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.

1. A historical review of the dye adsorption method for the estimation of soil colloids is presented, and the method is criticised chiefly from the point of view of the isoelectric theory.

2. A procedure for the detection of hydrous alumina in soils is described, involving the demonstration of the isoelectrio point of hydrous alumina by means of preferential dye adsorption in suspensions of various pH values.

3. Satisfactory results were obtained with a mixture of acidic Biebrich Scarlet and basic Iodine Green. The former is adsorbed by hydrous alumina only on the acid side of its isoelectric point, and the latter only on the alkaline side.

4. The characteristics of an ideal dye for use in studies such as those described are tabulated.

5. The applicability of the mixture of dye-stuffs finally selected is demonstrated for a series of soils of varying basic ratio, and including examples of lateritic soils and clays.

Diets with added fat at 25, 50 and 100 g/kg were formulated with four blends of beef tallow: soya oil, namely 100:0, 75:25, 50:50 and 0:100. An additional diet had no added fat (control diet) to give an experimental design of (3 × 4) + 1. A total of 96 individually penned pigs was used (mean initial and final live weights of 22·4 and 87·5 kg, respectively). The experiment was carried out during the period July 1985 to February 1986 at the Agricultural Research Institute, Hillsborough. Equal numbers of boar and gilt blocks were used and the pigs were fed individually to a scale to give equal amounts of digestible energy: live weight0·75 Neither concentration of fat nor blend of fat had any significant effect on the rates of live weight or carcass weight gain. Increasing concentration of fat significantly improved the carcass feed conversion ratio (P < 0·001), but the blend of fat had no significant effect. Neither killing-out yield nor the intake of digestible energy per unit of carcass gain was significantly affected by the concentration of added dietary fat nor the blend of fat. Fat treatments did not significantly affect the lean plus bone content of the ham joint, drip loss from or the depth of colour of the longissimus dorsi or the weight of flare fat. No evidence was found of synergistic effects between the fat and nonfat components of the diet nor between fats within the blends of fat on growth, digestible energy consumed per unit of carcass gain and carcass attributes. Boars had a more efficient conversion of feed to carcass gain than gilts (P < 0·01).

Two studies were conducted between 1991 and 1993 to assess the impact of grazing improved v. natural pasture at different stocking densities on animal and vegetation responses. In the first grazing season, goats of the West African Dwarf (WAD) breed were grazed at four stocking densities – 1·90, 2·86, 3·86 or 4·71 TLU/ha (Tropical Livestock Unit = 250 kg liveweight). Wet-season grazing lasted for 14 weeks while assessment was continued until kids were weaned at 120 days of age. There were significant (P < 0·05) changes in the content of legume and forbs in response to variations in stocking density. Liveweight gain per head was significantly (P < 0·05) higher at low than at high stocking density. The same trend was maintained with most aspects of reproductive performance. Goats at low stocking density were of a higher (P < 0·05) body condition score at parturition and had larger litter sizes than does stocked at high stocking density. Kid birth weight and liveweight gain were significantly (P < 0·001) higher at low than at high stocking density. The overall weight loss in does during nursing was similar at the different stocking densities.

In the following year, comparisons were made between three stocking densities, 2·11, 3·17 and 4·23 TLU/ha, on improved and unimproved pastures. Over 14 weeks of wet-season grazing, there was a significant (P < 0·01) decline in available dry matter except at the lowest stocking density on both pasture types. Weight gain per head decreased with increase in stocking density while the reverse was true for weight gain per unit of land. No significant differences were observed for reproductive performance between pasture types or stocking densities. Kid growth rate up to weaning declined with increase in stocking density (P < 0·001) while kid mortality rose with increase in stocking density (P < 0·01). Weight losses in nursing does were higher (P < 0·05) at low than at high stocking density.

In an earlier paper the estimation of the total digestible nutrients (T.d.n.) to be expected in ruminant feedingstuffs has been described (Glover, J. Duthie, D. W. & Dougall, H. W. 1960). In a like manner the average T.d.n. in pig feeds can be estimated. The necessary equations have been obtained in earlier papers (Glover & Duthie, 1958A, b). They are, respectively

where C.p. and C.f. are percentage crude protein and crude fibre, respectively, in the dry matter of the feed, D.c.p. is digestible crude protein and N.r. the nutritive ratio. They can be used directly for the estimation of T.d.n. because by definition T.d.n. is D.c.p.(N.r. + 1); thus the T.d.n. to be expected at different levels of C.p. and C.f. can readily be calculated. Table 1 shows in abbreviated form some of the values that are obtained in the ranges 0–30% C.p. and 0–40% C.f., while Fig. 1 illustrates in detail the effect on T.d.n. of changing C.p. and C.f. levels of the diet. This figure shows clearly the very marked effect of increasing C.f. depressing the digestibility of the total nutrients in pig feeds, a fact which is already well known.

The Agricultural and Related Industries Study Group of the Operational Research Society held a one-day meeting on ‘Decision Support Systems for Profitable Livestock Production’ on 18 November 1992 at the Meat and Livestock Commission, Milton Keynes, UK. The Group promotes the use of the scientific method in solving management problems. The aim of the meeting was to look at the contribution of advances in modelling towards improving management and hence profitability in livestock production. The first four papers concerned feeding and the remaining two breeding. A large part of the discussion could perhaps best be summed up by the regression equation which related dry matter intake and waste output from a cow. When the output was zero, the intake was reduced by 50%!

In a study of two breed groups, coarse wool Barki and ⅜ Merino ⅜ Barki, data were obtained on skin histology from birth to the age of 1 year, birthcoat fibre type arrays and fibre-follicle relationship.

The ⅜ Merino exceeded Barki lambs in the maximum S/P ratio, values of which were 3·40 and 5·64 obtained at 6 and 8 months in Barki and ⅜ Merino respectively.

Internal diameters of primary follicles ranged from 39·0 to 64·7 and from 41·0 to 56·8 μm; those of secondaries ranged from 19·8 to 34·9 and from 22·6 to 33·3 μm in Barki and ⅜ Merino respectively.

The ratio of primary to secondary follicle diameters showed high values in both breed groups; averages were 1·89 and 1·71 for internal diameter and 1·86 and 1·71 for external diameter in Barki and ⅜ Merino respectively.

Birthcoat fibre type arrays were mostly saddle, only 8·3% were plateau (P3) in both breed groups.

In Barki primary centrals grew halo hairs, super sickle (A, A′, B), primary laterals produced super sickle (A, A′, B), sickles, coarse and medium curly tips, and secondaries mostly grew medium and fine curly tips and histerotrichs.

In ⅜ Merino primary centrals produced halo hairs, super sickle (A, A′, B), primary laterals grew super sickle (A, A′, B), sickles, medium curly tips, and secondaries produced medium and fine curly tips and histerotrichs.

An account is given of methods which have been employed in laboratory and field studies of the actions of rolls on the soil. These studies have revealed little that is remarkable or unexpected concerning the actions of rolls on the soil, but they have clearly demonstrated that the exact actions of rolls differ widely according to the circumstances in which they are employed. When rolling is carried out in field experiments, it is necessary to perform tests to measure the exact effects produced on the soil. In this way it should gradually become more apparent when and how rolling is likely to be beneficial.

Of the methods which have been described, the last two, viz. tests of the consolidation, moisture content and tilth by means of a sampling tube, and of the mechanical resistance to the penetration of a probe with the automatic “resistance” recorder, are well adapted to use in field experiments. These methods are being used in many field experiments involving cultivations, and it is hoped that it may at some time in the future be possible by such methods to relate cultivations and crop yields through a knowledge of the soil structure.

Keen and Coutts(8) and Coutts(1) have suggested that the percentage of water in a soil at the sticky point is related to the colloidal content of the soil, as measured by “loss on ignition,” in the following manner:

S = mI + c,

i.e. by a rectilinear equation, and point out that the figure obtained for c approximates to the theoretical percentage of water held in the interstitial spaces of an ideal soil.

The starchy seeds of jackfruit (Artocarpus heterophyllus Lam.) contain 124 g crude protein and 740 g total carbohydrates per kg. The possible replacement value of jackseed meal (JSM) for maize in chick diets was evaluated in Peradeniya, Sri Lanka between 1986 and 1989. In Expt 1, the inclusion of 125 and 250 g raw JSM/kg diet severely depressed growth performance and increased mortality in chicks. Organ weights, relative to body weight, were also affected in chicks fed on diets containing 250 g raw JSM/kg diet. Subsequent analyses revealed lectins and trypsin inhibitors to be responsible for the toxic effects of raw JSM. Processing of JSM by moist-heat treatment completely destroyed these antinutritional factors. This was demonstrated by the results of Expt 2, where the feeding value of processed JSM was found to be comparable to that of maize up to 250 g/kg diet. Moist-heat treatment also improved the in vitro protein digestibility (56·7 v. 84·2%) and apparent metabolizable energy (8·97 v. 13·72 MJ/kg) values of JSM. In Expt 3, the inclusion of 500 g processed JSM/kg diet resulted in reduced broiler performance and lowered the apparent dry matter digestibility and apparent energy utilization of the diets. The non-starch polysaccharide component of the JSM may have been responsible for these negative effects.

The effect of rainfall, sowing date and yield on the percentage of nitrogen in the barley grain of certain representative plots on Hoosfield is studied.

All these factors are shown to have marked effects. The farmyard manure plot differs from the others, both in mean percentage and in the effects of rainfall and yield.

Changes in variety appear to have had little apparent influence, but there is a progressive decrease in the percentage of nitrogen which cannot be accounted for by changes in any of the above factors, and which may well be due to varietal improvement

Comparison is made with the results of the similar study on the permanent barley plots at Woburn.

The main findings of the present trials may be. summarized as follows:

(1) When ‘mineralized’, cooked potatoes are fed as the bulky supplemental food in the Lehmann system of pig-feeding, and the basal meal allowance is restricted to 3 lb. per head per day, bacon pigs are able to make as good progress, in respect both of rate of live-weight increase and economy of food conversion, and at every stage from 60 to 200 lb. live weight, as they would if kept on a diet composed wholly of balanced meal. In the present trials, pigs of about 200 lb. live weight were able to consume 15–17 lb. of cooked potatoes per day in addition to the daily allowance of 3 lb. of meal. It required, on an average, about 1030 lb. of cooked potatoes and 311 lb. of balanced meal per pig to fatten the animals from 60 to 200 lb. live weight. The cooked potatoes, when assessed on the air-dry standard of 13 % moisture, were able to replace the balanced meal on a lb. for lb. basis without detriment to the progress of the pigs, and the average saving of meal thus made possible amounted to about 225 lb. per pig, or 38·2 % of the total meal consumed per pig on the control, all-meal diet.

(2) Cooked potatoes should be introduced into the ration gradually and the allowance should be scaled according to live weight in the manner adopted in the present trials. When the amount to be fed is large, it is best to feed ‘mineralized’, cooked potatoes only during the morning and to place the basal meal in the trough towards the end of the afternoon.

Two dormant varieties of rice were harvested three times at intervals of 7 days after grain development and the seeds were subjected to different sunning and controlled humidity storage treatments. Germination percentages and moisture contents of the grains were recorded at intervals of seven days after harvest.

It was noted that the dormancy of the dormant rice seeds was broken early when the seeds were subjected to continuous sunning from sunrise to sunset, followed by the treatment where the seeds were preserved under 0 % humidity conditions at room temperature. There was no break of dormancy of rice seeds when the seeds were preserved under 94 % humidity conditions.

It was further noted that when the age of the seeds at the time of a germination test remained the same, the earlier the harvest, the earlier was the break of dormancy; and when the lapse of time after harvest remained the same at the time of a germination test, the later the harvest, the better was the germination.

It is suggested that dryness of the seeds helps in the early break of dormancy and wetness retards or completely stops the dormancy-breaking reactions. On drying, the kernels of rice seeds shrink in volume more than the glume covers resulting in an air-space between the glumes and the kernels. This air-space helps air-diffusion in and out of the seeds, resulting in quicker oxidation-reaction processes or possibly embryo respiration, and consequently the dormancy is broken early. Increase in temperature accelerates such reactions. It is further suggested that the dormancy of rice seeds depends on the interactions between the ‘embryo-sensitivity to inhibitors’ and the ‘state of oxidation-reaction processes’ inside the seeds.

In comparing the moisture contents of soils in the field, material precision is to be gained if the sticky points are also determined and the comparison based on the difference between the two values. There is a high degree of correlation between the moisture contents and sticky points of soils in moisture equilibrium with each other.

Besides retarding somatic development, hypophysectomy markedly increases the deposition of subcutaneous fat in foetal lambs (Liggins & Kennedy, 1968). Two hypophysectomized (HX) and two pituitary stalk-sectioned (SX) foetuses became available for dissection during a study of the growth of normal Romney sheep (Broad & Davies, 1980a, b and unpublished). The present report supplements the existing information concerning the effects of altered hypophyseal function on the carcass composition of foetal lambs (Liggins & Kennedy, 1968; Alexander, 1978).

Two objectives were in view in undertaking this research.; to ascertain the cost in energy of muscular work in the goat and to investigate the adaptability of the Douglas-Haldane method of indirect calorimetry to work experiments on this animal. It is to the results of human experiments chiefly, that the present position of the physiology of muscular exercise is due which owes comparatively little to experiments on other animals. Zuntz and his school (1) have, however, compared the effect of a fixed amount of work on men, horses and dogs, and Lusk (2) has carried out some investigations into the influence of work on the dog. The principal obstacle hitherto in the way of employing animals other than man for work investigations has been the want of a sufficiently adaptable technique. Zuntz's experiments on the horse were conducted by means of a tracheal cannula, a device that, though fairly adaptable for work experiments, is not always desirable. Lusk's experiments were carried out in his respiration calorimeter where the applicability was very limited. Boothby and Sandiford(3) and Kunde(4) have carried out metabolic investigations on dogs by means of the Benedict apparatus, but here again the device is only of limited value for work experiments, which none of these workers have apparently yet undertaken. It was believed therefore that, if the proposed experiments were a success, in addition to possessing a certain physiological value, they would open up a wide field of research of great practical significance.

This group, which is concerned with the applications of mathematics to agricultural science, was formed in 1970 and has since met at approximately yearly intervals in London for one-day meetings. The thirty-eighth meeting of the group, chaired by Professor A. Kassam of the University of Reading, was held in the Kohn Centre at the Royal Society, 6 Carlton House Terrace, London on Friday, 31 March 2006 when the following papers were read.

Soil available phosphorus (SAP) and potassium (SAK) are indispensable for crops, and their stocks are important for food production needed for a growing global population. This study analysed 991 soil profiles across a large part of Romania covering forestland, grassland and cropland in almost all ecological regions. This study investigated SAP and SAK stocks for different soil depths and characterized their magnitude and variability within land uses under different environmental ecosystems, soil classes and soil types, for a better soil and land management under a temperate-continental climate. Cropland soils present the highest SAP and SAK stocks. Chernozems, Phaeozems and Vertosols possess the highest SAP and SAK stocks in Romania, representing the largest country's pool. Both SAP stocks and SAK stocks are significantly correlated with basic environmental properties, existing direct correlations between SAP, SAK, soil organic carbon (SOC) and total nitrogen (TN) stocks. For all land uses, SAP and SAK stocks correlated significantly and directly with each other, as well as with annual temperature, clay content, pH and sum of base cations, and inversely with altitude, slope and annual precipitation. The best predictive values using multiple regression models and basic environmental driving factors were found for forestland stocks of SAP and SAK, followed by grassland stocks, while the lowest prediction occurred for cropland stocks, probably due to the long-term additional nutrient input performed by farmers in cropland that changed the natural conditions otherwise present in grassland, and especially in forestland. Based on these results some management measures are discussed.

Noy-Meir's simple but insightful model of grazing-system dynamics was used to draw broader inferences from empirical data generated by a 17-year field trial with beef cattle grazing a Mediterranean grassland in northern Israel. After calibration of its parameters against the field results, the model predictions were tested against an independent set of data obtained from the study site; they were within acceptable deviations from the inherently noisy field data. The calibrated model was used to analyse the effects of changes to two key grazing-management factors – stocking density and early-season grazing deferment – on biomass dynamics and forage consumption. The simulated results were used to calculate forage deficits and supplementary feed requirements for optimum herd performance during the growth (‘green’) season and throughout the year. The results revealed a critical stocking density of 0.7 Animal Units (AU)/ha, above which early-season deferment reduced the amount of supplementary feed required to maintain the optimum production of the herd. Optimum stocking is higher when the grassland is used mainly in the highly nutritious green season. Responses of the strongly seasonal Mediterranean grassland to the interaction between stocking density and early-season grazing deferment were expressed by a calibrated model, in terms that determine the efficiency of forage supplementation of the herd during the green season and throughout the year.