The relationship between carcass and meat quality research and industry requirements is examined with reference to changes in consumer demand.

It is argued that much applied research has not focused sharply enough on commercial requirements and that technology transfer has been slow. But there are signs that the pace of future development will be faster, associated with a reorientation of research objectives. The three key factors stimulating change are as follows.

(1) Increasing demand by retailers for a consistent product (a demand enforced by the buying power of the major multiple grocers).

(2) The reappraisal by breeders of selection objectives.

(3) Recent developments in sensor technology and the exploitation of information technology at the producer-processor interface.

The implications of each of these are discussed.

Driven by these factors research will be targeted increasingly on integrated systems from production to consumption, aimed at specific markets setting different balances between production costs and quality. These will be blueprints for best operating practices and the ‘state of the art’ against which new research developments will be evaluated.

Throughout the review, emphasis is placed on the importance of good communication between research workers and industry to confront change and realize the opportunities created.

A full lactation (300 days) experiment on 32 crossbred milch cows, separated into two groups was carried out. Group 1 (control) was given a concentrate mixture consisting of 400 g groundnut cake, 300 g crushed maize, 270 g wheat bran, 20 g mineral mixture and 10 g common salt per kg; while in group 2 (experimental) the groundnut cake was replaced by water-washed neem seed kernel cake (WWNSKC). Roughage was common in both the groups. Digestion and balance study on nine cows in group 1 and eight in group 2 was carried out after 3 months experimental feeding. Milk yield was recorded twice daily and butter fat, protein and total solids were determined every month in the milk of each animal. The results showed that there was no significant difference (P > 0·05) in the milk yield, butter fat content, organoleptic evaluation of milk, dry-matter intake, digestibility of nutrients, haemoglobin, SGOT, SGPT, acid phosphatase and alkaline phosphatase in blood and reproductive ability of the cows in the two groups. The nitrogen balance was higher in the WWNSKC group (P < 0·05) due mainly to less excretion of urinary nitrogen and a concomitent decrease in blood urea nitrogen. It is concluded that water washing of neem seed kernel cake, whose potential availability in India alone is about 0·9 Mt annually, can convert this cake, hitherto going waste, into an excellent high protein animal food and can be used for feeding milch animals without any adverse effect. It is recommended that this technology be adopted by all neem seed-cake producing countries, specially those developing countries having chronic shortage of foods and fodders for animal feeding.

A study was made of the effect of fibre level in forages on eating and rumination behaviour. Eight forage diets were prepared from the leaf and stem fractions of two grasses and two legumes and were given at hourly intervals to four steers under steady-state conditions. Eating and rumination behaviour were measured automatically by recording changes in intra-oesophageal pressure.

Mean voluntary intake of leaf was higher than that of the stem fractions (9·9 v. 5·6 kg/day; P < 0·001). This was associated with a shorter mean retention time in the rumen of the leaf than that of the stem fractions (21·4 v. 30·6 h; P < 0·001) and a lower concentration (g/100 g dry matter (DM)) of fibre (52-0 neutral-detergent fibre (NDF) and 30·5 acid-detergent fibre (ADF) v. 68·2 NDF and 45·3 ADF). Similar values (P > 0·05) between diets were found for both the water and DM contents of the rumen (60·1 kg, 7·8 kg). Voluntary intake was not related to either.

No difference was found between forage diets in the mean time (132 min) and number (18·7) of periods spent eating each day (P > 0·05). Legume leaf fractions were eaten at a faster rate (g/min) than either the grass leaf or the stem fractions. Voluntary intake was related to the rate at which food was eaten (r = 0·89; P < 0·01) but no relationship was found with the time taken to eat food (r = –0·14; P>0·05). Eating rate was related to the level of both NDF (r = –0·91; P < 0·01) and ADF (r = –0·96; P < 0·001).

Differences between diets were found in rumination times (mean 425 min; P < 001), the number of boluses regurgitated during each period (27·6; P < 0·05) and during each day (485; P < 0·001), and in the weight of boluses (455 g; P < 0·05). No differences (P > 0·05) were found between diets in the mean number of rumination periods each day (17·6), the mean time spent ruminating during each period (24·3 min), the mean rate at which boluses were regurgitated (53·2 s per bolus), the interval between boluses (5·1 s), and the DM in a bolus (27·5 g). Rumination time and the number of boluses regurgitated either per period or per day were not related to the fibre content of the diet (P > 0·05).

The regurgitated boluses from leaf fractions were chewed less than the stem fractions (43·7 v. 54·7 chews per bolus). The regurgitated boluses of lucerne leaf were chewed at a faster rate (1·13 chews per s; P > 0·05) than regurgitated digesta of the other diets which were chewed at similar rates (0·97 chews per s; P > 0·05). The total number of rumination chews made each day by animals given lucerne leaf (12 300) was much lower (P < 0·001) than that by animals given the other fractions (25 300). The number of chews made on each bolus was related to fibre levels in the diets (NDF, r = 0·78, P < 0·05; ADF, r = 0·91, P < 0·01).

It is concluded that the voluntary intake of high-fibre diets is not always restricted by rumen fill or rumination. The ease with which forage is eaten should be investigated as a factor influencing intake of fibrous forages.

The use of cottonseed (CS) as an energy and protein supplement to high wheat-straw diets was studied in a digestion and nitrogen balance trial, and as a component in fattening diets in a feeding trial. The proportions of CS studied were 0, 60, 120, 180 and 240 g/kg diet dry matter (DM). DM intake per kg M0·75 was 33, 31, 40, 31 and 29 g, respectively. The digestibility coefficient of organic matter was 415, 463, 417, 441, 350 g/kg DM and of neutral-detergent fibre was 350, 436, 411, 309, 334 g/kg DM. Nitrogen balance was –2·52, 1·1, 5·38, 5·63, 7·60 g/day respectively, for the same order of treatments. The effect of high proportions of CS in the diet in restricting DM intake and reducing its digestibility was evident. The results of the feeding trial were in agreement with those of the digestion trial and indicate the proportion of 120 g CS per kg DM as optimal and maximal.

The effects of mixed v. mono-grazing by steers and sheep on individual animal growth rate, pasture carrying capacity and live-weight output per ha were measured in a 4-year (1978 to 1981) experiment, after a preliminary familiarization year, 1977. Annual stocking rate treatments consisted of three monosteer, three mono-sheep and seven mixtures of steers and sheep. Annual average stocking rates were 2·11 steers † 8·1 ewes per ha under mixed grazing and, under mono-grazing, 4·44 steers and 15·2 ewes per ha. The range from low to high in stocking rate in mono- or mixed grazing was close to 40%. Over the 4 years a total of about 280 steers, 900 ewes and 1100 lambs were used.

Overall, mixed grazing increased average lamb daily live-weight gain (ADG) to weaning and to drafting from 246 to 265 g (P < 0001) and from 211 to 223 g (P < 0·001) respectively. Steer ADG for these periods was increased from 1·419 to 1·520 kg (P < 0·01) and from 0·950 to 1·094 kg (P < 0·001). The choice of reference mono-grazing stocking rates for comparisons of mixed v. mono-grazing ADG can affect these results. Average live-weight outputs (kg/ha) from grazing for the mono-steers, mono-sheep, and mixed grazing were 663, 690 and 714, the range in the latter over the seven mixed grazing treatments being from 605 to 805. Stocking rate was the main factor affecting output per ha. Because of the management rules used in this experiment mixed grazing effects are more appropriately assessed through ADG and measures based on it than on output per unit of area.

Models were fitted relating steer and lamb ADG to lamb weaning and lamb and steer drafting to stocking rates of steers and ewes. Mixed grazing benefits to steer and lamb ADG to drafting were greater as their proportion in the mix declined and increased with stocking rate. At the 50% proportion, lamb and steer ADG were improved by 5·2 and 3·4% respectively at low stocking rate and 9·4 and 6·6 at high stocking rate. Predicted steer ADG to lamb weaning for a given steer stocking rate increased with increases in ewe proportion up to five ewes per ha and decreased rapidly with further increments in ewe proportion.

Mixed grazing efficiency was also evaluated through the Relative Resource Total. This showed that under mono-grazing 10 to 13% more area was required to produce the same grazing season output as under mixed grazing. The 10% improvement in carrying capacity was exceeded for ewe: steer frequencies ranging from 1·5: 1 to 10: 1. Explanations for this greater efficiency in resource capture/use under mixed grazing are discussed.

Substitution rates for lamb ADG to weaning (2·35) and to drafting (2·86) and for steer ADG to drafting (0·21) were fairly constant over the 4 years 1978 to 1981.

Selection of mixed stocking rates to suit growth rate targets for different animal types and to match food supply with demand under varying soil/climatic/topographical conditions is discussed.

The assumption that observed values for litter size result from a set of thresholds which impose a discontinuity to the visible expression of a continuous underlying variate has been tested using data from the French sheep recording scheme: 629 724 natural lambings for 32 different pure breeds and 66 379 litters obtained after synchronization treatment in 15 breeds. Frequencies of single, twin, triplet and higher-order births varied regularly with litter size within each fecundation type. The coefficient of variation of litter size was remarkably constant from breed to breed under both natural (0·35 to 0·40) and induced lambings for which it was higher (0·40 to 0·45). The regression of the difference between the first two thresholds of an underlying normally distributed variate on prolificacy was slowly negative for natural fecundation, but not significant for induced fecundation. A significant effect of fecundation type was found, resulting in a lower incidence of induced than of natural twin litters for the same level of prolificacy. Multivariate polynomial regression of frequencies on natural and induced prolificacy was used to predict expected frequencies of litter size and the proportion of lambs of each birth type.

Four experiments were carried out to measure the effects of exposure to a cellulase preparation on the degradation characteristics of whole barley straw and its botanical fractions. The effect of chemical pre-treatment (NaOH and H2O2) on treatment with a cellulase preparation and the addition of propionic acid to inhibit loss of dry matter were also studied during the fermentation of ensiled straws. Samples of each preparation were incubated in polyester bags in the rumens of three sheep to estimate degradability. The data were described using the equationp = a + b (1—ec) where p is degradability at time t and a, b and c are constants.

The pH of ensiled straw was consistently decreased (P < 0·01) and the solubility increased (P < 0·01) by treatment with a cellulase preparation and by increasing the period of ensiling. The b values were decreased by increasing the length of the ensiling period (F < 0·01). The increase in the solubility of the treated botanical fractions was particularly apparent for the leaf blades, followed by leaf sheath, with the internodes being least affected (P < 0·01). However, treatment with a cellulase preparation had little or no effect in increasing the potential degradability (a + b) of any botanical fraction. The degradability of the whole plant and botanical fractions of straw increased (P < 0·01) with NaOH treatment and was further improved (P < 0·01) by alkaline H2O2 treatment. The increase was greater in internodes than in leaf sheath (P < 0·01). Treatment with a cellulase preparation and chemical pre-treatment had little or no effect on the 48-h dry-matter loss (DML) and the (a + b) values, but it increased (P < 0·01) the a values and solubility.

DML from straw treated with a cellulase preparation during fermentation decreased (P < 0·01) from about 60 to less than 10 g/kg with 30 g propionic acid added per kg straw to inhibit bacterial activity. The decreased fermentation loss was reflected in an increase in the 48-h DML and potential (a + b) values of straw treated with a cellulase preparation.

The comparative effect of spraying wheat straw, maize stover and maize cob with sodium hydroxide and alkaline (sodium hydroxide treated) hydrogen peroxide over a range of moisture contents was evaluated. The effect of concentration of hydrogen peroxide on straw subsequently ammoniated was also investigated. No differences (P < 0·05) were detected between sodium hydroxide and similar concentrations of sodium hydroxide used to provide alkali for alkaline hydrogen peroxide treatments. When however, gaseous ammonia was used as the source of alkali there were significant linear increases in degradability with increasing concentrations of hydrogen peroxide. At 48 h incubation, degradability values for untreated, ammonia-treated, 10, 50 and 100 g alkaline (ammonia) hydrogen peroxide per kg were 528, 595, 640, 676 and 716 for wheat straw, 618, 652, 683, 717 and 743 for maize stover and 392, 467, 585, 632 and 686 g/kg for maize cob respectively. It is concluded that the use of gaseous ammonia as the source of alkali seems a possible practical method of using hydrogen peroxide to increase degradability of straws.

Operant methods were used to measure the responsiveness to earth of five groups of seven weaner piglets held in a flat-deck cage. Lifts on a lever produced access to an earth trough, an empty trough, or had no effect. Group lever lifting performance was unaffected by earth in the trough, but at least one individual, the ‘worker piglet’, operated the lever more than the others to gain access to earth. Once the lid of the trough was opened other piglets were attracted to the earth and spent more time using the earth trough than the empty trough. Previous experience of earth appeared to modify lever lifting behaviour. In one group, a worker piglet did not emerge, and in another the worker operated the lever for earth at a reduced rate. The number of piglets using the earth trough and the amount of time spent utilizing it was reduced by prior exposure to earth. It is concluded that earth is a mild reinforcer to weaner piglets, that it will sustain a low rate of responding on an operant schedule, and that a component of its reinforcement value is its novelty.

Air temperatures were measured every 2 h in 12 growing-finishing pig houses. All houses were operated on the all-in, all-out, principle. Data were collected for two fattening periods in each house. Stocking density, feeding system, pig type, and the farmer's skill were standardized. Every 2 weeks, the houses were visited and live weight, mortality rate, the incidence of coughing and tail biting, and the extent of dirty lying areas were recorded.

Air temperature limits could be isolated from the complex of factors affecting behavioural and health problems of pigs observed within these experiments. Sensitive periods within the growth period of the pigs seem to exist. At the onset of the fattening period (20 to 30 kg), pigs which have been transported from other farms need special care. During summer, mortality rate was lowered when the periodicity of the temperature cycles was lowered for 40- to 50-kg pigs, whereas for heavier pigs the mean maximal air temperature was important also. With respect to coughing, a statistically significant negative relation with the air temperature in the pig house was found for all weight classes, with interactions from the number of different temperature cycles within a 24-h period. In order to avoid dirty lying areas for 20- to 40-kg animals, air temperatures should be between 20 to 24°C, whereas for diarrhoea, animals of 40 to 50 kg were especially sensitive to the occurrence of low air temperatures. For minimizing tail biting, an optimal air temperature range of 20 to 22°C is suggested.

Semen was collected from boars of proven fertility and diluted with Zorpva base using the antibiotic treatments: benzylpenicillin and streptomycin; polymixin B; tylosin; neomycin; gentamycin; kanamycin or lincomycin and spectinomycin. The last combination provided an economical treatment with enhanced quality and preservation of motility. The addition of trehalose (1 g/1) and potassium chloride (0·25 g/1) improved the preservation of acrosomes. The resulting ‘Reading’ variant was compared with Zorpva at days 4 to 6 of storage in a split ejaculate trial using 40 sows slaughtered 9/10 weeks after insemination. Conception rates were significantly higher using Reading (16/20) compared with Zorpva (8/20; P < 0·05) and the effect was particularly marked at days 5 and 6. The mean number of embryos per pregnant sow was 11·6 (Reading) v. 9·4 (Zorpva), representing 51% and 42%, respectively, of ova shed, as measured by counting corpora lutea.

There is evidence that the growth of female rats and sheep may be constrained by physiological concentrations of glucocorticoid hormones. This study was designed to examine the effects of trilostane, an inhibitor of adrenal steroidogenesis, on serum cortisol concentrations and growth in pigs.

First, trilostane was tested at three doses (250 mg, 500 mg and 1000 mg per pig) to examine its effect on serum cortisol concentrations. A reduction in serum cortisol concentration was observed 2 to 4 h after oral administration of trilostane (P < 0·05) and the adrenal response to a challenge dose of ACTH was reduced 4 to 6 h after administration (P < 0·05), at all doses tested. In a second experiment, trilostane (9·24 mg/kg body weight) was administered orally to 10 pigs twice daily for 35 days to examine its effects on growth rate. A further 10 pigs received a placebo. Trilostane did not affect weight gain or carcass composition, but caused a reduction in food intake (P < 0·05). Adrenal weight was increased by trilostane treatment and liver weight was reduced.

These results show that trilostane is effective at lowering serum cortisol concentrations acutely, but suggest that physiological concentrations of glucocorticoid hormones may not retard growth rate in barrows.

A food-driven pig growth model was developed from two existing mathematical models. The new model predicts daily growth and heat production of early-weaned pigs. An existing pig growth model was altered by replacing the environmental component with a heat transfer model. The heat transfer model was further refined by partitioning latent heat loss between the skin and lungs, adding a thermal resistance for hair coat, and increasing tissue thermal resistance. Results from this combined model were compared with experimental observations of daily piglet growth and heat production at 15°C, 20°C, 25°C and 30°C. Good agreement existed between observed data and model predictions for piglet growth. Heat production predictions did not compare as well with experimental observations as did growth, especially when piglets lost weight.

Investigations were made of the effects of the fi-agonist cimaterol on the growth and hormone status of normal and double-muscled Belgian White-blue bulls. Results indicated that repartitioning effects of this agonist may in part be mediated indirectly through an alteration in the levels of metabolic hormones and that the growth promoting effect is transient.

Milk composition in Awassi sheep was determined in relation to time of milking, stage of lactation and age of ewe. About 80 ewes of the main flock of the Kraim Centre, were used. Fat, total solids and solids not fat proportions were not significantly affected by age of ewe, but they increased as stage of lactation advanced. With equal intervals of milking of 12 h, milk fat and total solids proportions were higher in the evening milk than in the morning milk although no differences between the morning and evening in the quantity of milk obtained were observed.

Sodium bicarbonate had no effect on the dry-matter (DM) intake of heifers given a complete mixed diet of grass silage, molasses, barley, soya-bean meal and a mineral mix (660, 140, 100, 85 and 15 g/kg DM respectively) when it was incorporated into the mix at 20 and 40 g/kg DM or sprinkled on top of the diet at a rate of 350 g/day. In a second experiment, cows in mid lactation were given a complete mixed diet of silage, barley, soya-bean meal and minerals (660, 240, 85 and 15 g/kg DM) or the same diet with the barley replaced with molasses at 140 g/kg DM. Sodium bicarbonate was sprinkled on top of the diets at 0, 450 or 900 g/day. There were no significant effects on DM intake in the final week of each 3-week period. However, there was an apparent interaction of diet and sodium bicarbonate on the initial acceptance of the diet, with the intake of the diet in week 1 being significantly lower than the final intake with 900 g/day sodium bicarbonate in the absence but not in the presence of molasses.