Four equally spaced feeding levels, estimated to cover the range of commercial practice, were examined using a total of 208 pigs over the live-weight range 28–100 kg. The pigs were penned in groups of six or eight and were balanced for sex within pens. Three centres participated in the experiment contributing five, two and one replicates respectively.

Efficiency of feed conversion was not significantly affected over the range of feed intakes studied, thus daily gain was linearly related to feed intake. A 10 decrease in feed intake increased killing-out percentage by 0·3 unit and decreased backfat thickness by 1 mm at both the shoulder and mid rump. The corresponding changes in the percentages of subcutaneous fat plus skin and meat were similar in magnitude at approximately 0·85 unit.

Muscle quality was reduced with higher feed intakes but weight of liver, as increased. Details of other offal weights and carcass measurements are given.

Short-duration pigeonpea can give up to three harvests in environments with mild winters (e.g. minimum temperature above 10 °C) such as those prevailing in peninsular India (Sharma, Saxena & Green. 1978; Chauhan, Venkataratnam & Sheldrake, 1984). This is mainly due to the short time (about 120 days) taken to produce the first flush, and the strong perennial character of pigeonpea. The seed yield of short-duration pigeonpea in this multiple-harvest system may reach 5·2 t/ha (Chauhan et al. 1984).

Two-year-old tea bushes were given NPK fertilizer on 12 November 1986 and 14CO2 on 22–23 December 1986 and 9–10 January 1987. Late-autumn fertilizer dressing stimulated photosynthate accumulation in the whole bush, especially in overwintering leaves and roots. Large amounts of photosynthates in overwintering leaves provide the nutrition required for early spring budding. Lateautumn dressing also accelerated the transport of photosynthates from leaves to roots in winter, where photosynthates, with absorbed nitrogen, synthesized more animo acids, especially theanine and phenylalanine. The re-use of photosynthates stored in the roots of the dressed bushes during shoot growth the following spring was also facilitated by late-autumn dressing. The contents of amino acids and caffeine in the shoots of dressed bushes were much higher than those in the control, whereas the content of polyphenol was lower than in the control. The results indicate that late-autumn dressing improves the quality of spring green tea.

An experiment was conducted to examine the effect of fertilizer (triple superphosphate) and stocking rate on animal and pasture productivity on Sumba Island, Eastern Indonesia. The Ongole heifers used in the 1-year experiment gained weight during the wet season and lost weight during the dry season at stocking rates of 0·5 and 1·0 head/ha when grazing native Themeda pasture. The dryseason weight loss was arrested when a prepared seed-bed pasture, which contained 21 % Siratro at the start of the experiment was grazed at a stocking rate of 1·5 head/ha. Increasing the stocking rate to 2·5 head/ha on this pasture resulted in an increase, in the weed component of the pasture from 12 to 84% in 1 year.

The mineral content of plucked samples of pasture indicated that levels of Ca and Mg were generally adequate for growing beef cattle and that Na supplementation would be beneficial. Plant N concentration was below 1·5% in the Themeda and Imperatacomponent but above this in the legume at the prepared seed-bed site. The P concentration in the Themeda and Imperata was always below the 0·24 % level required by cattle, as it was in the legume at the end of the experiment.

The introduction of herbaceous legumes into pastures under set stocking conditions can lead to pasture instability.

Management of beef suckler cattle herds requires a difficult but vitally important balance between farm profits, animal health and welfare and sustainable food production. A dynamic programming (DP) model was implemented to investigate the consequences of replacement and management decisions on the interactions and possible trade-offs between animal welfare, fertility and profitability in breeding beef suckler cattle herds. The model maximized profit from the current cow and all successors by identifying the best keep/replace decision. The 150 states incorporated in the DP model were all combinations of: ten cow-parity, five calving periods including one barren state (five in total) as fertility indicators and three body condition scores at weaning as an animal welfare indicator reflecting feeding and nutritional conditions of animals. Statistical models were fitted to data from a breeding suckler cattle herd, consisting of performance records of 200 cattle over 5 years, to parameterize the DP model. Estimated parameters used in the DP model were: (i) probabilities of transitions between states and (ii) probability of involuntary culling. These estimates were used in the form of conditional probabilities of successful or failed (as a result of involuntary culling) transitions to the next state. In addition, statistical models were used to estimate probability of calving difficulty. There was strong evidence (P< 0·001) that parity affected calving difficulty and weak evidence (P = 0·067) that parity affected the incidence of involuntary culling. The DP model outcomes indicated that cows calving very early, i.e. those who conceived in the first 21 days after artificial insemination, showed reduced frequencies of calving difficulty as well as voluntary culling, and so gave better financial returns than late-calving cows and barren cows. As a result, fewer replacements were needed that reduced the frequency of calving difficulty, further implying a win–win scenario for both profit and welfare. In contrast, in late-calving animals, the frequency of calving difficulty increased and they were less profitable and more prone to be culled. Results of sensitivity analysis showed that the optimum voluntary culling rate was sensitive to commodity market prices. These findings suggest well-informed nutrition and reproduction management could deliver a win–win outcome for profit and animal welfare.

The effects of several dietary regimens on the fat-free mass and the dry-matter, ash and potassium-40 content of selected bovine muscles were estimated. Muscle data from 104 half-sib Angus steers were secured at several stages of growth and after several feeding regimens. The results indicated that a hay diet, by comparison to a higher energy silage diet in the early feeding period (216–340 kg live weight), suppressed the fat-free weight, reduced the dry-matter content and increased the ash content of several muscles. These effects of early diet were reversed, however, when the animals were subsequently fed higher-energy rations and slaughtered at heavier weights (409 and 454 kg live weight). Data on potassium-40 gamma emissions by composite muscle samples confirmed the existence of age- or weight-associated decreases and suggested possible dietary influences on potassium levels in bovine muscles. The trends in these data indicated that low dietary energy (hay feeding) in the early feeding period delayed the decline in muscle potassium that normally accompanies maturation.

Records on 884 litters and 3051 bunnies of the Bauscat (B) and Giza White (G) breeds were used to construct different selection indices.

A series of selection indices and subindices were constructed for both B and G does. An index or subindex based on litter size at weaning, mean bunny weight at weaning, litter size at birth and litter weight at birth could be practically applied to improve the productivity of B and G does, under local Egytian conditions. Preweaning mortality did not contribute significantly to the different selection indices and subindices. Litter weight at birth made a large contribution to the different indices and subindices constructed. Litter size at weaning contributed little in the subindices to be used to select for mean bunny weight at weaning. Mean bunny weight at weaning made a lower contribution to the subindices to be used to select for litter size at weaning. The expected genetic gain in litter size at weaning was slight in all of the selection indices and subindices constructed because of low heritability values for this trait. Considerable genetic improvement for doe productivity of the G breed might be achieved through selection for mean bunny weight at weaning.

Four selection indices and subindices were constructed for B and G rabbits. The index or subindex based on 6-week weight and 8-week weight was the best criterion for selection for the genetic improvement of 6-week weight and 12-week weight. Six- and 8-week weight contributed substantially while 12-week weight contributed little to the value of most of the selection indices and subindices constructed. The highest total genetic gain attributable to 6- and 12-week weight was obtained when the selection indices or subindices including 6-week weight and 8-week weight were used.

The major portion of nitrogen nutrition of flooded rice is met through the mineralization of organic forms of N present in soil. This is true even when fertilizer nitrogen is added. The mineralization of organic matter under waterlogged conditions is governed mainly by the prevailing chemical and biological conditions. In recent years, attempts have been made to characterize the products of hydrolysis of soil organic nitrogen (Asami & Hara, 1970; Shinde, 1978; Subba Rao & Ghosh, 1981). Information on different fractions of nitrogen in waterlogged rice soils is scanty.

Grain yield, plant height, spike length, grain weight per spike, 100-kernel weight, protein quantity and quality of Mexipak wheat grown with four rates of applied nitrogen (0, 75, 150 and 225 kg N/ha) and five rates of applied zinc (0, 1·25, 2·5, 5·0 and 7·5 kg Zn/ha) were measured. All these attributes were affected significantly by nitrogen fertilization in a linear manner. Differences among rates of applied zinc were significant for grain weight per spike, 100-kernel weight, grain yield and protein quantity and quality.

In an earlier paper (Little, McLean & Winter, 1977) we reported a technique for the measurement of the phosphorus content of the diet consumed bygrazing cattle, which recently has been used successfully to measure the dietary intake of phosphorus by sheep grazing Mitchell grass (Astrebla spp.) pastures in western Queensland (Beale & McMeniman, 1978). In this technique, phosphorus of salivary origin is distinguished from that of plant origin in samples extruded by oesophageally nstulated animals by prior labelling of salivary phosphorus with the isotope 32P following the intravenous infusion of Na2H32PO4. The difference in specific activity between saliva and extruded bolus is used as the basis of the calculation of the phosphorus content of consumed herbage. Oesophageally nstulated animals may graze experimental pastures for an hour or more while samples are collected from them. It is important to have an accurate measure of saliva speoific activity, representative of that secreted during the grazing period; therefore, application of the technique is facilitated if the rate of change in saliva specific activity during collection periods is slow and linear.

A study of the birthcoat and its relation to kemp succession in the adult fleece of coarse-wool Awassi and Hamdani sheep was carried out, as an aid to early selection. Lambs were covered, at the age of 2 months up to 15 months, by fixing patches of canvas on six body positions.

Both Awassi and Hamdani birthcoats had high halo hair grades. The animals played the dominant role in affecting different traits of the birthcoat which indicated the importance of genetic factors in further development of the birthcoat. The birthcoat of both types of lambs showed only coarse (plateau) and less coarse (saddle) fibre type arrays.

Hamdani had more kemp as Gt and G2 (first and second generations respectively) than Awassi sheep. The shed Gx following the different fibre type arrays, showed some overlapping between plateau and saddle. The same arrays of the birthcoat behaved differently on the different positions, where generally the anterior positions had less kemp than those posteriorly. Percentages of shed fibres were 100, 17·14, 2·38 and 0·35 of halo hairs, super sickles, sickles and chalky curly tips respectively in Awassi. Corresponding figures were 100, 29·26, 5·87 and 7·73 in Hamdani. In Awassi, halo hairs, of the birthcoat, showed a relatively high correlation (P < 0·01) with G1 kemp on the hip and britch. Within saddle array, in Awassi, the correlation between halo hairs and Gx kemp showed the highest values (P < 0·01), whereas in Hamdani the correlation between super sickles in the birthcoat and G2 kemp showed medium values (P < 0·05).

Selection of high halo hair grade lambs, in the birthcoat, that have saddle arrays, with high percentage of sickle fibres in Awassi and with low percentage of super sickles in Hamdani, would result in low percentages of kemp in the adult fleece. High halo hair grades would be necessary for early survival of lambs.

The effect of fertilizers in increasing the yield of clover seed was examined by a series of manurial trials. The initial mineral status of the crop and the extent of the uptake of the applied nutrients were determined by analyses of the leaf. The techniques for sampling and analysing leaves to determine mineral status are described.

The high yields of seed and lack of response to fertilizers in trials at Cambridge led to their being repeated at Saxmundham on land known to be extremely deficient in minerals. Even then there was a response only to phosphate which although significant was small.

Leaf samples were also collected from commercial crops of red clover in 1955, 1956 and 1957. The analyses of these samples indicted that none of them was as deficient as the crops at Saxmundham, and no relationship was found between mineral status and seed yield.

It is concluded that yields of red clover seed in Eastern England are not likely to be increased materially by the application of fertilizers.

The conclusions of the 1927 experiments in spacing have been tested in greater detail in 1928 and are confirmed.

From the 64-plot scheme containing a series of spacings in quadruplicate the following points emerged:

(1) Variation of the width between the rows influenced the yields of sugar beet roots, the expectation of highest yield being on the narrowest spacings. There was a significant increase in yield to be gained by using 15” or 18” spacing instead of 21” or 24”. On the other hand width between the rows did not seem to influence the yield of tops and crowns.

(2) Variation of the distance between plants in the rows up to 10” had no significant effect on the yield of roots. There was some evidence that above that figure a reduction in yield took place. It is interesting to note that in the case of the tops, spacing between the plants influenced the tonnage. There was a significant difference between the yields on the 4″ and 8″, and 4″ and 10″, but not between the 4″ and 6″, 6″ and 8″ or 8″ and 10″ spacings.

The percentage emergence from monogerm sugar-beet seed in field experiments was reduced by high soil moisture content and soil compaction, but was unaffected by soil temperature. Seed lots were differentially influenced when the soil conditions were very adverse. Pelleted seed emerged a little better in good soil conditions and was not more sensitive to high soil moisture content than raw seed.

The relation between laboratory germination and the number of emerged seedlings was variable and followed no obvious trends, and there was no consistent rank order in the emergence ability of four commercial cultivars.

Propionate and glucose metabolism were compared in two groups of Scottish Blackface ewes, one in which ewes had been fitted with vaginal pessaries impregnated with progesterone-analogue for the synchronization of oestrus and the other when ewes were in anoestrus. In ewes given the same amount of feed, the production rate of propionate increased significantly (P < 0·05) from 33 in anoestrous ewes to 44 gC/day in ewes with pessaries. The proportion of glucose-carbon apparently synthesized from propionate also increased significantly (P < 0·05) from 0·31 in anoestrous ewes to 0·44 in ewes with pessaries. The proportion of glucose-carbon apparently recycled was also significantly (P < 0·01) increased from 0·12 to 0·22. No changes were observed in glucose concentration, production rate or oxidation rate between the two groups of ewes.

Attempts were made to relate various parameters of growth in wheat substitution lines to final yield of grain and assess the extent to which such relationships could be useful as early predictors of yield. The associations were measured by calculating correlation coefficients, partial regression coefficients, standard partial regression coefficients and independent contribution to yield. Significant correlation coefficients were common but significant partial regression coefficients were rare. The remaining estimates provided a ranked order of characters associated with yield. Those parameters of vegetative growth showing most association with final yield were themselves related fairly directly to ear and grain size. It was concluded that direct estimates of yield must remain the most appropriate character on which to base selection in cereals.

When growing Cheviot hoggs were wholly maintained indoors on a very poor quality hay fed ad libitum they had a low food intake and consequently were losing weight. A 40 g. supplement of ‘Fodder Yeast’ greatly increased the hay intake of the sheep, and this was accompanied by a steady gain in body weight. Increase in body weight appeared to be accountable for by the increase in food consumption. These findings, obtained in a pilot experiment, require confirmation with a larger flock of sheep.