Six silages were prepared from a primary growth of red clover using additives of 21 formic acid/t fresh crop together with formaldehyde at 0, 16, 34, 52, 77 or 117 g/kg crude protein (CP) in the crop. These silages were offered to appetite, either alone or with a urea supplement at 19·4 g/kg total dietary dry matter (D.M.), to 60 British Friesian steer calves with an initial mean live weight of 106 kg.

Formaldehyde treatment restricted silage fermentation, the effect increasing with level of application. However, butyric acid and 2, 3-butanediol content increased at intermediate levels of application. Protein degradation in the silages was reduced by formaldehyde treatment, as evidenced by a decline in ammonia-N and an increase in insoluble-N content with increasing level of formaldehyde application. The recovery of applied formaldehyde in the silages was low (less than 13%) but increased with level of application.

Intake, live-weight gain and feed conversion ratio followed quadratic trends, with formaldehyde having a deleterious effect at high levels of application. The decline in these production measurements was associated with declines in the apparent digestibility of D.M., organic matter (OM), N and energy with increasing level of formaldehyde application, although there was no effect of formaldehyde on cellulose digestibility. Urea supplementation tended to increase intake and live-weight gain at formaldehyde levels greater than 34 g/kg CP, and apart from the expected increase in N digestibility, did not affect the digestibility of other dietary components. As urea supplementation did not overcome the adverse effects of high levels of formaldehyde application on intake, live-weight gain and digestibility, it appears that the supply of rumen-degradable N was not the major limiting factor on these diets.

N retention followed a quadratic trend with level of formaldehyde application, increasing at intermediate levels (30–50 g/kg CP) and then declining markedly at the highest level of application. A similar trend was evident when N retention was expressed as a proportion of live-weight gain, suggesting possible formaldehyde effects on carcass composition. However, carcass composition data did not confirm any formaldehyde effect. Urea supplementation did not affect N retention, and N balance data indicated poor utilization of the supplementary urea N.

When considering the use of formaldehyde, relative to a formic acid control, in additives applied to red olover at ensiling, these data demonstrate little advantage in favour of formaldehyde and serious disadvantages when large quantities of formaldehyde are applied.

Nitrogen (0, 150 kg N/ha), sulphur (0, 50, 150 kg S/ha) and molybdenum (0, 400 g sodium molybdate/ha) fertilizers were applied to kale sown in spring on soils either low (4 mg/kg, site L) or high (22 mg/kg, site H) in sulphate (SO4-S). The plots were harvested after growing periods of 100, 160 and 220 days. Dry-matter (D.M.) yields were determined on each occasion and comprehensive plant analyses carried out on material harvested at 160 days.

Nitrogen application increased both the D.M. yield and nitrate content of kale grown at both sites, and increased S-methyl cysteine sulphoxide (SMCO) content in kale grown at site H and in the plots receiving S fertilizer at site L. Glucosinolate content was unaffected by N application in kale grown at site H, but was higher in the absence than in the presence of N in kale grown at site L. Molybdenum fertilizer had no effect upon D.M. yield or upon any aspect of plant composition.

At site H, S fertilizer application produced a range of soil SO4-S values from 10 to 23 mg/kg on day 160 and had no effect upon either kale D.M. yield or composition. At site L, corresponding soil SO4-S values ranged from 4 to 9 mg/kg; as soil SO4-S was reduced, concentrations of plant sulphate declined first, followed by SMCO and then protein-S (% D.M.), with the reductions in SMCO and sulphate being more pronounced in the presence of N application. Glucosinolate and nitrate contents, and the yields of D.M. and protein N, were unaffected by restricting fertilizer S supply.

It was concluded that SMCO synthesis in kale is stimulated by the application of N when soil SO4-S values are high, but is progressively reduced as soil SO4-S declines below 9–10 mg/kg, particularly if N is applied at the same time to stimulate synthesis of plant protein and hence the incorporation of S into protein. Use of this technique to produce kales of low SMCO content for animal feeding is discussed, utilizing tests to define soils initially low in SO4-S. It was further concluded that sulphate and SMCO function as storage of S that is taken up in excess of requirements for plant protein synthesis, thus explaining their ease of manipulation by soil fertility practices.

First (I1), second (I2) and third-generation (I3) inbreds were compared with openpollinated spring-sown onion populations in field trials at five sites over 2 years. The open-pollinated populations were earlier maturing and gave higher yields and a lower proportion of bullnecked plants than the inbreds but the latter had a lower proportion of unmarketable double bulbs. The mean level of expression of each character differed considerably between individual trials. The effect on sprouting within each year resulted from factors operating prior to storage; bulbs from all sites were stored at Wellesbourne in a common environment yet large differences in the proportion of sprouted bulbs from different sites occurred by the following spring.

Interactions were found between the type of population (inbred and open-pollinated) and the macro-environment. Inbred populations showed a greater linear response to environment for yield, skin colour and proportion of bullnecked plants, but were less responsive for percentage of double bulbs.

The results are discussed in relation to the evaluation procedures for inbreds.

Three experiments were conducted to assess the effects of several methods of dietary presentation of 250 g/day of a fully soluble liquid supplement (LS) on the voluntary intake of oat straw by non-productive cows fitted with a rumen fistula (Expt 1), pregnant beef cows (Expt 2) and lactating beef cows (Expt 3). In each case the cows received fixed daily amounts of barley (2 kg for Expts 1 and 2; 3 kg for Expt 3). LS contained (g/kg) about 1100 crude protein (as urea), 30 calcium, 15 phosphorus and 50 salt plus trace elements and vitamins. In Expt 1, provision of LS in either the drinking water, or via the rumen fistula or sprayed on to the straw increased voluntary straw intake by about 12%. In Expt 2, provision of LS, whether by spraying on the straw or in a molasses lick, increased straw consumption, but giving LS in the drinking water did not. In both Expts 1 and 2 the digestibility of the oat straw was not significantly affected by the dietary supplement, any increases in metabolizable energy intake being reflexions of increased intakes. In Expt 3 there was no difference in the voluntary intake of oat straw by group-fed lactating beef cows offered LS in either the drinking water or as a molasses lick.

Giving LS sprayed on the straw, or incorporating it into a molasses lick to housed animals, are convenient and practical methods of supplementing ruminant diets to increase their voluntary straw consumption. Inclusion of LS in drinking water gave inconsistent results, but the method warrants further investigation.

Conformation of carcasses from 98 steers from ten different sire breeds was classified according to two visual systems and two objective measurements, which were related to both commercial and dissected carcass composition of their hindquarters. The visual carcass conformation systems, unlike the objective systems, accounted for only a small percentage of the variation in some carcass traits after adjusting for the weights of the right hindquarter and of dissected fat from that hindquarter. Of the carcass conformation systems tested, the objective measurement of area appears to be the best predictor of carcass traits, with the variation in the weight of meat being reduced by 13·4% (P < 0·001) by the inclusion of area measurements. It is suggested that an objective assessment of carcass conformation might be of use in a national carcass classification or grading system.

An experiment was carried out over a 3-year period at two locations in the central rainlands of Sudan under rainfed conditions at one site and under supplementary irrigation at the other to study the effects of cultivars and cultural practices on growth and grain yield of sunflower. Four cultivars, namely, Manohurian, Peredovik, Hungarian-A and Hungarian-B and four intra-row spacings of 15, 30, 45 and 60 cm (in rows 60 cm apart) were tested with three sowing dates starting on 15 July and following at 15-day intervals. Manchurian outyielded the other three varieties under supplementary irrigation whereas under rainfed conditions the reverse was true. This was attributed to the relative earliness in flowering of the varieties and their moisture requirements. Manchurian was the tallest with the thickest stem and a larger head at both locations compared with the other three varieties. Under rainfed conditions, the early sowing date of 15 July gave a significantly higher grain yield than the other two sowing dates, with the last sowing date of 15 August giving significantly least. This is attributed to decreasing moisture availability with delayed sowings. But under supplementary irrigation the effect of sowing date was less marked. Contrasting effects of sowing dates on plant height and stem circumference were obtained under the two systems of production. Under rainfed conditions there was a decrease in plant height and stem circumference with delayed sowing, whereas under supplementary irrigation the reverse was true. A contrasting response of plant height to spacing was also obtained; wider intra-row spacing was associated with taller plants under rainfed conditions and shorter plants under supplementary irrigation. Wider spacing was associated with thicker stems and larger heads at both locations. On the evidence obtained, 45 cm intra-row spacing is recommended for rainfed planting and 30 cm intra-row spacing for irrigated production of sunflower.

A study was made of the relationship between yields in particular size grades of carrots and onions and the number of plants per unit area with a view to providing adjustments to yields for differences in plant densities. It is concluded that the relationship for individual small grades cannot be fitted consistently by a single mathematical equation but that estimates of yields in small grades are best obtained by fitting a common equation to the accumulated yield at the limits of the grade and obtaining the yield by difference. Eleven previously published equations which have been shown to fit the relationship between total yield and plant density for a number of crops are compared with one newly developed for graded produce. It was found that the latter,

where y = yield/ha, ρ = number of plants/m2 and A, B and C are constants, generally leads to the best fits when a large range of densities is present, but it is argued that, for adjustment of yields for small differences in densities such as are obtained in variety trials, a simpler equation such as a second degree polynomial is equally effective.

Negative calcium and phosphorus balances were produced in two experiments on six horses fed diets containing 2·6 or 4·3% total oxalate. The main calcium and phosphorus loss was in faeces. The urinary loss of calcium was reduced and that of phosphorus increased. A positive balance of magnesium was maintained. No clinically significant changes in blood concentrations of calcium, phosphorus, magnesium or alkaline phosphatase were produced. The bulk of ingested oxalate was unaccounted for in faeces and urine. It is suggested that the intestinal bacterial flora utilized the oxalate. The results supported the hypothesis that dietary oxalate is the cause of equine nutritional secondary hyperparathyroidism which arises when horses graze several tropical grass species.

An experiment to determine the effect of concentration of boron in irrigation water on tissue Ca/B ratio and yield of lentil, barley and oats is described and the results discussed. Tissue Ca/B ratio is a better index for detecting B toxicity in plants. The grain and straw yield of lentil and barley decreased on and beyond 3 and 6, and 6 and 8 mg B/1 in irrigation water, respectively, but there was no effect on green fodder yield of oats.

Five calcareous soils (pH 7·3–7·7) designated A-E, deficient in or responsive to Zn and containing Fe in the critical or adequate range, were used in a glasshouse study on maize to assess the effects of P alone or in combination with Mg, Zn or both on the content of Fe in maize.

Overall, P significantly depressed Fe in maize. When Mg was applied to a P or PZn treatment, it either depressed or had no effect on Mg in maize but it significantly (P < 0·001) increased Fe. For the soil where Fe in maize was increased with P treatment, the Zn concentration in the tissue was relatively very low. By contrast, in another exception where PMg treatment depressed Fe in maize, tissue Zn concentration was relatively very high. There was a significant negative correlation (r = –0·45; P < 0·05) between Zn and Fe in maize tops.

An experiment was made with growing pigs, to investigate the effect of water restriction in combination with self-fed diets of reduced energy content upon carcass quality.

The diets compared contained 5 and 30% of lucerne hay and the water treatments were ad libitum or progressively restricted amounts during the finishing period (60–90 kg live weight).

Both increasing the proportion of lucerne meal and restricting water intake reduced significantly depth of backfat and the weight of total subcutaneous fat. There was no interaction between the treatments.

The results are discussed in the light of the findings of Cunningham & Friend (1966).

Three plastic formulations of both Dursban and Dimilin were tested as controlledrelease pellets against larvae of C. pipiens and A. aegypti. Each pellet had an initial concentration of 0·116 μg/l. Results showed that Dimilin did not appear to give as high percentages of larval mortality as Dursban although in most cases a clearly delayed inhibition of adult emergence was noted. Larval mortalities of 90–100% were obtained in 3–14 (in the case of C pipiens) and 1–12 (in the case of A. aegypti) days when the second instar larvae were treated with Dursban formulations. With the Dimilin formulations no more than 31% (in case of C. pipiens) and 24% (in case of A. aegypti) larval mortalities occurred up to 13–14 days until completion of pupation.

The results obtained showed that formulation 1 (polyvinyl chloride + dibutyl phthalate + toxicant) was the most effective of the three tested ones, followed by formulations 2 (polyvinyl chloride + dibutyl phthalate + triton X·100 + toxicant) and 3 (polyvinyl chloride + dibutyl phthalate + triton X·100 + ammonium carbonate + citric acid + water + toxicant), respectively. This was so on the basis both of percentage of larval mortality and time post-treatment. The durations of effectiveness of Dursban pellets were 123, 94 and 86 days for the formulations 1, 2 and 3 respectively. However, on the basis of number of tests with over 90% larval mortality, formulation 2 gave the highest level (13 tests) followed by formulation 3 (12 tests) and finally formulation 1 (10 tests). Therefore, consideration must be given to the cumulative effect of these factors of activity when using these formulations for control of mosquito larvae. Activity indices also proved that there was no definite variation in the toxicity of both DDT-susceptible and resistant strains against these formulations. Such results were obtained with Dimilin which confirmed that formulation 3 was the most effective one. The durations of effectiveness were about 112–115 (11–67% inhibition of adult emergence), 111–113 (11–93% inhibition of adult emergence) and 102–113 (12–100% inhibition of adult emergence) days for formulations 1, 2 and 3, respectively, for the susceptible and resistant lines of C. pipiens and A. aegypti.

Results of rostral tooth development determined both visually and by post-mortem radiographic examination were used to provide age ranges and median ages for stages which could be seen between 1 and 2 years old. These showed that intra-oral eruption of the permanent rostral teeth was of little value in age estimation during the second year of life. However, utilizing the stages of tooth development which could be seen radiographically the maximum age range before differentiation was 5 months (1 year 1 month from 1 year 6 months and 1 year 5 months from 1 year 10 months). Thus it appeared that rostral tooth radiography was of more use in age estimation than intraoral eruption of the permanent teeth.

A field experiment was made with pigeon pea (Cajanus cajan (L.) Millsp.) at the Indian Agricultural Research Institute, New Delhi, during the rainy seasons of 1975 and 1976 to study the effects of plant type, plant population density and the application of phosphate fertilizer on growth and yield of pigeon pea. Cultivars BS-1 and UPAS-120 produced significantly more grain with 100 × 103 plants/ha, whereas the cultivar Prabhat produced most when 200 × 103 plants/ha were grown. Application of 13 kg P/ha increased most growth and yield attributes and increased the grain yield significantly over the control to which no P was given; however, no additional increase was obtained when 26 kg P/ha was given. The highest-yielding cultivar BS-1 benefited most from phosphate fertilizer.

Some applications of near infra-red reflectance (NIR) analysis in plant breeding have been tested. Prediction of the nitrogen content of cereals, kale and beans, and nitrogen and oil in rapeseed was sufficiently accurate for screening purposes although wheat straw gave a less accurate result. The prediction of nitrogen content of wheat grain could be supplemented by the simultaneous estimation of grinding resistance and bran cleanliness, characters of importance for bread-making quality. Hagberg falling number, sodium dodecyl sulphate (SDS) sedimentation volume and loaf volume could not be accurately predicted by NIR. Encouraging results were obtained for predicting malting quality of barley and the digestibility of kale samples.

Field studies were made for 2 years on a sandy loam soil under dryland conditions of north-west India with three pigeon-pea varieties in relation to plant density and the application of phosphate fertilizer. Varieties Pusa Ageti and P4785 with better developed root system and profuse nodulation had higher grain and stalk yield, and higher N and P yield than Prabhat. Root and shoot growth and root nodulation were adversely affected with increasing plant densities in the range 50 × 103 and 150 × 103 plants/ha. Stalk and total N and P yield increased with increasing plant density. Plant density of 117 × 103 plants/ha produced maximum grain yield of 1·53 t/ha. Phosphorus fertilizer promoted root and shoot growth, intensity and volume of nodulation and increased grain, stalk, N and P yield. The effect of plant density on grain yield was more pronounced in the presence of phosphate fertilizer. The economic optimum rate of P ranged between 22·1 and 23·1 kg/ha under different plant densities.

The growth and development of two new maize hybrids (FARZ 27 and FARZ 23) were studied in density experiments located at two contiguous ecological zones in Nigeria. The range of planting density used was from 2·6 to 6·6 plants/m2. Within this range, the relationship between dry-matter yield and density was asymptotic at final harvest. At the forest location of Jago (7·3 °N, 4·2 °E), both varieties attained optimum grain yield at planting density of 4·4 plants/m2, while at the derived savannah location of Alagunmu (7·8 °N, 4 °E), FARZ 23 attained optimum grain yield at 4·4 plants/m2 and FARZ 27 attained its optimum grain yield at 6·6 plants/ma2. This response of the new maize varieties to density treatments indicates that they could be planted at higher densities than are now used in the country.

Differences between varieties did not quite reach statistical significance but, at both locations, FARZ 27 produced more dry matter and grain per unit area than FARZ 23. FARZ 27 gave its higher grain yield mainly by producing more seeds per unit area than FARZ 23. Physiological measurements like net assimilation rate, crop growth rate and leaf area index were also higher for FARZ 27, although there were no significant differences between the varieties at most sampling dates. The partition of dry matter was identical in both varieties, although FARZ 27 showed a slightly better balance by partitioning more assimilates to the grain. Also, there was an indication of remobilization of stored assimilates from the stem to the grain in both varieties. Both varieties produced more dry matter and grain at the derived savannah location of Alagunmu than at the forest location of Jago. Physiological measurements were also higher at the derived savannah location.

Field experiments were made at the Punjab Agricultural University, Ludhiana, during 1974–5 to 1978–9 to study the possibility of improving wheat yield by more efficient use of radiant energy through modification of the shape of the canopy under varying levels of fertilizers, irrigation and seed rates. The results showed substantial yield increase by sowing half the seed and fertilizers in one direction and half in rows at right angles, giving a spacing of 22·5 × 22·5 cm, thereby intercepting more light, which showed a significant direct relationship with yield, but there were negative correlations with soil temperature. The increase in row spacing decreased the yield. With 33% extra fertilizer than the local recommendation, sowing the crop in two directions gave 0·96 t/ha (33·4%) higher yield, whereas none of the other sowing methods showed significant increase. Mixing varieties to form a prismatic canopy gave higher yield than the mean of the varieties sown alone. Irrigating the crop more than thrice did not prove beneficial. North-south row direction tended to improve yield compared with east-west rows. Seed rates varying from 50 to 200 kg/ha showed neither significant effect, nor interaction with canopy shape except in 1978–9 when 150 kg seed/ha showed yield improvement over 100 kg/ha.

The nutritive value of a new forage pea (Pisum arvense), commercially available as ‘Rosakrone’, was assessed by feeding the seeds in ground form to laying hens as a supplementary source of protein in diets based on mixed cereals. Like other pulse seeds they were found to be relatively deficient in methionine. The effect of this on egg production was overcome by adding synthetic methionine to the diet.

However, there was also present an anti-nutritive factor, similar in action to that found in other pulse seeds, which caused live-weight loss and reduced the rate of lay to about 0·85 of normal in 20 weeks with 40% pea meal in the diet. This anti-nutritive factor appeared to be heat stable.

Measurements were made of changes in body water, estimated by the dilution of deuterium oxide, in six Hereford x British Friesian lactating cows in their second lactation and in four of the same animals in their third lactation. The animals were subjected to a prolonged period of underfeeding followed by a period of realimentation. Milk yields were measured twice daily whilst measurement of live weight and certain blood constituents were made at 7-day intervals during the experimental periods in both years. During underfeeding milk yield differed markedly among the cows and it appeared that the cows with a higher milk potential maintained a higher yield but in doing so they incurred a greater loss of body weight. On refeeding there was little or no response in milk yield. Weight losses during the second lactation consisted mainly of body fat (calculated by difference) but the four higher yielding cows lost appreciable amounts of body water and probably significant amounts of body protein. In the third lactation all four cows lost less body fat but more body water and probably body protein than they did in the second lactation. On refeeding all animals in both years except the two lowest yielders in the second lactation gained substantial amounts of body water and probably protein but relatively little or no body fat. Significant negative and positive correlations were obtained between plasma glucose and loss of body water and between plasma free fatty acids and loss of body fat respectively.