The plasma concentrations of glucose, insulin, lactate, cortisol and free fatty acids were investigated in normal pigs and those with the homozygous and heterozygous genetic mutation for malignant hyperthermia (MH). Blood samples were obtained during a 24-h resting period, a glucose tolerance test and during a treadmill test with submaximal physical load conditions. The homozygous MH positive animals elicited the highest glucose concentrations and the homozygous MH negative animals the lowest at each sampling time during the 24-h period (P < 0·01). During the glucose tolerance test, the most pronounced post-prandial increase and the highest plasma concentrations of glucose were found for the homozygous MH positive animals (P < 0·01), which was associated with a late release of insulin. Increasing work loads during the treadmill test run resulted in an increase of plasma cortisol concentrations in all animals (P < 0·01), with the more pronounced increase for the homozygous and heterozygous MH positive animals. Plasma free fatty acid concentrations during the treadmill test differed between the genotypes (P < 0·05). A pronounced increase was found for the homozygous and heterozygous MH positive animals, whereas the MH negative animals provided very constant free fatty acid values, at a low level, independent of the work load. These results indicate that the genetic mutation for MH in pigs affects the metabolic pathways of the energy metabolism, resulting in higher plasma glucose concentrations at rest and higher lipolytic activities under physical load conditions.

Quality can be described under various headings. Deficiencies in muscle colour and structure lead in the extreme to pale, soft, exudative (PSE) or dark, firm, dry (DFO) meat. Intramuscular fat content (marbling) may be important but this varies between species. Eating quality relates to three major components. Texture is most important, followed by juiciness and flavour intensity. Flavour becomes more important when associated with unusual or ‘off’ odours.

The conversion of muscle to meat is accompanied by two major changes, the onset and resolution of rigor mortis and acidification of the tissue. Both the rate and extent of acidification may vary. If the rate is rapid, so that the pH reaches a low value when the temperature of the carcass is still high, PSE meat can result. The rate of acidification is largely determined by the degree of muscle stimulation immediately before and at slaughter.

Circular data originates in a wide range of scientific fields and can be analyzed on the basis of directional statistics and special distributions wrapped around the circumference. However, both propensity to transform non-linear to linear data and complexity of directional statistics limited the generalization of the circular paradigm in the animal breeding framework, among others. Here, we generalized a circular mixed (CM) model within the context of Bayesian inference. Three different parametrizations with different hierarchical structures were developed on basis of the von Mises distribution; moreover, both goodness of fit and predictive ability from each parametrization were compared through the analyses of 110 116 lambing distribution records collected from Ripollesa sheep herds between 1976 and 2017. The naive circular (NC) model only accounted for population mean and homogeneous circular variance, and reached the lowest goodness-of-fit and predictive ability. The CM model assumed a hierarchical structure for the population mean by accounting for systematic (ewe age and lambing interval) and permanent environmental sources of variation (flock-year-season and ewe). This improved goodness of fit by reducing both the deviance information criterion (DIC; −2520 units) and the mean square error (MSE; −12.4%) between simulated and predicted lambing data when compared against the NC model. Finally, the last parametrization expanded CM model by also assuming a hierarchical structure with systematic and permanent environmental factors for the variance parameter of the von Mises distribution (i.e. circular canalization (CC) model). This last model reached the best goodness of fit to lambing distribution data with a DIC estimate 5425 units lower than the one for NC model (MSE reduced 13.2%). The same pattern revealed when models were compared in terms of predictive ability. The superiority revealed by CC model emphasized the relevance of heteroskedasticity for the analysis of lambing distribution in the Ripollesa breed, and suggested potential applications for the sheep industry, even genetic selection for canalization. The development of CM models on the basis of the von Mises distribution has allowed to integrate flexible hierarchical structures accounting for different sources of variation and affecting both mean and dispersion terms. This must be viewed as a useful statistical tool with multiple applications in a wide range of research fields, as well as the livestock industry. The next mandatory step should be the inclusion of genetic terms in the hierarchical structure of the models in order to evaluate their potential contribution to current selection programs.

Feeding cattle with on-pasture supplementation or feedlot diets can increase animal efficiency and system profitability while minimizing environmental impacts. However, cattle system profit margins are relatively small and nutrient supply accounts for most of the costs. This paper introduces a nonlinear profit-maximizing diet formulation problem for beef cattle based on well-established predictive equations. Nonlinearity in predictive equations for nutrient requirements poses methodological challenges in the application of optimization techniques. In contrast to other widely used diet formulation methods, we develop a mathematical model that guarantees an exact solution for maximum profit diet formulations. Our method can efficiently solve an often-impractical nonlinear problem by solving a finite number of linear problems, that is, linear time complexity is achieved through parametric linear programming. Results show the impacts of choosing different objective functions (minimizing cost, maximizing profit and maximizing profit per daily weight gain) and how this may lead to different optimal solutions. In targeting improved ration formulation on feedlot systems, this paper demonstrates how profitability and nutritional constraints can be met as an important part of a sustainable intensification production strategy.

Two Pietrain/Hampshire crossbred males and two Large White males were mated in equal numbers to 24 Large White females. Breed of sire did not affect litter size or total weight at birth or weaning. After weaning, on ad libitum feeding over the live-weight range 25 to 88 kg, the crossbred pigs grew more slowly to slaughter (5%) but with equal efficiency of live-weight gain. Crossbreds had higher carcass yields (3%) shorter carcasses (3%) and larger ‘eye-muscle’ areas (18%). Fat depths, joint proportions and cut-out values were not affected. The ‘eye-muscles’ of crossbreds were paler in colour and had a lower water-binding capacity than those of the purebreds, but pH1 values and transmission percentages did not differ.

The consumption of grass silage by each individual cow in a group housed during two consecutive winter-feeding periods was continuously recorded. During the first winter, one of two concentrates, containing high starch or high fibre, were offered on a sliding scale and half the cows were injected with bovine somatotropin (bST). During the second winter, one of two concentrates, containing high or low rumen-undegradable protein were offered at a flat rate ivith two-thirds of the cows receiving bST. The cows injected with bST had significantly greater yields of milk but their consumption of silage was similar to that of cows not treated with bST. The type of concentrate offered had no significant effect on silage consumption. Although there were significant variations in the consumption of silage from day to day, there were highly significant variations in consumption attributable to individual cows. This individuality of intake persisted in a consistent manner throughout a feeding period and could not be explained on the basis of milk production, body weight, age or parity. In 24 of the cows which were used in both years, their individual intakes for the two periods were significantly correlated. The possibility that this individuality may be of economic importance is discussed.

Previous work has shown that a sward height of 3-5 cm for sheep is the most efficient way of maintaining a balance between new .growth and decayed material. An unreplicated experiment was carrried out during 1985 using 77 cross-bred ewes and their Suffolk x twin lambs to graze a perennial ryegrass sward (Lolium perenne) cv Wendy between 29 April and 22 July (weaning). Animal performance was monitored and grazing behaviour noted. Sward height measurments were taken twice weekly with an HFRO sward stick on a 0.4 ha plot (P) and on the remaining 5.8 ha field (F). Grazing commenced on each area when the sward height reached 4 cm ± 1 and was maintained at this height on P by adjusting animal numbers. Physical data was recorded from a minimum core flock of 5 ewes and 10 lambs. Area F was set stocked at 12.4 ewes/ha. Areas F and P received 198 kg N/ha in total, applied at monthly intervals between early April and July. Net herbage accumulation was recorded at 21 day intervals under exclusion cages on each area.

Courtship behaviour in pigs has been extensively studied in recent years, and it is now clear that boar-originating cues are important in eliciting both proceptive and receptive behaviour in the female. What is less clearly understood is the pattern of development of the ‘boar-component’ stimuli in the young male. There are suggestions in the literature that both olfactory and auditory cues may be sub-optimal or even absent in the early post-pubertal boar, these possibly influencing his stimulatory value and hence mating efficiency. Thus, the present study was designed to evaluate the stimulatory value of young boars and to relate this to their mating performance.

This study provides a detailed description of the development of the gastrointestinal tract (GIT) of farmed red deer (Cervus elaphus) calves over the first 12 months of age. GIT development was measured using a combination of computerised tomography (CT) scanning and traditional slaughter plus dissection techniques. Red deer calves of a known birth date were randomly assigned to two treatment groups. A group of five animals were repeatedly CT scanned at 31, 63, 92, 135, 207, 275 and 351 days of age to identify GIT organs and determine their volume. From a group of 20 animals, subsets of four individuals were also scanned at corresponding ages (except 135 days of age). They were immediately euthanised and dissected after CT scanning to compare CT-scanned results with actual anatomical measurements. Individual organ weights were compared with their respective organ volumes determined by CT scanning and were found to have a strong, positive relationship. The combined rumen and reticulum (RR) CT-scanned volume was compared with its volume determined by the water-displacement technique and this also showed good correlation between the two techniques (R = 0.92). The allometric growth rates of organs, relative to animal live weight gains, in descending order, were the rumen, omasum, reticulum, abomasum, caecum blind sac, kidneys, spleen and liver. The red deer GIT was continuing to grow and develop when the last measurement was taken at 351 days of age. The greatest growth of the RR, when expressed in terms of empty weight, was between 31 and 92 days of age. Compared with sheep and cattle, it appears that the red deer have a similar or greater rate of RR development up until approximately 60 to 90 days of age; however, the final increments of GIT maturity in deer may take longer to complete, with the empty weight of the RR gaining 7.5 g/day between 275 and 351 days of age. CT scanning was validated in this study as a viable technique to follow GIT development in the same animals over time, and it provided novel information on allometric organ growth. The success of CT scanning highlights the potential future use of diagnostic imaging for GIT development studies.

Six groups of Israeli-Friesian intact male calves were studied over growth periods of 200 to 300 kg, 300 to 400 kg, and 400 to 500 kg live weight. Different ratios (85: 15, 70: 30 and 50: 50) of concentrate to roughage were compared. Two groups received the same ratio (85: 15 or 70: 30) throughout the experiment. In the other groups, the proportion of concentrates was progressively increased or decreased.

Live-weight gain in the first period ranged from 759 to 1013 g/day, i n the second period from 1095 to 1239 g/day and in the third period from 831 to 922 g/day. Overall rate of gain was highest in the groups receiving a constant ratio, regardless of the ratio used. Increasing the proportion of concentrates as the calves became heavier, which is common practice in Europe, did not improve performance and decreasing the proportion reduced performance. Only at 200 to 300 and at 400 to 500 kg live weight did a concentrate percentage higher than 50 result in improved performance.

Dry-matter intake, relative to live weight, was higher with a ratio of 70: 30 than with one of 85: 15 or of 50: 50 in each period. Animals on a constant ratio of concentrates to roughage gave the most efficient conversion of feed energy to live weight.

There were no significant differences in dressing percentage or in carcass composition.

A comparison was made of the carcass characteristics of 73 Charolais-sired and 86 Murray Grey-sired cattle slaughtered at about 20 months of age. Six Charolais and 10 Murray Grey sires were used. At a constant slaughter age (597 days) the Charolais-sired calves had significantly heavier pre-slaughter live weight (36 kg) and carcass weight (24 kg) and significantly less fat over the m. longissimus (2·8 mm), but there was no significant difference in killing-out proportion. In the dissected half-carcass, the Charolais-sired calves had significantly more meat (9·3 kg), more bone (3·5 kg) and less fat (1·9 kg). At a constant carcass weight (233 kg), Charolais-sired calves had significantly more meat (1·8 kg) more bone (1·9 kg) and less fat (3·5 kg) in the dissected side. After making allowance for the higher calf mortality from birth to weaning of Charolais-sired calves (0·041), the advantage in carcass weight was reduced to 13 kg. It is concluded that the Charolais breed is superior to the Murray Grey as a terminal sire.

The effect of bromocryptine on milk production was investigated in 32 crossbred ewes (Flemish Milksheep х Suffolk) with one sucking lamb, during lactation and during drying off. After weaning the lambs, all ewes were hand milked twice daily for 3 days. From day 4 onwards, the ewes were divided into four groups with equal mean daily milk production. Ewes of groups A and B were hand milked twice daily during the following 9 days. Ewes of groups C and D were dried off by reducing the milking frequency. They were milked on days 5, 8 and 12. In groups B and D, bromocryptin (1 ml of 1 g/l ethanol 50%) was injected intramuscularly twice daily while control ewes (groups A and C) received 1 ml ethanol 50%. Blood samples were taken by venipuncture prior to each injection and were assayed for prolactin, growth hormone, thyrotropin and cortisol.

Bromocryptine decreased plasma prolactin levels but did not alter growth hormone or cortisol concentrations during lactation or drying off. Thyrotropin levels were elevated by bromocryptine during drying off but were unaffected during galactopoiesis.

During lactation the daily milk production remained unchanged in control ewes while in bromocryptine-treated ewes a proportional decrease of 0·5 was observed. In all ewes the decrease in milk production occurring at drying off could not be accelerated or stimulated by bromocryptine.

It is concluded that prolactin plays an important role in galactopoiesis in ewes but its role is comparatively unimportant compared with other factors during mammary involution.

Changes in prices of the basic cereals make it necessary to have a reliable assessment of their relative nutritive values if maximum economic efficiency of pig production is to be attained. As the primary role of cereals in pig feeds is as a source of energy, it is on this basis that comparison should be made but with due allowance for any major differences in nutrient content which may necessitate differential supplementation.

Sorghum, or milo, is a cereal imported into the United Kingdom which, at times, may be competitive with other cereals for price per ton but about whose nutritive value there is some confusion. Sorghum has not often been compared with barley as a cereal for pigs, but its value relative to that of maize seems to vary widely, between 80 and 100% (Braude, Mitchell and Robinson, 1950; Hillier, MacVicar and Pond, 1954; Aubel, 1956; Loeffel, 1957; Peo and Hudman, 1958; Schruben, 1959; Vanschoubroek, Spaendonk and Nauwynck, 1964). Estimates of relative digestible energy values (DE) are equally variable; the DE value of sorghum has been assessed as 94·5% (Diggs, Becker, Terrill and Jensen, 1959) and 96·2% (Robinson and Lewis, 1962) that of maize, whereas the TDN value given by Evans (1960) is greater than that of maize. Robinson and Lewis (1962) consider the DE value of sorghum to be 140% ofthat of barley, but Evans (1960) quotes a TDN value for sorghum which is 111% of that of barley. While variation in the type of sorghum used may account for some of this discrepancy, Dammers and Djikstra (1961) found little difference between the varieties milocorn, kaffir corn, granifero and white dari, and only guinea corn differed in having a lower energy value.

The length of the oestrous cycle observed in 20 ewe lambs and 424 ewes of the Awassi breed gave mean values of 16·4 (s.d. 1·31) days for ewe lambs and 17·4 (s.d. 1·84) days for ewes. Plane of nutrition did not affect cycle length in ewe lambs and age of ewe (from 2 to 5 years) did not affect oestrous cycle length in ewes (P > 0·05). Of 40 ewes treated with progesterone intravaginal sponges 33 (83%) showed oestrus and 28 (70%) ovulated at the first (synchronized) and 31 (78%) and 30 (75%) at the repeat oestrus. Mean duration of oestrus was 40·0 (s.d. 16·37) h (range 8 to 72) for the first and 34·7 (s.d. 11·19) h (range 16 to 54) for the repeat oestrus. Ovulation rate, measured in the same ewes, gave mean values of 1·18 (s.d. 0·460) for the first and 1·223 (s.d. 0·440) for the repeat oestrus.

Most commercially available silage inoculants are supplied as freeze-dried preparations of lactic acid bacteria (LAB) which are rehydrated immediately prior to application to herbage (Wilkinson, 1989). One limitation of this approach is that rehydrated bacteria are likely to be less active initially than ‘freshly cultured’ (actively growing) cells. Thus an extended lag phase may precede the period of logarithmic growth of freeze-dried inoculants. From the above argument, it follows that freshly cultured bacteria may be preferable in order to enhance activity in the initial period of ensilage.

In two experiments, firstly the principle of using freshly cultured inoculants was examined in laboratory silos followed by a scale-up of the inoculant production process to investigate the practicability of using it in an on-farm system, and examining its effect on silage composition and cattle production response.

Twenty-eight Landrace × (Landrace × Large White) young female pigs (gilts) were allocated to one of four treatment groups at about 75 kg live weight. The gilts were mated at second oestrus and suckled their piglets for 35 days. Gilts were slaughtered 14, 21, 28 or 35 days after weaning. The ‘effective’ food conversion ratios (i.e. total gilt plus litter feed intake (kg) divided by total gilt weight gain plus litter weaning weight) of the four groups were 5·22; 4·70; 4·62; and 4·56 respectively. The differences were not statistically significant.

Neither carcass weights nor individual joint weights were significantly affected by treatment. Samples of 11 middle sections from the 14-, 21- and 28-day slaughter groups were boned and cured. Bacon produced from the streak blocks had poor colour, texture and moisture-holding capacity. It was concluded that streak blocks from gilts that had farrowed were unsuitable for curing as streaky bacon.

A total of 77 heifers (3⁄4 Charolais crossbred) completed a study which examined the effects of parity number on growth, changes in size of the carcass, carcass composition and meat quality. The experiment had a factorial design based on the factors: parity and level of finish. The parities were: 0 (maiden), 1, 3 and 5. At each parity animals were slaughtered at medium (EU fat class 3) and high (EU fat class 4H) levels of finish. All data were analysed by analysis of variance using individual animal observations, and linear, quadratic and asymptotic trends were explored. Where appropriate, regression equations were derived using individual animal values to describe the relationships between key parameters and the parity status of the finished animal. Animals calved at turn-out to grass in spring (April/May) and the cows were housed at weaning in mid October (mean lactation length of 163 days) and all pregnant animals were given a diet of grass silage without concentrate supplementation during the winter period. The medium level of finish animals were slaughtered 24 days after commencement of the breeding programme for parity 0 or at the end of lactation for the remaining parities, except for parity 1 animals which had a short finishing period. For the high level of finish treatment, parity 0 heifers had a longer finishing period, while all bred animals had a post-weaning finishing period. The high finish animals were finished on a diet of grass silage and concentrates. Birth weights of calves increased until the fourth parity, while weaning weights increased linearly until the fifth parity. Mean daily milk yield increased until the third lactation. Live weight, carcass weight and weights of saleable beef, separable lean and separable fat all followed asymptotic patterns of rapid initial increase and then tended to plateau with increase in parity. The asymptote values for live weight and carcass weight were 723·0 and 383·2 kg respectively. Statistically significant asymptotic relationships with parity number were obtained for live weight and various tissue weights. Nominal mature weight was assumed to be 0·99 of the asymptote and nominal mature weights for live weight, carcass weight, saleable beef, separable lean and separable fat were attained at parity (age, years) 4/5 (6·1), 3/4 (5·3), 4/5 (6·2), 3/4 (4·7) and 1/2 (2·7) respectively. The proportion of high-priced joints declined with increase in parity (linear trend P 0·01) thus indicating a reduction in relative growth of the main muscle groups of the hind limb. Shear value measurements on cooked muscle from the maiden and first parity animals indicated very tender meat, but tenderness declined with increase in parity (asymptotic trend P 0·001). Taking animals to the higher level of finish effected increases in carcass weight and separable fat in the carcass of 55·1 kg (P 0·001) and 72 g/kg (P 0·001) respectively, while separable lean declined by 53 g/kg (P 0·001). Cooked muscle from the high finish animals was less tender than from the medium finish animals (P 0·05). It was concluded that slaughtering cows at the third parity would enable a self replacing closed herd to be operated, while obtaining 0·97 of the potential maximum output of saleable beef from the cow, but there may be some compromise in the tenderness of the meat for some consumers by the third parity.

In west Asia, it is traditional for sheep to gain body condition when low-cost native pastures are available and to mobilize reserves thus built up at other times. With diminishing shares of native pasture, crop by-products and food grains are increasing in sheep diets, and facilitate feeding for constant body condition.

In a 2 × 2 × 2 factorial experiment, 48 Awassi ewes were individually fed indoors, nursed single lambs for 42 days, and were hand-milked from day 29 after lambing. Dietary treatments were imposed at different times: level of feeding (i) in the last 24 days of pregnancy (Lconstv. Lmob), (ii) in days 18 to 60 after lambing (Lconstv. Lmob), and (iii) level of fibre in days 60 to 102 after lambing (Fhigh v. Flow). Rations Pconst, Lconst, Flow and Fhigh were calculated to maintain body condition. Fhigh provided the calculated maximum ingestible quantity of barley straw and Flow provided 0·08 kg barley straw per kg diet. Live weights (M) of ewes and lambs, milk yield and milk quality were recorded.

With Pconst, and Pmob (0·51 and 0·33 MJ metabolizable energy (ME) per kg M0.75 per day), M gains were 140 and 23 g/day (P < 0·001). Lamb birth mass and subsequent maternal milk yield were not affected. With Lconst and Lmob (0·81 and 0·61 MJ ME per kg M0.75 per day), M changes were -28 and -70 g/day (P < 0·001) and milk yields (calculated in part from lamb growth) were 1042 and 892 g/day (P < 0·01). Fhigh and Flow (385 and 170 g acid-detergent fibre per kg dry matter) were compared in a two-period change-over design experiment. Milk yields were similar (414 and 427 g/day), milk fat concentrations were 64·8 and 72·9 g/kg (P < 0·001) and milk fat yields were 26·5 and 31·1 g/day (P < 0·001) but solids-not-fat and protein yields were not affected.

There were benefits and costs in manipulating body reserves in Awassi sheep. M at lambing affects milk yield and body condition around mating is known to improve lambing rate. The existence of body reserves also allows body condition to be lost in late pregnancy and early lactation without affecting health or apparent welfare, which simplifies management of pregnant ewes, permits feeding of milk-fat-increasing high-fibre diets but the ME to maintain increased body reserves must not be ignored.

Continuously grazed rye grassl clover swards with surface heights of 8 to 10 cm at 5 weeks before a synchronized mating and 7·5 cm at mating were grazed by 151 Greyface ewes stocked at 12 per ha until mating. The effects of two stocking rates (eight and 16 ewes per ha) for 6 weeks over the mating and post-mating period were then studied on live weight, body condition and reproductive peformance. Sward height fell more rapidly post mating when stocked at 16 ewes per ha than at eight ewes per ha, but remained above 3·5 cm until 4 weeks after first mating under both rates. Ewes stocked at 16 per ha became significantly lighter and leaner than ewes stocked at eight per ha. There was no significant effect of post-mating stocking rate on reproductive performance in terms of conception rate and lambing rate to first mating or lambing rate to all matings. Reproductive performance of Greyface ewes is therefore unlikely to be adversely affected by post-mating stocking rate on swards of 7 to 8 cm which do not fall below 3·5 to 4·0 cm until 3 to 4 weeks after mating.