus and potassium content than the tall varieties. Hobbit contained slightly less nitrogen than the tall varieties at maturity, and had a smaller concentration of nitrogen in the grain.

Applying 210 kg N/ha doubled grain yield in 1975. Applying nitrogen resulted in a largeincrease in number of ears and a small increase in number of grains per ear due to the development of more fertile spikelets per ear. Nitrogen decreased dry weight per grain, especially of the semi-dwarf varieties. With extra nitrogen, straw dry weight at maturity, shoot dry weight atanthesis and leaf area were all increased relatively more than grain yield, and stems lost moredry weight between anthesis and maturity than without nitrogen. The year 1976 was exceptionallydry and nitrogen had only small effects in that it affected neither straw dry weight nor numberof ears but slightly increased grain yield by increasing the number of spikelets and number of grains per spikelet. It also increased leaf area proportionately to grain yield. In 1975 nitrogen increased evaporation of water from the crop before anthesis but decreased it after anthesis, even though it continued to increase the extraction of water from below 90 cm.

The nutritive value of uromol, a heated product of urea and molasses, was compared with raw urea–molasses and groundnut meal in three metabolic trials on buffalo calves. The non-protein nitrogen (NPN) as urea or uromol contributed about 65, 48 and 30% of the nitrogen in the experimental concentrate mixtures, replacing partially or completely the groundnut meal of the control diets. The results showed that at 65% nitrogen replacement, the crude fibre and cellulose digestibilities and the nitrogen retention of the uromol diet was similar to that of the control but was significantly (P < 0·05) higher than the urea–molasses diet. At 48% nitrogen replacement the nitrogen retention in the uromol-fed animals was still significantly (P < 0·05) higher than the urea–molasses fed group. At 30% nitrogen replacement, the differences between the control, urea–molasses and uromol groups were not significant.

In vivo rumen studies with the diets containing 50% NPN replacement showed lower but sustained ammonia-N with uromol than the urea–molasses diet. The total volatile fatty acids (TVFA) in rumen fluid, though initially higher in the control and uromol groups, were not significantly different from the urea–molasses group. Abomasal studies with diets containing 65% N as urea or uromol indicated a higher total nitrogen content in the abomasal fluid of the control and uromol-fed animals than the urea-fed animals. The 24 h abomasal passage of total-N/100 g nitrogen consumed was 95·5, 93·5 and 77·9 g in control, uromol and urea groups, respectively. The TCA-precipitatable-N (TCA-N) was also higher in the first two groups. These studies suggest that uromol is safer and has a better feeding value than urea–molasses at high rates of nitrogen replacement.

In two field studies it was found that lucerne hay swaths sprayed with 3000 1/ha of 2% (w/w) aqueous potassium carbonate solution after cutting dried more rapidly than mechanically conditioned or control swaths; the ratio of drying rates being 2·17:1·43:1·00 respectively. Hay yields were increased in one of the two studies by the use of potassium carbonate.

The effect of different application rates was studied in a third trial using 200, 500 and 875 1/ha potassium carbonate solution, compared with mechanically conditioned and control swaths. After only 29 h of field exposure all swaths treated with potassium carbonate had dried to moisture contents below that required for baling (moisture: dry matter ratio < 0·3).

Setts of water yam (Dioscorea alata) weighing 350, 100, or 20 g were grown in the field. Tuber formation occurred in 50% of the plants at 8, 9·2, and 11 weeks after planting respectively, thus showing delayed tuber formation as sett weight decreased. Leaf area per plant and tuber yield per plant decreased with decreasing sett weight, but the tuber multiplication ratio increased with decreasing sett weight. There was a high coefficient of variation for tuber yield per plant and for leaf area per plant. It is suggested that the delayed tuber formation for small setts may be partly responsible for the low tuber yield per plant observed.

Field bean varieties were grown for 2 years on five plots varying in pH from 4·7 to 8·4. Non-aggressive Chocolate Spot infection was shown to be greater on plants grown in soil of pH 4·7 and 5·8 than on those grown in soil of pH 6·7, 7·7 and 8·4. Seed weight per plant was greater on soil pH 7·7 than on soil pH 4·7, suggesting that acid soil reduced plant vigour and consequently increased disease susceptibility. Varietal differences in infection were shown, although absolute resistance was not observed. Varieties differed in their susceptibility on soils of varying pH, and also showed different stability for susceptibility over the varying environmental conditions.