Metabolisable energy (ME) and absorbed protein appear to be more efficiently utilised for tissue gain in ruminants fed cereal compared to forage diets but the mechanisms involved are not understood. Forage and cereal diets differ in their pattern of rumen fermentation and hence the relative proportions of absorbed nutrients such as ammonia (NH3) and VFA (Seal et al, 1991). Splanchnic bed metabolism has been demonstrated to extensively modify both the quantity and form of absorbed nutrients (Reynolds et al, 1991) and therefore is an important site for the regulation of nutrient supply to the peripheral tissues. The present study was thus designed to examine the effect of forage versus cereal diet upon splanchnic nutrient metabolism in growing cattle.

Meat yield and quality are closely related to muscle development. The muscle characteristics mainly take place during embryonic and postnatal phases. Thus, genetic control of muscle development in early stages represents a significant stake to improve product quality and production efficiency. In bovine, several programmes have been developed to detect quantitative trait loci (QTL) affecting growth, carcass composition or meat quality traits. Such strategy is incontestably very powerful yet extremely cumbersome and costly when dealing with large animals such as ruminants. Furthermore, the fine mapping of the QTL remains a real challenge. Here, we proposed an alternative approach based on chemical mutagenesis in the mouse combined with comparative genomics to identify regions or genes controlling muscle development in cattle. At present, we isolated seven independent mouse lines of high interest. Two lines exhibit a hypermuscular phenotype, and the other five show various skeletomuscular phenotypes. Detailed characterisation of these mouse mutants will give crucial input for the identification and the mapping of genes that control muscular development. Our strategy will provide the opportunity to understand the function and control of genes involved in improvement of animal physiology.

Immunity-related traits are heritable in chicken, therefore, it is possible to improve the inherent immunity by breeding programs. In this study using the Illumina chicken 60K single nucleotide polymorphisms (SNPs) chip, we performed a set of genome-wide association studies to determine candidate genes and loci responsible for primary and secondary antibody-mediated responses against sheep red blood cell. A F2 population descended from a commercial meat-type breed and an Iranian indigenous chicken was used for this study. Statistical analysis was based on a mixed linear model utilizing genomic relationship matrix to prevent spurious associations. Correction for multiple testing was done by applying 5% and 10% chromosomal false discovery rates (FDRs) for significant and suggestive thresholds, respectively. Nine significant and 17 suggestive associated SNPs were identified. Most of the SNPs that were suggestively associated with the primary response of total plasma immunoglobulins were also significantly associated with this trait in secondary response. Three SNPs were located within a narrow region of 23 kb on chromosome 16. Pathway analysis for the genes surrounding the associated SNPs showed that they are involve in antigen processing and presentation, primary immunodeficiency, vitamin digestion and absorption, cell adhesion molecules, phagosome, influenza A, folding, assembly and peptide loading of class I major histocompatibility complex, lipid digestion, mobilization, and transport (FDR < 0.1). Interestingly, there were common regains associated with multiple immune-related traits.

Whole, dry barley treated with ammonia (A), whole, untreated barley (WU) or ground barley (G) were fed with hay and a little high protein concentrate to 7 to 11-month-old lambs. Most apparent digestibility coefficients were found to be 3 to 5 units higher in the diet with barley A than in diets with barley WU or G, the differences being significant. Calculation of the digestibility of barley by difference showed that the coefficients were 8 to 10 units higher in barley A than in barley WU or G as regards dry matter and organic matter. Digestion of crude fibre was better in both A and WU than in G. These differences were also significant.

There is a considerable literature on the effect of grinding and pelleting roughages on their intake and digestibility by ruminants. It is also well established that intake is correlated with digestibility, which parameters are themselves correlated with the rumen degradability of the roughages concerned (Hovell et al. (1986)). However there is little information in which the effect of processing on the intake and digestibility of roughages of known degradation characteristics has been examined. The objective of the experiment reported here was to examine the effect of grinding and pelleting on the voluntary intake and digestibility of two roughages whose degradation characteristics had been defined.

Four mature 63-69 kg Finn-Dorset ewes fitted with permanent rumen cannulae were used. The roughages were a hay (potential degradability 0.81), and a barley straw (potential degradability 0.57) given coarsely chopped, or ground and pelleted. The composition of the hay and straw is shown in Table 1, and the particle size distribution of the two forms is given in Fig. 1. Urea was added to the straw at 18 g/kg and to the hay at 3.6 g/kg (air dry), with 0.13 g sodium sulphate per g urea. A mineral/vitamin supplement was also given. The experimental design was a latin-square with 21 d periods. Food was offered to 10-15% excess of voluntary intake. Voluntary intakes and digestibility were measured during the last 7 d of each period.

Dominance allows animals priority of access to resources when these are limited. It is common practice to feed dry sows once or twice daily a relatively small amount of food. This can lead to high competition for food, when there are no provisions for individual feeding of group housed sows. In contrast, competition for food should be low when offered ad libitum. This study was designed to investigate the effect of feeding regime on the measurement of hierarchies in group housed dry sows.

Four groups of 12 multiparous sows were housed in deep straw pens (3.1 m2/sow). Two groups were offered a high fibre diet ad libitum from a three-space hopper (LC) and two groups were floor-fed 3 kg/sow of a standard diet once daily (HC). The diet composition is given in Brouns et al (1992).

Groups were allocated to treatment after service. After two months on treatment, the dominance of every sow in each pen was determined in a feed competition test between all possible dyads of sows. A more detailed description of this test is given in Brouns et al (1992). The results of this test indicated how many pen mates each sow dominated (DR). This was used to calculate an index of linearity for the hierarchy (Appleby, 1983) giving a value between 0 and 1, where 1 indicates a completely linear hierarchy.

Feeding different groups of 1 year-old prepubertal female rainbow trout for 0, 4, 8 or 12 months on either high (1.0% body weight day-1) or low (0.4%) rations produced significant changes in fecundity, total egg volume and in the percentages of fish which spawned. Fish fed high ration for the first 4 or 8 months of the year-long cycle had up to 56% higher fecundities even after weight influences had been partitioned by covariance analysis. Groups of fish fed high ration for the first 4 months of the cycle included the highest percentages of spawning fish. By optimising feeding regimes commercial hatcheries could produce up to 3x more eggs from existing stocks.

Heat production, energy and nitrogen balances of artificially reared piglets from specific pathogen free sows, housed in a respiratory chamber, were measured over five successive periods of 7 days each from 4 to 39 days of age. The experiment was carried out at an environmental temperature decreasing from 33 to 27°C. The mean weight increased from 1·5 (at day 4) to 11·9 kg (at day 39). Daily rate of gain increased from about 100 g in periods 1 and 2 to 502 g per piglet in the fifth period.

Daily protein deposition, as measured via nitrogen balance, increased from 17 to 96 g; fat deposition increased from about 0 to 100 g. Body composition at the start and end was determined by a comparative slaughter technique. Protein and fat content had a high correlation coefficient with body weight (R2 = 0·69 and 0·89, respectively). At birth these values were much lower, 0·24 and 0·01 for protein and fat, respectively.

Nitrogen balance compared with slaughter technique led to an overestimation for protein deposition of proportionately 0·07. Fat gain measured from slaughter was proportionately 0·08 lower than that calculated from energy balance.

Ratio of gain estimated from protein and fat gain with the balance technique relative to that measured ranged between 0·93 to 1·15 in various periods.

The objects of this investigation were to discover the amount of current inbreeding, the extent of any genetic divergence between the beef and dairy types, and whether the breed was dominated by an élite group of herds as for example, in the British Friesian (Robertson, 1953). An extensive investigation by Sewall Wright (1923a), (1923b) and McPhee and Wright (1925), (1926) established that there was at that time little current inbreeding and that genetic divergence between Dairy and Beef Shorthorns was negligible. This work adds to and corroborates their findings and throws some light on breed structure.

The sampling technique in this investigation is based upon Wright (1925). If consisted of noting the number, parents, grandparents and great-grandparents of a randomly selected sample of 128 females registered in Coates’ Herd Book, Vol. 94, 1948. Simple random lines were traced back from each great-grandparent as far as 1900, a toss of a coin deciding whether to record a sire or a dam. The information contained in Coates’ Herd Book made it a simple matter to record in addition the mate of the randomly selected ancestor, thus providing 16 random lines behind the eight great-grandparents.

The histological characteristics of the skin of docked and undocked fat-tailed sheep were studied at 15-day intervals between birth and 90 days of age, then every 30 days until 180 days and every 3 months until 1 year of age. Data presented in this paper were recorded at birth, 30, 60, 120,180 and 360 days of age. The fleece characteristics were studied at 1·0,1·5 and 2·0 years of age.

The skin structure was similar in docked and undocked Rahmani sheep and did not differ from that of other breeds of sheep.

The effect of docking was significant at most ages of the study on internal diameter of primary follicles and on the external and internal diameters of secondary and on average diameters of wool follicles (P < 0·05). The effect of docking was highly significant on each of staple length and wool diameter.

A study of the intake potential of a range of well-preserved silages offered to lambs over several years showed that, of the many parameters considered, those with the greatest positive effect on DM intake were sugars in the grass as ensiled, residual sugars and protein nitrogen in the silage, with ethanol concentration in the silage having a negative effect (Henderson, Anderson and Phillips, 1984). In the experiments reported here ADD-F (85 per cent formic acid) from BP Chemicals International was applied to ryegrass at a rate sufficient to conserve much of the sugar (WSC) in the silage by inhibiting the growth of the micro-organisms on the grass. The initial lowering of the pH should also inhibit the activity of the plant enzymes, conserve protein nitrogen (PN) in the silage and prevent extensive deamination.

In 1986 first-cut perennial ryegrass, and in 1987 Italian/perennial ryegrass, was ensiled direct-cut, untreated or treated with 5 1 ADD-F/t grass in 100t capacity clamp silos. The grass was cut with a mower and lifted with a precision-chop forage harvester. The acid was pumped onto the grass through a dribble bar sited over the pick-up drum.

Lambs were fed diets in which peat replaced equivalent alfalfa hay. Gains were depressed by proportionately 0·14, 0·32 and 0·56 due to 100, 200 and 300 g peat per kg, respectively, during a 63-day feeding period. Lambs fed peat required more dry matter per unit gain. Necropsy examination of heart, kidney, liver, spleen, lung, and pancreas revealed no gross abnormalities from feeding of peat. Rib eye area was reduced at 200 and 300 g dietary peat per kg. There were no differences in taste of cooked loin sections due to peat. These studies support the safety of feeding peat for use as a dietary carrier at 20 to 30 glkg diet or as a dietary diluent at higher levels.

Milk protein genes are among the most intensively expressed and they are active only in epithelial mammary cells of lactating animals. They code for proteins which represent 30% of the proteins consumed by humans in developed countries. Mammary gland development occurs essentially during each pregnancy. This offers experimenters attractive models to study the expression mechanisms of genes controlled by known hormones and factors (prolactin, glucocorticoids, progesterone, insulin-like growth factor-1 and others) as well as extracellular matrix. In the mid-1970s, it became possible to identify and quantify mRNAs from higher living organisms using translation in reticulocyte lysate. A few years later, the use of radioactive cDNAs as probes made it possible for the quantification of mRNA in various physiological situations using hybridisation in the liquid phase. Gene cloning offered additional tools to measure milk protein mRNAs and also to identify transcription factors. Gene transfer in cultured mammary cells and in animals contributed greatly to these studies. It is now well established that most if not all genes of higher eukaryotes are under the control of multiple distal regulatory elements and that local modifications of the chromatin structure play an essential role in the mechanisms of differentiation from embryos to adults. The technique, known as ChIP (chromatin immunoprecipitation), is being implemented to identify the factors that modify chromatin structure at the milk protein gene level during embryo development, mammogenesis and lactogenesis, including the action of hormones and extracellular matrix. Transgenesis is not just a tool to study gene regulation and function, it is also currently used for various biotechnological applications including the preparation of pharmaceutical proteins in milk. This implies the design of efficient vectors capable of directing the secretion of recombinant proteins in milk at a high concentration. Milk protein gene promoters and long genomic-DNA fragments containing essentially all the regulatory elements of milk protein genes are used to optimise recombinant protein production in milk.

Pigs and poultry have this in common in their place on the farm, they can both exist as separate and distinct units, more or less divorced from the general economy of the farm as a whole. Except in special circumstances, pigs cannot exist solely on farm grown foods and must rely on purchased foods, which in most cases have to be imported into this country. Egg production can, however, be maintained at a reasonably high level on home produced feeding stuffs. This is well illustrated by what has happened in Northern Ireland during the war years. During the seven years prior to the war, there was a remarkable increase in pig population, and in 1939 the number of pigs was approximately two and a half times what it was in 1932. This expansion was due to more or less stable prices brought about by the operation of the Northern Ireland Pigs Marketing Board, and was based on imported cereal foods, maize from the Argentine and wheat offals from Australia. A poultry population of some ten million also consumed large quantities of imported feeding stuffs. In the autumn of 1939, the rapid decrease in supplies of feeding stuffs operated immediately against the pigs, and by June 1940 there was a reduction of 41 per cent, in the pigs under two months old and an overall reduction in pigs of 24 per cent, as compared with June 1939. This reduction continued until 1944, but there are signs of some improvement this year with promises of better supplies of feeding stuffs.

Three changeover experiments, each with 16 milking cows, were conducted to evaluate the effects of stage of growth of lucerne, level of feeding of lucerne or ryegrass and level of inclusion of barley. The artificially dried and processed forages were in the form of cobs and given to cows in addition to a basal ration of hay. Late-cut lucerne (organic matter digestibility, OMD, 55%) promoted significantly lower milk yields than early-cut lucerne (68% OMD). When offered ad libitum in two meals each day both forages were eaten in quantities of about 13 kg dry matter. Ryegrass cobs (79% OMD) produced more milk than lucerne cobs (59% OMD) but gave similar milk yields per unit of digestible organic matter. Production rations supplying similar amounts of digestible organic matter and composed of different proportions of lucerne cobs and rolled barley gave similar milk yields. It is concluded that the relative milk-producing value of processed forages depends on their content of digestible organic matter. However, their bulk may limit their value and the inclusion of cereal with the dried forage may be worth while.

The effects of two levels of roughage (18 or 40%), of DES implantation (36 mg, twice), and of the addition of adjoining dirt yards to pens with concrete slatted floors, on the behaviour of intact male calves, were examined in a 2 x 2 x 2 factorial experiment. Observations were carried out on four days, every 15 min for 24 hr. Activities recorded were: standing, lying, eating, drinking, ruminating, jumping and idling.

Animals on the high roughage diet spent 26% more time eating, 5% more time drinking, and 19% more time ruminating, than those on the low roughage diet.

Most of the rumination was performed while the animals were lying down. Animals allowed yards adjoining their pens spent 20% less time ruminating and 13% more time jumping than animals confined to pens alone. Those allowed the yard preferred to stand there and to lie down in the pen. The yards were used more on a cool day than on a hot day.

The advent of genetic evaluations for fertility traits in the UK offers valuable information to farmers that can be used to control fertility problems and safeguard against involuntary culling. In addition to estimated genetic merit, proof reliabilities are required to make correct use of this genetic information. Exact reliabilities, based on the inverse of the coefficient matrix, cannot be estimated for large data sets because of computational restrictions. A method to calculate approximate reliabilities was implemented based on a six-trait sire model. Traits considered were interval between first and second calving, interval between first calving and first service, non-return rate 56 days post first service, number of inseminations per conception, daily milk yield at test nearest day 110 and body condition score. Sire reliabilities were calculated in four steps. Firstly, the number of effective daughters was calculated for each bull, separately for each trait, based on total number of daughters and daughter distribution across herd-year-seasons. Secondly, multiple-trait reliabilities were calculated, based on bull daughter contribution, applying selection index theory on independent daughter groups. Thirdly, (great-) grand-daughter contribution was added to the reliability of each bull, using daughter-based reliability of sons and maternal grandsons. An adjustment was made to account for the probability of bull and son or grandson having daughters in the same herd-year-season. Without the adjustment, reliabilities were inflated by proportionately 0·15 to 0·25. Finally, parent (sire and maternal grandsire) contribution was added to the reliability of each bull. The procedure was first tested on a data subset of 28 061 cow records from 285 bulls. Approximate reliabilities were compared with exact estimates based on the inverse of the coefficient matrix. Mean absolute differences ranged from 0·014 to 0·020 for the six traits and correlation between exact and approximate estimates neared unity. In a full-scale application, sire reliability for the fertility traits increased by proportionately 0·47 to 0·79 over single-trait estimates and the number of bulls with a reliability of 0·60 or more increased by 42 to 115%.

The effects of culling, natural wastage and different correction and exclusion procedures on estimates of lactation parameters have been examined in test station records of 1042 Danish Red cows. A total culling rate of 20% was applied to the initial material, of which 11% represented obligatory culling for disease, injury and infertility and 9% ‘paper’ culling for performance at four different stages of lactation.

Exclusion and correction of short records generally resulted in overestimates of the sample mean and underestimates of the selection differential produced by culling. In all instances, the variance of the sample prior to culling, and the loss of variance attributable to culling, was underestimated in samples containing short or corrected records.

It was concluded that field data cannot provide material suitable for objective studies of selection and that a reappraisal of the effects of age, lactation, season, etc., in the controlled conditions of test stations may well be justified. An absence of culling in test stations contributes to the large estimates of variance and heritability characteristic of station material.

Equations relating biomass to cumulative food ingested ad libitum were defined in rats from weaning to 200 days of age. Two inbred lines of the IIM strain: α, of medium adult weight, and b, of low adult weight, were fed on two different diets, × and Z. The following groups were formed: αX, αZ, bX and bZ. Body weight and food intake were recorded over a 1-day period every second day. For each of the four groups, body weight, W, could be described as a function of cumulative food intake (F) by the equation:

Each exponential term was assumed to measure the behaviour of a portion of the biomass. The first exponential term implied an intense growth and a high initial efficiency, which became effectively zero by about 100 days of age. The second exponential term implied a weak growth and a low but significant efficiency of food utilization. Type of diet influenced level of intake and was important at early ages (<100 days). At 46 days of age, animals of both lines were heavier and more efficient when fed on diet Z. The genetic influence determining final adult weight becomes evident after 46 days of age.

Forty-one Texel and Texel-Oxford sires were selected over 5 years (1978-82) on high and low adjusted 100-day weight from 174 ram lambs artificially reared from birth and performance tested. The correlated responses to selection were measured in 1103 crossbred progeny, out of an experimental group of crossbred ewes, the progeny being naturally reared in field conditions. Hierarchical analysis of variance was performed, fitting the usual fixed effects and interactions. Co-heritabilities (rAh2h2; rA is the genetic correlation between traits with heritabilities h12 and h22) were estimated from offspring-parent regression and from the realized responses to selection. The selection differentials achieved (1·70 standard deviations in 100-day weight between high- and low-weight sires) were lower than expected, due to mating difficulties, mortality and other requirements for the stock. The co-heritabilities for growth traits were generally positive but small (mean 0·08; s.e. 0·08). Though not statistically significant, lambs slaughtered at a fixed weight from the high-weight rams were slaughtered earlier with lighter and leaner carcasses, as expected. Similarly, lambs slaughtered according to fat cover from high-weight rams were slaughtered later with heavier slaughter and carcass weights. Generally, the co-heritabilities for carcass traits were not significantly different from zero for either slaughter group. On the basis of these results, selection on ram 100-day weight with artificial rearing may not offer any advantage over natural rearing in the improvement of lamb growth and carcass traits.