Piglets in litters, paired according to farrowing date, were redistributed during the first day after birth according to two schemes. In scheme AC–BD, one sow of the pair received the heaviest and the third heaviest quarters of the combined litters (based on weight post partum), while the other sow received the second heaviest and the lightest quarters. In scheme AB–CD, one sow received the heavier half, and the other the lighter half of the piglets. After 3 weeks under scheme AB–CD, the weight difference between the second and third quarters had become reversed, while under scheme AC–BD the difference was preserved. There was no evidence of a corresponding interaction in the selection of anterior or posterior teats. The rank correlation of the piglets' initial weight and suckling position was low for most sows. No marked differences were observed between fostered and unfostered piglets in the weight measures or suckling position. It is concluded that the growth of the piglets was influenced by the relative size of their litter-mates after redistribution, but that little of the effect could be explained by competition for the anterior teats.

Field experiments were made under natural rainfall during the winter seasons of 1972–3 and 1973–4 at the Indian Agricultural Research Institute, New Delhi, to study the soil water use by barley varieties as influenced by nitrogen rates, mulching and foliar application of antitranspirants. Both Ratna and Vijaya varieties of barley had similar efficiency of water use.

Total water use was not much different for various treatments but straw mulch and kaolin decreased evapotranspiration at tillering and pre-flowering stages enabling the plants to use more water at critical stages of grain formation. Application of nitrogen, straw mulch and a foliar coating of kaolin increased the efficiency of water use.

Two experiments with growing pigs showed that the addition of L-lysine hydrochloride to diets limiting in lysine content raised not only N retention but also true N digestibility as a percentage of the diet. The change achieved in amino acid balance had no consistent effect upon ED (digestible energy, kJ/g diet) and therefore the experiment did not support the hypothesis that non-linear changes in dietary ED, resulting from ingredient substitutions, could be attributed to associated changes in amino acid balance.

The body weight and fleece weight of Marwari and Magra sheep (rams) of the desert areas of north-western India are compared with those of Corriedale rams, which are being imported into India for improving the productivity of the local stock through cross-breeding. All three breeds showed marked seasonal fluctuation in their body weight. While the Corriedales lost more body weight than the indigenous breeds during peak summer, they appeared to endure the relatively poor winter pasture conditions somewhat better. Between July and October, with the availability of lush monsoonal pasture, all three breeds increased in body weight.

The greasy fleece weight of Corriedale rams was nearly double that of indigenous rams. The potential of the Corriedale ram for improving the productivity of the local stock is discussed.

The effects of nitrogen treatment on blade length and longevity were studied in primary growth of early and late varieties of perennial ryegrass, timothy and cocksfoot. Reproductive and vegetative tillers were examined in cocksfoot, but in perennial ryegrass and timothy the study was restricted to reproductive tillers, which accounted for a large proportion of the primary growth in these species. Results obtained by a technique which involved repeated recording of tillers were corroborated by those obtained by destructive sampling of tillers.

With respect to the blade length of culm leaves, responses to nitrogen shown by S. 23 ryegrass and S. 48 timothy were greater than those of the early-heading varieties S. 24 ryegrass and S. 352 timothy. However, blade longevity was appreciably reduced by nitrogen in the late varieties whereas the early varieties showed a much lower response.

Implications of these results in relation to the accumulation of senescing material in primary growth are discussed.

The pattern of leaf expansion in vegetative tillers of cocksfoot is discussed in relation to regrowth.

Four young lambs fitted with cannulas at the pylorus and at the ileo-caecal junction were used to study the effects of weaning on digesta flow and mineral absorption. Prior to weaning when milk alone was fed the small intestine was the major site for dry matter disappearance and for the absorption of Ca, P, Na and K. Both the small and the large intestine were, however, important sites for Mg absorption at this time.

After weaning, when the lambs were fed a concentrate diet, at least two-thirds of the digested dry matter disappeared within the reticulo-rumen. The small intestine, however, still remained the major site for the absorption of Ca, P, Na and K. Most Mg absorption, in contrast, now occurred anterior to the pylorus and it would appear that the move from hindgut to foregut as a site for Mg absorption was directly associated with the introduction of dry feed and the development of fermentative digestion within the reticulo-rumen.

Both before and after weaning the faeces was the major route for the excretion of Ca surplus to requirement and the faeces also became increasingly important as a pathway for P and Mg excretion once dry feed was given. The urine, in contrast, was consistently the major pathway for the excretion of Na and K.

Three groups (1, 2 and 3) of weaned Hereford steers were grazed separately on pasture. Groups 1 and 2 were supplemented with hay and oats during autumn and winter in an attempt to maintain two rates of live-weight gain, namely 0·8 and 0·4 kg/day, respectively. Group 3 was not supplemented and gained at zero and 0·11 kg/day during corresponding periods in the 2 years in which the experiment was repeated (years 1 and 2).

Supplementation ceased at the end of winter (September). Group 1 steers were slaughtered at the end of the growing season (January) when their mean live weight was 420 and 450 kg in years 1 and 2 at 19 months of age. Thereafter, groups 2 and 3 were removed from the plots and grazed together on another pasture at a reduced stocking rate until they attained the slaughter live weights of group 1 when they were slaughtered at 25 and 27 months of age, respectively.

Mean depth of fat cover over the eye muscle at the 10–11th rib in groups 1, 2 and 3 were 8, 6 and 4 mm in year 1, and 12, 5 and 6 mm in year 2, respectively. Group 1 carcasses had shorter skeletal dimensions, contained more fat and graded better than the carcasses of groups 2 and 3. The Longissimus dorsi muscles from group 1 were found to be the most tender in year 1 but no treatment effects were detected in year 2.

The results of 83 experiments with nine levels of nitrogen and six experiments with seven levels were used to investigate models of the response of spring barley to nitrogen. Of the eight models tested, the inverse quadratic, Greenwood's modification of the inverse linear and two intersecting straight lines represented the yield/fertilizer relationship well, although no one model fitted best at every site.

The three models differed little in their average predicted optimal yields, but a slightly smaller average optimal dressing was predicted from two straight lines.

Perkins & Jinks's (1971) analysis was used to detect and measure the interactions between the environment and the additive, dominance and epistatic effects of the genes for final plant height, spike length, 100-grain weight and yield per plant in three barley (Hordeum vulgare) triple test crosses (DL 3 × IB 226, DL 3 × Jyoti and Jyoti × P 113) raised in two environments (normal irrigation and no irrigation). The j- and I- type epistasis was more sensitive to environmental differences than the i-type epistasis. Similarly, additive gene action responded more to the different environments than did the dominance action of the genes.

Normal and ketotio ewes pregnant with twin lambs were injected intramuscularly with 0·5 mg/kg body weight of trienbolone acetate. In the normal animals there was no significant change in the concentration of glucose, ketones, glycerol or NEFA in plasma.

Induction of ketosis by starvation produced a significant fall in the concentration of glucose in plasma and significant increases in the concentration of ketones, glycerol and NEFA. Trienbolone caused no further significant changes in the concentration of the four metabolites in the plasma of ketotio sheep.

Primed continuous simultaneous intravenous infusions of tracer amounts of [2-3H] and [U-14C]glucose were used to measure total entry rate and irreversible loss of glucose. Trienbolone caused significant decreases in both these measurements in normal pregnant sheep. Production of ketosis by starvation had the same effect. Trienbolone produced no significant additional effect in the ketotic sheep and no alleviation of the clinical signs of the hyperglycaemic ketosis.

These results are discussed in relation to the assessment of the potential value of trienbolone as a treatment of pregnancy toxaemia of sheep.

The effects of food restriction on the growth and distribution of bone and on the relation between changes in long bone lengths and changes in limb muscle proportions were studied in 32 Duroc Jersey barrows. Sixteen pigs were fed ad libitum (H group) whilst the other 16 received the same diet on a restricted scale related to live weight.

Animals in each group were slaughtered at times such that the weights of bone in their half carcasses were spread evenly over the range 1·5–4·O kg. The right half carcasses were completely dissected using strictly anatomical criteria.

The results on the relative growth of bone were examined by covariance analysis using the allometric equation.

After adjusting for equal weight of total bone in the side L pigs had heavier femur, tibia-fibula, humerus and radius-ulna and lighter scapula and ribs than H pigs.

Relative to their weights all appendicular long bones were longer in L pigs than in H ones, while there was no such effect on spinal column length.

The effects of the treatment on fore limb muscle proportions relative to total muscle were significantly correlated (P < 0·01) with the changes observed in the lengths of the long bones forming their osseus bases. However, in the case of the hind limb the regression and correlation coefficients were not significantly different from zero.

A combination of a mineral balance and a radioisotope technique has been used to study the effect of increased intakes of dietary calcium and phosphorus on the Ca and P metabolism of mature, Ca-replete wether sheep. Between Ca intakes of 40 and 100 mg/ day per kg body weight Ca absorption remained constant at a level just sufficient to supply maintenance requirements. Above 100 mg/day per kg body weight, however, absorption increased in direct relation to intake. It is suggested that the increased absorption occurred by diffusion and that at lower Ca intakes, increased diffusion was offset by a corresponding decrease, until it reached a negligible level, in the rate of active absorption.

In spite of the fact that the wethers were already Ca-replete, the increased Ca absorption resulted in increased Ca retention and not as might have been expected in increased excretion. Increased retention was brought about by a decrease in the rate of bone resorption and bone accretion remained constant. Maximum retention occurred when bone resorption ceased and it was equal to the rate of bone accretion. It was only when retention of Ca reached a maximum that further increases in absorption resulted in increased excretion of Ca into urine and intestine. P retention was also increased with increased Ca and P intakes and probably occurred as a result of the increased Ca retention.

The relevence of these findings to the control of parturient paresis (milk fever) in the dairy cow by dietary manipulation is discussed.

Three experiments were carried out to study the effect of replacing milk carbohydrates and part of the milk fat in milk with partially hydrolysed starch (Protamyl 110). Male and female cross-bred lambs (Suffolk × (Finnish Landrace × Dorset Horn)) were used in these experiments. They were weaned from their dams after having received colostrum at 1–2 days of age. The experimental diets were given at room temperature, in eight aliquots, at 3-h intervals through an automated feeding unit. The level of feeding was 1·05 MJ/kg0·75 live weight/day.

In the first experiment, the diets were formulated to contain 28, 17 and 55% of their gross energy as protein, carbohydrate and fat respectively. Diet 1 contained glucose, while diets 2, 3 and 4 had 33, 67 and 100% of glucose respectively replaced by Protamyl. There were no significant differences in growth rate and food utilization between levels of starch inclusion.

In Expt 2, the maximum Protamyl that could be incorporated in lamb milk replacers was examined. Four experimental diets were prepared so that 17 and 55; 25 and 47; 33 and 39; and 41 and 31% of their gross energy was supplied by Protamyl or butter fat respectively. It was found that up to 33% of the gross energy of the diet (41% of the dry matter) could be replaced with Protamyl without adverse effects on lamb performance. When the level of inclusions was increased to 41% of the gross energy (49% of the dry matter), lamb performance was depressed, particularly during the first 15 days of the experiment.

In Expt 3, a direct comparison was made between Protamyl and lactose. The two diets used were similar in composition to diets 1 and 4 in Expt 1, except that lactose was used as a control instead of glucose. There were no differences in growth rate or food utilization as a result of replacing lactose with Protamyl.

The results are discussed in relation to the development of carbohydrases in new born ruminants.

Twenty-four lactating Jersey cows, grazing a 3-week regrowth of nitrogen-fertilized Chloris gayana cv. Pioneer pastures selected a diet containing 18% crude protein and were given 0, 2 or 4 kg/day of fresh Leucaena leucocephala or 250 g/day of formal-casein. The effect of the treatments on milk production was measured in a 4 × 4 latin-square design experiment with experimental periods of 14 days.

Mean milk yield of unsupplemented cows was 9·6 kg/day, 10·1 kg/day when cows were supplemented with formal-casein and 10·3 kg/day when fed 2 or 4 kg Leucaena/day. Yields of solids-not-fat, protein, casein, butterfat and short and medium-chain (C4–C16) fatty acids in milk fat were higher when cows were fed supplements (P < 0·01). Intake of digestible organic matter was lowest on the unsupplemented diets although feed in excess of 40 kg D.M./cow/day was offered and cows had little difficulty harvesting feed with a mean bite size of 350 mg organic matter/bite and mean grazing time of 507 min/24 h.

It was concluded that a tropical grass diet containing 18% crude protein was deficient in protein for lactating cows and that small quantities of the legume Leucaena can alleviate such a deficiency.

The effects of farmyard manure (FYM) and P and K fertilizers on soil properties were studied at the end of a 3-year (1972–5) field experiment at New Delhi, India. Each year a crop of rice and wheat was grown. FYM was applied at 0 or 15 t/ha, phosphorus at 0, 30 and 60 kg P2O5/ha and potassium at 0 or 60 kg K2O/ha. Treatments included application of manure and fertilizer to rice or wheat alone or to both the crops. FYM application increased organic C, total N and available K and P in the soil, the effects being greater when both rice and wheat received FYM. Application of FYM slightly decreased the soil pH. Phosphorus and potassium fertilizer increased available P and K in the soil, respectively.

Experiments were carried out on oil-seed rape, variety Zollerngold, to determine the effects on flower and pod development when (1) the supply of carbon assimilates was reduced by shading or leaf removal at different stages of development or (2) the supply of assimilates to the more apically positioned flowers or pods on the terminal raceme was increased by removing 15 of the most basal flowers or pods.

A decrease in the production of carbon assimilates led to fewer flowers and pods developing to maturity and when the stress continued over most of the period of pod development the pods were smaller and had fewer seeds which were also lighter in weight.

Removal of the 15 basal flowers or pods led to more of the apically positioned flowers developing into mature pods and the other pods becoming heavier with bigger husks, heavier seeds and sometimes a greater number of seeds.

The results of a shading experiment in a controlled environment cabinet suggest that stresses in the supply of carbon assimilates around the time of anthesis are particularly harmful since in addition to reducing the number of pods which develop they appear to restrict the capacity for compensatory growth in the pods that remain when the supply returns to normal.

In field experiments made over 3 years Pentland Crown and Majestic gave, in general, higher total and dry matter yields from plots given no supplementary water and protected from rainfall throughout growth than King Edward or Maris Piper. However, on plots kept at or near to field capacity all varieties gave similar yields. Pentland Crown and Majestic were deeper rooting than the other two varieties at the time of tuber formation (when the production of new roots ceased) but the differences in rooting depth (ca. 100 mm) between the varieties were small. Except for the top 150 mm of soil, differences in water extraction between the varieties throughout the profile were also small. Neither these differences in water extraction nor the differences in rooting depth could be related consistently to the differences in varietal yield response between ‘wet’ and ‘dry’ plots.

A statistical analysis is presented of published laboratory data on 4407 soil horizon samples collected by the Soil Survey of England and Wales during 1950–73, to typify soil taxa. Seventy-five percent of the profiles have fine textured parent materials in both calcareous and non-calcareous categories. Moderate to large increases in clay content down the profile, which could indicate argillio horizons, are found in 56% of the profiles but the influence of lithological discontinuities has not been eliminated. Argillic horizons are commonest on calcareous or low grade metamorphic rocks and non-calcareous clayey or silty sediments. Less than half the average frequency of clay increase between middle and bottom horizons is shown in the igneous and high grade metamorphic lithological type.

pH gradient down the profile is not clearly related to altitude. The pH change (0·7) between top and bottom horizons in profiles from calcareous and igneous parent materials is twice as great as in other non-calcareous profiles. There is usually less clay in the top horizons than in others; the top horizon contains more than 35% clay about half as frequently as the lower horizons. Clay content categories have closely similar frequency in middle and bottom horizons. Gleying in horizon 1 is observed somewhat less frequently with increasing CaCO3. No consistent trend is found in the other horizons. Soil pH in 0·01 M-CaCl2 (pH8) is between 5·1 and 7·0 in 51% of all samples. pH5, values less than 4 occur in only 8% and are twice as common in top horizons (more than 5 cm thick) as in deeper ones. pH8, values greater than 7 are nearly twice as frequent (31%) in the bottom horizon as in the upper ones. Correlation of pH in water (pHw) with pH8 always exceeds 0·93 irrespective of lithological type. The difference of pHw from pH8 (δpH) calculated from the regression equation is 0·7–0·8 at pH6 values less than 4; it varies inversely with pH8, up to a value of 0·4–0·5 at pH6 greater than 7. Neutrality (pHw, 7) corresponds to pH8 6·5–6·6. There is no indication that δpH is related to altitude or gleying intensity but it varies according to lithological type by about 0·1 unit. Organic-matter content, as indicated by loss on ignition (950 °C) minus 10% of the measured clay percentage (LOIadj%) is little affected by lithological type; decrease with depth is steeper at pH8 less than 4 than at higher pH. Gleyed top horizons contain more organic matter than ungleyed; gradient down the profile is positively related to gleying intensity.

The overall multiple regression of cation exchange capacity (CEC) on clay percentage and organic matter (LOIadj%) is (CEC = 1·21 + 0·40 clay% + 1·32 LOIadj), accounting for 61·4% of the total variance. When lithological types are considered separately the partial regression coefficients for clay percentages are greater in the two calcareous lithological types than in the non-calcareous. With lithological type 5 the large constant term and small coefficient of clay percentage indicate considerable contribution to CEC from particles or aggregates larger than 2 μm. Partial regression coefficients (lithological types 1–4 taken together), although similar both within horizon and within gley category are nevertheless shown to be significantly different. Within pH8 category, both partial regression coefficients increase directly with pH. Calculation of mean values of CEC on a clay basis for horizon 3, where contribution from organic matter is minimal, does not show significant differences between pH8 categories or gley categories.

Although quantification of relationships has been possible, correlations are rarely high, so that predictive power is limited. Availability of soil group or subgroup categorizations using constant definitions based on objective measurements is suggested as a useful way of increasing predictive power within resulting smaller groups. The calculation of geographic (areal) distribution is probably the most useful purpose of a data bank of routine measurements, but the selection of samples to typify soil taxa used in this study would preclude such a use.

The shape of the lactation curve of Sahiwal cows was estimated by fitting a gamma function to 2034 lactations made by 681 cows at two farms in Indo-Gangetic plains of Northern India. The persistency of lactation yield was estimated by three methods: P1, the coefficient of variation among weekly yields; P2, ratio of lactation yield to peak yield, and P3, from the gamma function.

The gamma function fitted to the weekly yields explained 75·9% of the variation. A least-squares analysis of different traits associated with lactation curve shape indicated significant influence of parity, period and season of calving on the lactation curve. The lactation yield, peak yield and daily yield up to the peak were highest for winter calvers, while persistency was highest for monsoon calvers. The milk yield traits showed an increase up to the second or third lactation, while the persistency decreased from the first to eighth lactation with increase in parity order. The lactation curve was also more flat in the first lactation than later. The lactation yield and persistency increased with increase in age at calving independent of parity order. The lactation yield, peak yield, persistency and daily yield up to the peak were positively correlated with service period, lactation length and calving interval.

The heritability and repeatability estimates of different traits, genetic and phenotypic correlations of lactation milk yield with different persistency measures indicated that P2 is a better measure of persistency. The peak yield could be used as a criterion of selection in early lactation to bring about improvement in lactation yield and persistency.

Two experiments are reported in which mature, castrated male sheep were used to study the effect of a change of magnesium status, as induced by a continuous intravenous infusion of magnesium, on the faecal output of magnesium. In the first experiment, three artificial diets differing markedly in fibre content but extremely low in magnesium were used and in the second experiment, natural diets of frozen grass and of hay and ground barley.

With the artificial diets, unit change in plasma magnesium concentration gave the same increase in faecal magnesium output with all three diets but on average faecal magnesium output was highest for the diet containing the highest content of fibre and least for the diet containing an intermediate amount of fibre, and the differences, though small, were statistically significant. With the natural diets, there was no significant difference between diets in the increase in faecal magnesium output in response to a change of plasma magnesium concentration but the order of response was much greater than for the artificial diets. It is concluded that absorption of magnesium from the gut is depressed at high plasma magnesium concentrations.