Data were collected from 549 Barki and Merino cross sheep during 1967, 1968 and 1969 to study the relation between kemp production and body vigour. The study also included the staple length and greasy fleece weight. The results showed that:

Age had a marked effect on the traits studied. Whereas kemp frequency (score) declined slightly as age proceeded, showing a significant reduction in the seventh shearing season, the staple length and fleece weight decreased after the second shearing season.

Differences due to sex, year and breed occurred, though the pattern differed in the different traits.

Kemp showed a highly significant correlation with birth and weaning weights, as indicating the animal vigour, and was negatively correlated with fleece weight.

Staple length was negatively correlated with birth and weaning weights and positively correlated with fleece weight.

Fleece weight was positively correlated to birth and weaning weights and negatively correlated to kemp score.

Kemp score in the Barki sheep was shown to be quite repeatablo (repeatability = 0·5).

Forages and faeces from 28 digestibility experiments with cattle or sheep were extracted with neutral detergent solution, with and without sodium sulphite, or sequentially extracted with acid-pepsin, ethyl alcohol, diethyl ether and either ammonium oxalate or hot water. Ammonium oxalate was used to extract small amounts of non-protein material not extracted from legumes by hot water. Compared with sequential extraction the average protein-free organic residues after extraction with detergent, with and without sodium sulphite, were significantly lower in legumes and faeces, but not in grasses. The largest differences occurred in faeces from grasses for which the recoveries of cell walls as percentages of the faecal organic matter were found to be 59·2, 62·0 and 66·4 respectively, after extraction with neutral detergent plus sodium sulphite, neutral detergent alone and sequential extraction with various solvents. It was considered that the differences were due to extraction of cell-wall constituents by both detergent and sulphite.

Grasses and legumes comprising poor to good quality temperate and tropical species were fed to either cattle or sheep in 36 digestibility experiments. Cell wall in these forages was the ash-free and protein-free residue after sequential extraction with acidpepsin, organic solvents and either water for grasses or ammonium oxalate for legumes. The average amount of cell wall digested per 100 g forage OM was 40·0±0·59 g in grasses and 19·8±1·85 g in legumes. It was considered that within grasses and within legumes the physiology of ruminant digestion, rather than forage quality, was the main determinant of the average amount of cell wall digested and the difference between grasses and legumes was due to interaction of the ruminant digestion process with the physical structure of the cell wall. Of forage factors governing variation about the physiological average, the total cell wall had some effect on the amount of cell wall digested, but the lignin concentration in the cell wall had no effect.

Among grasses and legumes the average, apparently undigested, protein-free non-cell-wall component was 6·2±0·13 g per 100 g forage OM. This component and digestible protein relative to total protein varied among different sets of data. It was concluded that only the component of digestible organic matter which was governed by the relative proportions of cell walls and cellular contents was predictable from chemical composition. It was considered that selection in plant breeding should be based on both digestible cell wall and cell-wall content instead of digestible organic matter.

Survival of buffalo sperm in glycine-yolk extenders stored at 5°C was investigated. Eight glycine-yolk extenders containing variable levels of glycine (1·7 and 3·8%), glycerol (0 and 7%), fructose (0 and 1%) and 20% egg yolk, were compared with the conventional 4% glycine–50% egg yolk (control 1) and a 0·2 mol Tris-yolk extender (control 2). The highest rate of sperm survival in glycine extenders occurred in the one containing 1·7% glycine, 7% glycerol, 1% fructose and 20% egg yolk. All glycine extenders however, including control 1, were statistically (P < 0·01) inferior to the Tris-yolk. Sperm survival at the 4th day of storage for the glycine extenders ranged between 30 and 63% but it was 83% for the Tris-yolk.

Adjusting the pH of the glycine extender to 6·5 increased the percentage of sperm survival but it was still below that occurring in the Tris-yolk. Sperm survival in glycine yolk adjusted to pH values of 5·9, 6·5 and 7·1 were 55, 65 and 60% compared with 75% for the Tris-yolk control.

The relationship between body weight, testes volume and circumference as computed for 42 slaughterhouse buffalo bulls (Bos bubalis). Animals ranged in body weight from 290 to 610 kg, testes volume (testes plus epididymides without scrota) from 102·5 to 296·7 ml and testes circumference (testes with scrota intact) from 21·31 cm. Relationships between body weight and testes volume, body weight and testes circumference, testes circumference and testes volume were all linear and correlations (r) were, 0·986, 0·932, 0·951 and were highly significant. Regression equations were calculated and it was clearly shown that buffalo bull testes volume is a function of body weight and could be easily predicted either from body weight or from testes circumference.

Comparisons between the testicular size of the buffalo bull (B. bubalis) and domestic bull (B. taurus) based on calculations from prediction equations showed that the testes size of the buffalo bull was half that of a domestic bull of similar body weight.

Two 16-week experiments with lactating Ayrshire cows were conducted to study the effect on milk production of replacing barley with dried molassed sugar-beet pulp on an equal dry-matter basis. The cows on all treatments received equal weights of hay, groundnut cake and minerals but the contents of barley and of sugar-beet pulp each varied from 0 to 80% in the different concentrate mixtures. The total daily intake of dry matter expressed as a percentage of live weight averaged 2·64 and 2·72 in the two experiments.

The average yield of milk in the two experiments was 18·8 kg/cow per day, and, within each experiment, the mean yields of milk and the contents of solids-not-fat and crude protein were not significantly different on the contrasting feeding treatments. The intake of water was significantly increased as the dried beet pulp replaced the barley but no major changes occurred in the proportions of V.F.A.S in the rumen liquor.

It is concluded that barley and dried molassed sugar-beet pulp had the same feeding value on a dry-matter basis when used in the production ration of milking cows. It is suggested that for most purposes barley and dried sugar-beet pulp are interchangeable on an equal weight basis, but for more precise feeding the two feeds should replace each other on an equal dry-weight basis.

In a survey of soils in South Central England matric suctions were measured frequently during 1962 and 1963. Results for the period October to May are given for sites lying above the influence of the regional ground water table and show the matric suctions to which the soils drain. Sandy soils drain within 2 or 3 days to a definite field capacity at about 50 mbar suction. Loams and clay loams, though from profile appearance regarded as freely drained, take up to about 1 week to drain to a fairly constant suction of 40–50 mbar, which can also be regarded as field capacity. However, suctions prevailing during this time are less – about 20 mbar. The prevailing suctions in clay soils are about 10 mbar in the topsoil (13 cm) and – 10 mbar in the subsoil (38 cm). These soils drain slowly but steadily when rain ceases and no definite field capacity is evident. For the sandy soils, loams and clay loams, the matric suctions characterize the upper limit of the available water capacity (AWC) of the soil. The values are less than almost all previous estimates or assumed values. For the clays the upper limit of AWC remains best estimated by field sampling at the time of interest.

Sets of data were selected from 66 nutritional experiments on crop plants with large beneficial effects of at least two of the nutrients, nitrogen, potassium and phosphorus, and the data, the logarithms of the data, and the reciprocals were statistically analysed. It was shown that the beneficial effects of the nutrients were additive much more often on the reciprocal scale, than when a logarithmic transformation, or none at all, was used.

Kloka spring wheat grown on a sandy-loam soil was given 50, 100, 151 or 201 kg N/ha as fertilizer, was irrigated during drought or not irrigated, and was sprayed with CCC (2-chloroethyltrimethylammonium chloride) or not sprayed. Samples, taken approximately weekly from brairding to heading and less frequently to maturity measured the production of dry matter. The dried samples were analysed for percentage N, P, K, Ca, Mg and Na and the uptakes of these were calculated to measure the effects of treatments on the composition of the crop and the weights of nutrients it contained.

Increasing amounts of fertilizer-N up to 151 kg N/ha increased the maximum weight of straw without irrigation and up to 201 kg N/ha with irrigation; similarly, maximum weights of ears were with 100 kg N/ha without irrigation and 151 kg N/ha with irrigation. The maximum weight of straw was at flowering and of ears at maturity. Irrigation increased yields of straw and ears, more with the two larger than with the two smaller amounts of fertilizer-N. Spraying with CCC decreased the yield of straw, and did not affect the yield of ears.

Increasing amounts of fertilizer-N increased percentage nutrients in the green crop and in the straw, and of N, P and Mg in the ears. Effects of irrigation and spraying with CCC on composition differed between nutrients and between ears and straw, sometimes increasing, sometimes decreasing, and sometimes having no effect, on percentage in dry matter.

Increasing fertilizer-N increased the maximum weight of N, K, Ca and Na in the crop. P and Mg increased with up to 151 kg N/ha, but was no more with 201 kg N/ha. Maximum weight of N, P, Mg and Na was found at or near maturity, of K at heading and of Ca at flowering.

When an organic calcareous soil was air-dried for 2 days and re-wetted to a wide range of moisture contents, well below saturation, nitrite accumulated within 1–2 days. At the same time much nitrate was formed and more carbon dioxide was released than from soil kept moist. On further incubation of re-wetted soil for 3–5 days, the nitrite concentration decreased rapidly. Since 15N-labelled nitrate was reduced to nitrite after air-drying and re-wetting, and no nitrite was formed in autoclaved soil, nitrate was microbially reduced.

Eighty-three per cent of added 15N tracer was recovered from the soil 2 days after re-wetting to 70 % moisture, indicating that 58 ppm N had been lost; 10 ppm N of this was released as nitrous oxide. Autoclaved soil to which nitrite was added did not evolve nitrous oxide, suggesting that nitrite was reduced biologically rather than decomposed chemically.

Three other soils were treated similarly; two, which were non-calcareous, accumulated no nitrite. Fresh calcareous soils with high respiration rates and good capacities to denitrify when waterlogged are most likely to form nitrite after drying and moderate re-wetting.

Results of this study show that daily intake of dry matter (DM) and digestible energy (DE) was lower for the ‘warm’ environment and ‘high’ fibre groups. Efficiency of DM utilization was also lower for these groups. However, efficiency of DE was essentially the same for both rations, being lower in the ‘warm’ group. The lower intake in the ‘warm’ environment was attributed mainly to the longer length of time that animals spent resting, which resulted also in lower growth rates. The data indicate that increasing the caloric density of feed, to compensate for reduced consumption, would make it possible to obtain proportional increases in energy intake. As interactions were negligible, this situation would apply to both environments studied.

Steer calves, underfed either from birth to 16 weeks of age, or from 16 to 32 weeks of age, recovered well on refeeding, but only the latter expressed compensatory growth.

Carcass characteristics (dressing percentage, carcass length, depth of muscle and fat at the tenth rib, yield and joint distribution of saleable meat, proportions of muscle, fat and bone) of steers underfed in early life were remarkably similar to those of continually grown steers when slaughtered at the same live weight, despite their greater age.

Plane of nutrition in early life had no apparent effect on the ultimate eating quality of meat (longissimus dorsi muscle) or on its connective tissue and fat content.

Four experiments are described in which attempts were made to increase the number of live lambs born per ewe per unit time. In the first experiment 22 Scottish Half-bred ewes were subjected to an artificial photoperiod. This resulted in 95 % of the ewes being mated 128 days after their previous lambing. It was estimated that artificial photoperiod brought the breeding season forward by about 5 weeks. The use of 1500 i.u. Pregnant Mare Serum had no significant effect on mean litter size. In the second experiment three artificial photoperiods were compared with natural daylength. In Group 2 photoperiod was decreased rapidly on 2 April from 18 to 10 h, in Group 3 photoperiod was decreased gradually on 2 April from 24 h and in Group 4 photoperiod was decreased rapidly on 28 May from 18 to 10 h. Group 5 was the control. Median intervals from parturition to next conception for Groups 2–5 were 70, 138, 68 and 131–5 days respectively; median intervals from onset of decreasing daylength to conception were 129, 200, 83 and 118–5 days respectively. Treatments 2 and 4 significantly reduced the interval from parturition to next conception but treatment 3 was unsuccessful. The interval from onset of decreasing daylength to conception was significantly shorter for treatment 4 than for treatment 2.

In Exp. 3 an unsuccessful attempt was made to extend the natural breeding season by preventing photoperiod from increasing for 3 months after 22 December.

In Exp. 4 a similar photoperiodic pattern was used for Groups 9 and 10 (16 h photoperiod decreasing rapidly to 8 h on 18 February). The contrast was that in Group 9 most of the ‘light’ was natural, in Group 10 all the ‘light’ was artificial. This pattern was compared with the natural daylength pattern (Group 8), an equinoctial treatment (Group 11) and a short-day treatment, 8h light, 16 h dark (Group 12). The median intervals from parturition to next conception for Groups 8–12 were 194, 102, 99, 156, 155 days, respectively. There was no significant difference in this interval between Groups 9 or 10. Type of ‘light’ therefore had no influence on the median interval from parturition to next conception; but photoperiodic pattern did. A rapid increase to 16 h light followed by a rapid decrease to 8 h (Groups 9, 10) was more effective than either the equinoctial treatment (Group 11) or the short-day treatment (Group 12). The treatments imposed on Groups 11 and 12 were more effective in shortening the median interval from parturition to next conception than the natural daylength pattern (Group 8). Time of year of mating had no effect on lambing percentage.

It was concluded that the sensitivity of sheep to photo-stimulation varied directly, with time from the onset of the next natural breeding season and with the speed of photoperiodic decrease.

Results of a co-ordinated trial carried out at twenty centres indicated that performance of growing pigs (20–90 kg) was not affected by straw bedding in pens, or by small differences in the protein content of barley meal which was used as the main cereal in the diet. Also, no adverse effects were observed when cereals only were fed in the morning and an appropriately balanced compound mixture was fed in the afternoon.

Sheep were given artificially dried grass either in the long form or as pellets, and their energy retention measured. Experiments were made both at the maintenance level of feeding and when feed was offered ad libitum. An analysis of the effects of preceding and current daily feed consumption on heat production was made and both exact and approximate methods of estimating the mean food intake to which a determination of heat production should be referred, are given. Pelleting the dried grass increased voluntary intake of dry matter by 27%, and the intake above maintenance by 59% The metabolizable energy of the grass was depressed by pelleting but the net availability of metabolizable energy for production was 52% for pellets and 40% for long material. The percentage of the gross energy supplied above maintenance which was retained was 28% greater for pellets than for long dried grass. The results show that energy retention of the sheep was almost doubled when the grass was pelleted.

Four equally spaced feeding levels, estimated to cover the range of commercial practice, were examined using a total of 208 pigs over the live-weight range 28–100 kg. The pigs were penned in groups of six or eight and were balanced for sex within pens. Three centres participated in the experiment contributing five, two and one replicates respectively.

Efficiency of feed conversion was not significantly affected over the range of feed intakes studied, thus daily gain was linearly related to feed intake. A 10 decrease in feed intake increased killing-out percentage by 0·3 unit and decreased backfat thickness by 1 mm at both the shoulder and mid rump. The corresponding changes in the percentages of subcutaneous fat plus skin and meat were similar in magnitude at approximately 0·85 unit.

Muscle quality was reduced with higher feed intakes but weight of liver, as increased. Details of other offal weights and carcass measurements are given.

Potential cellulose digestibility, measured by incubation in vitrofor 6 days, decreased during floral development in perennial ryegrass, Wimmera ryegrass, cocksfoot, oat and tall fescue. The rate of decline was slower than for cellulose digestibility measured after incubation in vitro for 2 days only. Morphological fractions ranked in order of descending potential cellulose digestibility – leaf blade, inflorescence, leaf sheath and stem.

Lignin content was determined chemically by the method of Van Soest (1963) and lignified tissue was assessed by staining transverse sections of leaf blades and leaf sheaths with safranin and fast green. Both lignin and lignified tissue increased with maturity. Lignified tissue increased mainly through increase in the number of scleren-chyma cells, but was also affected by the formation of lacunae or cavities between the vascular bundles in leaf blades of cocksfoot and in leaf sheaths of all species studied. For 19 samples of leaf blades and leaf sheaths, potential cellulose digestibility had significant negative correlations with both lignin content (r = -0·862) and lignified tissue (r = -0·905). Limitations to the techniques used to assess lignification and further factors which may affect the relationship between lignification and potential cellulose digestibility are discussed.

Organic-S and sulphate-S were measured in the Northern Guinea savannah zone down soil profiles under undisturbed natural vegetation, and in land cleared and cropped, with and without fertilizers and farmyard manure. The main soil type was a drained, red to red-brown, sandy clay to clay loam (pH 4·1–5·6 in 0·01 M-Cal2), which strongly sorbed sulphate.

Organic-S was most in the surface layers and decreased with depth. Root remains from the natural fallow vegetation, present up to 9 years after clearance, strongly influenced the distribution of organic-S. The roots disappeared after 19 years, when distribution of organic-S mainly reflected crop-root distribution; amounts of organic-S were related to crop yields. FYM was less effective in maintaining organic-S than fertilizers containing P and N.

Profiles under natural vegetation contained little sulphate-S but it accumulated in the sub-soil after clearance when S was not removed. The sulphate pattern of profiles under unfertilized crops resembled that under natural vegetation. All fertilized sites had a well-defined sulphate sorbtion pattern, the deepest maximum was at 50 cm on a plot where more than 800 kg S/ha had been applied in nineteen annual aounts. Sulphate-S ranged from > 1 ppm, in the deepest samples, to 52 ppm at the absorption maximum.

Almost all the sulphur applied was in the profiles or removed in harvested crops, showing that losses from erosion and leaching were small.

The oestrogenic activity and coumestrol content of ‘diseased’ and ‘clean’ white clover and lucerne were investigated. It was found that both coumestrol content and oestrogenic activity were increased in diseased white clover. However, there was insufficient coumestrol to account for the oestrogenic activity and it was suggested that other factors (e. g. oestrogen potentiator, unidentified oestrogen) were involved.

The main objective of the experiments described was to compare the effects of milling straw and/or soaking or spraying it with sodium hydroxide on its digestibility and acceptability to sheep. Some preliminary trials were made in the laboratory to compare different alkali treatments with respect to losses of organic matter, chemical composition and digestibility in vitro.

In a feeding trial of Latin-square design, involving six sheep, the following treatments of barley straw were compared: C, chopped; M, coarsely-milled; OIL, chopped and soaked in 1·5% NaOH (9 g NaOH/100 g straw); CIH, chopped and soaked in 3·0% NaOH (18 g/100 g straw); CS, chopped and sprayed with 16 % NaOH (8 g/100 g straw); MS, milled and sprayed with 16 % NaOH. After treatments OIL and CIH the straw was washed; this caused losses of organic matter of 28 and 32%, respectively. For CS and CM the excess NaOH was neutralized by addition of 7·4 ml propionic acid/100 g straw.

The straws were given with supplements of purified soya protein, minerals and vitamins. The digestibility of energy for the straw was (%): C, 40·4; M, 39·1; CIL, 65·0; CIH, 64·4; CS, 57·3; MS, 60·2. Dry-matter intake (g/kg W0·75 per day) was: C, 26·7; M, 36·2; CIL, 37·1; CIH, 44·2; CS, 48·4; MS 53·6.