Corriedale and Dorset Horn castrate male (wether) lambs reared at pasture were weaned at 19 kg live weight (LW), brought indoors and fed a high protein diet such that half of each group grew at ca. 200 g/day and the other half at ca. 100 g/day. Animals were slaughtered at 25 and 30 kg LW and chemical composition (protein, fat, energy, water and ash) of the body determined. The relationship between each body component and shorn empty-body weight was examined by regression analysis.

Within levels of feeding the results were similar in the two breeds. When comparisons were made between feeding levels, the slower-growing animals contained more fat, energy and ash than the faster-growing group, less water, but similar amounts of protein at any given empty-body weight.

Forty-eight 4-month-old lambs, reared worm-free from birth, were allocated to six groups and offered ad libitum a complete diet containing 139 g crude protein/kg D.M. One group was killed at the outset as initial control (CI). Further groups, ALC, 1, 2, 3 and 4 were dosed daily for 84 days with zero, 1000, 3000, 5000 and 5000 larvae of Ostertagia circumcincta, respectively. Lambs in group 4 also received anthelmintic (fenbendazole, 5 mg/kg) on days 21, 42, 63 and 84. Lambs were killed after 98 days and their carcasses and those of the initial controls analysed for fat, protein and mineral contents.

Wheat (Triticum aestivum L.) cv. Gamenya was grown in a Mediterranean type environment in two separate field experiments, to determine the effects of nitrogen application and date of seeding on floret survival. One treatment, intermediate in nitrogen level and sowing date, was common in both experiments. Rates and durations of spikelet initiation and durations of the floret initiation period were estimated. At maturity, yield and yield components were measured and occurrence of individual grains at each floret position on odd-numbered spikelets were recorded. The time of floret initiation relative to terminal spikelet formation and the subsequent occurrence of grain were examined.

Florets developed first in spikelets 5-13 and last in spikelet 1. Added nitrogen hastened the initiation of florets but did not affect the number initiated; it also increased the numbers of grains per spikelet. In the last sowing date treatment, time to floret initiation decreased, but the sequence of floret initiation was unaffected.

Numbers of florets and grains on tillers were less than on main shoots. Only about 28% of all florets initiated developed into grain.

The main conclusion was that the florets which initiated before the terminal spikelet formed grain and those that initiated afterwards did not; we accordingly postulate that the vascular system between the rachis and the floret develops as the floret is initiated, but that after terminal spikelet formation, this is inhibited and further grains then fail to develop.

The effects of plant population density, defoliation and removal of pods and apical buds on dry matter, nodulation and nitrogen accumulation in field bean (Viciafaba L.) were investigated in the field in 1973 and 1974.

In 1973 seed yield, dry matter and nitrogen accumulation were similar at 50 and 150 plants/m2 while in 1974 40 plants/m2 was significantly different from 80, 120 and 160 plants/m2 which were similar in these attributes. At similar densities, these crops generally had similar leaf areas and nodule weights/m2 during the early pod-filling period while at earlier growth stages leaf area and nodule development were greater at the higher plant population densities. Leaf area and nodule weight per plant were positively correlated as were absolute growth rate per plant and nitrogen assimilation rate per unit weight of nodule.

Substantial leaf removal reduced weight but not the nitrogen assimilation rate of nodules determined from plant nitrogen content. Leaf removal did not significantly reduce dry matter but reduced nitrogen yield by reducing seed yield provided that the removed leaves were accounted for.

Pod removal reduced dry-matter and nitrogen yield as well as nitrogen assimilation rate of nodules. Pod removal, however, substantially increased number and weight of nodules. Most of these late-formed nodules were located on the older parts of the lateral roots. Removal of the shoot apex had minor effects on nitrogen yield but reduced nodulation towards the completion of pod-filling.

In a comparative study of some factors that influence the body weights of 36 Friesian, 54 Holstein, 22 Holstein-Friesian, 24 Jersey and 17 Brown Swiss calves born during 1964–9 at the Moor Plantation dairy herd, Ibadan, breeds differed significantly (P <0·01) at all ages. Highly significant sex differences (P <0·01) existed at 4 and 8 weeks of age. The season of birth significantly influenced the weight at 4 and 8 (P < 0·05) and at 12 weeks (P < 0·01). The season × sex and season × breed interactions significantly affected the weights at virtually all ages but the sex × breed interaction did not. The birth weight exerted a highly significant influence (P < 0·01) on all other body weights. It reduced the residual variation as well as the differences and interactions between the main effects. After adjusting for birth-weight differences, body weight was significantly (P < 0·05) influenced at various ages by breed of calf, season of birth, sex × breed and season × breed interactions. The sex and season × sex interaction effects on adjusted body weights at all ages were negligible (P > 0·05).

Experiments were made on a sandy clay loam soil with five crops to determine the effects of thorough loosening of the subsoil and deep incorporation of nutrients on yields during the subsequent 4 years.

Loosening to 0·9 m increased fresh-weight yields by between nil and 95% depending on the crop and season. Responses were still considerable 4 years after the initial loosening and there was no evidence of any decline with time. Deep incorporation of nutrients did not improve yields.

Loosening gave a durable increase in the volume of coarse pores and decreases in bulk density and penetrometer resistance. It also nearly doubled the rate of root extension when estimates were made for one crop, consistently increased water extraction from below 30 cm and, on occasion, reduced plant water stress.

It is concluded that most of the benefits from deep loosening resulted from improvements i the rate at which plants could extract water rather than nutrients from the subsoil.

Substrate and nitrogen metabolism of ruminant muscle was studied in vitro using a perfused sheep hemidiaphragm preparation. Glucose, acetate, propionate and butyrate were taken up by the perfused muscle at a constant rate over 2 h. Rate of acetoacetate uptake declined over the perfusion period. Net production of 3-hydroxybutyrate over the perfusion period was observed.

Release of alanine and glycine by the perfused muscle could not be accounted for by protein breakdown, implicating muscle as a site of synthesis of these amino acids. The perfused muscle metabolized aspartate and arginine to a considerable extent, but the branched-chain amino acids only to a small extent. Only a small proportion, approximately 5%, of the alanine produced by the perfused muscle was derived from glucose.

In the presence of amino acids, at twice the concentration found in plasma, and insulin, some amino acids showed a net uptake by the diaphragm but when cysteine was omitted from the perfusate, all amino acids with the exception of arginine showed a net output. Evidence was obtained that protein synthesis was reduced in the absence of cysteine. The output of Nτ methylhistidine by the preparation was much higher than could be accounted for by estimates of protein breakdown using isotope dilution techniques. These data are, however, consistent with the view that Nτ methylhistidine is not a good index of muscle protein breakdown in sheep.

Right sides of carcasses of 12 buffalo, nine ½ Friesian ( Friesian x Egyptian Baladi) and nine ¾ Friesian ( Friesian x ½ Friesian) bulls slaughtered over the body-weight ranges 161–560 kg for buffaloes and 176–448 kg for cattle were cut according to the Chicago style of cutting. Allometric growth pattern and distribution of muscle and bone in the various cuts were examined.

Buffaloes were similar to cattle in that muscle and bone in the limbs showed an increasing distoproximal growth gradient. On the ventral line of the trunk, muscles showed an increase in growth impetus from plate to brisket while bone followed a reverse pattern. In buffaloes, growth coefficients of muscle and bone of all dorsal cuts were similar except in the sirloin and chuck where bone was later maturing. In cattle, there appeared a posterior-anterior increase in growth impetus of muscle from the shortloin towards sticking. Within and between genotype-group results indicated that growth of a fatless cut is governed by the growth of its muscle rather than that of its bone.

Compared with Friesian crosses, buffaloes had significantly greater percentages of their total muscle and muscle-plus-bone in the expensive cuts. As total muscle weight increased, the proportion of muscle in BLRC (see p. 318) decreased in cattle but remained almost constant in buffaloes. It was concluded that the previously reported inferior carcass composition of buffaloes relative to cattle is compensated by better carcass conformation and tissue distribution of buffaloes.

Literature dealing with disposal of farm wastes is mainly concerned with smell, heavy metal toxicity, nutrient accumulation and soil physical conditions. Soil is required to filter and absorb the solid material and release a filtrate free from pollutants while remaining relatively unaltered. The importance of soil type in reducing pollution potential is recognized but little study has been made of the effect of pollutants on soil morphology. This paper reports changes observed in a fine silty and fine loamy typical brown earth of the Rheidol series on terrace gravels after treatment with pig slurry. It is concluded that pig slurry spread at the rate of 50 m3/ha per week will cause this permeable soil to deteriorate under an average rainfall of 1117 mm/year unless rest periods are given.

Four synthetic pyrethroids: fenvalerate, deltamethrin, cypermethrin and permethrin were evaluated as spray deposits on cotton leaves for their contact toxicity to adults of the parasite Chelonus blackburni Cameron (Braconidae). Fenvalerate was found to be the least toxic of the four pyrethroids. In another study five organophosphorus insecticides (profenofos, bromophos ethyl, chlorpyrifos, quinalphos, monocrotophos), three carbamates (U.C.51762, carbosulfan, bendiocarb) and diflubenzuron were evaluated for their contact toxicity to the same parasite. U.C.51762 (carbamate group experimental insecticide) and diflubenzuron were less toxic while the five organophosphorus insecticides, carbosulfan and bendiocarb were highly toxic to the parasite.

Contact toxicity of spray deposits of four synthetic pyrethroids were studied against parasitization and subsequent development of the parasite C. blackburni on thin strips of egg cards Corcyra cephlonica Stainton. It was observed that fenvalerate was not reducing oviposition or affecting subsequent development of the parasite and emergence from the parasitized eggs while the other pyrethroids, permethrin, cypermethrin and deltamethrin, were toxic.

Soils from grass-arable cropping sequences and from an experiment where grassland had been treated with slurry were dispersed by shaking as a soil-water mixture, followed by ultrasonic treatment. Organo-mineral particle size fractions were separated by sieving and by sedimentation.

Generally, concentration of C and N in the fractions decreased with increasing particle size. However, when expressed as weight of C per fraction maximum contents were in the 2–10 μm range. With N, maximum contents occurred about 2 μm. Largest differences in C and N contents between soils were found in the 0·2–20 μm size range.

Identification of the source of the materials in the various fractions was attempted by interpretation of the C/N ratios, but was generally inconclusive.

Sheep were used to study the utilization of low quality native hay supplemented with urea by different methods. Urea supplement was fed either once daily or twice daily or the same quantity of urea used to spray the hay before feeding. These treatments were compared with basal and groundnut cake based supplemented controls. An attempt was made to balance both the mineral and energy intakes. The provision of extra nitrogen in the form of either urea or groundnut cake resulted in improved weight gain, feed intake and feed conversion. Feeding of urea-sprayed hay marginally improved live-weight gain, feed intake and feed conversion over the other methods of urea supplementation. Dry-matter digestibility and nitrogen retention were increased and urinary nitrogen excretion reduced by feeding the urea-sprayed hay.

Pre-anthesis stem reserve contribution to grain yield was assessed in two spring barley cultivars of contrasting height. It was greatest in the taller, but final grain yields were similar. Partitioning of total reserve capacity to various plant parts showed that the leaf and sheath below the peduncle were most important, followed by stem internodes which had increasing reserve capacity up to internode 4.

It is suggested that stem reserves are valuable for yields commonly achieved in U.K. commercial practice.

High grain yields were associated with large positive increases in stem dry weight after anthesis. This would indicate that the source capacity to boost yield is more than proportional to that required to fill the grain alone.

In a 3 × 3 latin-square design experiment, 12 British Friesian steer calves with rumen cannulae were offered three red clover silages to appetite, either alone or with a urea supplement of 18.9 g/kg total dietary dry matter (D.M.). The silages were prepared from a second cut of red clover using additives of 2·11 formic acid/t fresh crop together with formaldehyde at 0, 31 or 123 g/kg crude protein (CP) in the crop.

The control silage was well preserved, as indicated by a low content of volatile fatty acids and ammonia N. Formaldehyde treatment generally restricted silage fermentation, although there was an increase in the content of butyric acid at the intermediate level of application, and an increase in 2, 3-butanediol content at the high level of application. A decline in ammonia-N content and an increase in insoluble-N content, with increasing level of formaldehyde application, indicated that formaldehyde had been effective in reducing protein degradation in the silages.

Formaldehyde treatment depressed intake, the apparent digestibility of D.M., organic matter (OM), N, cellulose and energy, and N retention, the effect being particularly evident at the high level of application. Behavioural observations showed an increase in eating time on the formaldehyde-treated silages. Urea supplementation increased intake of the formaldehyde-treated silages, but did not influence intake of the control silage, and increased N retention on all silage diets. Apart from an improvement in apparent N digestibility, urea supplementation did not influence the digestibility of other dietary components.

Within the rumen, formaldehyde treatment reduced ammonia-N concentration and the molar proportions of propionate and butyrate, and increased the molar proportion of acetate. The rate of D.M. and cellulose disappearance from treatment silages suspended in the rumen in nylon bags was reduced by formaldehyde treatment, the effect being most evident at the high level of formaldehyde application. A similar effect on rate of D.M. disappearance was observed when the control silage was placed in nylon bags, indicating that the adverse effect of formaldehyde was probably due to an effect on the rumen environment. Urea supplementation increased rumen ammonia-N concentrations, although this effect was not as great on the high formaldehyde silage, and increased the rate of D.M. and cellulose disappearance from silage in nylon bags.

It appears that the lower intake and the poorer utilization of dietary N on the high formaldehyde silage may have been due to a reduction in the rate of digestion within the rumen. While there was some response to urea supplementation, it could not restore the apparent rate of digestion in the rumen to levels observed on the control diet. Hence, factors other than the supply of rumen-degradable N in the diet must have been responsible for the depression of digestion within the rumen.

Soya-bean plants were grown for 40 days in a range of root temperatures from 10 to 25°C either in a root medium containing N but uninoculated or in a N-free medium but inoculated with Rhizobium japonicum. Low root temperature restricted growth in both cases but the plants depending solely on symbiotic N-fixation were much more affected. At 10 CC root temperature plants failed to nodulate but both nodulation and nitrogen fixation increased greatly in the range 15–25°C. It is concluded that soya beans sown in cool soils would benefit from applied nitrogen at sowing time.

Four experiments were carried out to study the possibility of replacing milk proteins for lambs with Toprina yeast (G) grown on hydrocarbons. In Expt 1 the effect of replacing all the milk protein with Toprina was studied in the presence of milk fat or a mixture of lard and coconut fat. In Expt 2 the maximum level of Toprina yeast that could be used was studied. In Expt 3 the effect of treatment of the yeast with acid on the digestion of Toprina proteins in the small intestine of pre-ruminant lambs (fitted with re-entrant cannulae in the terminal ileum) was examined. In Expt 4 the effect of the supplementation of acid-treated yeasts with tryptophane and methionine was studied using growing rats.

The results of Expt 1 showed that lambs given milk diets grew faster (145 v. 80g/day) and converted feed more efficiently than those given Toprina yeast. Apparent digestibility of nitrogen of skim milk was higher (93%) than that of Toprina yeast (84%). The poorest results were obtained from lambs given lard and coconut as the source of fat and Toprina yeast as the source of protein. In Expt 2 it was found that progressively replacing the casein protein by yeast protein (0, 33, 67 and 100%) resulted in a linear reduction in daily live-weight gain, feed conversion and nutrient digestibility, but at 33% replacement of milk protein any effect on lamb performance appeared to be small. In Expt 3 the flow rates of dry matter, nitrogen and its fractions (soluble and insoluble in water) and fats were highest with the raw yeast, intermediate with acid-treated yeasts and lowest with skim milk. Apparent digestibility of nitrogen up to the ileal cannula was 67, 77 and 88% for raw yeast, acid-treated yeast and skim milk respectively.

In Expt 4, raw yeast supplemented with methionine was found to be as good a protein source as casein for growing rats. The supplementation of acid-treated yeasts with tryptophane did not improve rat performance, but supplementation with methionine increased growth rate and improved efficiency of feed and protein utilization. Acid hydrolysis of yeast also improved its nutritive value, but the full improvement was only obtained when the diet was supplemented with methionine.

It is concluded that yeast protein can provide only about one third of the protein in milk replacers for lambs; prehydrolysis of the yeast may help to increase this proportion without reduction in animal performance.

In the first of two experiments 45 ewes were treated on day 141 of gestation with either prostaglandin F2a or saline. Doses of 10, 15, 20 or 25 mg PGF2a failed to induce lambing earlier than in control animals. A further 50 ewes were similarly treated on day 144; neither dose level of PGF2a nor day of administration had any effect on the interval from injection to lambing compared with controls. In a second experiment 159 ewes were randomly assigned to one of four treatment groups as follows: (1) 20 mg oestradiol benzoate (ODB); (2) 16 mg dexamethasone; (3) 15 mg PGF2a; (4) 2 ml saline. Ewes were injected on either day 143 or 144 of gestation and on each of those days animals were injected either in the morning or evening. The mean times to induction of lambing were 38·6 ± 20·8; 44·2 ± 18·1; 83·5 ± 39·8 and 82·9 ± 43·1 h for the four treatments respectively. Neither day nor time of treatment had any significant effect on the interval to lambing. Both ODB and dexamethasone induced parturition earlier than PGF2a or saline (P < 005).

The net energy values for growth and fattening of two artificially dried tropical grasses-, pangola (Digitaria decumbens) and setaria (S. sphacelata var. sericea cv. Nandi), of similar estimated metabolizable energy content (8·07 and 7·96 MJ/kg D.M.) were determined with cattle using a slaughter technique. Growing cattle with a mean initial weight of 175 kg were given equal quantities of dry matter of the two grasses at each of three planes of nutrition above maintenance for a period of 152 days.

The initial energy, fat and protein content of the total body of the 24 test animals was estimated from regressions relating fasted live weight to theśe components, derived from 12 similar cattle slaughtered at the beginning of the feeding period. The final energy, fat and protein content of the test animals was determined directly by chemical analysis. The metabolizable energy (ME) content of the grasses was estimated from the level of digestible energy (DE) determined with eight cattle, assuming that ME = 0·815 DE.

The cattle fed pangola gained more live weight, empty-body weight, fat, protein and energy than animals fed similar quantities of setaria. The net energy value for growth and fattening (NEf) was determined using regressions relating energy retention to the quantity of dry matter eaten. NEf in MJ/kg dry matter was 2·27 for pangola and 1·31 for setaria.

Efficiency of utilization of ME for growth and fattening (kf) was.27·7% for pangola and 16·9% for setaria. These values for tropical grasses are lower than any values reported for temperate pasture species. Thus the lower efficiency of utilization of ME may cause the lower production of cattle which graze tropical grasses.

It was concluded that as the kf values of different tropical grasses are not constant, kf values should be measured on a wider range of tropical grasses so that this factor can be taken into account when evaluating grasses in animal production systems.

Two groups of weaned sheep weighing about 30 kg, one born in March and the other in September, were each divided into two and given ad libitum one of two pelleted diets, ruminant diet A or ruminant diet AA6. The March-born sheep commenced experiment in July and those born in September in January. The experiment continued for 4½ years. At intervals sheep were killed and the fat protein and ash contents of their digesta-free bodies determined.

The voluntary intake of feed showed a seasonal periodicity with minima in the winter and maxima in summer. The amplitude was 30% in the 1st year and in subsequent years averaged 13%. Those given the higher quality diet (AA6) consumed slightly less than those given the poorer one.

Mean daily feed intake averaged over 6-month periods from January to July and July to January was invariant with age during 4 years of observation. In this time the sheep increased in weight from about 30 kg to about 130 kg. There were, however, considerable differences between individual sheep in the amount of feed they habitually consumed.

The body weight of the sheep increased and eventually plateaued. The asymptotic weight defined as A in the equation W = A–Be–kt, where W is weight at time t and B and k are constants, was related to the mean daily feed intake averaged over 6 months; mean daily feed intake measured over 6 months was proportional to a fractional power of body weight indistinguishable from 0·75, the interspecies power to which metabolism is proportional. Growth of wool during successive 6-month periods did not vary with age of animal but differed significantly between animals.

Fasting metabolism of the sheep was 316 kJ/kg W0·75 for wethers and 336 kJ for rams.

Analysis of the bodily composition data showed that over a range of digesta-free body weight from 46 to 130 kg it was not possible, on statistical grounds, to distinguish between linear relationships between body weight and its fat, protein, ash and water content, and allometric ones. The linear relationships had marginally smaller residual standard deviations and the regression coefficients show that the gain of the empty body in these sheep consisted of 68% lipid, 8% protein, 1% ash and 24% water. The lipid in the carcass accounted for 88% of the total lipid gain and half the accretion of protein and ash was in the carcass. These results confirm those of Searle, Graham & O'Callaghan (1972) based on tritium dilution which showed that post-puberal growth in sheep is of constant composition.

The results of the metabolic studies are shown to be consistent with the growth studies.

Growth to maturity, as affected by different hypotheses related to the determinants of maintenance energy expenditure and the regulation of appetite, was examined algebraically. It is shown that mature weight is the rate of feed intake divided by the rate of maintenance metabolism per unit weight, and for defined feeding systems the rate constant for the approach to mature weight is the rate of maintenance metabolism divided by the feed equivalent of unit gain.

The implications of the results in terms of the measurement and prediction of feed intake and the use of metabolic body size as a scaling factor in comparative and genetic studies of growth are briefly discussed.

Nine normal lactating Murrah buffaloes from the Punjab Agricultural University Dairy herd were used to assess the effect of showers and evaporative cooling on plasma oxytocin concentration, let-down time, milking time and milk yield in buffaloes. The animals were showered four times daily between 10.30 and 16.30 h or provided with evaporative cooling from 07.00 to 21.00 h. In the hot and dry period the oxytocin concentration in buffaloes given a shower was significantly greater than that of the buffaloes of the control group. In the hot and humid period there was a similar trend.

It is concluded from these studies, that cooling may increase the effective milk ejection reflex because the milk-ejection response to a given blood oxytocin concentration is different when the animal is heat stressed from when it is cooled.