The mating response and lambing outcome was studied in 584 sheep in twentyeight farm flocks after treatment with progestagen impregnated intravaginal sponges and PMS during June/July (period of late anoestrus). Each pessary carried a dose of 30 mg ‘Cronolone’ (9α-fluoro-11β-hydroxy-17α-acetoxy-progesterone; SC-9880, G. D. Searle) in finely dispersed form; half the number of pessaries carried an additional dose of 400 mg progesterone. Intravaginal treatment was for 12 days; a single intramuscular injection of 500 i.u. PMS (Burrough's Wellcome) was made at pessary withdrawal. Breeding was by natural service, using 10% rams. The response was 98·8% bred in the 4 days after treatment, 61·2% conceptions in those served and an average of 1·65 lambs/conception. This resulted in the birth, within the period of about 1 week, of 100 ‘early’ lambs for every 100 ewes exposed to rams. The addition of 400 mg progesterone to pessaries or the injection of a dose of 5 mg progesterone at sponge withdrawal did not improve response beyond that found with ‘Cronolone’ alone.

Effects of phosphorus fertilizer, initial profile water storage and seasonal rainfall on yield and water use by dryland wheat on loamy-sand and sandy-loam soils were studied for a 2-year period (1973–5). Plant available water at seeding varied from 62 to 205 mm, seasonal rainfall varied from 62 to 154 mm and available P status ranged from 9·5 to 18·5 kg P/ha. Four rates of phosphorus 0, 15, 30 and 45 kg P2O5/ha were tested. Available water at seeding, seasonal precipitation and the available P status of soil determined the yield response to phosphorus fertilizer. Response to P application was observed up to 15 kg and 30 kg P2O5/ha in loamy-sand and sandy-loam soils respectively. Growth and yield of wheat were highly correlated with the available water at planting plus seasonal rainfall. Total water use did not change in loamy-sand soil, but it increased by 16 mm in sandy-loam soil with the application of phosphorus. The profile water depletion pattern, further, indicates that the fertilized crop used more water from layers below 135 cm in loamy-sand and 22·5 cm in sandy-loam soil.

The possibility of a sub-clinical state of thiamine deficiency in young cattle and sheep is discussed. A trial was carried out on six MAFF experimental husbandry farms in which groups of animals were given 100 mg of thiamine per day orally throughout the rearing period. Measurement of erythrocyte transketolase showed that the dosed group gave a significantly lower percentage thiamine pyrophosphate effect than the control group. There was no difference in weight gain of the two groups during the limited period of the trial.

Twelve accessions of pigeonpea (Cajanus cajan [L.] Millsp.) were grown on an Alfisol in a humid ecozone in Nigeria in 1989. At 4 and 8 months after planting (MAP), the primary growth was cut to determine the effect of age at first pruning on stump survival and coppice regrowth, and also on total herbage yield in a 12-month pruning cycle. It was clear that a height of 3 m or more is adequate for pigeonpea to receive its first cut with only 10% stool mortalities. Cutting the primary shoot at 8 MAP (in the dry season) ensured greater stump survival and also stimulated rapid coppice shoot regrowth, indicating the advantage of coppicing in the dry season and also at maturity. The total leaf and wood dry matter (DM) production in a 12-month cycle is greatest if the primary shoot was first cut at 8 MAP. This suggests that allowing the trees to become established is beneficial in the pruning management of pigeonpea. Accessions 11563 and 11575 have the ability to produce 7 t/ha of leaf DM from two prunings when first cut at 8 MAP, and significantly outperformed the local variety. The study revealed that pigeonpea does not coppice well and its biomass yields are much lower than that of Leucaena leucocephala.

Experiments were made on twelve rams to determine the effects of hormonal treatment on rams with poor libido. Testosterone and PMS were used and sexual behaviour, and semen characteristics such as volume, motility, impedance-change frequency and dead percentage were studied. The libido was higher in testosterone-treated rams than in the PMS-treated, or in the control rams. Volume of ejaculate was also higher in the former group. There was not much difference in the motility ratings. Impedance change frequency was slightly lower and dead percentage higher in the semen produced by testosterone-treated rams than in other groups.

The figures analysed in the subsequent pages were obtained (by the kind permission and help of Prof. S. Pennington) during the five years, May 1920 to May 1925, from the College Farm dairy cows at University College, Reading, and before proceeding, a few notes on the herd and its management are desirable.

The herd is small (14–18 animals), and was established in 1908 by purchasing non-pedigree Dairy Shorthorn heifers which have since been “graded up” by the use of Pedigree Dairy Shorthorn bulls. The cows are typical Dairy Shorthorns, of a fairly large size, and the degree of fatness normally maintained might be described as good thriving condition, and probably better condition than average dairy cows.

Results obtained from the plots of a field experiment may be subject to’ representational errors'; that is, they may not exactly reproduce the results that would be expected if the same treatments were applied to whole fields. In particular, the treatment applied to one particular plot often has the potential to affect the adjacent plots; such an effect may be positive or negative according to circumstances, and its magnitude cannot easily be estimated. This paper shows, on theoretical grounds and by simulations, that nearest-neighbour (NN) analysis cannot be relied upon to mitigate the effects of such inter-plot interference, even when the residual variance of the NN analysis is substantially, and by normal criteria significantly, smaller than that of conventional (randomized block) analysis. In certain circumstances, NN analysis of data affected by interference produces greater average bias in estimated treatment differences than conventional analysis.

The moisture equivalent has been measured (by a technique requiring only small quantities of soil) for a number of samples comprising Natal and Sind soils. It is concluded that while with the latter (alkaline and saline) soils the moisture equivalent gives valuable information, it adds little to the data obtained by other methods for the Natal soils. The xylene equivalent of the Natal soils has also been measured; from the moisture equivalent and the xylene equivalent, the imbibitional water can be calculated if the specific gravity of the soil is known.

Equations expressing the moisture equivalent and the xylene equivalent of the Natal soils in terms of their loss on ignition and mechanical composition are obtained, and the significance of the relative values of the numerical coefficients in these equations is discussed.

In the present paper, a simplified procedure using few in situ data points is derived and then evaluated (using a large database) against reference values estimated with the standard nylon bag first-order kinetics model. The procedure proposed involved a two-stage mathematical process, with a statistical prediction of some degradation parameters (such as lag time) and then a kinetic model derived by assuming degradation follows zero-order kinetics to determine effective degradability in the rumen (E). In addition to the estimation of washout fraction and discrete lag, which is common to both procedures, the simplified procedure requires measurement of dry matter losses at one incubation time point only. Thus, interference of the animal rumen will be much reduced, which will lead to increased capacity for feed evaluation. Calibration of the zero-order model against the first-order model showed that suitable estimates of E can be obtained with disappearance at 24, 48 or 72 h as the single incubation end time point. The strength of the calibration is such that an end incubation time point as low as 24 h may be sufficient, which may reduce substantially the total incubation time required and thus the impact on the experimental animal. Relevant regression equations to predict reference values of parameters such as lag time or E are also developed and validated.

From 1969 to 1971, 743 animals (indigenous Zebu and European dairy cattle, lactating or dry cows and heifers) received oestrous cycle synchronization treatments at government-owned and private ranches and farms in the Tanzanian highlands (West Kilimanjaro); 445 matching animals served as controls. Treatment schedules consisted of chlormadinone acetate (CAP) given daily for 14 days (10 mg/day) orally; or a single CAP injection (50 mg) followed by 4 or 5 days of oral treatment (10 mg/day) 9–12 or 11–15 days later. In addition, some groups received either estradiol valerate (5 mg) together with the CAP injection, or 10 mg/day mestranol from day 11 to 15, together with CAP; one treatment group received 1000 i.u. of HCG after the last CAP medication and were inseminated 12 and 24 h thereafter. Animals were either inseminated or bred naturally. With all treatment schedules, good synchronization, unimpaired fertility and consistently a significant reduction of anoestrus was achieved. Oestrogen treatments had no effects; treatment with 1000 i.u. of HCG was unsuccessful. Management factors, food supply and phase of reproductive life had significant impacts on treatment success and fertility. Synchronization can be used successfully under a wide range of management conditions to unfold existing potentials of artificial insemination in Bos indicus and Bos taurus in the tropics.

1. Data from eleven forages fed in digestibility trials were used to obtain statistical relations between organic matter intake (I), faecal dry matter output (F) and the concentration of nitrogen (N), copper (Cu), magnesium (Mg) and silicon (Si) in faecal dry matter.

2. Exploration of multiple regressions using all variables, and their products, gave a prediction relationship with four variables that was slightly better than that for nitrogen alone, as obtained by Arnold & Dudzinski (1963). FN and the products of(FN × FCu) and (FN × FSi) were the contributing variables. The eleven forages could not be brought into a single expression.

Agroecosystem decision support systems typically rely on some types of weather data. Although many new digital weather and forecast datasets are gridded data, the current authors feel that evaluating previous methods with data of increased archive length is critical in aiding the transition to new datasets that lack extensive archives. To that end, the present paper reviews the improvements made to an artificial neural network for forecasting weather-based potato late blight (Phytophthora infestans) risk at 26 locations in the Great Lakes region. Accuracies of predictions made using an early model, developed in 2007, are compared with accuracies of predictions made using a new 10-year hourly optimized model. In nearly every comparison by month, forecast lead time and spatial region, the newly optimized model is more accurate, especially when the weather is conducive to high disease levels.

It has been known for many years that agricultural grasses become less nutritious as they approach maturity and ripen their seed. The grass plant in its earlier weeks of growth makes a heavier draft on soil nitrogen than later in the season, with the result that its tissues are particularly rich in protein. As the grass continues to grow, the protein, now formed in lessening quantities, is distributed throughout a greater bulk of the plant and thus its percentage in the dry matter is reduced. From a study of the analytical data on record of grasses examined at several stages of growth, it may be summarised that as a grass matures the protein, ash, fat and water decrease while the carbohydrates (nitrogen-free extract) and fibre increase. Further, in addition to the larger percentage in their dry matter of protein and mineral constituents, the leaves and shoots of very young grass are more succulent, palatable and digestible than the leaves of the older plant. These facts have been used in giving advice as to the best period at which to cut for hay, i.e. the stage of growth at which the grass will yield the largest amount of digestible matter per acre. This will vary somewhat with different species, but the weight of scientific evidence is in favour of cutting at or shortly after the flowering period. It will thus be seen that chemistry has contributed valuable information in relation to the best time or period for the harvesting of grass for hay.

The effects of immunization against luteinizing hormone releasing hormone (LHRH) and melatonin were studied during autumn and winter 1989 in yearling red deer stags initially aged 14 months and weighing 90–96 kg. Four out of five stags immunized against LHRH and six out of eight stags immunized against melatonin developed detectable levels of antibody titre. Immunization against LHRH reduced plasma LH concentration and both delayed and reduced weight loss associated with the rut (autumn); however, it had no effect upon carcass weight and dressing-out percentage was slightly lowered, showing that non-carcass components had been affected. Immunization against melatonin had no effect either on weight loss during the rut or on the rate of liveweight gain during winter and spring. Plasma concentrations of LH and testosterone were not affected by melatonin immunization; however, plasma prolactin concentration was consistently, but non-significantly, higher in immunized than control animals.

1. The main objectives of the breeding programme were to develop two types of soyabeans:

(a) High yielding, non-shattering, resistant to lodging, determinate in habit, with pods formed 5-6 in. from ground level, for mechanical harvesting.

(b) High yielding, non-shattering but with no qualifications as to habit, for hand harvesting by African farmers.

An account of the breeding programme carried out on twelve crosses is given. The breeding method used was a combination of the bulk and pedigree methods.

1. Balance experiments, in which urine was collected by a catheter inserted into the bladder, were carried out on four lactating ewes on two diets of fresh spring herbage and on one of hay plus cake, and the metabolism of magnesium, calcium, phosphorus, potassium and sodium were studied.

1. Thirty Rhodesian soils were cropped with weeping love-grass (Eragrostis curvula) for up to 11 months in the glasshouse, the potassium released on cropping being compared with soil contents and that released on prolonged suspension in dilute CaCl2 or by reaction with H-exchange resin.

2. Love-grass produced up to 33 tons of dry matter and removed up to 700 lb. of K2O/acre, and releases of non-exchangeable potassium ranged from 3 to 2931b. K2O/acre. With some soils potassium uptake by love-grass (and K-release) was about 60% of that reported for perennial rye-grass, showing that different crops have differing abilities to use non-exchangeable potassium reserves.

The average serum T4(D) of nine non-pregnant buffaloes was 5·5 ± 1·4 μg/100 ml. It increased slightly to 6·2 ± 4·2 μg/100 ml in 37 6–7 month pregnant buffaloes. Nevertheless the difference was not significant. When the pregnancy reached 8–9 months, the T4(D) was 9·0 ± 3.8μg/100 ml which was significantly higher than that at 6–7 months (P < 0·01). At full term (9–10 months), T4(D) decreased to 3·6 ± 2–6 μg/100 ml which was significantly lower than that at 8–9 months (P <0·001).

In 1 month post-partum buffaloes, the average T4(D) was 5·1 ± 3·4 μg/100 ml, while T4(D) of 1-month-old buffalo calves was very high, i.e. 13·6 ± 3·2 μg/100 ml.

The total serum T3 (RIA) of late-pregnant buffaloes decreased markedly from that of 8–9 month pregnant (P< 0·001). At 1 month post-partum, T3 rose to 143·4 ± 33·0 μg/100 ml which was significantly higher than that at late pregnancy (P < 0·001). The mean serum T3(RIA) of 1-month-old buffalo calves was relatively high, i.e. 281·0 ± 106·2 μg/100 ml which was significantly higher than 143·4 ± 33·0 ng/100 ml of their darn buffaloes (P < 0·001) at the same period of time.

The RT3U values of 6–7 (35·9 ± 4·2%) and 8–9 (34·7 ± 2·0%) month pregnant animals were highly significantly different from 31·1 ± 3·1 % of the full-term pregnancy (P < 0·001).

From 62 days of gestation to parturition, 20 Finnish Landrace x Dorset Horn ewes were each offered one of four diets with roughage to concentrate ratios of 20:80; 40:60; 60:40 and 80:20, at daily metabolizable energy and digestible crude protein intakes of 490 kJ and 3·55 g/kg W0·75 respectively. Plasma concentration of free fatty acids, glucose and urea were determined weekly, and nitrogen balance and digestibility trials were carried out at 70–80 and 130–140 days of gestation.

On all treatments the concentration of plasma free fatty acids increased during pregnancy from approximately 200–600 μ-equiv./l and the concentration of glucose and urea decreased by approximately 25%.

Digestibility coefficients for dry matter and organic matter increased from 58 to 68% and from 60 to 70% respectively as the proportion of concentrates in the diet increased and were not affected by stage of gestation. The apparent digestibility of nitrogen was not affected by the energy concentration of the diet.

Between mid and late gestation there was a mean increase in daily nitrogen retention of 2·5 g and an improvement in the efficiency of nitrogen utilization of 19 percentage units.

Nitrogen retention and the efficiency with which the apparently digested nitrogen intake was retained increased as the dietary energy concentration was increased. The mean daily increases in nitrogen retention were 0·0135 and 0·0039 g for each percentage unit increase in the concentrate portion of the diet at mid and late gestation respectively. The corresponding values for the improvement in the efficiency of nitrogen utilization were 0·13 and 0·10%.

Meat quality comparisons were made between a total of 43 infertile bulls and 42 steers in five separate trials. Tenderness, juiciness and flavour were tested by taste panel for each of the five trials, making 15 subjective tests, while objective tests were made of tenderness (Warner-Bratzler shear) and juiciness (industrial press) in the five trials, making a further ten tests.

From this total of 25 different groups of assessments no significant difference between bull and steer meat was detected in 21; of the four groups of assessments where significant differences were detected, two favoured the bulls and two favoured the steers; the quality of all the samples was acceptable.

It is concluded from the overall results that in terms of practical meat quality there was no difference between the bulls and steers used in these five trials.