The objectives of this study were to investigate the effect of level and timing of silage supplementation during early lactation on animal performance and dry matter intake (DMI). Two farm-lets were established with a high (1253 kg DM/ha) and low (862 kg DM/ha) grass availability at turnout. In spring, cows were assigned to one of two treatments as they calved over 2 years; high grass (HG) and low grass (LG). During period 1 (week 1–6), cows on the HG treatment were offered a high daily herbage allowance (DHA) with low silage and the LG treatment were offered a low DHA with high silage. In period 2 (week 7–12), half of the cows from the HG treatment in P1 switched to the LG treatment in P2 and vice versa as 20 LG cows in P1 switched to the HG treatment in P2. Cows on the HG treatment in P2 received a high DHA with no silage and the LG treatment received a low DHA with 3 kg DM/cow silage. Grass DMI was significantly higher for the HG treatment during both periods (+1.6 and +3.4 kg DM/cow/day, respectively). The HG treatment produced +0.9 kg milk/cow/day and had a higher protein concentration (+1.1 g/kg milk) compared to cows on the LG treatment during period 2. Differences in animal performance observed in period 2 were maintained throughout the 8-week carryover period.

Accurate information on metabolizable energy and true digestible amino acid (TDAA) content of sorghum grain is important in order to formulate sorghum-based poultry diets accurately. Estimates of ingredient nutritional values using bioassay methods require live birds and special facilities, which are time-consuming and costly. Accordingly, prediction by mathematical models would be of some considerable benefit. Sixty-eight samples of sorghum grain, representing 32 different varieties, were used to test the correlation between TDAA and nitrogen-corrected true metabolizable energy (TMEn) with total essential amino acids. Two methods of multiple linear regressions (MLR) and artificial neural network (ANN) models were used to find the relationship between total amino acids (model inputs) with TDAA and TMEn contents (model outputs) in sorghum grain. The fitness of the models was tested using R2, mean square (MS) error and bias. There is a strong relationship between total amino acid concentration with both TDAA and TMEn content in sorghum grain. The TDAA and TMEn values were more accurately estimated by ANN model compared to values obtained from the MLR model. The R2 values corresponding to testing and training of the ANN model showed a higher accuracy of prediction than the equation constructed by MLR method. Based on the experimental evidence, it is concluded that the TDAA and TMEn values in sorghum grain can be predicted from total essential amino acids using ANN models. Consequently, this method provides an opportunity to reduce the risk of formulating an unbalanced TDAA diet for poultry.

The current study was conducted over four years between 2016 and 2019 to determine the effects of regulated deficit irrigation (RDI) before and after harvesting of sweet cherry on yield, physiological, vegetative and fruit quality parameters. The current study used the 0900 Ziraat sweet cherry cultivar grafted onto Gisela 6 rootstock. There were six different treatments: IC, (Control) where soil moisture was kept at field capacity for each irrigation, I25, with 25% deficit irrigation of IC after harvesting, I50, with 50% deficit irrigation of IC after harvesting, I25BH, with no-deficit irrigation 30 days after full bloom and 25% deficit irrigation after this period, I50BH, with no-deficit irrigation 30 days after full bloom and 50% deficit irrigation after this period, and IFRM, with farmer's treatment of excessive irrigation (150% of ET) from colouring of fruit till harvest and 50% deficit irrigation after harvesting. When compared to IC, water saving ranged from 20.2–45.6%. The fruit yield obtained under I25 was increased by 21.8% in the last year of the current study than the yield obtained under IC treatment. Trunk and shoot growth increased for all treatments. Leaf water potential (Ψmd) and stomata conductance (gsw) were affected by RDI. IFRM and I25 had a positive effect on fruit size, the same as IC. Water deficit (IBH50) applied before harvesting increased fruit flesh firmness. I25 treatment (25% water deficit after harvesting) can be applied by sweet cherry growers because it leads to high yield, better fruit quality and water saving.

The addition of aluminium salts to culture solutions and to soils will bring about certain changes; these may be summed up as follows:

1. A change in the hydrogen ion concentration, which will vary in amount with the original buffer properties of the solution or the soil.

2. A change in the buffer properties of the solution or the soil; the hydrogen in concentration of a culture solution containing an aluminium salt will tend to remain more constant than that of a normal culture solution during the period of growth of the plant, when both start at the same pH value.

3. Precipitation of soluble phosphate as aluminium phosphate except in solutions or soils more acid than pH 3·5 to 4·0; this might lead to phosphate starvation in water cultures but would have little or no effect in a soil, where the particles would remain accessible to the plant roots.

This paper reviews extensive work at Jealott's Hill and elsewhere in England and Wales on the agronomic effects of including various levels of urea in 2:1:1 NPK fertilizers combine-drilled with spring cereals.

Little evidence of phytotoxicity was found with fertilizers containing up to 12% urea and providing about 0·6 cwt N/acre. The inclusion of 20% urea reduced braird more frequently on soils of high pH than did lower proportions although grain yields were seldom affected adversely. Such soils are not uncommon, especially in the barleygrowing areas of Southern and Eastern England, where perhaps a quarter of the cereal acreage may be located on soils of pH 7·7 and above.

1. Plants of S.48 timothy were established on a 1 ft square pattern for production of seed. Two series of plots, one irrigated and one not irrigated, were treated with three levels of applied nitrogen: 0 (NO), 87 (Nl) and 261 (N2) lb N per acre (0, 97·5 and 292·5 kg N/ha) per annum, for 3 years. In this, the first of two papers, only vegetative aspects of growth are considered. Since the irrigation treatment started only 2 weeks before most of the data were recorded, effects of irrigation on vegetative growth were generally small.

2. The number of tillers per plant was increased by application of nitrogen; the lower increment was more effective than the additional nitrogen in the higher dose.

3. The weight of tillers per plant was increased by nitrogen at both levels of application. The mean weight of each tiller was increased by nitrogen after the first year, predominantly in the N 2 treatment. In the second year, irrigation also increased the weight per tiller.

4. The weight of roots per plant was significantly affected by application of nitrogen. In the first year, the weight was increased by nitrogen in irrigated plots; in the second year the roots were significantly heavier in the Nl treatment than in N0 and N2 treatments, where weights were similar; the same situation existed in irrigated plots in the third year, but in non-irrigated plots the weights of roots were similar in N1 and N2 treatments and were heavier than in the N0 treatment. Irrigation had positive effects on the weight of roots in the first and second years.

Male and female New Zealand White rabbits were exposed for 3h to 34 °C and 36 °C (both at 40% r.h.) when hydrated and dehydrated. Females had lower rectal and skin temperatures and respiratory rates than males (P < 0·001). Differences between the sexes in rectal temperature were greater at 36 °C than at 34 °C. Withholding water for 24h significantly increased the responses in rectal temperature; the differentials between hydrated and dehydrated males and females being 0·3 °C and 0·2 °C, respectively. In contrast, respiratory rates were lower in dehydrated than in hydrated rabbits, suggesting that the former were attempting water homeostatis at the expense of thermoregulation.

The results suggest that the performance of rabbits in the tropics is likely to be maximized when drinking water is available at all times, and that of males, particularly breeding bucks, might be improved simply by housing them in the coolest available location. Significant individual differences in observed responses point to the need for genetic studies of heat tolerance and the possibility of developing better adapted genotypes.

Data collected over a period of 11 years at the Ebini Livestock Station in the intermediate savannahs of Guyana were analysed to determine the effect of breed or cross, sire, sex, year and season of birth of calf, and age and length of calving interval of the dam on weights at birth and at 4, 8 and 12 months of age, in Santa Gertrudis, Sahiwal and Brahman cattle. The heritability of body weights at the different ages was estimated.

The results on the influence of growing various crops in five fixed annual sequences on the changes in available and total phosphorus and potassium content of a Tolewal sandy loam (Typic Ustipsamment) are reported. The available phosphorus content showed an increase in each of the five crop rotations after completion of two cycles. The maximum increase was observed in groundnut-based cropping sequences whereas the increase under the other three rotations was more or less of the same order. A slight decrease in the available P content during the 3rd year was observed after the harvest of bajra in a bajra fodder–potato–wheat sequence which was replenished after the harvest of potato and wheat. Total P content of the soil also showed an increase in all five rotations after completion of two cycles. A decrease in total P content of the soil was also observed after the bajra harvest. Balance sheet of P indicated net gain of P in all five crop rotations and the maximum gain of 62 kg P/ha was observed in the maize–wheat–moong rotation. Theavailable K status of the soil showed an increase in each of the five cropping sequences after completion of two cycles. The available K status after harvest of various crops in the rotation could not fully explain the dynamics of K availability. The total soil K content indicated a negative K balance in each of the five crop rotations after completion of three cycles and the maximum negative balance occurred in a maize–wheat–moong sequence. The negative K balance was related to the amount of fertilizer K added and that removed by the crops. The results suggested the need for modifying the existing K fertilizer recommendations to compensate gradual loss of native K soil fertility.

Two changeover experiments, each on eight buffalo heifers, were conducted in two different years to determine the effect of wilting lucerne herbage (Exps. 1 and 2) and berseem herbage (Exp. 2 only) on voluntary dry-matter intake. The dry-matter content of the herbages increased by field wilting from 27 to 50 and from 26 to 44% for lucerne in Exps. 1 and 2 respectively, and from 21 to 31% for berseem. The drymatter intake, nutrient digestibility coefficients, nutritive value index and retention time of undigested residues were determined for each fresh and wilted herbage.

Wilting increased the dry-matter intake of lucerne from 2·3 to 2·8 and from 2·1 to 3·5 kg per 100 kg body weight in Exps. 1 and 2 respectively. Berseem dry-matter intake was increased from 2·2 to 3·1 kg per 100 kg body weight. Digestibility coefficients of all nutrients of both herbages increased by 6–20%. Retention times were unaffected by wilting. The nutritive value indices for lucerne and berseem in Exp. 2 increased by 160 and 60% respectively. In Exp. 2, the average loss of herbage dry matter due to wilting was 3·8%. The higher consumption of the wilted herbages is ascribed to their lower water content. The practical implications of these results are discussed.

1. Extremity skin temperature changes in British and Zebu cross cattle examined in moderate thermal environments followed a thermoregulatory pattern similar to that describedby Whittow (1962). At low environmental temperatures, ear and lower leg skin temperatures were usually only slightly above air temperature. At a variable time after air temperatures began to rise or the animals were fed, extremity skin temperatures increased suddenly to near trunk skin temperature.

2. In eight of the ten pairs of animals studied in rising ambient temperatures and during feeding after fasting for 36–72 hr, increases in ear temperature were measured in the British animal before similar changes occurred in its Zebu counterpart. Changes in lower leg skin temperature followed a similar pattern.

Trunk skin temperatures and respiratory frequencies were significant higher in British cross animals than in Zebu cross animals of similar thermal history. The mean rectal temperature of both British and Zebu cattle was 38·5 °C.

Analysis of 21 years' cotton yield data from factorial experiments at three sites in the Sudan Gezira established that yields were significantly increased by nitrogenous fertilizer, that close spacing outyielded wide spacing and that variety X1730A (L type) outyielded variety MSDS (a Sakel type). The effect of nitrogen varied depending on variety and spacing and there were also marked variations from year to year in the effects of nitrogen, spacing, variety and some of the interactions. Year-to-year variations in the overall level of yield were very pronounced and accounted for more than half of the total variance at each site. Causes of year to year variation and the mechanism of the treatmenteffects will be discussed in subsequent papers.

Four diets were fed to two Friesian bull calves fitted with re-entrant duodenal cannulae. The diets contained no poultry litter (diet 0); 30% poultry litter (diet 30 D); 50% poultry litter (diet 50 D) or 30% poultry litter which had been ensiled at 45% moisture content for 3 weeks (diet 30 W). The total flow of digesta from the abomasum was measured over four 24 h periods for each diet.

The flow of dry matter and organic matter to the duodenum was similar on all four diets but the percentage of apparent digestion occurring in the stomach was higher when the diets containing poultry litter were fed.

Less nitrogen was digested in the hind gut on diet 30 W than the other three diets. Greater amounts of the nitrogen ingested and also of the nitrogen flowing to the duodenum were apparently digested in the hind gut on the diet containing no poultry litter. Microbial protein synthesized/100 g organic matter apparently digested in the stomachs was lowest when the calves were fed the 30 W diet.

The results obtained in these experiments were then used to evaluate the results of growth trials previously reported.

Six litters of pigs farrowed, reared and fattened on a ration of barley meal, weatings, soya-bean meal, meat meal and minerals failed to thrive and in the later stages of fattening many of the pigs showed typical symptoms of vitamin A deficiency.

Six comparable litters raised under similar conditions and on the same meal mixture with ° 1 or 2% of a commercial cod-liver oil of guaranteed purity and standardized vitamin content made good progress and nearly all the pigs weaned in these litters were fattened for pork or bacon.

Estimations of liver reserves of vitamin A of the pigs receiving no cod-liver oil indicated that the liver store was exhausted soon after weaning. All pigs receiving cod-liver oil gradually increased their liver store of vitamin A. The stores rose approximately in proportion to the level fed and period of feeding. There was no evidence that the higher levels of cod-liver oil had any practical advantage over °%.

The symptoms shown by the pigs receiving no cod-liver oil included loss of appetite, cessation of growth, impairment of vision in daylight, abnormal gait, convulsive fits and nervous collapse. Pneumonia and/or inflammation of the intestines was found in all of seven pigs that died during the fattening period.

This group, which is concerned with the applications of mathematics to agricultural science, is sponsored by the Agricultural and Food Research Council. It was formed in 1970, and has since met at approximately yearly intervals in London for one-day meetings. The twenty-third meeting of the group, chaired by P. H. Nye of the Department of Plant Sciences at the University of Oxford, was held in the Wellcome Meeting Room at the Royal Society, 6 Carlton House Terrace, London on Friday, 7 May 1993, when the following papers were read.

The absolute and relative growth of the liver, kidney, heart and lung-and-trachea were studied for 64 female, 64 castrated male and 64 intact male indigenous Nigerian pigs between birth and 672 days of age. Highly significant (P < 0·001) sex and age influences were obtained for the absolute and relative weights of the liver, kidney and heart. At 280 days of age, the four organs on average weighed 28 times their birth values; the terminal weights averaged 1·31 times their values at 280 days. Organ growth became stabilized after 280 days.

The allometric equation: Y = aXb, transformed to its linear form log Y = log a + b log X, was employed to examine the relationship between organ weight and body weight. The growth coefficients 6 obtained ranged from 0·787 for kidney to 0·850 for lung-and-trachea and were similar to values reported in the literature. The accompanying highly significant R2 values strongly indicate that the functions of these organs are related to overall metabolism, which in turn is strongly dependent on body size.

The live-weight gain, efficiency of food conversion, energy and nitrogen accretion as edible carcass, and the forestomaeh development were measured in three groups of calves fed for 10 weeks (days 19–89 of life) either a diet of 4·5 1 of milk daily, or a concentrate meal containing 4% sodium propionate ad libitum, or a concentrate meal ad libitum. All groups had access to lucerne chaff and water ad libitum.

The mean live-weight gains of the three groups of calves were 47·5, 36·6 and 37·1 kg respectively even though their total energy and nitrogen intakes were not significantly different. The provision of dietary propionate did not improve the efficiency of food conversion or of energy or nitrogen accretion as the calves ate less of the meal containing propionate and more lucerne chaff. The differences in live-weight gain could be accounted for by the differences in carcass weight. Associated with the higher live-weight gain was a much higher efficiency of food utilization and of edible carcass energy and nitrogen accretion. The superior efficiency of the unweaned calves was concluded to be due to the liquid portion of the diet by-passing the rumeno-reticulum into the abomasum where the efficiency of utilization of highly digestible protein and carbohydrate is greater. The concentrate plus propionate fed calves ate less concentrate but more chaff and had a lower efficiency of food utilization and edible carcass energy accretion than the other weaned group of calves.

The weight of rumeno-reticular tissues was greater in the weaned than in the unweaned calves, although the meal plus propionate group ate similar quantities of chaff to the unweaned group. In all groups, the degree of papillary development was related to the intake of concentrates plus roughage. The most appropriate manner to describe ruminal tissue weight is discussed.

In the Journal of Agricultural Science for October 1921, Dr J. W. Capstick described a calorimeter large enough to take a full-grown pig or a small bullock. This apparatus was in regular use up to the end of 1923 and proved, on the whole, quite satisfactory.

Hotroom treatment of ewes during the last two-thirds of gestation resulted in the birth of lambs which were significantly lighter than lambs born to nutritionallydeprived ewes. Neither high temperature nor undernutrition had significant effect on the density of either primary or immature secondary wool follicles, but the total number of mature secondary follicles tended to decline in the lambs from unheated ewes as the level of nutrition declined, and was significantly reduced by a further 30 % in the hotroom group.

In a second experiment, heated and unheated ewes fed to appetite were compared with unheated ewes pair-fed to the hotroom level of feed intake. High temperature had no apparent effect on maternal wool growth, but did reduce total wool follicle number in new-born lambs by approximately 50%. This effect was most marked with respect to mature secondary follicles (only 18% of unheated mean), less so in immature secondaries (56% of unheated mean), and barely discernible amongst primary follicles (93% of unheated mean). None of the differences in follicle numbers between the two unheated groups was significant.

The results suggest that the effects of high temperature on wool follicle development in the sheep foetus are akin to those of extreme undernutrition.