The relationship between seed rate and use of pesticide (chlorpyrifos and aldicarb) on tiller density and herbage yield of a conventionally established autumn re-seed (i.e. grass sown after a previous grass crop) of Italian ryegrass (cv. RvP) was investigated in small plot trials at three sites in Yorkshire, Berkshire and Devon in August 1984. Plots were also sampled for pests and earthworms. Pesticide enhanced yield at all sites at the first harvest in October 1984, particularly at the low seed rates, but this effect did not persist until the spring harvest in 1985. Tiller density and herbage dry-matter yield increased logarithmically with increasing seed rate. Frit fly was the major pest and the proportion of infested tillers increased linearly with seed rate. Low seed rate in combination with appropriate insecticide was more cost effective than untreated higher seed rates in the establishment of autumn re-seeded Italian ryegrass.

Effects of plant density ranging from 44444 to 133333 plants/ha and tillage practices (planting in flat beds (control), in the furrows of open ridges, on the top of open ridges, in the furrows of tie-ridges and on the top of tie-ridges) on growth and grain yield of sorghum were investigated at Kobo, a typical semi-arid area in Ethiopia, during 1980, 1981 and 1982 cropping seasons. Plant growth was limited in the flat beds because they were likely to be deficient in soil moisture and sometimes in the tie-ridging treatments, due to waterlogging. However, planting on the top of tie-ridges produced 1·6, 0·4 and 1·8 t/ha more yield than in the flat beds, the method commonly practised by the Kobo farmers, during 1980, 1981 and 1982 respectively. In all seasons, the effect of plant density did not show marked differences. The plants rather adjusted their reproductive growth and development to the seasonal rainfall and presumably to the available soil moisture at the grain-filling periods. It was concluded that the highest plant density did not reach the optimum for the area. Planting sorghum on the top of tie-ridges is recommended.

Data are reported on a phenomenon in which piebald lambs having a coat of intermediate hairiness have black wool which is not only longer and coarser than the white wool on the same animal, but which has a different coat structure in terms of the fibre type array. Possible explanations for this effect which is apparently caused by the gene that restricts the production of pigment to certain areas of the skin are discussed. Hairy lambs and woolly lambs did not have this coat difference between the two colours.

Breeding records over 12 years (1977–89), involving 455 West African Dwarf does derived from an original population of 133 breeding does, were used to examine the influence of dam age on the incidence of multiple births and perinatal reproductive wastage due to abortion and neonatal deaths. The animals were semi-intensively managed in two goat research units at the University of Ibadan Teaching and Research Farm.

The regression results showed that the variable component, multiple births, increased (P < 0·01) linearly with advancing age of the doe, while the incidence of abortionsand neonatal deaths increased (P < 0·01) exponentially with doe age. Graphs plotted from the regression results indicated a sharp increase in the incidence of abortion and neonatal deaths between the ages of 6 and 7 years. This suggests that the practice of keeping these animals for longer than necessary, especially in rural areas of the country where they are mostly reared and kept for prestigious reasons, should be re-evaluated. Therefore it is recommended that to maintain an economically viable production system, does should be culled between the ages of 6 and 7 years and the provision of replacements planned accordingly.

Chromic oxide was used to assess the herbage intake of three tropical pastures mixtures namely: Cynodon plectostachyum and Centrosema pubescens (E); E plus Stylosanthes gracilis; Digitaria decumbens plus Centrosema pubescens and Stylosanthes gracilis, by-White Fulani (Zebu) steers and the use of faecal nitrogen to estimate digestibility of grazed herbage.

Chromic oxide recoveries in faecal organic matter ranged from 94·60% in treatment F to ca. 97·2 and 97·5% in treatments E and G respectively.

Positive relationships were found to exist between faecal organic matter nitrogen and herbage organic matter digestibility. Correlation coefficients of the ‘local’ regression equations obtained were positive but of low magnitude in some instances. Estimated mean organic matter intake was comparable to, but slightly lower than, the figures for animals of corresponding live weights in temperate countries while digestible organic matter intake was much lower.

The mean organic matter digestibility values were ca. 70·2 and 66·7% respectively for the two grazing seasons studied.

Two procedures were followed to train boars to mount a dummy sow for semen collections. Of thirty-nine boars which were introduced to the dummy sow with no previous training twelve were trained successfully. Of eight boars which were first allowed daily mating with an oestrous sow in the pen housing the dummy sow, seven were trained successfully.

Measurements of semen characteristics were made on twenty-five fertile boars including nine boars (morphological characteristics only) in use at commercial insemination centres.

The mean ejaculate volume of thirty-four ‘first’ ejaculates was 173·7 ml. (range 85–275 ml.). The mean volume of the fluid fraction was 109·3 ml. (range 15·220 ml.). For second ejaculates these values were 156·9 ml. (range 80·220 ml.) and 93·2 ml. (range 25·165 ml.).

The mean sperm concentration in thirty-five ‘first’ ejaculates was 284·5 x 106/ml. (range 11 × 106/ml. to 925 × 106/ml.). The mean concentration for ten second ejaculates was 224·4 × 106/ml. (range 18 × 106 to 295 × 106/ml.).

In samples collected in successive 20 ml. fractions the highest concentration was found in the first 20–40 ml. In some boars the spermatozoa were distributed more uniformly throughout the ejaculate than in others.

The mean number of spermatozoa per first ejaculate was 28·26 × 109 (range 0·77 × 109 to 80·0 × 109). The mean for second ejaculates was 15·88 × 109 (range 0·76 × 109 to 44·17 × 109). The mean initial pH of thirty-four first ejaculates was 7·22 (range 6·85–7·9); for second ejaculates it was 7·54 (range 7·22–8·0).

There was a marked increase of pH with time after collection when semen was stored in open vessels; this did not occur when semen was stored in filled stoppered vessels.

The mean pH of the sperm fraction in six ejaculates was 7·06 (range 6·8–7·4); the mean pH for post-sperm fractions of the same ejaculates was 7·36 (range 7·0–7·6).

The freezing points of three ejaculates were –0·54, –0·55 and –0·56° C.

The mean methylene blue reduction time for seven ejaculates was 5·0 min. (range 2·5–6·5 min.). The reducing power of boar semen was virtually unaffected when all the spermatozoa were killed by freezing.

Motility of boar semen was lost rapidly when it was examined under a cover-glass; motility was restored by aeration (removal and replacement of the cover-glass).

The mean percentages of nine morphological classes of spermatozoa in ejaculated semen of fertile boars were as follows: Malformed heads, 3·0; malformed middle-pieces, 2·7; bent tails, 4·5; coiled tails, 0·9; headless, 0·3; tailless, 0·3; broken necks, 0·1; neck beads, 11·8; middle-piece beads, 17·18.

The decline in the concentration of spermatozoa in successive fractions of an ejaculate was associated with a decline in the frequency of middle-piece beads.

The semen of one sterile boar showed a mean frquency of 77% malformed middle-pieces.

The mean percentages of the above classes in samples from the vasa deferentia of nineteen fertile boars were: malformed heads, 5·7; malformed middle-pieces, 5·1; bent tails, 3·6; coiled tails, 0·06; headless, 0·6; tailless, 0·3; broken necks, 0·1; neck beads, 17·4; middle-piece beads, 59·2.

The average percentages in samples from vasa deferentia of four sterile boars were: malformed heads, 11·9; malformed middle-pieces, 30·7; bent tails, 9·1; coiled tails, 0·5; headless, 0·4; tailless, 0·5; fractured necks, 0·9; neck beads, 24·2; middlepiece beads, 30·0.

The mean testis and epididymis weights were 359·2 and 84·7 g. Expressed as percentages of body weight the weights were 0·285 and 0·068. The mean within pair differences in weights were 48·9 g. (between testes) and 8·5 g. (between epididymides).

The macroscopic and microscopic histological features of the testes are described. Tubular atrophy associated with impaction was found to be a common feature of this sample of boar testes. There was no clear relationship of the histological features of the testes either to semen characteristics or to fertility. It is shown that fertile boars may show grossly pathological testes characteristics. The cause of the observed pathological changes was not identified. The findings are discussed.

Forty-six cows in store condition (mean ± S.E. body weight of 366 ± 8 kg) were fed individually either 3 or 4 kg of coarsely rolled sorghum grain/head/day for the last 100 days of pregnancy and the subsequent 70 days after parturition. Eleven of the cows on each level of feeding had their calves weaned at 3 days of age.

For the last 100 days of pregnancy, 3 kg of grain/head/day was an adequate ration for survival, but cows fed this ration lost a mean of 34 kg of body weight over this period compared to 8 kg by cows fed 4 kg of grain/head/day. Only 78% of the cows fed 3 kg grain/day survived to 70 days after parturition, whereas all cows fed 4 kg/day survived. There was a 44% incidence of retained placentae and metritis in cows fed 3 kg grain/day whereas those fed 4 kg/day had only an 18% incidence. Weaning of the calves at 3 days of age reduced the body weight loss of the cows by a mean of 40 kg over the first 70 days of lactation, but the effect was less for cows fed 3 kg grain (27 kg) than for those fed 4 kg grain (53 kg).

Birth weight of the calves was not affected by the level of grain fed to the cows, but calves weaned and given 3 kg of milk/day plus a 50/50 creep of lucerne chaff and sorghum grain grew faster than calves not weaned and given only a sorghum grain creep.

The omission of a source of calcium in the grain ration resulted in no apparent adverse clinical effects in the cows. The Na:K ratio of the saliva indicated that nine of the cows had been depleted of Na.

Some of the factors affecting the rate of loss of water from a drying system are shortly reviewed. These factors fall into two groups: (1) the drying system itself, and (2) the environmental conditions. The second group may include (a) diffusion of water vapour through the air, (b) bulk air movements due to (i) temperature gradients between different parts of the drying vessel, (ii) temperature lowering of the drying mass itself due to evaporation, (iii) lower density of moist air, (iv) inevitable disturbances introduced by experimental conditions such as weighing or movement of apparatus, (v) the geometry of the system. It is shown that of the external factors the most important are (2 (a)), (2 (b) (i)) and (2 (b) (ii)); (2 (b) (iv)) may produce irregularities in the rate curves of airdry granular materials; (2 (b) (iii)) and (2 (b) (v)) appear to have little or no effect.

The important part played by calcium carbonate in maintaining the fertility of the soil makes it of interest to investigate all the causes which determine both its formation and decomposition. A number of processes which are continually going forward in the soil tend to diminish the stock of calcium carbonate present; yet, in spite of this, and without frequent additions of chalk or lime from other sources, most soils, under normal conditions, remain more or less in a state of fertility. An equilibrium is set up by which the withdrawal of calcium carbonate is balanced by the results of another set of actions which restore base to the soil. This enables many soils which contain only very small quantities of lime to retain their neutral reaction and so to produce fair crops.

Because of environmental and economic constraints, we need to determine the effects of nitrogen fertilizer application on nutrient availability and fertilizer recovery, especially in regions of limited rainfall. This study was conducted to provide information on effects of N rate on yields and N recovery by standard and semi-dwarf spring wheats (Triticum aestivum L.) sown at two dates.

Ammonium nitrate was applied to spring wheat at rates up to 272 kg N/ha each year for 4 consecutive years. Only grain was removed from the plot at harvest. Wheat types did not differ in grain yields, but these yields were significantly reduced in 2 of 4 years by late sowing. Average grain yields for late sowing were greatest at 34 kg N/ha, but yields for early sowing approached maximum at the 68 kg N for semi-dwarf wheat and 136 kg N/ha for the standard wheat.

Semi-dwarf wheat was lower than standard wheat in grain and flour protein concentration and baking absorption. Late sowing (May 30) reduced test weights, flour yield and baking absorption, but increased wheat protein concentration as compared with early sowing (April 30). Leaching of fertilizer N below the 90 cm depth ranged from 152 to 378 kg/ha at the 272 kg N/ha/year rate, and was greater for the late than for the early sowing. Fertilizer N that could be accounted for averaged 87 and 82% for early and late seeding respectively. Water-use efficiency was reduced by late sowing.Soil-water extraction by wheat to the 120 cm depth was greater for high N rates.

These 4-year results showed that semi-dwarf and standard wheats had only slight differences in total grain production. Also, for efficient use of applied fertilizer and available soil water, wheat should be sown in the spring as soon as soil and weather conditions permit.

Several investigations (Shaw & Norton, 1906; Darnell & Copeland, 1936; Kimberley, 1976) have reported no appreciable loss of nutrients of unbroken grain voided by cattle. Although the chemical composition of voided whole grain may be similar to the grain as fed, losses in grain dry matter ranging from 10 to 26% for cereal grains passing through the alimentary tract of steers have been measured (Toland, 1976, 1978a, 6). In one of these studies (Toland, 19786) the disappearance of grain dry matter of whole oats and wheat in nylon bags suspended in the rumen for 48 h was approximately 20 and 35 % respectively. Further analyses of this dry matter remaining in the nylon bags for 48 and 96 h of incubation would indicate which components of the grain were being broken down in rumen fermentation. This report provides information on the differential loss of the fibre and starch components of the grain dry matter from incubation in nylon bags for the two varieties each of oats and wheat and for an additional cereal grain, triticale.

The water consumption was determined of thirty-seven Large White suckling sows that were tethered on grass. The mean consumption was 43 lb. a day, the variation between sows, and of particular sows from day to day, being particularly wide. The consumption was practically unaffected by weather and was nearly the same in summer and winter; it was impossible to demonstrate any relation between consumption and number or weight of litter, but there was evidence of a slight decrease as lactation progressed.

It is evident from a brief discussion that exact balance experiments as to the partitions of water for its various uses in the body of the pig are badly needed. It is hoped that the facts given here may draw attention to this point which has been neglected in animal nutrition studies.

The hull or husk of rice, comprising the lemma and palea, provides a fitting enclosure for the caryopsis. The physiological significance of the hull in seed dormancy has been examined by comparing the effects of its removal on germination, seed vigour, assimilate mobilization and ethylene production in germinating seeds of six rice genotypes; two each belonging to dormant, semi-dormant and non-dormant groups. Hull removal promoted the above parameters in all three categories of seeds, but the effect was relatively higher in dormant seeds compared with less dormant categories. Ethylene production in non-dormant seeds was initiated after imbibition of water, normally before visible emergence of the radicle. It peaked when the radicle began to protrude and declined thereafter. In comparison, dormant seeds produced very low levels of ethylene during germination; however, hull removal resulted in a dramatic rise in its production. Overall, ethylene evolution at the radicle protrusion stage correlated negatively with germination time. It was concluded that ethylene production starts with breaking of the caryopsis coat and peaks when the radicle ruptures it completely, at the stage of radicle visible emergence. Removal of the hull facilitates germination and ethylene production can be a good indicator for the progress of germination.

Activity biosensors have been used recently to measure and diagnose the physiological status of dairy cows. However, owing to the variety of commercialized activity biosensors available in the market, activity data generated by a biosensor need to be standardized to predict the status of an animal and make relevant decisions. Hence, the objective of this study was to develop a standardization method for accommodating activity measurements from different sensors. Twelve Holstein dairy cows were monitored to collect 12 862 activity data from four types of sensors over five months. After confirming similar cyclic activity patterns from the sensors through correlation and regression analyses, the gamma distribution was employed to calculate the cumulative probability of the values of each biosensor. Then, the activity values were assigned to three levels (i.e., idle, normal and active) based on the defined proportion of each level, and the values at each level from the four sensors were compared. The results showed that the number of measurements belonging to the same level was similar, with less than a 10% difference at a specific threshold value. In addition, more than 87% of the heat alerts generated by the internal algorithm of three of the four biosensors could be assigned to the active level, suggesting that the current standardization method successfully integrated the activity measurements from different biosensors. The developed probability-based standardization method is expected to be applicable to other biosensors for livestock, which will lead to the development of models and solutions for precision livestock farming.

The aim of this study was to investigate whether social rank (SR) and stability in the order of entrance to the milking parlour are associated with production traits. The study was conducted on a dairy farm where cows (n = 215) were managed in three groups according to lactation stage (group 1: 78 cows, 0–100 days in milk (DIM); group 2: 65 cows, 101–200 DIM and group 3: 72 cows, >200 DIM). SR was calculated from observations made from agonistic behaviour performed at the water troughs and feed bunks of each pen (n = 3). The animals were classified into three levels of dominance based on at least five clear interactions, resulting in: 61 dominant, 75 intermediate and 69 subordinate cows based on SR. Stability in the order of entry was estimated as the standard deviation of the entry position. SR was weakly correlated with milk yield, urea and protein content in milk. The results showed that stable cows had higher milk production and entered the milking parlour after the non-stable animals. Stability in the order of entry to the milking parlour was not affected by SR. Overall, the use of milking facilities appears to be associated with production traits rather than SR.

The effect of nitrogen and a plant growth regulator regime (chlormequat chloride followed by 2-chloroethylphosphonic acid) on the crop performance of a hybrid (cv. Luchs) and a conventionally bred winter rye (cv. Sentinel) were investigated in two field experiments each year between 1993 and 1995 at Winchester, UK. Internode length and dry weight/unit length of internodes was measured in order to assess the effect of the growth regulator regime on stem structure. Grain yields were 15% higher in the hybrid Luchs than in Sentinel. With high levels of applied nitrogen, both cultivars lodged in all seasons and this was most severe in 1994 when 88% of the crop lodged in Sentinel and 52% in Luchs. Plant growth regulator treatment consistently reduced lodging but did not eliminate it. Reductions in lodging were not always associated with an increase in grain yield. In the hybrid cultivar, the growth regulator treatment reduced yield in 1993 and 1995 when 2-chloroethyl-phosphonic acid was applied at GS49 and GS39 respectively, but increased yield in 1994 when applied at GS37. Growth regulator consistently reduced stem length, and the percentage reduction in length of the individual internodes within the stem was strongly influenced by the timing of the 2-chloroethylphosphonic acid component of the PGR treatment. Growth regulator reduced internode lengths by up to 25% in Sentinel and 35% in Luchs, and this was associated with reductions in the dry weight of internodes by up to 32% in Sentinel and 38% in Luchs. Consequently, dry weight/unit length of the stem was not increased by growth regulator treatment. Yield reductions in Luchs following growth regulator treatment may have been due to reduced stem reserves which have been associated with tolerance of stress in rye. Both cultivars were highly responsive to nitrogen. Economic optima varied from season to season, but they ranged over three years, from 175–273 kg/ha nitrogen, and were greater than the currently recommended application rates. Crop lodging increased with increasing nitrogen rate even when plant growth regulator was applied and yield penalties from lodging would have been high, if weather conditions during grain maturity had been unfavourable.

1. Two methods of castrating male lambs have been compared—the Burdizzo and knife methods. No difference was found in subsequent growth rate.

2. Two methods of docking male and female lambs have also been compared—searing and crushing with the Burdizzo. No difference was found in subsequent growth rate.

3. There was a tendency for ram lambs to have a higher initial weight than ewe lambs, and their rate of growth between the ages of 2 and 10 weeks was definitely greater than that of ewe lambs.

There is evidence that selection for small body size in mice results in a decrease in the total number of muscle fibres in a given muscle (Luff & Goldspink, 1967; Hanrahan, Hooper & McCarthy, 1973). It has also been shown that small chickens have fewer muscle fibres in certain muscles than larger chickens (Smith, 1963). This type of work has not, however, been extended to a study of the larger domestic animals. At Göttingen in Germany, Haring et al. (1966) have developed a breed of miniature pig which, at 6 months of age, was about a third of the body weight of commercial pigs. We therefore decided to investigate the muscles of these miniature pigs and compare them with commercial pig muscles, paying particular attention to the number of muscle fibres.

Experiments were carried out in four successive years to compare the plough and the cultivator as implements for preparing a seed bed for wheat after potatoes: in the last two years direct drilling was introduced as a third treatment. Very diverse conditions were experienced, and an attempt has been made to formulate practical recommendations.

Changes in amino acid and glucose metabolism in response to increments of rumen escape protein (REP) were studied in groups of lambs of three differing dietary histories and consequent weights, but similar ages. Crossbred wether lambs (Merino × (Border Leicester × Merino)) were fed to obtain three distinct growth patterns. The LW group (n = 15) were offered a low quality roughage diet throughout the experiment. The MW group (n = 19) were offered a high quality mixed diet followed by the same low quality diet as LW lambs. The HW group (n = 8) were offered a high quality mixed diet throughout. All diets were offered once daily ad libitum. The LW, MW and HW groups had liveweights of 18, 32 and 41 kg respectively at the commencement of supplementation, and were 33±0·1 weeks of age. REP supplements (formaldehyde-treated casein) were offered at 0, 20, 40, 60 or 80 g/day to MW and LW lambs and at 0 or 40 g/day to HW lambs.

REP increased basal digestible organic matter intake (DOMI), liveweight gain (LWG) and urinary N excretion and tended to increase N balance in LW and MW lambs. DOMI, N intake, N balance and LWG were all higher (P < 0·05) in HW compared to MW and LW lambs. REP tended (P < 0·10) to increase LWG in each dietary history group.

Blood glucose concentration was higher (P < 0·01) in HW than in other lambs but was not significantly altered by REP supplementation. Irreversible loss of glucose was greater (P < 0·01) in HW lambs and increased (P < 0·001) with REP for LW and MW lambs. REP increased (P < 0·05) phenylalanine (Phe) concentration in blood, Phe flux and oxidation and whole body rates of protein synthesis and degradation. HW lambs had higher (P < 0·05) values for all these parameters than did MW and LW lambs.

REP increased (P < 0·05) plasma concentrations of insulin-like growth factor-1, and plasma insulin increased (P < 0·05) in MW but not in LW or HW lambs. REP had no effect on plasma growth hormone (GH) concentration. Plasma concentration of insulin was higher (P < 0·05) in HW than in MW or LW lambs, while GH was not significantly affected by dietary history.

The results show that supplementation of ruminant diets with REP increases the rate of flux and oxidation of amino acids, and the rate of glucose utilization. Amino acid supply appears to influence glucose utilization more through oxidation rate than supply, and this relationship is affected by previous dietary history (weight for age) and energy availability, either from the diet or from body stores.