The metabolic activity of spermatozoa, obtained from Awassi, German Mutton Merino, Corriedale and Dorset Horn rams, waa measured every 2–4 weeks over a 2-year period.

Atomic Absorption Spectroscopy (AAS) is the usual method for the direct determination of small amounts of manganese in plant materials (Christian & Feldman 1970; Heanes, 1981) and other substances (Carnrick, Slavin & Manning, 1981). However, it uses the highly sophisticated and expensive Atomic Absorption Spectrometer, which requires a reasonable degree of technician expertise, and is therefore not suitable for routine chemical analyses in Third World countries.

The effect of different amounts of irrigation water on the salts in Gezira soil has been studied by comparison of different rotations in two long-term experiments at the Gezira Research Farm. The conclusion is drawn that none of the rotations studied shows any evidence of salts rising or accumulating in the profile. There is some evidence of a removal of salts from a 6 ft. profile.

The results are given of an investigation of the successful production, and of the chemical composition and feeding value, of maize silage made from early maturing varieties of hybrid maize grown for three consecutive years in the south of England. The maize was ensiled at a stage when the cob contributed approximately 50% of the total crop and the dry-matter content of the crop varied from 16·3 to 27·2%. The mean crude protein content of the dry matter of the silage was 9·5% (range 7·9–11·2%). Average weight losses in the silo were fresh matter 25%, dry matter 30%, crude protein 25%, and soluble carbohydrates 40%.

In three controlled feeding trials with cows and heifers in milk, maize silage was found to be equal in nutritive value to a ration of mangolds and oat and tare silage when fed on an equal dry-matter basis. The silage was very palatable and a daily ration of 50 lb. was consumed.

It is concluded that although maize silage compares favourably with an average crop of cereal -legume silage in feeding value, its adoption on a wide scale cannot be recommended in view of the relatively low yield of dry matter per acre, the high costs of production and the appreciable silo

In a 7×7 diallel-cross experiment utilizing parents with varying resistance to mosaic virus disease and of different horticultural types significant heterosis over the better parent was found in number of days between sowing and flowering and over the mean of the two parents in other characters. The combining ability analysis revealed that genetic control of most character variation was due to additive effects.

It is suggested that pedigree and/or backcross methods are most appropriate for improving this chilli population.

The weights of components of the alimentary tract were recorded in 55 swamp buffaloes and 51 zebu cattle slaughtered at Bogor in West Java. These were related to hot carcass weight (HCW) and slaughter live weight (SLW), the latter being calculated from locally developed regressions relating live weight to chest girth. Huxley's (1932) allometric equation was used in its logarithmic form as the basis for covariance analyses of the data. A stepwise regression analysis was also undertaken using a linear model relating HCW and gut component weight to species, sex, age and slaughter condition with SLW as the independent variable.

There were significant differences in dressing percentage between buffaloes (38·1 %) and zebus (44·8%) at 340 kg SLW and these were due to species differences in full gut weight rather than weights of other non-carcass components. The allometric growth coefficients for total gut, or gut component, were generally higher in buffaloes than zebus, but the differences were not statistically significant. Together with other published data, these observations suggest that the gut contents may contribute more to the increase in live weight of buffaloes than in zebus.

At the same SLW or HCW, the buffaloes had the heavier weights of full and empty total gut, full and empty reticulo-rumen and total gut contents. At the same total empty gut weight, buffaloes had the heavier empty reticulo-rumen. It was suggested that Indonesian swamp buffaloes and zebu cattle fed on village-type low-quality diets may also differ in the rate of development of their alimentary tract and this could have implications for their comparative nutritional physiology.

In a long-term cultivation experiment comparing mouldboard ploughing, shallow cultivation and direct drilling, soil compaction was identified as a problem. Root growth was restricted and this possibly caused a decline in grain yield of spring barley. The residual effects of a slant-legged subsoiler (Trade name, ‘Paraplow’) on the growth and yield of spring barley up to 34 months after its use were measured.

In 1982, soil not loosened with the ‘Paraplow’ had a grain yield of 5·16 t/ha and cultivation with the ‘Paraplow’ either 22 or II months previously had a negligible effect. Although the implement improved mean plant establishment by up to 12 plants/m2, compensatory tillering occurred in the treatments that initially had fewer plants, thus reducing differences in dry-matter production and grain yield at harvest. The long-term system of cultivation had a larger effect on grain yield than the ‘Paraplow’ did. Grain production on direct-drilled and shallow cultivated soils exceeded that after mouldboard ploughing by up to 0·55 t/ha (P < 0·05). The ‘Paraplow’ used 22 months previously increased grain yield by 0·47 t/ha on a direct-drilled soil that had become compacted.

In 1983, the emergence of seedlings was low (54%) due to waterlogging of the seed bed between germination and emergence. The ‘Paraplow’ used 8 months previously increased the mean number of plants that emerged by 20 plants/m2. More seedlings survived on the soil loosened by the ‘Paraplow’ because it drained more freely than the undisturbed soil. Cultivating with the ‘Paraplow’ 11, 23 and 34 months previously increased grain yield by 0·27, 0·29 and 0·13 t/ha respectively, but the mean grain yield was only 2·70 t/ha. This improvement was caused by a greater number of grains per m2 on the soils loosened with the ‘Paraplow’. Grain weight was unaffected by cultivation system or by ‘Paraplow’ treatment.

This paper provides information on the extent and containment of intraclass correlation (ICC) concerning group-feeding trials on suckler cows. The research comprised the re-analysis of six previously reported experiments and a parallel simulation study. ICC coefficients were estimated for eight variables. They were seen to be higher in experiments on bulls compared with those on cows and more notable in the measurements of live weight gain compared with final weight. Moreover, the ICC coefficients were generally high for all variables measuring behavioural patterns. The simulation study showed that using a single animal as an experimental unit could be valid in certain situations, but it could not be extended to cover all the cases. The simulation study also showed that the common mixed model approach had significant problems when the ICC was slight. In general, the research strengthened the arguments that much more effort should be placed on the planning and statistical analysis of group-feeding experiments, especially in behavioural studies.

The drying rate of leaves and stem internodes from flowering culms of two varieties of Italian ryegrass (Lolium multiflorum) were measured in the laboratory in controlled conditions of temperature (28 °C), relative humidity (22%) and air speed (40 cm/sec), without treatment, or after being subjected to thermal treatment or to mechanical damage followed by thermal treatment. The two treatments increased the drying rate of leaves and, to a greater extent, stem internodes.

While it cannot be concluded that all treatments that increase crop drying rate will increase the rate for stems more than for leaves, these results are considered to indicate the possibility of devising practical treatments which will. Such treatments could reduce leaf shatter and consequent serious loss of dry matter during the field drying of grass crops.

The grading-up system, in the Ayrshire Cattle breed, whereby the descendants of non-pedigree cows enter the registered (Herd Book) population, is studied principally from three aspects: (1) its numerical importance in the population; (2) the breeding structure of herds practising grading-up, and (3) the possible genetic effect of grading-up on milk and fat yield.

Cows at various stages of grading-up are noted in an Appendix to the Herd Book. The numerical importance of the grading-up system has varied with the rate of expansion of the breed as a whole—being greatest during the most rapid expansion—but, at all times, Appendix cows have had more registered female offspring than have pedigree cows. The volume of grading-up was regulated by the number of cows in Appendix B. Some 6% of the pedigree females registered in the last 30 years have Appendix A mothers and a further 5% or so owe their existence to grading-up during the last 30 years.

On average, the proportion of herds registering bulls is not greatly different among the herds which grade-up and those which do not. Similarly, the ratio of males to pedigree females registered was about the same in both types of herd. None-theless, there appears to be considerable selection against Appendix animals in the ancestry of bulls compared with cows, and none of the large bullbreeding studs appear to pursue a grading-up policy. A greater proportion of Ayrshire herds were grading-up in Scotland than in England.

Entry into Appendix B of the Herd Book is confined to cows reaching a qualifying yield. The daughters (A) of these B cows mated to unselected pedigree bulls were found to yield significantly more in their first lactation (36 gal. milk and 14 lb. butterfat) than contemporary pedigree Ayrshire heifers in the same Scottish milk recorded herds in 1955. Part, if not all, of this superiority is thought to be genetic.

A ruminant animal is largely dependent upon microbial protein synthesized within the reticulorumen for amino acids to meet its requirements for maintenance and production. The major precursor for rumen microbial protein synthesis is ammonia arising both from degradation of feed proteins within the rumen and from nitrogen recycled to the rumen. The concentration of rumen ammonia-N required to sustain maximal rates of microbial protein synthesis in vivo has been variably reported to range from 22 to 235 mg ammonia-N/1 rumen fluid (Miller, 1982). Most experiments which have investigated the concentrations of rumen ammonia-N required for maximal rates of microbial protein synthesis have used the addition of urea to the diet as the means of increasing rumen ammonia-N concentrations. However, little attention has been paid to the effects upon rumen ammonia-N concentrations and upon the efficiency of rumen microbial protein synthesis of supplying increasing amounts of a readily degradable protein in the diet, although Beardsley et al.(1977) found that as increasing amounts of soya-bean meal were fed to sheep, net losses of N across the forestomachs of the sheep were increased. In this paper, two experiments are described in which increasing amounts of soya-bean meal were fed to sheep receiving a basal ration of rolled barley and hay; the digestion of organic matter (OM) and of amino acid N (AAN) within the rumen, the net quantities of microbial AAN entering the small intestine and the efficiency of rumen microbial AAN synthesis were measured.

It is of great importance that milk should possess a pleasant flavour, but in spite of much trouble which is devoted by farmers and dairymen to this aspect of dairying, it happens from time to time that mishaps do occur. Taints and flavours in milk are due chiefly to the following three causes:

1. The activity of contaminating micro-organisms.

2. The action of milk on metals.

3. The influence of the foods eaten on the milk produced.

It must be admitted that we have very little knowledge of the subject of milk flavours and taints, and there seems little doubt but that the blame for many taints caused by micro-organisms has been associated wrongly with foods and sometimes with manures.

A detailed study of nitrogen use efficiency (NUE) and its components in three cultivars of winter wheat, Hereward, Rialto and Riband was undertaken in cultivar trials conducted in Northern Ireland in 1998 and 1999. Yield, grain N concentration, harvest index (HI), nitrogen harvest index (NHI), N uptake efficiency (NUpE), total N uptake, grain N off-take, N utilization efficiency (NUtE) and NUE itself all showed significant variation between sites. Cvars Hereward and Rialto had similar mean values across all the sites for many of the characteristics, with Riband usually differing. In all but one characteristic, grain N concentration, the responses of the three cultivars varied significantly from trial to trial and this, along with the substantial variation between sites, indicates that genetic control of the characteristics is partial. The amount of N applied as fertilizer accounted for little of the variation among the trials with weak associations for NUpE, which decreased, and grain yield, which increased with increasing fertilizer N. Neither grain yield nor NUE was associated with the amount of N taken up by the crop, but grain N concentration increased and NUtE decreased significantly. HI and NHI differed significantly among the cultivars, diverging at higher N uptakes, with Hereward and Rialto being similar and distinctly different from Riband. Grain yield was only weakly associated with NUpE but was strongly and positively associated with NUtE and NUE. The strong negative association between NUtE and NUpE highlights the potential and the urgency of understanding factors influencing uptake of nitrogen by crops. The extent of the non-genetic, i.e. environmental and management, variation in the characteristics, along with the relative similarity of the cultivar means, throws up a challenge to plant breeders, agronomists and researchers wishing to improve NUE genetically and through management. As with yield and other characteristics, a large number of trials will be required to identify consistent differences in NUE among cultivars. Thus, while mechanisms underlying NUE, NUpE and NUtE need to be understood, the possibility of using the HGCA UK Recommended List database to investigate NUE and identify cultivars with improved NUE should also be considered. Since in each of the HGCA trials cultivars have access to the same available N, and since grain yield=available N×NUE, grain yield itself is a surrogate for the NUE of cultivars. Grain N concentration is only determined in a few cultivars at present but could be used as an indicator of optimal N availability in individual trials, allowing variation in NUE of cultivars in response to agro-ecological factors on NUE to be studied.

A trial of open-pollinated (OP) cultivars and hybrids of different origins was conducted in 1986–1988 at two sites in the central clay plains of Sudan, rainfed at one site and under supplementary irrigation at the other. Throughout this study, the patterns of growth of the OP cultivars differed greatly from those of the hybrids, despite differences amongst cultivars within each group. Differences in seed yield between OP cultivars and hybrids under irrigation were not significant; but, under rainfed conditions, the hybrids gave higher yields than the OP cultivars. Partitioning efficiency (PE; reproductive mass: total biomass) increased more rapidly during flowering and seed filling in the hybrids than in the OP cultivars; differences in PE between the two groups were significant. The higher leaf area index, leaf area duration and crop growth rate of the OP cultivars were compensated to some extent by the higher PE and leaf efficiency values of the hybrids, resulting in similar seed yields of all cultivars under irrigation. Overall, irrigation increased seed yield by 0·6–1·9 t/ha and increased oil content by 8–15%.

The experiments reviewed in the preceding pages have been carried out on a light loam soil very poor in lime, in a district of medium rainfall (20–25 inches).

The chief conclusions drawn from the results are as follows:

1. Although the heaviest crops have been obtained with an annual application of dung, they are little heavier, and more costly to obtain, than the crops obtained with a biennial application of dung, especially if in the alternate year a light dressing of “artificials” including nitrate of soda be given.

2. A complete mixture of “artificials,” including nitrate of soda, has given good average crops, but not equal to those given by a biennial application of dung.

3. For the soil and other conditions of Garforth nitrate of soda is distinctly better for the hay crop than sulphate of ammonia. This is doubtless largely associated with the poverty of the soil in calcium carbonate.

A field experiment was made with sorghum hybrid CSH-1 during the rainy seasons of 1968 and 1969 on a sandy loam soil to study the influence of amounts and sources of phosphate fertilizer on phosphorus nutrition. Concentration of P in the crop and uptake increased with increasing amounts of phosphate and with increasing proportions of water-soluble P in triple superphosphate-dicalcium phosphate and triple superphosphate-rock phosphate mixtures. Relative effectiveness values were calculated from P uptake at harvest by a multiple regression method. For triple superphosphate, nitrophosphate (30% water soluble P), dicalcium phosphate and rock phosphate (from Jordan) the values were respectively, 100, 74, 61 and 22.

Sugar-beet seed germinates unsatisfactorily, largely because the true seeds are enclosed in tough woody coats. Experiments at Cambridge have been carried out to test whether treatments of the seed, which remove some of the coat, are beneficial. The general results indicate that such treatments are commercially sound, especially when seeding conditions are dry. Treatment with strong sulphuric acid, which can only be carried out by seed merchants, is effective: it accelerates and increases germination, giving a greater plant population at harvest, and this normally leads to larger yield. Increases up to 2 tons of unwashed beet per acre have been obtained.

During recent years increasing use has been made of carcass measurements to assess differences in the conformation, growth rates and carcass quality of bacon pigs. The measurements usually taken are: (a) thickness of back fat at one or more points, (b) thickness of flank at one or more points, and (c) the length of the carcass. Whilst at present there is fairly general agreement as to where the back-fat and flank measurements should be taken, the same agreement is not found in the case of carcass length.