Two experiments, involving 144 and 168 pigs weaned at 22 to 31 days, to investigate the response to inclusion of copper (CuSO4.5H2O), copper plus carbadox/sulphadimidine or copper plus avoparcin supplements in starter and grower diets were made. The carbadox and sulphadimidine levels were 50 and 100 mg/kg diet respectively in both diets. Avoparcin was included at 40 mg/kg in the starter diets and 20 mg/kg in the grower diets. In the first experiment the levels of copper were either 180 or 340 mg/kg in the starter diets and either 90 or 270 mg/kg in the grower diets. In the second experiment the levels were either 20 or 180 mg/kg in the starter diets and either 10 or 180 mg/kg in the grower diets.

In the starter period of the first experiment, supplementation with carbadox/sulphadimidine or avoparcin proportionately increased the rate of growth by 0·41 and 0·07 respectively in relation to supplementation with 340 mg copper per kg diet (P < 0·05). Neither supplement improved growth rate in the grower period. In the second experiment there were no significant differences in growth rate. However the rates of growth in both the starter and grower periods were higher in pigs receiving carbadox/sulphadimidine than in those receiving avoparcin, while these in turn grew slightly faster than those receiving copper only.

Taking into account the costs of the supplements the inclusion of the carbadox/sulphadimidine supplement produced an economic benefit compared with the other treatments.

In response to environmental threats, numerous indicators have been developed to assess the impact of livestock farming systems on the environment. Some of them, notably those based on management practices have been reported to have low accuracy. This paper reports the results of a study aimed at assessing whether accuracy can be increased at a reasonable cost by mixing individual indicators into models. We focused on proxy indicators representing an alternative to the direct impact measurement on two grassland bird species, the lapwing Vanellus vanellus and the redshank Tringa totanus. Models were developed using stepwise selection procedures or Bayesian model averaging (BMA). Sensitivity, specificity, and probability of correctly ranking fields (area under the curve, AUC) were estimated for each individual indicator or model from observational data measured on 252 grazed plots during 2 years. The cost of implementation of each model was computed as a function of the number and types of input variables. Among all management indicators, 50% had an AUC lower than or equal to 0.50 and thus were not better than a random decision. Independently of the statistical procedure, models combining management indicators were always more accurate than individual indicators for lapwings only. In redshanks, models based either on BMA or some selection procedures were non-informative. Higher accuracy could be reached, for both species, with model mixing management and habitat indicators. However, this increase in accuracy was also associated with an increase in model cost. Models derived by BMA were more expensive and slightly less accurate than those derived with selection procedures. Analysing trade-offs between accuracy and cost of indicators opens promising application perspectives as time consuming and expensive indicators are likely to be of low practical utility.

There have been suggestions that positive feedback from the meal may stimulate the performance of undesirable behaviour, such as stereotypies, in the post-feeding period. The aim of this work was to measure the short-term effects of a meal on the post-feeding behaviour of the pig.

Pigs (70 kg live weight) were offered food ad libitum for 7 days and then given a restricted food allowance for 23 days (experiment 1) or 14 days (experiment 2). In experiment 1, the food allowance was given in one, two or three meals per day. In experiment 2, the food allowance was given in two meals per day and comprised ingredients which supplied glucose at different rates (starch, glucose/starch, starch/guar gum). The pigs' posture and behaviour were recorded in three 1-h periods during the day on 2 days consecutively during the ad libitum feeding period (time period 1) and on pairs of days on three (periods 2, 3 and 4: experiment 1) or two (periods 2 and 3: experiment 2) subsequent occasions during food restriction. The meal frequency or estimated rate of glucose supply had no significant effects on posture or behaviour. In both experiments activity increased with the duration of food restriction. In periods 1, 2, 3 and 4 of experiment 1 the proportions of observations spent were: standing 0·244, 0·260, 0·706 and 0·728 (s.e.d. 0·0346); nosing 0·073, 0·094, 0·229 and 0·253 (s.e.d. 0·0169); rooting 0·032, 0·037, 0·108 and 0·133 (s.e.d. 0·0133). In periods 1, 2 and 3 of experiment 2 the proportions were: standing 0·247, 0·302 and 0·446 (s.e.d. 0·0240); nosing 0·045, 0·075 and 0·138 (s.e.d. 0·0113); chewing 0·101, 0·126, 0·155 (s.e.d. 0·0121). In experiment 1 feeding rate increased with duration of restriction (P < 0·001), but was unaffected by treatment. It is concluded that post-feeding behaviour was influenced more by long-term changes in state (i.e. prolonged food restriction) than by short-term effects of the meal.

The majority of New Zealand dairy goat farmers utilise cultivated green-fed fodder dominated by perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), but evidence from other ruminant species suggests that milk production may be improved when using a more diverse array of species within the green fodder. The aim of this experiment was to determine whether feeding lactating dairy goats a mixed-species green fodder (MF, consisting of perennial ryegrass, timothy (Phleum pratense L.), prairie grass (Bromus willdenowii Kunth), white clover, red clover (Trifolium pratense L.), lucerne (Medicago sativa L.), chicory (Cichorium intybus L.) and plantain (Plantago lanceolata L.) improves dietary intake, milk yield and composition compared with a standard ryegrass and white clover green fodder (SF). Thirty-six mid-lactation goats were housed indoors in pairs and split into two groups (A and B). The trial was split into three periods – firstly a uniformity period of 6 days, in which all goats were fed a combination of both green fodder types, followed by two treatment periods (P1 and P2) of 12 days, respectively. For P1, group A was fed MF and group B was fed SF, and then the group diets were switched for P2. Goats fed MF had 13% greater dry matter intake and 7% greater milk yield than goats fed SF. In addition, the milk protein and fat concentration of goats fed MF were 4% greater than for those fed SF, whereas there was no effect on milk lactose concentration. There was no treatment effect on the levels of protein, glucose, urea or non-esterified fatty acids in the blood of the goats. An effect of green fodder type on milk fat profile was demonstrated, with proportions of pentadecylic acid (C15:0), cis-vaccenic acid (C18:1 c11), linoleic acid (C18:2 n6) and α-linolenic acid (C18:3 n3) being increased in response to MF consumption. In contrast, iso-C15 and iso-C17 proportions were lesser. In summary, this study demonstrated that goats fed MF increased green fodder intake and milk production compared with goats fed SF. The green fodder type affected the fatty acid profile of goat’s milk, with MF increasing the levels of beneficial polyunsaturated omega fatty acids (linoleic and α-linolenic acids).

Twelve male 8-month-old lambs were used in a 6-month feeding experiment to determine the effects of dietary Mo, Mo + S and Zn supplements on the body retention and tissue accumulation of dietary Cu, Zn and Fe. The lambs were divided into four groups of three lambs each and each group was fed ad libitum one of four diets. A control diet was based on palm kernel cake (PKC) and grass hay. Three additional diets were the control supplemented with either Mo or Mo + S or Zn. At 3 months of the experiment, feces and urine were collected and sampled for 6 days. At the end of the experiment (6 months), blood was sampled and then the sheep were slaughtered. The liver and kidney were removed and sampled for chemical analysis. In comparison with the control, each dietary supplement decreased (P < 0.05) the Cu concentration in the liver, but only the Mo + S supplement decreased it to a safe range of below 350 μg/g dry matter. This was accompanied by the body retention of dietary Cu of 24.6%, 6.7%, 2.5% and 6.5% for the control, Mo, Mo + S and Zn treatments, respectively. The blood plasma concentration of Cu was decreased (P < 0.05) by the Zn supplement, but was not affected by other supplements (P > 0.05). It was concluded that from the supplements tested, only Mo + S appeared to be effective in reducing the retention and liver accumulation of the dietary Cu to prevent chronic Cu toxicity in sheep fed PKC-based diets.

Fifty-four multiparous Yorkshire × Landrace sows were allocated equally to receive an intramuscular (i.m.) injection of 3 ing oestradiol-17β (E2) or no injection at 112 days of gestationto determine the effect of E2 on the timing and duration offarrowing. All sows received an injection (i.m.) of 10 mg prostaglandin F2x af 113 days of gestation. Of the soivs allocated to treatment, 21 oestrogen-treated and 19 control sows were assigned to be observed for the onset of parturition. A further six oestrogen-treated and eight control sows were included to increase the data base for litter production. The time of piglet delivery was monitored between 08·00 and 18·00 h on day 114 of gestation. Blood samples were obtained from each offour piglets from four E2-treated and five control litters. More E2-treated (8/21) than control sows (1/19) farrowed before 08.00 h of day 114 (P < 0·05) although, for those sows farrowing during the observation period, there was no effect on the time to onset or duration of parturition. Plasma oestradiol concentrations were higher (P < 0·06) in piglets delivered by E2-treated sows. However,this was not associated with any effect on piglet pre-weaning survival. It is concluded that exogenous oestradiol can influence the timing of onset offarrowing in some sows. Although further refinement in terms of timing of E2 injections is required, it seems likely that exogenous E2 may have a useful role to play in hastening the induction of parturition in sows.

1. Two trials were carried out to investigate the effects of high-copper supplementation of isonitrogenous diets containing either white-fish meal or soya bean meal as the sole protein supplement.

2. There was no difference in performance between the two diets when they were fed unsupplemented with copper in trial 1. The addition of 250 mg copper per kg diet significantly and similarly improved performance on both diets.

3. Liver-copper stores, but not kidney-copper stores, were significantly increased when the copper-supplemented diets were fed. The level of the liver-copper stores on the soya bean meal supplemented diet was, however, some 400g/kg less than that on the white-fish meal supplemented diet. The significance of this clearly established finding is discussed.

Forty-eight pregnant Manchega dairy ewes bearing twins or singles penned in groups of six during the last 11 weeks of gestation were used to study the effects offorage type (Italian ryegrass hay or alfalfa hay) and number of foetuses (one or two) on voluntary dry-matter (DM) intake and digesta kinetics. Hays were supplemented with 0·6 kg/day of concentrate. When measured directly for group-fed ewes, forage DM intake was affected byforage type (P < 0·01), whereas litter size had no significant effect. An internal (rumen-undegradable DM) and an external (chromium III oxide) marker were also used to determine intake of individual ewes to account for errors in diagnosing litter size. Estimated DM intake confirmed the effect offorage type on DM intake and revealed the effect of litter size on food intake (F < 0·05). Forage type also affected chromium III oxide fractional outflow rate and flow of undegradable DM, whereas litter size only had an effect at the end of pregnancy by reducing hay intake, rate of passage and digesta flow mainly with alfalfa diets. In conclusion, DM intake, rate of passage and digesta flow was higher with alfalfa hay than with ryegrass hay, in spite of the similar DM apparent digestibilities of both hays. Furthermore, litter size affected DM intake at the end of pregnancy causing an intake decline, which was greater with alfalfa hay than with ryegrass hay.

Castrated male sheep were offered a roughage without (control sheep, no. = 8) or with calcium, phosphorus and sodium (CaPNa sheep, no. = 8; Ca, P and Na intake 34, 10 and 17 g/day per sheep respectively, given twice daily as drench). Food intake and live-weight change were unaffected. Water intake and urine excretion were higher whereas dry-matter apparent digestibility, nitrogen retention and wool growth were lower in the CaPNa sheep. The excretion of allantoin in urine indicated no differences in microbial protein absorption from the gut. There were small differences in the proportions of volatile fatty acids, numbers of protozoa and mineral concentrations in rumen fluid between the sheep in the two groups. Retentions of Ca, P and Na were higher in the CaPNa sheep, whereas retention of potassium was lower.

Testicular tissue was studied in domesticated yak and in wild yak x domesticated yak (F1 and F2) bulls at 6, 12, 18 and 24 months of age by stereology for quantitative histology and by comparative studies on the lactate dehydrogenase (LDH) isoenzyme spectrum, LDH activity and the percentage content of LDH isoenzymes in testes. The results indicated that all three types of yak were similar in both the characteristics of ultrastructure of testicular tissue and the degree of germ cell development. The process of spermatоgenesis was initiated and sperm were produced for the first time at the age of 12 months in all three yak types. All yak types exhibited similar age-related increases in weight of testes, volume density of both the seminiferous tubules and seminiferous epithelium and height of seminiferous epithelium but all these indexes were slightly affected by season. The number of LDH isoenzyme bands after electrophoresis varied with age as follows: four bands were present at 6 months of age, five bands at 12 and 18 months and six bands at 24 months of age. The sixth band was LDH-x, which appeared between the LDH4 and LDH5 band. These results indicated that yak bulls reach sexual maturity at 24 months of age and that puberty is not affected by infusion of wild strains.

The effect of the duration of grazing (experiment 1) and starvation time and placement in the rumen of inert bulk material before grazing (experiment 2), on the rumen content ferment ability, was investigated by means of measuring cumulative gas production. In experiment 1, a comparison was made of four durations of grazing (1, 1·75, 2·50 and 3·25 h) after overnight starvation. Rumen samples taken from the cows after 1 h of grazing had higher values of total accumulated gas with less (P < 0·05) time required to reach the maximum fermentation rate than cows grazed for 3·25 h. Following grazing, a 7·75·h starvation period was imposed on the four treatments. The extent of fermentation was significantly lower (P < 0·01) after starvation than immediately after grazing (49·7 v. 60·8% of incubated dry matter (DM), respectively). Experiment 2 consisted of a factorial combination of two durations of starvation before grazing (16·5 (LS) and 2·5 (SS) h) with the presence or absence in the rumen of 12·5 kg of a synthetic indigestible material. Before grazing the total accumulated gas production was less (P < 0·05) for the LS than for the SS cows. After the grazing session, the total gas of rumen samples from the LS cows was significantly higher (P < 0·05) than for the SS cows.

This was in agreement with the observed higher DM intake during grazing and DM rumen pools after grazing in LS cows. For both starvation periods, the presence of inert rumen bulk led to a higher total gas, a shorter half-time and less DM left unfermented. The measurement of fermentation kinetics by cumulative gas production was suitable to detect changes in rumen content fermentation patterns due to the clearance of material from the rumen (effect of starvation) or DM intake during the grazing sessions.

The aim of the present study was to evaluate water absorbing capacity and the drying and cooling rates of fur in farmbred male mink (Mustela vison) following 10 s of simulated diving. Comparisons were made between adult animals with summer and winter fur. The water loss from a swimming pool following diving in summer amounted to 146 (s.e. 14) g and 152 (s.e. 9) g in dry and wet mink, respectively (P > 0·05). During winter the corresponding values averaged 148 (s.e. 9) and 125 (s.e. 7) g, respectively (not significant: P > 0·05). No significant differences between summer and winter were found for dry mink. In wet-coated mink, on the other hand, water loss from the swimming pool was significantly greater (P 0·05) in summer than in winter. Drying of the fur was slow and significantly (P 0·05) affected by season so that half of the 100 g water absorbed by fur evaporated within 20 min during winter (at –2°C) whereas in summer (at +18°C) it took 60 min. A slower drying rate in summer could be benefical as it allows long-term body cooling in warm environment. Cooling constants of winter-coated dry mink (0·01955 (s.e. 0·00183) per min) were not significantly different (P > 0·05) from those of winter-coated wet mink (0·02091 (s.e. 0·00144) per min) indicating that energy costs of wet fur after diving are not critical for the survivial of the mink during winter.

Consumer reaction to bacon from boars and castrates, whose production and processing characteristics were known, was determined in 122 households consisting of 238 respondents. On a seven-point scale the mean scores for six organoleptic characteristics were similar for each sort of bacon relative to that usually purchased. A proportion of 0·045 of cooks scored boar bacon at the point of strongest rejection (unappetizing aroma) during cooking but less than 001 considered that the flavour was very much stronger than their usual bacon. Few respondents marked boar bacon inferior to their usual bacon for eating characteristics. On a comparative basis the frequency distribution of scores for flavour, juiciness and pleasantness of aroma on the plate was slightly in favour of castrate bacon but was of little importance. Using the production and processing data obtained and accepting no adverse consumer reaction to boar bacon, a financial advantage to the producer of entire male pigs for bacon manufacture over castrates was demonstrated (£2·95). However, if the retailer should not reward the curer for the extra leanness of the boar then the curer might be at a financial disadvantage.

A molassed sugar-beet product with added urea and dicalcium phosphate was evaluated as an energy and protein source for housed lactating ewes. Comparisons were made with a barley-vegetable protein and a barley-urea concentrate each formulated to supply approximately the same amount of crude protein. The overall performance of ewes and lambs given barley and vegetable protein was very significantly superior to that of ewes receiving the sugar-beet product. At 6 weeks after lambing the ewes given barley and vegetable protein had lost 57% (with singles) and 23% (with twins) less weight and their lambs had grown 28% (singles) and 48% (twins) more quickly than for ewes receiving the sugar-beet product. The intermediate performance of the ewes receiving barley and urea illustrated that the difference between the barley-vegetable protein concentrate and the sugar-beet product was both an energy and a protein effect.

In two experiments 480 and 360 pigs were housed in groups of 10 and given diets containing different proportions of cassava between 35 and 87 kg live weight. The cassava contained 672, 34, 57 and 39 g/kg air dry matter of starch, crude fibre, total ash and insoluble ash respectively. The diets in the first experiment contained 0, 238, 475 or 713 kg cassava per t. In the second experiment the different levels of dietary cassava (0, 150, 300 or 450 kg cassava per t) were combined in a factorial design with different levels of tallow (0, 50 or 100 kg tallow per t). The pigs were given quantities of food calculated to give isoenergy intakes on the assumption that air-dry cassava contained 14·2 MJ digestible energy (DE) per kg. The feeding scale increased with time to give a maximum daily allowance of DE of 31·8 MJ per pig. Relative to each MJ of DE the calculated levels of lysine and of methionine plus cystine in the diets were 0·64 g and 0·39 g respectively.

In both experiments, increasing levels of cassava resulted in significant reductions in growth rate but had no effect on the conversion of food to live weight or on carcass weight. In both experiments, the diets with the highest inclusions of cassava produced pigs with the thickest backfat. The effect was not significant in the second experiment but in the first experiment the differences were significant between diets with the highest and intermediate levels of cassava. There was a significant interaction between cassava and tallow on growth rate with the depression due to high levels of cassava being reduced when 100 kg tallow per t was included in the diet.

The results of these growth experiments suggested that cassava of the type used here was of similar value to barley on an energy basis when used in diets based on barley and soya bean meals.

With the objective of studying the response patterns of two biotypes of different body (structural) size to stocking rate (SR) in terms of individual growth rate (ADG), meat production per ha (PROD) and backfat thickness (BFT) under grazing conditions, 64 steers of two biotypes of the Angus breed of different body size were used: small-sized (SB: frame score of 1·3 (s.d. 0·7)) and medium-sized (MB: 2·9 (s.d. 0·6)). Four levels of SR were applied (1·8, 2·3, 2·8 and 3·3 steers per ha). The experiment lasted 241 days (April to December). Animals were weighed every 14 days, forage availability (FA) was estimated on four occasions and BFT was recorded at the end of the experiment (between 12th and 13th ribs). There were no differences between biotypes in ADG. SB tended to be earlier maturing showing higher BFT (4·39 v. 3·97 mm; P = 0·22). ADG was affected by SR and was higher at lower SR (0·612, 0·529, 0·414 and 0·375 kg/day, for 1·8, 2·3, 2·8 and 3·3 steers per ha, respectively). Individual average daily gain of the MB was more variable across the seasons of the year. None of the variables showed effects of the biotype × SR interaction but differences in ADG between biotypes as a function of the SR were observed as a trend (P = 0·29). Despite the difference in frame score between biotypes it was not possible to associate it with consistent differences in the response variables. Individual productivity (potential) of MB was not reflected in a greater productivity per surface unit. The data from this experiment do not allow the choice of a particular biotype in order to optimize the productivity of the pastoral production systems.

A dynamic simulation model was used to predict the long-term effects of published heat stress-associated fluctuations in conception rate (CR) and milk production (MP) on the monthly MP pattern in Israel. The model results showed that the pattern of seasonal decline and rise in CR, and hence conception occurrences, produces a similar pattern of MP. This pattern closely resembles that of actual MP in Israel in 1987 and in 1988. On the other hand, seasonal correction factors for MP have no marked effect on the shape of the MP curve. These results show that in order to stabilize MP throughout the year, the prevention of seasonal (summer) decline in CR would be more effective than direct efforts to prevent seasonal MP decline.

A molassed sugar beet product with 32% crude protein and containing added urea (8%), dicalcium phosphate, trace elements and vitamins was evaluated in two experiments as a protein source for intensively-fed 100 kg British Friesian steers. Comparison was made with an equal amount of crude protein supplied as a mixture of decorticated groundnut and cottonseed meals.

Both forms of supplementation equally and significantly increased live-weight gains and improved food conversion ratios compared with those recorded when the basal diet consisted of barley with no protein supplement.

The new concern in Britain which links diet to health is likely to have a major impact on the agricultural and food industries. Five years ago consumers were not interested in the health issue but now consumer groups are lobbying for change. Health has become the second most important factor considered by a housewife when shopping for her family, the first being whether the food is appetizing.

Both the DHSS and MAFF have accepted, the 1984 COMA panel's report on diet and cardiovascular disease which sets out a programme of preventive measures with recommendations to the general public, medical practitioners, health educators, food producers, manufacturers, distributors and caterers and to Government. Specific changes in the British diet are advocated for the first time with a suggested reduction in saturated fat intake of 25% and in total fat of 15%.