Many studies have shown that milk fat globule (MFG) diameter varies in dairy cows in relation to diet and/or breed. However, the mechanisms governing the size of the fat globules remain hypothetical. Our objective was to determine the variable biochemical characteristics (fat, protein, fatty acids (FA), casein and calcium (Ca) contents) between individual milk which differed in both MFG diameter and membrane content, in order to speculate about the links between milk synthesis and MFG secretion. With this aim, we built five databases of individual milk samples from 21 experiments performed between 2003 and 2011. Three of them grouped data from trials dealing with breed/diet effects and included information about: (i) MFG size/membrane, fat and protein contents (n=982), (ii) previous parameters plus FA profile (n=529) and (iii) previous parameters plus true protein composition and calcium contents (n=101). A hierarchical clustering analysis performed on these three databases yielded four groups differing in the MFG characteristics. We observed significant differences among groups for the following parameters: (i) fat content and fat : protein ratio; (ii) de novo and polyunsaturated FA contents; (iii) Ca contents. These relationships could result from potential process regulating the synthesis and secretion of MFG: (i) the apical membrane turnover for MFG secretion and (ii) cytoplasmic lipid droplet formation in the lactocyte during its migration from the basal to the apical pole. The two other databases grouped data from trials dealing with milking frequency (n=211), milking kinetics and milk type (residual v. cisternal) (n=224). They were used to study the relationships between the size of the MFG and milk composition for high native fat contents (from 60 up to 100 g/kg in residual milks). We observed curvilinear relationships between the size of the MFG and fat content, as well as with the fat : protein ratio. This result suggests that MFG diameter reaches a threshold but mechanisms are still unknown.

The use of family selection indices has been proposed as a promising selection method for increasing prolificacy in pigs. Responses of up to 0-50 pigs per litter per generation are predicted from selection programmes using information from the dam and from relatives (full and half-sibs) of the dam and sire. In order to test this method in populations of finite size, the rates of selection response and the accumulation of inbreeding have been studied by simulation along 10 generations in a selected herd of 10 sires and 100 dams using five different family selection indices (Id, Ifd, Ihd, Ifs, Ihs). Two undesirable features were evident: (a) the standard deviations of indices were lower than those expected; and (b) the increase of inbreeding was up to three times that expected without selection. Both effects increased with the complexity of the family index reducing the rates of selection responses per generation, when a genetic model with dominance was assumed, to values close to 0·20 piglets, similar to those obtained with the basic index (Id). Some results of inbreeding effects on reproductive traits in three strains of an old closed herd of Iberian pigs are also presented. Multiple regression analysis of data from 4657 litters indicated a decrease in the number of live born ranging from 0·14 to 0·35 piglets per 10% increase in dam or litter inbreeding coefficient.

This study assesses the utility of saliva samples to monitor the time course of the acute-phase response to different viruses in pigs under field conditions by using time-resolved immunofluorometric assays (TR-IFMA). A total of 30 pigs from three different farms, located in Southeast Spain, were used. Farm 1 had outbreaks of porcine circovirus type 2, farm 2 had infections with porcine reproductive and respiratory syndrome virus and farm 3 had concomitant infections with both viruses. Serology was used to determine the time of seroconversion of pigs to two different pathogens. The levels of two acute-phase proteins (APPs), C-reactive protein (CRP) and haptoglobin (Hp), were measured in saliva and serum samples and compared with pig's serology. Kinetic curves of both APPs across the study obtained in saliva samples were similar to those of serum, with R of 0.68 and 0.78 for CRP and Hp, respectively. The median CRP and Hp concentrations in saliva were higher around the theorized time of infection, according to previous experimental studies, and at seroconversion of animals. CRP increments were apparent 1 week before the increments obtained in Hp. These findings indicate that salivary APP concentrations, by using TR-IFMA, can be used in longitudinal studies as non-invasive early indicators of health status.

Six weaned lambs were allocated to each of eight restricted feeding treatments with 1·00, 0·85, 0·71, 0·57, 0·43, 0·29, 0·15 or 0 of the diet as perennial ryegrass and the remainder as white clover, and to one ad libitum treatment with perennial ryegrass offered alone. A further six lambs were offered white clover ad libitum starting on day 15. Lambs on the restricted treatments received the same daily allowance of dry matter relative to live weight, adjusted at weekly intervals to allow the greatest possible intake without any rejection of herbage. Fresh cut herbage was offered daily and measurements were made over 69 days. Twelve additional lambs were slaughtered at the beginning of the experiment, and all lambs on restricted treatments were slaughtered at the end.

Increasing the proportion of clover in the diet increased the intake of nitrogen, empty-body-weight gain, carcass weight gain and nitrogen retention. When herbage was offered ad libitum, lambs ate significantly more clover than ryegrass and gained weight faster.

The weight of gut contents decreased as the proportion of clover in the diet increased. The digestibility of the organic matter, energy and nitrogen of the mixed diets simply reflected the digestibilities of the two herbages and their proportions in the mixture.

Enhancing the quality of beef meat is an important goal in terms of improving both the nutritional value for the consumer and the commercial value for producers. The aim of this work was to study the effects of different vegetable oil supplements on growth performance, carcass quality and meat quality in beef steers reared under intensive conditions. A total of 240 Blonde D’ Aquitaine steers (average BW=293.7±38.88 kg) were grouped into 24 batches (10 steers/batch) and were randomly assigned to one of the three dietary treatments (eight batches per treatment), each supplemented with either 4% hydrogenated palm oil (PALM) or fatty acids (FAs) from olive oil (OLI) or soybean oil (SOY). No differences in growth performance or carcass quality were observed. For the meat quality analysis, a steer was randomly selected from each batch and the 6th rib on the left half of the carcass was dissected. PALM meat had the highest percentage of 16:0 (P<0.05) and the lowest n-6/n-3 polyunsaturated fatty acids (PUFA) ratio (P<0.05), OLI had the highest content of t11-18:1 (P<0.01) and c9,t11-18:2 (P<0.05) and SOY showed the lowest value of monounsaturated fatty acids (MUFA) (P<0.001), the highest percentage of PUFA (P<0.01) and a lower index of atherogenicity (P=0.07) than PALM. No significant differences in the sensory characteristics of the meat were noted. However, the results of the principal component analysis of meat characteristics enabled meat from those steers that consumed fatty acids from olive oil to be differentiated from that of steers that consumed soybean oil.

Milk yields of three strains of Scottish Blackface ewes (Lewis, Lanark and Newton Stewart) were recorded over periods of eight weeks on reseeded pasture and on hill pasture. There were no differences in milk yields between strains in the respective environments, but there were significant differences between environments in all three strains.

Relationships between udder width and milk yield were investigated in the Lewis and Newton Stewart strains.

Analyses of milk samples (taken by hand) showed there were no significant differences in the contents of fat or solids-not-fat. There was evidence that the percentage of fat and solids-not-fat in all groups tended to decrease initially and then to increase gradually as lactation advanced.

Live-weights of the ewes were compared and it was shown that the Lewis ewes were characteristically lighter than either of the other strains.

On the reseed all lambs were approximately equal in live-weight and condition. On the hill the Lewis lambs were inferior in weight and condition, and it is suggested this reflected the Lewis strain ewes' grazing preferences for higher ground.

Two experiments were carried out to evaluate the effect of incremental levels of Gliricidia sepium (gliricidia) and Leucaena leucocephala (leucaena) on forage intake, diet apparent digestibility, microbial nitrogen supply and live-weight changes in cattle. In each experiment, 20 intact and five fistulated crossbred steers (Bos taurus × Bos indicus) were used. Napier grass basal diet was offered ad libitum alone or supplemented with 7·5, 15, 22·5, or 30 g dry matter (DM) per kg metabolic body weight (M075) gliricidia (experiment 1) or leucaena (experiment 2). In experiment 1, total DM intake increased but not significantly with gliricidia supplementation (5·2, 5·1, 5·2, 5·4, 5·7 (s.e.d. 0·21) kg/day) while intake of napier grass was depressed linearly (5·2, 4·7, 4·5, 4·3, 4·2 (s.e.d. 0·21) kg/day; P < 0·05). In experiment 2, supplementation with leucaena increased the total DM intake linearly without depressing the intake of napier grass (5·2, 5·8, 6·2, 6·6, 6·7 (s.e.d. 0·31) kg/day; P < 0001 and 5·2, 5·3, 5·3, 5·3, 5·0 (s.e.d. 0·21) kg/day respectively). Neither gliricidia nor leucaena supplementation affected the apparent digestibility of the diet or in sacco DM degradation characteristics of the forages. Rumen ammonia and live-weight gain were increased linearly (P < 0·05) by supplementation from 130 to 215mg/l (experiment 1) and 75 to 113mg/l (experiment 2), from 306 to 478 g/day (experiment 1) and from 538 to 850 g/day (experiment 2), respectively. However, since the responses were linear, further experiments are required to quantify the responses to higher levels of these legume supplements.

A study was carried out to compare the fermentation parameters and kinetics of digestion of a range of different foods in the rumen of two breeds of sheep (Churra and Merino). Ten mature sheep (five Churra and five Merino), each fitted with a rumen cannula, were used in this study. In situ rumen degradability of both dry matter (DM) and cell wall was greater in Churra than in Merino sheep, the breed differences being significant for most of the foods used in the study (P < 0·05). These differences were greater when the foods had a higher cell wall concentration and this could be related to differences in the ruminal environment. However, when the foods were incubated with rumen fluid their in vitro organic matter (OM) degradability was similar in both breeds. Rumen pH was higher (P < 0·05) and ammonia concentrations were lower (P < 0·05) in Churra than in Merino sheep. Rumen volatile fatty acid concentrations tended to be higher in Merino than in Churra sheep, though differences were only significant just before feeding (P < 0·05). The ratio acetate: propionate was higher in the Churra than Merino breed before and 12 h after feeding (P < 0·05). Protozoa numbers in rumen liquid were similar for both genotypes. The greater degradation of forages in the rumen of Churra sheep is discussed in relation to the possible higher activity of fibre-degrading micro-organisms and the greater buffering capacity of the rumen contents against fermentation acids, which could result in more favourable conditions for the microbial degradation of foods in the rumen.

A total of 252 lambs was subjected to two contrasting growth rates (high and low) for 7 weeks commencing at 6 weeks of age, factorially arranged with two contrasting growth rates (high and low) from 13 weeks to slaughter. Growth rate was controlled either by weaning lambs at 6 weeks and feeding indoors throughout on differing levels of a concentrate diet (84 lambs in experiment 1) or by grazing at differing sward heights up to weaning at 13 weeks after which weaned lambs were grazed at differing sward heights and where necessary housed from early October and offered differing levels of concentrate and silage (168 lambs in experiment 2). Lamb slaughter weights on each growth rate treatment covered the range 40 to 48 kg live weight.

Increasing the growth rate between 6 and 13 weeks from 213 to 320 glday in experiment 1 and from 191 to 291 g/day in experiment 2 did not significantly affect the fat depth measured at various locations throughout the carcass, the weight of perinephric and retroperitoneal fat, fat grade or the total lipid content of soft tissue dissected from the shoulder joint when lambs were taken to slaughter weights. Increasing the growth rate between 13 weeks and slaughter from 136 to 338 g/day in experiment 1 and from 99 to 146 g/day in experiment 2 significantly increased the depth of carcass fat and fat grade but, though lipid content of the tissue in the shoulder also increased, this difference was not significant.

Carcass fat depth, perinephric and retroperitoneal fat, fat grade and lipid content of the shoulder tissue increased as slaughter weight increased. The effect of carcass weight on carcass fat was greater on the high plane of feeding from 13 weeks than on the low plane. For example, mean fat depth increased by 0·52 mm/kg increase in carcass weight on the high plane compared with 0·13 mm/kg on the low plane.

Comparing the effect of plane of feeding and carcass weight on carcass fat depth the high finishing plane of feeding had an effect equivalent to an increase of 3·8 kg carcass weight. The equivalent figure for the depth of tissue over the 12th rib was 2·8 kg while in relation to fat grade the effect was smaller at 1·0 kg carcass weight.

Genetically reducing boar taint using low-taint lines is considered the most sustainable and economic long-term alternative to surgical castration of male pigs. Owing to the high heritability of the main boar taint components (androstenone, skatole and indole), breeding is an excellent tool for reducing the number of tainted carcasses. To incorporate boar taint into breeding programmes, standardized performance testing is required. The objective of this study was to develop and formally present a performance test for the main boar taint compounds on live breeding candidates. First, a standardized performance test for boar taint was established. A biopsy device was developed to extract small tissue samples (200 to 300 mg) from breeding candidates. Quantification of boar taint components from these small samples using specialized chemical extraction methods proved accurate and repeatable (r = 0.938). Following establishment of the method, biopsy samples of 516 live boars (100 to 130 kg live weight) were collected in the second step. Various mixed linear models were tested for each boar taint compound; models were ranked in terms of their information content. Pedigree information of 2245 ancestors of biopsied animals was included, and genetic parameters were estimated using univariate and multivariate models. Androstenone (in μg/g liquid fat (LF): mean = 0.578, σ = 0.527), skatole (in μg/g LF: mean = 0.033, σ = 0.002) and indole (in μg/g LF: mean = 0.032, σ = 0.002) levels obtained by biopsy were plausible. Heritability estimates for androstenone calculated with univariate (0.453) and multivariate (0.452) analyses were comparable to those in the literature. Heritabilities for skatole (0.495) and indole (0.550) were higher than that for androstenone. Genetic and phenotypic correlations were similar to those published previously. Our results show that data on boar taint compounds from small adipose samples obtained by biopsy provide similar genetic parameters as that described in the literature for larger samples and are therefore a reliable performance test for boar taint in live breeding candidates.

Scans of the m. longissimus and overlying fat at the 12th rib were taken, just prior to slaughter, on 254 lambs using the Scanogram and Danscanner ultrasonic machines. The lambs were from a ram breed trial and comprised six sire breed × five dam breed groups. Mean live weight at slaughter was 44·5 kg.

The precision with which scan measurements predicted comparable carcass measurements and carcass lean content (g/kg lean) was examined within groups with variation in live weight eliminated.

Residual s.d. for the prediction of carcass m. longissimus area from the corresponding scan measurement was 141 and 158 mm2 for the Scanogram and Danscanner respectively (s.d. of carcass m. longissimus area was 162mm2). Residual s.d. for the prediction of lean from the best combination of fat measurements was 32·0 for the Scanogram and 35·8 for the Danscanner (s.d. of lean was 38·5). M. longissimus did not increase the precision of lean prediction.

In a comparable evaluation of the Scanogram, involving 147 lambs, the residual s.d. for the prediction of lean was 24·0 (s.d. = 28·9).

The levels of precision obtained were low and it is debatable whether the ultrasonic techniques examined would be of value for carcass lean prediction in practical applications. They might be of use in selection programmes within nucleus flocks of the more important meat sire breeds or as an aid in experiments for differentiating between animals of widely differing composition.

Data on 2120 lambs produced over 7 years in the Animal Breeding Research Organization synthetic Dam Line (49% Finn, 22% East Friesian, 16 % Border Leicester and 13 % Dorset Horn) were analysed by least squares. The effects of sex, age of dam, year of birth, birthrearing class, and age of lamb on weights at birth and at 4, 8, 12 and 16 weeks of age were all appreciable. However, pooled within-year correction factors should be adequate in adjusting records for selection. Heritability estimates for weights at the five ages ranged from 0·17 to 0·24 by the sire component method and from 0·18 to 0·28 by regression of offspring on dam. Previous reports of differences in heritability in singles and in twins were not confirmed. Estimates of the genetic correlations among the various lamb weights were high (0·62 to 1·04) indicating that selection for weight at one age should result in increased weights at all ages.

The objective of this study was to evaluate the ability of the plant extracts Yucca shidigera, Quillaja saponaria and a combination (a blend of capsicum, carvacrol and cinnamaldehyde) to stimulate piglet and sow performance when used as supplements in the diets of lactating sows. These extracts were selected for their potential benefits to health, appetite and digestion. Eighty hybrid sows were housed in conventional indoor farrowing crates from day 107 of gestation until weaning. Sows were allocated according to parity, live weight, fatness and past reproductive performance, to one of four dietary treatments: control (C), combination (COM, 100 g/t food), yucca (Y, 200 g/t), quillaja (Q, 250 g/t). Between days 107 to 114 of gestation, sows received 2·5 kg food per day of their respective diet. During lactation food was offered ad libitum with sow food intake (FI) recorded daily. Faecal samples were obtained from sows daily in order to measure diet digestibility using titanium dioxide as an external marker. Piglet live weight and sow P2 backfat were recorded on days 1, 7, 14 and 21 and at weaning on day 23 (s.e.2·5). Piglet live weight and rectal temperature were measured at birth and 24 h of age. Piglet growth between birth and 24 h was significantly affected by sow treatment. Litters from COM sows held the greatest advantage (117 v. C 99, Q 77, Y 107 g per pig per day, P < 0·01, s.e. = 7·9). Piglet body temperature at birth was also higher in COM litters when compared with treatment C (38·58 v. 37·95oC, P < 0·05)). Q and Y piglets were intermediate between the two. Sow treatment had no effect on piglet performance between day 1 and 14 of lactation. However, between days 15 and 21, piglets from COM sows again significantly outperformed all other treatments (COM 290, C 246, Q 235, Y 255 g per pig per day, P < 0·001, s.e. = 9·3). Piglet weights on day 21 were also significantly greater for the COM sows (6878 g v. C 6584 g, Q 6330 g, Y 6498 g, P < 0·05 s.e. = 132). No benefit was seen from supplementation with either yucca or quillaja extracts on piglet growth. Sow FI and P2 backfat loss between parturition and weaning were unaffected by treatment. However, diet digestibility was enhanced by all supplements during week 1 of lactation in terms of dry matter, organic matter and crude protein. It is concluded that some plant extracts may enhance piglet and sow performance prior to weaning.

This study was conducted on 94 Frieswal (5/8 Holstein Friesian 3/8 Sahiwal) crossbred bulls of three different grades, categorized based on their semen freezability visualising Group 1 (consistently freezable semen producer bulls, N = 11), Group 2 (inconsistent freezable, N = 16) and Group 3 (Non freezable, N = 67). Each group was further divided into two classes that is young (up to 30 months) and adult (31 to 70 months) bulls depending upon their age. Sperm morphology was studied by using the eosin-nigrosin staining technique. Bulls age significantly (P < 0.01) affected semen quality and sperm morphology. In adult bulls, semen volume, mass activity and sperm concentration were 36%, 17.56% and 19.6%, respectively, higher than young. Initial progressive motility (%) and livability showed significant (P < 0.01) improvement with the advancement of age (43.37 ± 1.21 and 67.71 ± 1.11, respectively, in young; 53.02 ± 1.11 and 74.17 ± 1.03, respectively, in adult). In young bulls, sperm head, mid piece, tail abnormality and total abnormal sperm percent (12.38 ± 0.92, 4.87 ± 0.24, 11.01 ± 0.60 and 28.26 ± 1.34, respectively) were 1.85, 1.27, 1.20 and 1.44 folds higher than that of their mature stage (6.69 ± 0.64, 3.82 ± 0.32, 9.14 ± 0.64 and 19.66 ± 1.31, respectively). Significant reduction (P < 0.01) in micro cephalic sperm, free heads, bent mid piece, looped mid piece and proximal protoplasmic droplets were observed at mature age as compared with their younger stage. In bulls of consistent freezing category, abnormal sperm heads significantly decreased from 4.40 ± 0.31% to 3.28 ± 0.02% on maturity. Similarly, in inconsistent freezing grade bulls sperm head abnormality (9.28 ± 0.75% to 5.13 ± 1.20%) and total abnormal sperm percent (24.89 ± 1.43 to 18.73 ± 3.40) was decreased over the age. On the contrary, in non-freezing category bulls’ sperm morphology did not show significant (P > 0.05) improvement with age advancement, rather some abnormalities like long slender head, under developed/deformed head, abaxial implantation of mid piece, double mid piece, stump tail and distal protoplasmic droplets tend to increased significantly (P < 0.05) with age of bulls. Results indicated that in potential Frieswal bulls semen quality and sperm morphology were improved from young to mature stage, where as, in poor quality (non-freezing) semen producer bulls neither the morphology nor the semen quality showed any improvement with maturity. It was recommended that crossbred bulls producing more than 25% morphologically abnormal sperms in young age (below 30 months) along with poor progressive motility (<50%) and low sperm concentration (<1000 million/ml) need immediate culling with out any expectation of further improvement in semen quality with age advancement.

Increased intestinal permeability (IP) can lead to compromised health. Limited in vivo IP research has been conducted in chickens. The objectives of the current study were to develop a model of increased IP utilizing lipopolysaccharide (LPS Escherichia coli O55:B5) and to evaluate IP changes using the lactulose, mannitol and rhamnose (LMR) sugar permeability test. In addition, fluorescein isothiocyanate dextran (FITC-d), d-lactate, zonula occludens (ZO-1) and diamine oxidase (DAO) permeability tests were employed. Male Ross chickens were reared until day 14 on the floor in an animal care facility and then transferred to individual cages in three separate experiments. In each of experiments 1 and 2, 36 chicks were randomly allocated to receive either saline (control) or LPS (n=18/group). Lactulose, mannitol and rhamnose sugar concentration in blood was measured at 0, 30, 60, 90, 120 and 180 min in experiment 1, at 60, 90 and 120 min in experiment 2 and at 90 min in experiment 3 (n=16/group). Lipopolysaccharide was injected intraperitoneally at doses of 0.5, 1 and 1 mg/kg BW in experiments 1, 2 and 3, respectively, on days 16, 18 and 20, whereas control received sterile saline. On day 21, only birds in experiments 1 and 2 were fasted for 19.5 h. Chicks were orally gavaged with the LMR sugars (0.25 gL, 0.05 gM, 0.05 gR/bird) followed by blood collection (from the brachial vein) as per time point for each experiment. Only in experiment 3, were birds given an additional oral gavage of FITC-d (2.2 mg/ml per bird) 60 min after the first gavage. Plasma d-lactate, ZO-1 and DAO concentrations were also determined by ELISA in experiment 3 (n=10). Administration of LPS did not affect IP as measured by the LMR sugar test compared with control. This was also confirmed by FITC-d and DAO levels in experiment 3 (P>0.05). The plasma levels of d-lactate were decreased (P<0.05). Plasma levels of ZO-1 were increased in the third experiment only and did not change in the first two experiments. Lipopolysaccharide at doses of 0.5 and 1 mg/kg did not increase IP in this model system. In conclusion, the LMR sugar can be detected in blood 90 min after the oral gavage. Further studies are needed for the applicability of LMR sugars tests.

Around 70% of total seed phosphorus is represented by phytate which must be hydrolysed to be bioavailable in non-ruminant diets. The limited endogenous phytase activity in non-ruminant animals make it common practice to add an exogenous phytase source to most poultry and pig feeds. The mature grain phytase activity (MGPA) of cereal seeds provides a route for the seeds themselves to contribute to phytate digestion, but MGPA varies considerably between species and most varieties in current use make negligible contributions. Currently, all phytases used for feed supplementation and transgenic improvement of MGPA are derived from microbial enzymes belonging to the group of histidine acid phosphatases (HAP). Cereals contain HAP phytases, but the bulk of MGPA can be attributed to phytases belonging to a completely different group of phosphatases, the purple acid phosphatases (PAPhy). In recent years, increased MGPAs were achieved in cisgenic barley holding extra copies of barley PAPhy and in the wheat HIGHPHY mutant, where MGPA was increased to ~6200 FTU/kg. In the present study, the effect of replacing 33%, 66% and 100% of a standard wheat with HIGHPHY wheat was compared with a control diet with and without 500 FTU of supplemental phytase. Diets were compared by evaluating broiler performance, ileal Ca and P digestibility and tibia development, using nine replicate pens of four birds per diet over 3 weeks from hatch. There were no differences between treatments in any tibia or bird performance parameters, indicating the control diet did not contain sufficiently low levels of phosphorus to distinguish effect of phytase addition. However, in a comparison of the two wheats, the ileal Ca and P digestibility coefficients for the 100% HIGHPHY wheat diets are 22.9% and 35.6% higher, respectively, than for the control diet, indicating the wheat PAPhy is functional in the broiler digestive tract. Furthermore, 33% HIGHPHY replacement of conventional wheat, significantly improved Ca and P digestibility over the diet-supplemented exogenous phytase, probably due to the higher phytase activity in the HIGHPHY diet (1804 v. 1150 FTU). Full replacement by HIGHPHY gave 14.6% and 22.8% higher ileal digestibility coefficients for Ca and P, respectively, than for feed supplemented with exogenous HAP phytase at 500 FTU. This indicates that in planta wheat PAPhys has promising potential for improving P and mineral digestibility in animal feed.

A study was conducted to evaluate the effects of pre partum (PRE) and post partum (POST) dietary energy and nutrient supply (E) and their interactions on feed intake, performance and energy status in dairy cows of three breeds. In this experiment, the effects of three energy and nutrient supply levels (low (L), medium (M), high (H)), both pre-calving and post-calving, were investigated, using a 3×3 factorial arrangement of treatments. In both phases (84 days pre- and 105 days post-calving) E levels applied to a total of 81 multiparous cows of breeds Simmental (SI), Brown Swiss (BS) and Holstein–Friesian (HF; n=27 for each breed), were 75%, 100% and 125% of recommendations of the German Society of Nutrition Physiology (GfE). Dry matter intake (DMI) was restricted, if energy intake exceeded target values. Pre partum DMI and energy intake were different as designed, liveweight and body condition score (BCS) of SI cows were higher, but EB was lower, compared to BS and HF cows. Milk yield and composition were influenced by all three main experimental factors (EPRE, EPOST, breed). Energy-corrected milk yield was 25.6, 28.6 and 30.1 kg/day for LPRE, MPRE and HPRE as well as 21.5, 30.1 and 32.6 kg/day for LPOST, MPOST and HPOST, respectively. Numerically, only for milk protein content the interactions EPRE×EPOST and EPRE×breed reached significance. Impact of energy supply pre-calving was more pronounced when cows had lower energy supply post-calving and vice versa. On the other hand, milk yield response of cows to energy supply above requirements was greater for cows that were fed on a low energy level pre partum. Impact of energy level pre partum was higher for HF cows, showing that their milk production relies to a greater extent on mobilization of body reserves. Increasing energy supply pre partum led to a more negative energy balance post partum, mainly by increasing milk yield and content, whereas feed intake was slightly reduced. Increasing energy supply post partum enhanced milk yield as well as milk protein and lactose content. Calculated energy balance corresponded well with liveweight and BCS change. Response of milk yield to increasing energy supply followed the principle of diminishing returns, since energy was increasingly partitioned to body retention. Increasing energy supply pre partum enhances milk yield and content post partum, but exacerbates negative energy balance and its consequences.

Maturing patterns of carcass muscle, fat and bone and of body organs were established relative to live weight, using data from 20 Dorset Horn rams and 20 Dorset Horn wethers. The sheep were fed a pelleted ration from soon after weaning and individual sheep of both groups slaughtered at 6-kg increments in live weight from 18 kg to maturity at approx. 100 and 96 kg for the rams and wethers, respectively. This small difference in mature weight was mostly due to the weight of the testes and the increased weight of the head in mature rams.

As proportions of live weight, the mature rams had more carcass muscle and bone and less carcass fat than the mature wethers. In the mature animals the body organs in general comprised similar proportions of live weight in the two groups. However the head, hide and blood were proportionately heavier in the mature rams. The liver and alimentary tract were heavier in the mature wethers.

The maturing patterns for the three carcass tissues were not different for the two groups. However, many of the body organs matured on different patterns in the rams and wethers.

As the mature live weights and the maturing patterns for carcass tissues and some body organs were not different for the two groups, comparisons of the proportions of these tissues in rams and wethers would yield similar conclusions on an equal weight basis, as on the basis of the same proportion of maturity. However, comparisons of the proportions comprised by some body organs need to take account of different maturing patterns, as comparisons at different stages of maturity will each give different answers.

The faecal egg count (FEC) and total egg output is reduced in parasite-resistant sheep and breeding sheep for resistance should reduce infective larval contamination of pastures. This research compares lambs and rams from the parasite-resistant flock, Rylington Merinos, with unselected controls at the same level of larval challenge and the same level of food supply in an animal-house environment. The sheep were penned individually. The parasite resistant sheep excreted 0·85-fold less eggs than the control animals after infection with Trichostrongylus colubriformis and Ostertagia circumcincta for 12 or 18 weeks. During the infection period the parasite resistant lambs had higher plasma immunoglobulin concentration and higher ratio of globulin to albumin than the control animals. In the mature rams these genotype differences diminished. They also had lighter mass of the small intestine with a higher proportion of mucosa, but heavier mass of the large intestine. Parasite infection caused a depletion of blood glutathione in the lambs given food at maintenance or 1·5 × maintenance, and the parasite-resistant sheep (both lambs and rams) also had lower glutathione concentration. Maintaining good body nutrient reserve before the infection reduced the egg output in the early stage of the infection. Food intake had little effect on worm egg production in young sheep given food at maintenance or above. It is suggested that an improvement of nutrition, sulphur-containing amino acids in particular, is required to recover the loss of productive performance caused by the infection.

Three groups of eight yearling Friesian steers were fed on pelleted diets containing ground barley straw, maize and soya bean meal, the percentages of straw in the diets being 10, 30 and 50 (treatments 1, 2 and 3). The crude protein level was adjusted to 12% in all diets on an air-dried basis.

Daily live-weight gain for treatment 2 was 7% greater than for treatment 1, and 12% greater than for treatment 3. Voluntary feed intake was also greater in treatment 2, by 16% when compared with treatment 1 and 4% when compared with treatment 3. The efficiency of feed conversion decreased by 10% for each 20% increase in dietary straw level.

Weight loss during lairage was greater on treatment 3, as were total gut fill and omasum weight. The bone content of carcasses was similar for all treatments; carcass lean was increased in treatment 2. Carcass and channel fat was severely depressed in treatment 3.

The results are discussed in relation to dietary effects on carcass composition.