An emulsion of [3H]triglycerides was used to investigate how circulating triglycerides are partitioned between milk fat, body fat and use as an energy source in lactating sheep. Immediately after intravenous injection of the emulsion the radioactivity in the blood was predominantly associated with the triglycerides of the fraction that contained chylomicrons and very low density lipoproteins. The radioactive triglyceride was used both as a precursor of milk fat and as a source of energy. The proportions utilized for these two purposes were determined experimentally and the amount retained in the carcass lipids was found by difference. In separate control experiments with nonlactating sheep the total radioactivity in the body lipids was determined by carcass analysis. This total together with that accounted for by oxidation amounted to 98% of the total radioactivity injected. These results established that the emulsion was a reliable model for the purpose intended.

The proportion of the labelled triglyceride that appeared in milk fat declined from 45% at 17 days after lambing to 8–10% at 73 days after lambing. The proportion that was oxidized was also lower in late lactation so that retention in carcass lipids was substantially increased at that time.

Eighteen growing cattle with a mean live weight of 180 kg were used to study the influence of restricted water on feed intake, nutrient utilization and nitrogen metabolism in Zebu cattle in the Sudano–Sahelian ecological zone of Nigeria.

Feed intake and water consumption were negatively correlated (r = 0·63). As the amount of water intake was reduced from 15·8 to 11·91/day, the mean feed intake increased from 5·6 to 6·8 kg D.M./day; water to feed ratios decreased from 2·83 to 1·75 and average daily live-weight gain as well as apparent feed utilization efficiency improved significantly from free-choice water to 50% of free-choice water treatments respectively.

Apparent digestibility coefficients of almost all the nutrients from the 75 and 50% of free-choice water treatments indicated progressively higher (though not significant) values than those of the free-choice water treatment. Nitrogen metabolism did not indicate any difference in the nitrogen intake in any of the three treatments; however, nitrogen balance and nitrogen retained as a percentage of nitrogen intake were significantly (P < 0·05) higher on the 50% of free-choice water treatment.

The survival ability of these Zebu breeds of cattle under water stress during the acute water scarcity of the protracted dry period of the Sudan–Sahelian zone of Nigeria could probably be attributed to increased recycling of nitrogen as well as a reduction in nitrogen loss during the period.

The present study deals with the reproductive performance of an imported Suffolk flock and the cross-bred ewes resulting from upgrading the local Ossimi sheep with the Suffolk. A total of 1738 ewe records were available for the study.

No significant difference was found between Suffolk and Ossimi ewes in conception rate or proportion of multiple births. However, the Ossimi ewes (mated to Suffolk rams) weaned 25 more lambs per 100 ewes lambing than the imported ewes. The cross-bred ewes were of better reproductive performance than both pure-breds. The best Suffolk cross-bred ewes were those of 40–49 % Suffolk breeding. They weaned 21 more lambs per 100 ewes run with the rams than the local ewes. Reproductive performance of the cross-bred ewes declined with increasing Suffolk genotype above this proportion.

Under the prevailing sub-tropical conditions, the Suffolk ewes have an anoestrous period of 200 days from late January to late July or August; the local ewes showed oestrous activity throughout the year, but with some irregularity.

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).

1. A balanced factorial experiment was carried out with forty-eight Merino ewes. There were two levels each of the four factors: environmental temperature, thyroxine status, vitamin A intake and progesterone status. Each ewe was killed at 25 days' pregnancy; its uterus was weighed and portions were prepared for histological examination. A number of morphological indices were then measured.

2. With respect to uterus weight there were significant interactions between thyroxine level, environmental temperature and progesterone level, and between thyroxine level and vitamin A intake. In the absence of thyroxine injections, heat and supplementary vitamin A increased mean uterus weight; in the absence of either of these, thyroxine injections increased it. Heat or vitamin A with thyroxine injections maintained normal mean weight. Progesterone influenced the temperature effect only in the presence of thyroxine.

3. Where thyroxine injections were given at normal temperatures uterus weight was significantly correlated with plasma vitamin A concentration. There was a similar correlation where thyroxine injections were given in the absence of dietary vitamin A.

4. There were no significant treatment effects or interactions on any of the histological indices examined. The height of the glandular layer of the endometrium, however, increased with increasing uterus weight, while the density of transected glandular tubules declined. There was no correlation between height of the stratum compactum or of the glandular epithelium and uterus weight.

5. In ewes with dead embryos the means of the following indices were significantly greater than in ewes with live ones: height of the stratum compactum, height of the glandular layer, height of the gland epithelial nuclei; the density of glandular tubules was less.

6. In the hot-room, gland epithelium height was correlated with mean rectal temperature.

7. Expansion of the glandular layer is not associated in all subgroups with more embryonic deaths and cannot therefore be their main cause. The observations do not indicate that early embryonic deaths are due to insufficiency of ovarian hormones; nor do they account for the marked improvement in viability associated with thyroxine injections.

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.

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.

A Short preliminary note on this disease was published Nov. 1912(4), and since that date further investigations have been carried out into the life-history of the organism, and its effect on the host plant. As 1 there showed the disease is caused by a bacterium for which I propose the name Pseudomonas seminum.

1. The effects of l-thyroxine therapy and a low plane of nutrition on some of the non-carcass components of live weight in New Zealand Romney ewes were investigated.

2. Thyroxine treatment significantly lowered the weight of the gastrointestinal tract contents. A low plane of nutrition and a longer total starvation immediately pre-slaughter had little effect in lowering the weight of the gastrointestinal contents. Alimentary tract ‘fill’ accounted for a group mean loss of live weight of up to 5 lb.

3. Thyroxine treatment lowered the weight of the empty gastric tract, while a low plane of nutrition reduced the weight of both the empty gastric and intestinal tracts. The combined treatment effects accounted for a loss of up to 3 lb. in the weight of the empty gastrointestinal tract.

4. Neither treatment significantly reduced the weight of the omental and mesenteric fat depots.

5. The weight of the thyroid gland was unaffected by either treatment.

6. A low plane of nutrition significantly reduced the weight of the liver, kidneys and the heart but had no effect on the weight of the spleen. Thyroxine therapy significantly reduced the weight of the liver and tended to increase the weight of the kidneys and the heart.

The yield results are reported for an experiment in which 21 rates of nitrogen fertilizer were applied on pure-sown swards of four grasses, S. 24 and Barvestra perennial ryegrass, S. 37 cocksfoot and S. 53 meadow fescue. Growth curves fitted to the herbage yield data for each grass in each year are presented. On average the total dry-matter yield curves for the two ryegrasses were similar to one another, but showed a slightly smaller response to nitrogen rates below 300 kg/ha than did S. 23 ryegrass in an earlier experiment, and a more rapid decrease in response at higher rates. S. 37 cocksfoot had a similar dry-matter yield response to the ryegrasses at the low nitrogen rates, but the response decreased more rapidly at nitrogen rates over 250 kg/ha. The dry-matter yield response of S. 53 fescue decreased even more rapidly with nitrogen rates over 200 kg/ha. The mean estimates of the optimal nitrogen rate for each of the four grasses, i.e. the nitrogen rate at which the dry-matter response had decreased to 10 kg/kg N, was 380, 372, 357 and 327 kg N/ha for S. 24, Barvestra, S. 37 and S. 53 respectively, compared with 409 kg/ha for S. 23 ryegrass in the earlier experiment.

Greenbug infestations to sorghum can cause severe and above economic threshold damage in the Great Plains of the United States. The current study was conducted to identify quantitative trait loci (QTLs) and potential candidate genes residing within the QTL region responsible for greenbug resistance in an advanced mapping population. Inter-crossed populations are useful in detecting QTLs tightly linked to genetic markers with high resolution. In the current study, QTLs responsible for greenbug resistance in sorghum were mapped using an inter-cross population derived from two parents, BTx623 (greenbug-susceptible line) and PI 607900 (greenbug-resistant line). Molecular markers for 115 loci were used to construct a linkage map which eventually facilitated tagging portions of the sorghum genome regions responsible for greenbug resistance. The molecular genetic map covered all the chromosomes of sorghum with a total genome length of 963·0 cM. The advanced mapping population revealed and confirmed the location of greenbug resistance loci, which explained a high phenotypic variation from 72·9 to 80·9% of greenbug resistance. The loci for greenbug resistance were mapped to the region flanked by markers Starssbnm 93 and Starssbnm 102 on chromosome 9 with an increased allelic effect from the resistant parent. The locations of these loci were compared with a previous study on QTL analysis using an F2 mapping population. The results from the present study were in agreement with the findings in the F2 QTL analysis and identified QTLs had a better confidence interval. The markers/QTLs identified from the current study can be effectively utilized in marker-assisted selection and map-based cloning experiments.

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.

It is shown that contrary to the statements of Kluyver and others, maltose undergoes slight hydrolysis (to the extent of about 2% when 1% solutions of maltose are used) when heated with hydrochloric acid under Herzfeld conditions. It is preferable therefore to adopt 10% citric acid, under the conditions formerly laid down, in estimating cane sugar in plant extracts when maltose is likely to be present.

The intake of dry matter from a pasture of Pangola grass by lactating dairy cows was measured. The chromic oxide administration technique was used. It was shown that the intake of dry matter was significantly higher in the dry season than in the wet. Reasons for this were discussed. An assessment of the nutrient intake of the animals was made and it was concluded that if the requirements of cattle in temperate climates was taken as a guide, this was adequate for at least maintenance and production of 1½ gal. per day of milk in the wet season. Under dry season conditions the intake of total digestible nutrients was adequate for the same level of production, but the digestible protein level was considerably below requirement. It was therefore concluded that supplementation with protein concentrates in the wet season was unnecessary save for high-yielding cows, but that all cows required concentrates during the dry season conditions of the experiment.

Extensive sheep and goat farming is common in the rangelands of Gökçeada Island, NW Turkey. The aim of the current study was to investigate the behaviour of indigenous Gökçeada sheep over these rangelands and factors influencing their behavioural characteristics. Grubbing (with chisel ploughing to a depth of 20 cm), burning (the entire top part of plants) and cutting (10–15 cm stalk on the surface of the soil) were carried out on selected rangeland to reduce prickly burnet (Sarcopoterium spinosum (L.) Spach) from the vegetative covering, then forage crop seeds were sown to improve plant cover. Forty head of Gökçeada-bred sheep were placed in eight fenced plots (half seeded, half unseeded) on reclaimed and natural rangeland for 2 years. Sheep behaviour was observed for a period of 1 year. Each plot was arranged with a stocking rate of 2·67 sheep/ha and contained five sheep that grazed freely within each plot. Sheep behaviour was observed diurnally through direct observation by time sampling (10 min) and continuous sampling methods. During the period of 1 year, the observed sheep spent an average of 0·53 of their time grazing in daylight, 0·30 of their time in rangelands on other activities and 0·17 in the paddocks. Significant differences were observed in the time of grazing, resting, locomotion and rumination by season. The highest grazing ratio was noticed in spring while the lowest was in summer. Sheep exhibited walking behaviour 10·6 times/day. The sheep mostly (0·66) grazed on prickly burnet throughout the year although, when available, they tended to prefer herbaceous plants. The behaviour of sheep in the two natural (unreclaimed) plots was significantly different from those placed in other plots, mainly due to the mass of prickly burnet shrub found in the natural plots.

A series of experiments were carried out at 14 sites in the major arable areas of the UK, in the years 1993–94, 1994–95 and 1995–96 to determine the causes and extent of over-winter plant losses of two autumn-sown cultivars of white lupin (Lupinus albus L.).

Over the three seasons frost was the major cause of plant losses. Two mechanisms (one known and one not previously reported in the UK) of frost tolerance under field conditions were identified: (i) lignification of the root parenchyma early in the life of the seedling, and (ii) a large vernalization requirement of the main-stem apex, which delays stem elongation in older plants. A model was developed that could be used to predict the susceptibility of these lupin cultivars to the first severe frost of the winter using accumulated thermal time (above a base temperature of 3 °C).

The effect of sowing at the beginning or end of a sowing window, calculated to optimize plant architecture the following summer, therefore varied with the weather during the autumn/winter period. A combination of cool autumn weather and late sowing (outside of the sowing window) resulted in plant losses due to a lack of lignification of the root parenchyma. In unusually warm autumn conditions (1994–95 and 1995–96) plants sown at the beginning of the sowing window were well developed before the first frosts occurred, with consequent stem elongation and plant losses.

Although losses due to pests were not severe (c. 3 to 5 plants/m2), plants were attacked during the autumn by grey field slugs (Deroceras reticulatum Muller), bean seed flies (Delia platura Meigen), and probably thrips (Thrips angusticeps Uzel, Noctuidae), although this has not been confirmed. The fungal pathogens Fusarium spp. and Botrytis cinerea Pers. caused losses in conjunction with frost damage.

In an experiment on permanent grass at Rothamsted during 1975–9 fertilizer-N was applied each year either by injecting an aqueous solution of urea (supplying 250, 375 or 500 kg N/ha) in spring, or by broadcasting ‘Nitro-Chalk’ granules (supplying 100, 200, 300, 400 or 500 kg N/ha) in six equal dressings for each of six cuts.

Dry-matter production was largest on plots injected with urea through knives 30 cm apart, and more N was recovered from the injected than from the broadcast applications. Aqueous urea injected at the 60 cm knife spacing nitrified more slowly and persisted in the soil longer than urea injected at 30 cm spacing; this persistence caused grass to grow more uniformly throughout the season, but yields were less. Injecting the nitrification inhibitor sodium trithiocarbonate (STC) with the aqueous urea postponed N uptake much less than doubling knife spacing, but the inhibitor substantially diminished percentage N03-N in harvested grass.

In spring 1977 individual plots were split to measure N residues. Half-plots thus received N at the specified rates, either in 4 successive years (1975–8) or in two pairs of successive years (1975 and 1976; 1978 and 1979). In 1977 urea injected in the 2 previous years gave large residual effects, which were increased by STC and also by injecting in bands 60 instead of 30 cm apart. Broadcast ‘Nitro-Chalk’ had much smaller residual effects. In 1979 residual effects of N applied in the 4 previous years were apparently small, regardless of the method of application, because clover became abundant on plots not given N.

In 1978 dry-matter production was smaller where N had been given each year during 1975–8 than where N was withheld in 1977. Analysis showed this was caused by a shortage of potassium. This effect was most pronounced where 375 or 500 kg N/ha had been injected in bands 60 cm apart.

The results showed that a single, injected application of aqueous urea increased yields of dry grass as effectively as equivalent repeated dressings of ‘Nitro-Chalk’.

Six spring varieties of oats were sown in a glasshouse in winter and in spring. The grain was analysed for oil, protein and kernel content and 1000-grain weight, and the maturation period was measured.

Oil content varied from 2·4 to 7·9% and protein content from 7·9 to 16·3%. Varietal differences in oil content between varieties were recognized and these were maintained at both sowing dates.

Winter sowing, in comparison with spring sowing, resulted in an increase in oil and kernel content and 1000-grain weight, and a decrease in protein content. The increased oil content was partly due to increased kernel content, while the decrease in protein content was partly due to changes in 1000-grain weight.

The maturation period was not affected by sowing date, but was positively correlated with oil content. Oil and protein content were not negatively correlated, and there were indications that it may be possible to select varieties which will produce grain high in both oil and protein.

The phosphorus requirement of the buffalo (Bos bubalis) for maintenance has been determined from the data of two feeding and balance experiments each with twelve animals in randomized block designs and one with six animals using 3x3 latin square designs in duplicate. The level of phosphorus intake was varied by adding appropriate quantities of sodium dihydrogen phosphate in Exp. 1, by adding wheat bran in Exp. 2 and by adding dicalcium phosphate in Exp. 3.

Regressions of phosphorus outgo (7) on P intake (X) gave values of 14–7 g/day in Exps. 1 and 2 and 17–2 g/day in Exp. 3. These values can be taken to be estimates of the P requirement of the adult buffalo for maintenance.

The initial and final serum inorganic phosphorus in Exp. 1 also indicated that the phosphorus requirement was between 12 and 17 g/day.

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.