Environmental conditions (Clark & Quin, 1949; Daws & Squires, 1974; Degen & Young, 1980) and total feed intake (Clark & Quin, 1949; Forbes, 1968; Degen & Young, 1980) influence the water intake of sheep. In general, high temperatures increase the requirements for water needed for evaporative cooling and high feed intakes necessitate more water for excretion of waste products. This study was designed to measure water intake and estimate the partition of water output in sheep maintained at four air temperatures and offered four levels of a ration.

1. Results are reported of an experiment carried out under commercial conditions to obtain information on the effect of four different levels of allmeal feeding on the performance and carcass grading results of fattening pigs.

2. There were four treatments. All pigs were given the same meal mixtures and were fed dry and ad lib. up to four different daily maximums, namely, 6½, 6, 5½ and 5 lb. meal/pig/day. There were five pens of nine group-fed pigs on each treatment, involving a total of 180 pigs. The pigs were on experiment from approximately 8 weeks of age to bacon weight. Comprehensive carcass measurements were made on all pigs.

3. The results showed that as the level of feeding was decreased, the growth rate of the pigs, back fat thickness and belly thickness were reduced, and the depth and breadth of eye muscle were increased, while the efficiency of food utilization, carcass dressing percentage and carcass length were not markedly affected. Commercial grading results similarly improved as the level of feeding was reduced.

4. It was concluded that under the conditions prevailing, the maximum daily meal allowance should be of the order of 5½ lb./pig in order to obtain relatively satisfactory carcass grading.

5. Subdivision of the carcass measurement and commercial grading data according to sex of pig showed that in general at each level of feeding the carcasses of the female pigs were superior to those of the male animals.

The possibilities of segregating pigs according to sex during fattening as a means whereby undue retardation in the growth rate of the females might be prevented without adversely affecting their carcass grading, was discussed.

Field experiments were made in the rainforest zone of Western Nigeria over three cropping seasons on the effects of potassium fertilizer of one local cassava cultivar 53101 and two improved cultivars 60506 and 60447 which were F1 hybrids of the former. The results showed that K-fertilizer increased the starch yields only slightly. Cultivar 60506 produced significantly higher starch yields (P < 0–01) than the local strain, 53101, while cultivar 60447 gave lower starch recovery than the local cultivar.

A definite influence of K application on the cyanide (HCN) content of the tuber roots could not be established. The peeled tubers of the improved cultivars contained much less cyanide than those of the local 53101 strain (P < 0–01). Potassium had the highest (0·72–1·28% dry weight basis) while phosphorus had the lowest concentration (0·06–0·12%) in the peeled tuber. Owing to its higher yielding capability the unfertilized 60506 removed larger amounts of potash (average 110·9 kg k20/ha) from the soil than unfertilized 53101 (average 82·2 kg k20/ha).

Gilts of the ‘Palouse’ breed were divided into two groups; one group was full fed from weaning to 1501b. and the other group was fed 70% of full feeding. After six generations, one-half of the pigs in each group were shifted to the other plane of nutrition, thus forming four groups: high-high (HH), low-high (LH), low-low (LL) and high-low (HL). F10 gilts were slaughtered 38 or 100 days post-coitum to study reproductive and prenatal phenomena.

1. Ten successive generations of controlled feeding had no significant effect on: length of Fallopian tubes, weight of corpus luteum, percentage of implantation, number of viable foetuses, foetus weight, weight of placental membranes, volume of placental fluids or embryonic mortality.

2. There were significant differences between the high and low planes of nutrition in: weight of pituitary, thyroid and adrenals, weaning weight, puberty weight, puberty weight to birth weight, puberty weight to weaning weight and puberty age. The effect of six generations of controlled feeding was not maintained when the plane of nutrition was changed from high to low or low to high.

3. The frequency of silent heat and the number of services per conception was lower in the low planes than in the high planes.

4. Ova migration occurred in both directions in 41% of the gilts; one to four ova migrated. The foetal sex ratio ranged from 4:0 to 1:7 with an average of 1:1. The sexes were unevenly distributed in the horns.

5. Foetus weight at 38 or 100 days post-coitum was not affected by plane of nutrition or sequence in the uterine horn.

6. Within-litter variations were highest in the volume of allantoic fluid followed in order by variations in weight of placental membranes and then the amniotic fluid and foetus.

7. Foetal mortality was not related to sequence in the uterine horn or the number of implantations.

8. There seemed to be two peaks of early prenatal mortality, one at implantation and another at the onset of organo-genesis.

Digestibility trials have been carried out with sheep on a sample of dried grass and a grass meal, both of which were artificially dried on an experimental band drier. The analyses of the two materials were affected by the fact that the grass was cut in August after a very dry summer and the herbage was contaminated with a certain amount of stemmy material.

The digestibility of the two samples is of a high order and, with the exception of that of the crude protein, equal to the values quoted by Woodman for short grass. The sheep put on weight during both trials and there was a retention of nitrogen and mineral matter in all cases. The dried grass would appear to contain an adequate amount of available calcium, phosphorus and potash for the plane of nutrition at which it was fed.

The carotene content of Palestinian fodder plants, vegetables and wild plants was determined. The examined fodder plants were: Egyptian clover, Fahli clover, lucerne, horse beans, field peas, vetch, oats, barley, cow peas, maize, pencillaria, Sudan grass and leaves of beetroots. The examined vegetables were: leaves of radish, mangold, sweet potato, spinach, cauliflower, parsley, lettuce, kohlrabi, onion and cabbage. The wild plants examined were: nettle, mallow and portulaca.

Twelve 6–8 months old male Barbados Blackbelly lambs were used in a 4 × 4 latin square experiment with three replicates to study the utilization of diets made from local by-products and containing 64, 93, 125 or 143 g crude protein/kg D. M.

Both dry-matter (mean 750·1 g/day) and digestible-energy (mean 6·2 MJ DE/day) intakes, and their digestibility coefficients increased, though not significantly, with increasing dietary protein concentration. However, nitrogen digestibility, urinary-nitrogen output and nitrogen retention all increased significantly (P < 0·01) with increasing dietary protein concentration.

Metabolic faecal nitrogen and endogenous urinary nitrogen derived from the intercept of significant regressions of nitrogen intake against urine and faecal nitrogen outputs were 5·07 g/kg dry matter eaten and 3·46 g/day (0·35 kg W0·75) respectively. The diets had a mean biological value of 73·6%. The digestible crude protein requirements for maintenance were (g/day) 29·0, 38·4 and 26·6 when estimated from nitrogen retention, factorially and from live-weight performance respectively.

For three consecutive years American hybrid maize was grown, under replicated experimental conditions, in the south of England. Each season, the influence of the spacing of the plants and the use of nitrogenous fertilizer on the yield and composition of the crop and of its separate portions of leaf, stem and cob was investigated.

The growth of the maize, and especially its yield of dry matter, were influenced by the weather conditions during the season. The weight of fresh crop varied, with season and treatment, from 126 to 278 (averaging 209), and of dry matter from 20 to 70 (averaging 50) cwt./acre.

Thinning below the established plant populations of up to 30,000 plants per acre regularly reduced these yields. Top-dressing with sulphate of ammonia increased them in 1947 and 1949, but decreased them in 1948.

The yield of crude protein varied from 2.2 to 5.0, and of soluble carbohydrates from 12 to 46 cwt./acre. The top-dressing increased the protein content of all portions of the plant.

The cob contributed, on a weight basis, 46% of the fresh crop, 49% of its dry matter, 54% of its crude protein and 54% of its soluble carbohydrates. Details are given of the chemical composition of the whole plant, and of its separate leaf, cob and stem, for each season and treatment.

A later paper will deal with the making of silage from the maize crops and with the yield, composition and nutritive value of the silage.

Very diverse views are expressed on the height to which water can rise in soils under the forces of capillarity. Alway and MacDole in the course of a brief historical review, point out that these estimates range from two or three feet only, to as much as two or three kilometres, although the majority do not exceed 200 feet. Most of the investigators who advance a high value for the capillary rise are careful to point out that in all probability the movement of water in this case would be exceedingly slow, owing to the excessive friction in the minute capillary spaces. Actual experiments on the rise of water in tubes of compacted soil result in low values, which are in all probability exceeded in the field. Warington in his book Physical Properties of Soil gives a typical table showing the results of Loughridgeb for Californian soils.

The associations between yield, nitrogen and soluble-carbohydrate concentration within S. 23 perennial ryegrass were investigated at three levels of nitrogen application. Controlled growth room conditions were used.

The simple correlation between yield and nitrogen concentration was negative at the low rate of nitrogen application, not present at the intermediate rate of nitrogen and positive though not significant at the high rate of nitrogen. Yield and soluble-carbohydrate concentration were only correlated (positively) at the low nitrogen rate.

At low nitrogen there were ‘efficient’ genotypes with relatively high yield and low nitrogen concentration. ‘Inefficient’ genotypes had relatively low yields and high nitrogen concentration. The majority of genotypes were neither markedly efficient or inefficient. The efficient genotypes at low nitrogen maintained their yield advantage at higher nitrogen levels with average nitrogen concentration and high numbers of tillers. Inefficient genotypes remained relatively stable in yield, numbers of tillers and nitrogen concentration.

Partial correlation indicated an underlying high degree of dependence between yield, nitrogen and soluble-carbohydrate concentration at all nitrogen levels. The association of yield and nitrogen concentration showed a similar trend over nitrogen levels to that obtained using simple correlation. Yield and soluble-carbohydrate concentration were positively related, and nitrogen and soluble-carbohydrate concentration inversely related, when the effects of the remaining attribute were eliminated.

Data extracted from Lee et al. (1977) confirmed that yield and nitrogen concentration for varieties under field conditions varied with level of nitrogen application in a similar manner to genotypes in the controlled growth room. The variety (Melle) could be characterized as being particularly efficient.

Both sets of results indicate that selection for high yield of nitrogen in herbage can best be achieved through selection for yield alone.

The mean yield of field beans grown for three consecutive years on a site infested with migratory nematodes was 1540 kg grain/ha in untreated soil and 1870 kg/ha in soil treated with dazomet.

Fertilizer nitrogen in amounts up to 250 kg N/ha decreased yield to 990 kg in untreated soil but increased it to 2220 kg in soil treated with dazomet. Fertilizer nitrogen did not affect nematode numbers or root blackening but decreased nodulation and increased mycorrhizal infection by Endogone sp. in untreated soil. Dazomet greatly decreased migratory nematodes of the genera Tylenchorhynchus and Trichodorus and eliminated Pratylenchus. It had little effect on root blackening in the top 10 cm of soil but decreased it in the next 10 cm. Infection with Endogone was almost eliminated.

Seven hundred and fifty purebred Angoni, Barotse and Boran cattle and their crosses sired by Friesian and Hereford bulls were compared for live-weight and carcass characters in Zambia. The cattle were born between September and December in three consecutive years and were reared on unimproved veld. In the first year all females and a random half of the males received supplementary feed in winter and the males were slaughtered at 2·5 years of age. The remaining males received the same total amount of winter supplementary feed prior to slaughter at 3·0 years of age. The males born in the second year were pen fed for a period prior to slaughter at 3·0 years of age. Males born in the third year were slaughtered at 3·5 years of age and received no supplementary feed.

Genotype differences were important at all live weights and there were year of birth x genotype interactions at the 0·5, 1·0 and 1·5 year weights and a genotype × feed treatment interaction at the 2×0 year weight. Boran purebreds were heavier than the Angoni and Barotse purebreds; at 3·0 years the differences were +42·3 kg ( + 12·9%) and + 25·2 kg (+ 7·7 %) respectively. Cross-breds had heavier live weights than their corresponding purebreds with Boran crosses consistently heavier than the Angoni and Barotse crosses. The Friesian and Hereford sired Boran cross-breds were + 51·0 kg (+13·5 %) and + 43·0 kg (+ 11·6 %) heavier respectively than the purebred Borans at 3·0 years of age.

There were large differences between the genotypes for all carcass characters with Borans having heavier carcasses than the Angonis and Barotses by + 20·3 kg (+ 10·6 %) and + 19·1 kg ( + 10·0%) respectively. The average carcass weight advantages of Friesian and Hereford crosses with the Angoni, Barotse and Boran breeds over the corresponding purebreds were + 40·3 kg ( + 19·0%), + 33·6 kg ( + 16·2%) and + 31·0 kg ( + 14·0%) respectively. There were few important carcass differences between the corresponding Friesian and Hereford crosses.

The mortality rate during the experiment was 8·2% with only small differences between genotypes.

The interactions found in the experiment indicated that breed comparisons should be conducted over a number of years and at various management levels. For growth and carcass production under the conditions of the experiment the use of exotic crossbreds is clearly advantageous.

The DTPA-extractable Zn in 28 Tarai soils was found to be significantly correlated with Bray's ‘percent yield’ values for rice and wheat. The critical limit of ‘available’ Zn, below which responses of both crops to applied Zn may be expected, was 0–53 mg Zn/kg soil. On the basis of this critical limit, it may be inferred that in the 16 Zn deficient soils, rice and wheat yields would respond markedly to zinc application. The magnitude of crop response in these soils was greater in rice (39–244%; mean value 117%) than in wheat (33–101%; mean value 60%).

Red deer stags in New Zealand were given a series of immunizations against GnRH at 9–12 months of age (spring/early summer) in 1989 and 1990 and the effects upon plasma concentrations of luteinizing hormone (LH) and testosterone during the rut (15–17 months; autumn) and upon body growth to slaughter at 22 months (spring) were studied in two experiments. Control animals showed a sharp peak in plasma LH and testosterone concentration during late summer/early autumn, just preceding the rut, with scrotal circumference increasing to a maximum during the rut; body growth stopped during the rut in Expt 1 but not in Expt 2. Immunization caused the development of significant antibodies against GnRH during late spring and summer, and reduced but did not eliminate the increase in plasma LH and testosterone and scrotal enlargement leading up to the rut. Immunization did not affect body growth or voluntary feed intake during the rut in either experiment, but in Expt 1 early immunization significantly increased growth during both the pre-rut and post-rut periods. Immunization did not effect dressing out percentage, slightly increased carcass fatness in Expt 1 but not Expt 2, and reduced velvet antler growth by 12 months of age.

The phosphorus fertilizer requirements and long term productivity of nitrogen-fertilized Gatton panic (Panicum maximum cv. Gatton) pastures, grazed by lactating dairy cows, were evaluated in a 7-year experiment. Cows grazed at 2·6 cows/ha on pastures that received annually 100 or 300 kg N/ha and each of 0, 22·5 or 45 kg P/ha. Cows received no energy supplements in years 1–3 and were offered molasses at 3·5 kg/day from year 4 to year 7. Cows grazed their experimental paddocks from the start of the wet season until they started to lose weight in the dry season.

In years 6 and 7 there was significantly less green pasture and leaf on offer in 300N pastures at 0P than with 22·5P and 45P. This was reflected in a reduced milk yield by cows at 300N/0P in these two years. There was no influence of rate of P fertilizer at 100N on milk yield in any year. Lactation milk yields at 300N in years 6 and 7 averaged 3930, 4310 and 4610 kg/cow (P<0·05) for 0P, 22·5P and 45P, respectively. Nitrogen fertilizer increased milk yield in each year (P<0·01) except the first. Milk yields at 100N and 300N averaged 2860 and 3320 kg/cow respectively in years 1–3 and 3720 and 4290 kg/cow in years 4–7.

The milk yield responses to P fertilizer were related to the greater amounts of pasture and green leaf on offer, which led to a higher proportion of leaf in the diet, and the response to P fertilizer was dependent on the rate of N fertilizer applied. Phosphorus intakes were estimated to be below that of published requirements for cows producing this quantity of milk. An annual model of P flow between plant, animal and soil pools demonstrated that at 100N/22·5P more P was returned to the soil as excreta (15·7 kg P/ha) than with 300N/22·5P (7·1 kg P/ha). The major pathway of return of P to the soil at 300N was through plant litter. Soil organic P was the largest, but least exploited, pool of phosphorus.

This study has illustrated how the demand for phosphorus by the plant in grazed pastures is modified by the input of N fertilizer, is poorly predicted from plant analysis and published standards for animal requirements, and indicates that a response in milk production may be mediated through the effects of P on leaf growth and not on dietary P content.

The foraging behaviour and dietary selection of free-ranging Awassi sheep and Negev goats when shepherded in the Negev Desert was determined. Measurements were made for 9 weeks (W1–W9) from the beginning of February, following winter rains and emergence of annual plants, to the end of March, after the herbaceous vegetation dried up. Since sheep are grazers and goats are intermediate feeders, it was predicted that goats would browse more and consume proportionately more browse than sheep. These predictions were only partially supported. In fact, the foraging pattern was similar between sheep and goats (Mantel test, P<0·05) until W8 and only towards the end, at W9, did patterns differ significantly (Mantel test, P=0·214) between these two ruminants. There was no difference (P=0·575) between sheep and goats in foraging; however, a period effect was found (P<0·001). In February (W2), sheep and goats grazed 0·69 and 0·71 of the time allotted for foraging and neither species browsed. Browsing commenced only at the beginning of March (W4), when goats browsed 0·08 of the time and sheep 0·07 of the allotted time for foraging. The proportion of time spent browsing increased at the end of March (W9) when annuals disappeared, but the total time spent foraging decreased: goats browsed 0·29 and grazed 0·25, while sheep browsed 0·19 and grazed 0·26 of the time allotted for foraging. Goats increased the proportion of browse consumed gradually throughout the season, whereas sheep maintained a relatively higher proportion of herbaceous plants and only in late March (W8), at which time very little herbaceous plants were available, shifted abruptly to consume mainly browse. In W8, browse composed 0·85 of the dry matter (DM) intake in goats and 0·62 of the DM intake in sheep. A simultaneous analysis of foraging time allocation and relative diet composition revealed that both small ruminants were more efficient in consuming browse than herbaceous plants, more so in goats than sheep. It was concluded that vegetation availability and foraging habits affected dietary selection. Both sheep and goats only grazed when herbaceous plants were abundantly available; differences between ruminant species were apparent when herbaceous plants became scarcer, at which time goats browsed more and consumed proportionately more browse than sheep. The results contribute to better understanding of feeding behaviour and dietary selection of sheep and goats under natural desert pastures and could be useful in the management of mixed flocks.

The modelling of the redistribution of soluble salts in soils, in which it is assumed that the amount of water transferred from layer to layer is related to the excess over field capacity of the water content of a layer, is critically examined.

The equation obtained from the dispersion equation by neglecting the diffusive term is solved for the leaching of surface-applied nitrates. It is shown that, by comparing the finite-difference form of this equation to the algebraic formulation of Burns' (1975) model, the two approaches are essentially the same, but that Burns makes approximations that are too inaccurate. In particular, it is incorrect to relate the transfer of water to the excess over the field capacity of the water content of the layer. Burns' model, when applied correctly, requiresmany calculations to be performed, which is costly of computer time. However, it is unnecessary in this problem as the analytic solution is simple and quick to apply.

Three experiments examined the effects on seedling emergence and seedling weight of covering pelleted, natural and pre-germinated seeds of the variety Pennlake with soil and other media.

Covering seeds with a peat-vermiculite mix gave significantly greater, earlier and more uniform emergence and seedlings with a lower coefficient of variation (c.v.) of weight than covering with soil.

Seedlings from pre-germinated seeds emerged more rapidly than those from natural and pelleted seeds and tended to be heavier when harvested 24 or 41 days after emergence. However, natural seeds consistently gave more uniform emergence than the other seed treatments and the lowest c.v. of seedling weight.

1. An experiment has been carried out with dairy cows to find whether feeding the same ration in different ways has any effect on milk yield or milk composition.

2. No differential effect on milk yield or milk composition of the three methods of feeding which were used could be demonstrated, in spite of an extremely accurate experimental technique. It was therefore concluded that there is no advantage in increasing the number of meals into which a ration is divided, or spreading the ration over a longer period.

Experiments on outdoor bush tomatoes cv. Sleaford Abundance were conducted during 3 years to compare seedling establishment from fluid-sown pre-germinated seeds with that from conventionally sown dry seeds and to compare the effects on ripening and yields of these establishment methods with transplanting. Fluid-sown pre-germinated seeds emerged about 15 days earlier than conventionally sown dry seeds from sowings made in late April (mean soil temperature at seed depth from sowing to emergence ranged from 9 to 11.5 °C) and about 6 days earlier from sowings made in mid-May (mean soil temperature ranged from 12 to 15 °C). The percentage seedling emergence from pregerminated fluid-sown seeds was, on average, 57% from the earlier sowings and 65% from the later sowings, 34 and 24% higher, respectively, than from dry seeds sown conventionally. Plants from fluid-sown pre-germinated seeds were about 50% heavier than those from dry seeds at all stages of growth up to flowering. Crops established by fluidsowing started to ripen 7 days earlier than those established from dry seeds, when averaged over sowing dates and years. Yields of ripe marketable fruit > 35 mm in. size from crops established from pre-germinated seeds were 35·2 t/ha, averaged over sowing and planting dates, 37% higher than from dry seeds though 51% lower than from transplants. In the two years with good growing seasons crops fluid sown in late April gave as good yields as those transplanted in late May and early June, after the last frosts, though in the cool wet year yields from fluid-sown crops were considerably lower than those from transplanted crops. Yields of ripe, marketable fruit from ‘bare-root’ plants raised from pre-germinated seeds in unheated Dutch-light structures were, on average, 48·5 t/ha, 25% higher than from plants raised in soil blocks in a heated glasshouse.