An extended milking interval of 24 h (24-h milking interval (24h-MI)) constitutes the acute phase of cow adaptation to once-daily milking (ODM). A recent trial including 724 24h-MI challenges demonstrated that milk yield responses to this acute phase of ODM are highly variable (from+22% to −52% of milk yield when switching to the 24h-MI, mean=−25.3%) and that factors such as stage of lactation parity and milk yield level influenced cows’ responses but did not account for all individual variability. Additional traits related to physiological, immune and behavioural adaptation were measured on a subset (96 observations) of this data set. This study aimed to determine (1) the relationship of these traits with cows’ milk yield responses, (2) their ability – combined with previously identified traits – to help predict milk yield responses to 24h-MI (adaptive profiles). The 24h-MI challenge consisted of three successive periods: one control week of twice-daily milking (cTDM), one single day of 24h-MI and then 13 days of TDM (pTDM). Milk yield responses to the 24h-MI (corrected for effects of stage of lactation, parity, milk yield level and milk yield) were related to physiological traits measured during cTDM (milk flow rate, presence or absence of interleukin-8) and to their changes during the 24h-MI (absolute increase in milk flow rate and relative udder distension). Analysis of associations between milk yield responses, stage of lactation, parity, milk yield level, proteolysis, udder expansion and immune traits found three adaptive cow profile clusters. Cows in cluster 1 had a less compliant udder than cows in cluster 2, and they lost more milk during the 24h-MI than cluster-2 and cluster-3 cows. After resuming twice daily-milking (TDM), cluster-2 cows fully recovered the milk they had lost during the 24h-MI. On the opposite, cluster-3 cows did not recover the milk they lost, likely due to udder inflammation during cTDM, as suggested by elevated concentrations of interleukin-8 in their milk. These results combining new traits with stage of lactation, parity and milk yield level constitute a first step towards predicting individual cow responses to a 24h-MI.

In comparative digestibility trials with growing pigs Latin squares are widely used as experimental designs. In this paper conditions for the application of Latin squares are explicitly stated and checked with real data. Data were collected at the Institute for Livestock Feeding and Nutrition Research in the Netherlands and consisted of digestibility trials run on pigs of 40 to 100 kg live weight. There is strong evidence for a certain form of period × animal interaction in the data. This may seriously affect estimates of treatment effects and results of significance tests. It is concluded that Latin squares are unsuitable for comparative digestibility trials with pigs growing from 40 to 100 kg. When there is no interest in statistical comparison of the diets under study, Latin squares can still be used. Some suggestions for alternative designs are given.

Whilst it is predicted that for finishing cattle (over 350 kg at start) fed grass silage diets, rumen degradable protein (RDP) should provide all protein requirements, previous studies have shown very variable growth responses from protein supplementation of cereal or starchy concentrates fed with grass silage. The protein source usually used being white fish meal which is high in rumen undegradable protein (UDP). This experiment investigated the response to fish meal supplementation of an energy concentrate based on either barley (starchy) or sugar beet feed (SBF, fibrous) when fed with good quality (64‘D’) grass silage to cattle in the finishing period of a traditional 18 month semi-intensive system.

Forty two 15 month and twelve 14 month old Friesian steers were blocked by weight and allocated at random to treatments (weights as fed):

• 1. 2kg barley plus minerals (2B)

• 2. 1.8 kg barley plus 0.2 kg fish meal (2BF)

• 3. 2 kg sugar beet feed plus minerals (2S)

• 4. 1.8 kg sugar beet feed plus 0.2 kg fish meal(2SF)

• 5. 4 kg sugar beet feed plus minerals (4S)

• 6. 4 kg barley plus minerals (4B)

The objectives of this experiment were to investigate the effect of adding a multi-enzyme product to a diet based on wheat, barley and soybean meal on faecal nutrient digestibility and nitrogen retention in early-weaned piglets.

A total of 36 pigs, weaned between 21 and 25 days of age, were assigned on weight and litter origin basis to two dietary treatments and placed in flat-deck pens of 6 pigs each. The design of the pens allowed total collection of urine and faeces separately.

There is increasing concern within all sectors of the UK pig industry with meat quality and particularly the eating quality of pork. Against this background, a collaborative study involving 6 organisations was carried out to investigate the relative influences of a number of production factors on the eating quality of fresh pigmeat. The results relating to two of these factors, namely feeding regime and sex of pig, are reported here.

Heritability estimates of death from enteritis or pneumonia, the two major causes of pre-weaning death at the U.S. Rabbit Experiment Station, Fontana, California, have been estimated. The data consisted of 15,329 observations made at the station from 1946 to 1961.

From birth to 14 days of age the death rate over the years increased from 0·2 to 6·1% During the period from 15 days to 56 days of age (weaning) the enteritis death rate was quite constant over the years (7·5%) while that of enteritis or pneumonia increased from 8·3% to 13·2%.

Heritability of death from enteritis or pneumonia for the period 15 to 56 days of age was estimated on the basis of paternal half sib analysis to be 0·12 ± 0·02. Based on an analysis of differences between dams within sires the corresponding estimate was 0·58 ± 0·05. The difference between the two estimates was attributed to maternal and non-additive genetic effects.

The genetic correlation between the two diseases under discussion was estimated to be 0·66 and 0middot;57 on the basis of differences among sires and among dams within sires respectively.

Breeding plans are suggested on the basis of the parameters estimated.

1. Two experiments were conducted to determine the feeding value of high moisture wheat straw treated with ammonia. The straw was chopped, water added to attain 350 g dry matter per kg treated straw, then treated with 84 or 90 g anhydrous ammonia per kg wheat straw dry matter and stored in a large plastic bag.

2. In Experiment 1, the treated straw was provided ad libitum to lambs in individual pens with either a control supplement (molasses and minerals), or 200 or 400 g of a soya bean meal- or maize gluten meal-based supplement.

3. Lambs fed the control supplement consumed 24·8 g of treated straw dry matter per kg live weight and lost 32 g live weight per day during the 28-day study. Source of supplemental protein did not affect live-weight gain or treated straw consumption. Level of supplement increased live-weight gains (P < 0·01) but did not affect treated straw consumption.

4. In Experiment 2, the lambs were fed one of three levels of supplement that each supplied 58 or 116 g of crude protein per day. Supplemental protein level increased cellulose digestibility (P < 0·01) with no effect on hemicellulose digestibility. Protein level did not affect treated straw consumption or live-weight gain.

5. Supplement level decreased cellulose digestibility (P < 0·01), hemicellulose digestibility (P < 0·01), and treated straw intake (P < 0·01) but increased live-weight gain.

6. The results are discussed in relation to the effects of amount and type of supplemental protein and level of supplementation on utilization of the treated straw.

Molecular techniques are important tools for microbiological studies in different habitats, and the internal transcribed spacer (ITS) has been proved to be useful for analyzing fungal diversity. The aim of this study was to use the ITS region to generate ruminal yeast profile and to identify ruminal yeast. DNA from ruminal digesta was extracted to amplify the ribosomal ITS region. The profile from the PCR products was visualized and the excised bands from the profile were identified as the genera Millerozyma, Pichia, Rhizomucor and Hyphopichia. Overall, the ITS resulted to be a simple, fast and sensitive approach that allowed profiling and identification of ruminal yeast that have not been previously described (Millerozyma and Hyphopichia) in the rumen microbial community.

Genetic parameters were estimated for wool quality, fleece characteristics and lamb production traits for Scottish Blackface sheep reared under extensive hill conditions in the UK. In two separate studies, heritabilities and genetic correlations were estimated for wool quality traits measured on lambs at 5 months of age and again on the shorn fleece a year later. The wool traits included birth coat length (BCT), 10-point scores for proportion of grey and kemp fibres present in the fleece (grey, kemp), British Wool Marketing Board (BWMB) recommendation (REC), greasy fleece weight (FLWT), BWMB fleece grade (FLGR), and average staple length (ASL). Genetic and phenotypic correlations were estimated between lamb wool traits and lamb live weights at birth (BWT), marking (at mid lactation with an average age of 7 weeks) (MWT), weaning (at an average age of 17 weeks) (WWT) and slaughter (SLWT), average fat depth (AVFD) and average muscle depth (MD). Individual lamb carcass measurements included Meat and Livestock Commission (MLC) conformation score (CONF) and fat class (FATC). Heritability estimates measured on 2524 or more live lambs were 0·69, 0·52, 0·26, 0·42 and 0·31 for BCT, ASL, grey, kemp and REC respectively. Heritability estimates for traits measured on the shorn fleece a year later for 1415 ewes were 0·37, 0·02, 0·57, 0·43, 0·46 and 0·14 for ASL, grey, kemp, REC, FLWT and FLGR respectively. Genetic correlations between FLWT in hoggets and other wool were positive and moderate to high in magnitude, ranging from 0·22 for kemp in lambs to 0·48 for grey in hoggets. Genetic correlations between REC and live-weight traits were 0·39 for MWT, 0·37 for WWT and 0·44 for SLWT. Genetic correlation between ASL and ultrasonic fat depth was 0·15 and for ASL and ultrasonic muscle depth was -0·30. The results indicate that the simple scoring systems derived to assess these traits are useful indicators of fleece quality, are highly repeatable over time and are a good gauge of likely future wool production. The results indicate that selection for heavier, leaner lambs should not compromise fleece quality, as assessed in this study.

The coypu (Myocastor coypus) is an aquatic rodent usually bred for fur production. Fluctuations in fur prices have led to coypu meat being considered as a genuine resource in commercial farms, which contribute to the diversification of agro-ecosystems. To characterize coypus as a meat resource, maternal and heterotic effects on birth weight, weaning weight, slaughter weight, number of days required to attain a weaning weight of l kg, and on two parameters of the Gompertz growth curve (asymptotic weight and maturing rate) were studied. Eight males and eight females of Standard (S) and Cognac (C) genotypes and of their reciprocal crosses (C × S) and (S × C), where the first letter denotes the paternal genotype, were used. Significant genotype, sex and (genotype × sex) interaction effects were evident for most traits. S animals were lighter than С at all ages. Hybrids with С mothers were heavier than their reciprocals. Maternal effects on the parameters of the growth curve were observed only in females. Heterotic effects were extremely significant. Favourable heterotic effects in immature animals were explained by a change in the F1 growth pattern. Males showed a dominant deviation toward low asymptotic weights and overdominance for high maturing rate. Females showed partial dominance of high asymptotic weight and over dominance for high maturing rate. This association of genetic effects would justify a productive system based on a terminal cross using С females and S males because of the higher maturing rate of both hybrids and the maternal effect of С genotype, a combination that allows higher weights at the usual slaughter age (6 months) or butchering of animals at earlier ages.

A map of the bovine genome will be an important tool for identifying genes causing congenital defects, and those controlling disease susceptibility and production traits in both beef and dairy cattle. Over 300 genes have already been mapped and a low resolution map should be available within two years. We are actively involved in the EC funded European Bovine Genome Mapping Group. To date our work has involved the development of markers and studies of experimental designs, two necessary precursors of a large scale bovine genome mapping project. In this article we briefly describe ongoing projects underpinning and improving the prospects for mapping bovine genes affecting disease and production.

For a linkage map of the bovine genome to be of use, the markers should display high levels of polymorphism. The most common markers on the map of the human genome are restriction fragment length polymorphisms (RFLPs), however these are usually diallelic, often with one allele at high frequency. We have been concentrating our efforts on the production of a relatively new class of marker, the micro-satellite.

Fast-myosin in frozen histological sections of eight, 10, 11 and nine muscles of the upper forelimb, lower forelimb, upper hindlimb and lower hindlimb, respectively, of goats was quantified by an immunohistochemical micromethod based on the enzyme-linked immunosorbent assay. The structure of the muscles is well preserved during the immunohistochemical measurement. High fast-myosin levels (more than 201 mg/g total protein) were observed in the triceps brachii (lateral head), rectus femoris, vastus lateralis, semitendinosus, semimembranosus, gastrocnemius (lateral head) and long digital extensor muscles. In contrast, low fast-myosin levels (less than 50 mg/g) were found in the triceps brachii (medial head), superficial digital flexor, vastus intermedialis, and soleus muscles. Fast-myosin-positive fibres (type II or fast-twitch type) were distributed more in the superficial regions than in the deeper regions in the triceps brachii (lateral and long heads), biceps brachii, brachialis, biceps femoris, vastus lateralis, vastus medialis, semimembranosus and gastrocnemius (lateral and medial heads) muscles. In contrast, type IIfibres were distributed more in the deeper regions than in the superficial regions in the extensor carpi radialis, deep digital flexor, cranial tibial, deep digital flexor and superficial digital flexor muscles. When the results obtained by the immunohistochemical micromethod were compared with those obtained by biochemical techniques and by histomorphometrical analyses, high correlations were noted. This technique could be used in research projects to study the muscle characteristics that determine meat quality.

The problem of applying a linear constraint on expected selection responses in a two-character independent culling levels scheme is investigated. A general equation is derived, the solutions of which specify the culling levels satisfying the constraint applied. Examples are given to demonstrate how different constraints can be applied by transforming one or more of the characters under selection.

Three experiments are described in which castrated male (steer) calves previously reared to 6 to 7 months of age on dried grass ad libitum gained weight faster, following turnout to pasture, than calves previously reared on a cereal/protein concentrate ad libitum. Rate of gain at pasture was found to be more an effect of previous rate of gain than of diet per se. There were indications that calves whose growth rate had been previously restricted ate more herbage per unit live weight than calves whose growthrate had not been restricted.

The aim of this study was to examine if enzyme supplementation could improve the performance of early weaned piglets by increasing nutrient digestibility of diets in which energy content was reduced by replacing wheat with barley or sugar beet pulp.

The following diets were supplemented with (+) and without (-) stabilised multi-enzyme premixes (E1, E2 and E3 respectively): diet W containing 706g/kg wheat and formulated to supply 14 MJ DE/kg, diets B and SBP in which DE was reduced to 13.25 MJ/kg by completely replacing wheat with barley or 185g/kg sugar beet pulp respectively. All diets were formulated to provide 150g/kg of apparent ileally digestible ideal protein, giving a crude protein concentration of about 217g/kg. Soya bean (200g/kg) and fish meal (75g/kg) were added at equal levels to all diets. Main enzyme activities in E1 were xylanase (T . longibrachiatum), amylase (B. subtilis) and pectinase (A. niger), in E2 beta-glucanase (T. longibrachiatum), xylanase (T. longibrachiatum) and amylase (B.subtilis) and in E3 beta-glucanase (T. longibrachiatum), amylase (B. subtilis) and pectinase (A. niger). The feeds were pelleted (3mm).

Heterosis for growth rate in pigs is usually expressed, and reviews of European and North American studies have been given by Sellier (1976) and Johnson (1981). Kennedy and Moxley (1980) observed heterosis of 0·044 to 0·067 for weight at 154 days and attributed some of the crossbred advantage to heterosis for resistance to atrophic rhinitis. Similarly, McGuirk, Bourke and Manwaring (1978) attributed some of the heterosis for growth rate in sheep to heterosis for resistance to pneumonia. Although little attention has been paid to interactions between heterosis and health environment, Barlow (1981) concluded from an extensive review of studies involving farm and laboratory animals that heterosis is environment dependent and is enhanced by increased stress. Sellier (1976) commented that it would be useful to examine the degree of heterosis with ‘specific pathogen free’ pigs raised in a healthy environment, and this study examined heterosis for days to 90 kg in Yorkshire × Landrace pigs under three different environments with respect to health conditions.

Angora and Cashmere goats produce two distinctive major fibres. The hair coat of the Angora goat consists essentially of a single fleece of Mohair grown by secondary hair follicles with a limited production of guard hair from primary follicles. The average fibre diameter ranges from 22 to 45 urn. In contrast, the Cashmere bearing goat has a double coat comprising coarse guard hair produced by primary follicles with the fine cashmere underhair (preferably 19 μm diameter or less) produced by secondary hair follicles. In the Angora goat, the fibres grow essentially continuously while in cashmere, hair follicle activity is determined largely by seasonal changes in photoperiod. The objective of this study was to investigate the effects of prolactin and melatonin, hormones implicated in the photoperiodic response, on the pattern of growth of secondary hair follicles isolated and maintained in vitro.

Female pigs (sows) which had lactated for about 10 days were allocated at random either to a control group or to a group given 75 mg methallibure per day for 5 consecutive days, followed by an intramuscular injection of 1000 IU PMSG. All sows were mated as soon as they came into oestrus and again 24 hr later. Nineteen out of 21 treated sows exhibited a controlled oestrus 9·4 + 0·25 days after weaning, compared with 21 out of 23 control sows in 8·2 + 0·64 days. Fourteen treated and 17 control sows conceived at that oestrus resulting in total pigs born per litter of 9·4 and 9·9 respectively. None of these differences was statistically significant.

The objective of any livestock breeder is the identification of stock of superior genetic merit with respect to some goal for the production of future generations; their objective is the estimation of genetic merit. Traditional breeders achieve this simply by visual appraisal. Some breeders have realised the value of collection of performance records to make the assessment more objective. The animal’s performance record however results not only from the animal’s genetic make-up but also from the management and other non-genetic factors (age of dam, age of measurements) that it has experienced. Best Linear Unbiased Prediction (BLUP) is a method to estimate genetic merit (or breeding values) of animals. BLUP is universally regarded as the best method available to us to predict genetic merit of animals when performance records have been collected In a variety of herd, year, season and management environments. Considerable investment of time and money Is made in the organisation of unique animal identification and collection of records. It is therefore appropriate that maximum use is made of those records in the accurate prediction of genetic merit of individual animals.

• 1. There are many ultrasonic machines using a range of techniques varying in sophistication to measure fat and muscle depths for predicting carcass composition. An evaluation of four techniques was conducted by the Meat and Livestock Commission (MLC) to enable potential users to select the most appropriate technique based on accuracy, practicality and cost.

• 2. A total of 150 commercial sheep comprising approximately equal numbers of castrates and ewes were evaluated in five batches of about equal size in lairage at one of two abattoirs. Live weight was recorded together with fat and muscle measurements from the Aloka, Dynamic Imaging, Dumatic and Velocity of Sound (VOS) ultrasonic techniques.

• 3. The Aloka is a B-Mode real-time medical scanner which is currently used on cattle in Australia. The Dynamic Imaging is also a B-Mode real-time medical scanner which is currently used in MLC's Sheepbreeder Service.