It is well known that the process of ensiling forage has a deleterious effect on intake. It is likely that the soluble constituents, produced during the fermentation, are responsible for a major part of this effect, although studies of infusion of constituents into the retlculo-rumen have shown that there Is no simple post-ingestive mechanism. Studies on feeding behaviour have shown that ruminants eat silage more slowly than unensiled forage and from this it has been concluded that ruminants may be aversive to the taste, smell or sight of silage. The question, however, of whether is this aversion to silage could explain reduced intake, when silage is the only food offered, remains. To provide a more definitive test of this question, soluble constituents were added to a high-quality low dry matter silage in combinations and levels typical of those reported in the literature. The effects of these additions on intake by sham-fed sheep was measured.

A model is developed in which the metabolizable energy (ME) requirement for growth and maintenance of the foetus, uterus and udder are described explicitly for sheep. The efficiency of the use of ME for the growth of the products of conception (kp) is assumed to be the same as that for growth in non-pregnant animals. Using the results from the model to calculate the efficiency of the use of ME for conceptus growth (kc) in the conventional manner yields values with a similar magnitude and similar variation with food quality as those estimated experimentally. It is concluded that separately accounting for the growth and maintenance of the foetus, uterus and udder is preferable in models but unnecessary in feeding standards.

1. Three experiments are reported in which chromic oxide, administered as a component of shredded paper at 09·00 and 16·30 hr daily, was used in the estimation of the faecal output of steers fed on silage and barley.

2. Four Friesian steers of 160 kg live weight were used in experiment 1. They were fed on grass silage ad libitum with controlled allowances of concentrate supplement. ‘Absolute’ recovery of Cr2O3 in total collections was 85–91%, though it was apparent that some faeces may have been lost from the total collections. ‘Relative’ recovery in grab samples was 97%.

3. Diurnal variation in Cr2O3 excretion was investigated in experiment 2 with four yearling Friesian steers. Faeces were sampled in three 24-hr periods at each natural defaecation. A significant and consistent diurnal variation was observed, with the lowest concentration of Cr2O3 occurring during the night. Concurrent grab samples taken at 09.15 and 17.00 hr over four days gave estimates of cr2O3 in the faeces which were 16·27% higher than the mean concentration for the three 24-hr sampling periods.

4. Day-to-day variation in the Cr2O3 content of grab samples was examined in experiment 3 with eight yearling Friesian steers. Four steers received 3·63 kg/head per day of barley supplement and four received 1·81 kg. Both groups were offered silage of 25% dry matter ad libitum. Faeces were sampled per rectum twice daily at 09.15 and 17.00 hr over four-day sampling periods. The degree of day-to-day variation was small and tended to be random.

In three experiments, 16, 24 and 22, May-calving Aberdeen Angus × British Friesian cows were subjected either to single suckling of their natural calves or to single suckling in addition to ‘foster’ suckling for the first 8 to 9 weeks of lactation. Foster suckling was achieved by the removal of cows from pasture twice daily and suckling of male Friesian calves while cows were confined in a creep. Average milk yield per cow removed by foster suckling and milk secretion rates of individual cows were measured at intervals and cows were grazed at equal grazing pressure. Single plus foster suckling increased estimated total yield over single suckling proportionately by 0·55, 0·18 and 0·34 in the three experiments respectively. After foster calves were weaned, milk secretion rate of foster-suckling cows was always higher than that of naturally suckling cows. In addition to a mean yield of about 300 kg milk per cow to foster calves, single plus foster suckling increased calf gain in the natural calves in each experiment although the increases were not significant. The apparent conversion of extra milk consumed by natural calves in the single plus foster suckling treatment was generally low in relation to figures quoted in the literature.

The heat production of fasted and fed littermate pairs of pigs weaned at 10, 17 and 24 days of age was determined between 16 to 34°C. Up to and including 34°C the post-weaning heat production of fasted pigs at 10 and 17 days of age decreased with rising temperature. Rectal temperatures of all 24-day-old fasted pigs were higher at 34°C than at 31°C. For fed pigs weaned at 10 days of age the heat production continued to decrease up to and including 34°C. The decrease between 28°C and 31°C and between 31°C and 34°C was comparatively small and rectal temperatures were slightly elevated at 34°C. The results indicated that for fed pigs weaned at 17 and 24 days the thermoneutral zone was in the region of 31°C and the lower critical temperatures were about 28°C.

This study investigated the benefits of hot-water spraying (HWS) as a diagnostic test to verify the absence of signs of life (SOL) before scalding in pigs slaughtered with carbon dioxide (CO2) stunning. A total of 37 108 finishing pigs from five German abattoirs (A to E) operating at 55 to 571 pigs per hour were assessed. Suspended pigs were sprayed onto the muzzle, head and front legs (143 to 258 s post sticking for 4 to 10 s, 57°C to 72°C). Any active movements during HWS were rated as positive test outcomes. In comparison, SOL were considered to be absent if a subsequent manual examination was negative and no active movements were observed following HWS. The incidence of pigs with activity during hot-water spraying (PWA) was restricted to two abattoirs (B: 0.25%; D: 0.02%; A, C, E: 0.00%). PWA showed movements of facial muscles (88%), mouth opening (78%), righting reflex (63%), isolated leg movements (35%) and vocalization (4%). The manual examination was positive in 71% of PWA (corneal/dazzle reflex: 67%/53%, nasal septum pinch: 33%), whereas all inactive pigs tested negative (P<0.001). The sensitivity for HWS as a test for SOL was calculated as 100%, dropping to 75% when only obvious and strong movements were taken into account. The specificity was >99.9% in either case. Any positive manual findings as well as any respiratory activity were instantly terminated using a penetrating captive bolt. Active movements triggered by the shot were shown to be an indicator for SOL (P<0.001). Video analyses revealed that spontaneous movements (SM) following sticking were present in 100% of PWA as opposed to 3.1% in pigs without such activity (controls). Results for different categories of SM in PWA v. controls were as follows: 100% v. 2.6% for mouth opening, 16.0% v. 0.1% for righting reflex and 22.0% v. 0.9% for isolated leg movements (all P<0.001). First mouth opening after sticking was observed later in PWA (28±24 v. 10±7 s), but mouth openings were observed for a longer period of time (141±44 v. 27±25 s) (both P<0.001). PWA with shorter mouth-opening intervals showed higher movement intensities during HWS and more positive manual findings (P<0.05). We conclude that HWS is a promising test for SOL. SM and sustained mouth opening in particular are indicators for compromised animal welfare and affected pigs should be shot by captive bolt.

Based upon the concept of ethological need, changes in time-budgeting from the baseline of that of feral conspecifics are considered to be detrimental to welfare. However, it is argued that domestication changes innate abilities and expectations, and that changes in behaviour may be appropriate adaptations to changes in environment. These opposing ideas present a difficulty in the use of time-budgets in the assessment of animal welfare.

This paper shows how experimentation can aid the interpretation of changes in behaviour seen in horses kept in a variety of environments, and so validate the use of time-budgets in the assessment of welfare.

Six 24 hour time budgets were compiled for 4 Thoroughbred geldings, aged 12-19, 15 - 16·5 hh, weighing 490 - 600 kg. They were kept in a variety of environments; (i) at pasture (approx. 7000 m2/head) (ii) in loose boxes (14 m2/head) fed hay ad libitum, (iii) in stalls (6 m2/head) fed hay ad libitum, (iv) in stalls fed hay to maintenance (v) in stalls fed pelleted hay to maintenance and (vi) in stalls fed alfalfa-maize cobs to maintenance, for one month at a time, in random order.

The effects of organic diets, with or without supplements of betaine, saponin, fructo-oligosaccharide and methionine, on the health, performance and gut flora of pullets were investigated. A comparison was also made between birds fed organic diets and those fed a non-organic diet. Day-old Lohmann Tradition pullets were reared in 24 groups of 64 chicks indoors until 11 weeks, and then in 48 groups of 24 to 27 chicks with access to range until 17 weeks of age. Groups of birds were fed one of eight diets, a conventional rearing diet with supplementary amino acids, an organic basal diet, organic basal plus methionine and organic basal supplemented with one of the test ingredients. At most stages of growth the birds fed the conventional diet and those fed the basal diet with methionine performed better than those that had no supplemental methionine. Other dietary treatments had no consistently significant effect on growth, the microbial populations within the gastro-intestinal tract of the birds or the number of parasite eggs excreted. After 5 weeks with access to range, the birds that were fed three out of five diets regarded as deficient in sulphur amino acids achieved similar weights (P > 0.05) to birds that received diets adequate in sulphur amino acids. Health and welfare of birds fed organic diets was not adversely affected; however, an investigation of birds housed in larger flocks and taken into the laying phase, when physical demands on birds are greatest, is required.

A 28-day experiment with 12 9-month-old cattle (275 kg initial weight, M1), used a 2 × 2 arrangement of treatments to compare the effect of doubling the ad-libitum quantity of long barley straw offered daily (25 or 50 g dry matter (DM) per kg M1) and sex/genotype (Limousin × Friesian steers or Friesian heifers) on intake and selection. All animals received a protein concentrate at 20 g DM per kg M10·75 per day. Prior to the experiment the cattle had grazed for 6 months and were given no pre-experimental change-over period. On day 1 animals were weighed (M1), allocated to treatment and penned individually. Animals were weighed on day 28 (M2). Doubling the amount offered did not affect straw intake (g DM per kg M3 per day; M3 = mean of M1 and M2) during days 22 to 28 (steers: 17·9, 17·2; heifers 14·3, 13·3; s.e. 0·50) but increased the proportion (g DM per kg DM offered) refused (steers: 258, 635; heifers: 412, 721; s.e. 22). During days 22 to 28, at each level of offer (25, 50), refused straw contained (g DM per kg DM) less leaf-plus-sheath than offered straw (25 g steers: 251, 430, s.e. 16·7; 50 g steers: 393, 450, s.e. 19·7; 25 g heifers: 304, 420, s.e. 7·2; 50 g heifers: 405, 446, s.e. 9·6). The sex/genotype effect on intake was attributed to differences in growth potential. Straw intakes increased significantly over the first 14 days, but there were no differences between days 15 to 21 and days 22 to 28. It is concluded that an excess-feeding strategy, involving a doubling of the ad libitum amount of barley straw offered did not result in growing cattle consuming more straw, in contrast to published results with sheep and goats. However, the cattle did show a limited ability to selectively consume leaf-plus-sheath in preference to stem but the improvement in diet digestible organic content (estimated in vitro) was presumably insufficient to stimulate intake.

New Zealand is primarily an agricultural country. Sixty per cent of all its production, including nearly 100% of its exports, comes from farms and is produced by only 17% of the total labour force. Within the agricultural industry sheep farming is dominant. Wool provides between one-third and one-half of the total exports and lamb and mutton about one-sixth. Over 90% of the wool and lamb produced and about 50% of the mutton is exported.

The prominent place that wool occupies in New Zealand’s farming strikes any visitor from Britain. The wool cheque naturally exceeds the income from other sources on the sheep stations of the Southern Alps where Merino sheep are grazed, but on lower hill farms selling cast-for-age or surplus two-tooth ewes to fat-lamb breeding farms and store lambs to hogget fatteners the wool cheque is still usually more than half the income.

Sixty-nine rams of three crossing-ram breeds were mated on 11 farms over 3 years to produce crossbred ewes for a large field trial. Scottish Blackface and Welsh Mountain ewes mated to Bluefaced Leicester rams had larger litters at weaning than those mated to Border Leicester and the Animal Breeding Research Organisation's Damline rams. The crossbred Bluefaced Leicester lambs were heavier than the other crossbred lambs at both birth and weaning.

Ten crossbred (Karan Swiss) cows were induced to calve about 1 month prior to expected term using either 25 mg dexamethasone alone (Group B) or 25 mg dexamethasone in combination with 25 mg vetoestrol (Group C). Another five animals served as controls (Group A). The average time interval from injection to calving was not significantly influenced by the two treatments used, and was 52·2 ± 4·07 h and 49·0 ± 1·55 h for groups B and C respectively. The mean gestation lengths for animals in groups A, B and C were 283·60 ± 2·77, 255·20 ± 1·93 and 255·20 ± 2·3 days respectively. The calves born from cows induced to calve early were significantly lighter at birth compared to controls (P < 0·05). The average live-weight gain over the first 12 weeks among calves was not significantly influenced by treatment averaging 2·58 ± 0·07, 2·81 ± 0·16 and 2·20 ± 0·16 kg/week for groups A, B and C respectively. Foetal membranes had not been voided by 24 h in the animals induced to calve early and hence required manual intervention. The length of the service period, number of services per conception and the milk yield of the cows induced to calve was not significantly different from their previous records (P > 0·05).

Increasing the provision of non-fibrous carbohydrates (NFC) during the prepartum period is a feeding strategy that has been recommended to facilitate the transition to the onset of lactation and improve dairy cow performance, but results are contradictory, probably because most studies have confounded the effects of level and source of energy. The objective of this experiment was to evaluate the effect of the source of carbohydrate offered in the prepartum diet on postpartum cow performance. Holstein dairy cows (n=24) were assigned to receive diets with either low (LNFC), or high (HNFC) levels of NFC during the last 3 weeks before expected calving date according to a randomized complete block design. Soybean hulls and corn grain were the main energy ingredients in the LNFC and HNFC total mixed rations (TMR), respectively, and diets were designed to be isocaloric and isoproteic. After calving, all cows were managed as a single group until day 56 postpartum and grazed on improved pastures and were supplemented with a TMR. Body condition score evaluation and blood sampling were performed weekly throughout the experimental period to monitor the metabolic status of the animals. Prepartum glucose concentrations tended to be greater in HNFC than LNFC, but there was no effect on prepartum or postpartum insulin concentrations. Although nutrient intake was greater in the immediate week after calving in HNFC than LNFC, treatment did not affect milk yield and composition. In conclusion, increasing the NFC intake during the prepartum period, at a similar level of energy and protein intake, had a marginal residual effect on postpartum intake, and did not affect metabolic status or milk production.

This study determined the correlated responses in reproductive performance after five generations of divergent selection for components of efficient lean growth rate in Large White pigs.

Data were collected from five generations of pigs divergently selected for daily food intake (DFI), lean food conversion (LFC), lean growth rate on ad-libitum feeding (LGA) and lean growth rate on restricted or scale feeding (LGS). In each selection group, there were high, low and control lines, each consisting of 10 boars and 20 gilts. Animals were mated at around 9.5 months of age. Pregnant gilts were fed 2.5 kg daily and farrowed sows up to 3.5 kg twice daily of a 160 g/kg DM crude protein and 132 MJ/kg DM digestible energy ration. Animals were farrowed at 414 (s.d. 19.7) days of age, on average. No cross fostering was practised. Piglets were offered creep feed containing 235 g/kg DM crude protein and 160 MJ/kg DM digestible energy from 14 days and were weaned at an average of 35 (s.d. 3) days. Litter traits were measured on 1220 selected Large White gilts, with 13030 piglet birth weights and 9951 weaning weights.

The use of additives such as ractopamine (Rac) in pregnant sows during early-mid pregnancy is an alternative to increase foetal and progeny growth and development. However, Rac supplementation in finishing pigs can lead to behavioural and physiological changes similar to the typical stress responses. The objective of this study was to evaluate the effects of dietary supplementation with Rac in pregnant sows from day 25 to 50 of gestation (pre-hyperplastic stage) on piglet’s vitality, blood parameters, number, diameter and perimeter of muscle fibres in semitendinosus muscle and developmental characteristics of piglets at birth to weaning. Forty-one hybrid sows were divided into three dietary treatments: (1) control diet without Rac (control), (2) addition of 10 mg/kg of Rac (Rac10) and (3) addition of 20 mg/kg of Rac (Rac20). Higher numbers of low-vitality piglets (P<0.05) were observed in Rac-fed sows, regardless of dose, compared with the control group. Very low-density lipoprotein levels were lower in the Rac10 group when compared with the Rac20 group at day 21. Haematocrit was greater, and the mean corpuscular haemoglobin concentration was lower in piglets from Rac-fed sows. No significant statistical differences were detected regarding piglets body weight, average daily gain, blood gasometry, complete blood count and muscle fibre measurements in semitendinosus muscle. The use of Rac in pregnant sows reduced the vitality parameters of piglets but did not improve the performance from birth until weaning and did not negatively influence the haematological parameter and lipid metabolism.

Exercise and physical training are known to affect gastrointestinal function and digestibility in horses and can lead to inaccurate estimates of nutrient and energy digestibility when markers are used. The effect of exercise on apparent nutrient digestibility and faecal recoveries of ADL and TiO2 was studied in six Welsh pony geldings subjected to either a low- (LI) or high-intensity (HI) exercise regime according to a cross-over design. Ponies performing LI exercise were walked once per day for 45 min in a horse walker (5 km/h) for 47 consecutive days. Ponies submitted to HI exercise were gradually trained for the same 47 days according a standardized protocol. Throughout the experiment, the ponies received a fixed level of feed and the daily rations consisted of 4.7 kg DM of grass hay and 0.95 kg DM of concentrate. The diet was supplemented with minerals, vitamins and TiO2 (3.0 g Ti/day). Total tract digestibility of DM, organic matter (OM), CP, crude fat, NDF, ADF, starch, sugar and energy was determined with the total faeces collection (TFC) method. In addition, DM and OM digestibility was estimated using internal ADL and the externally supplemented Ti as markers. Urine was collected on the final 2 days of each experimental period. Exercise did not affect apparent digestibility of CP, crude fat, starch and sugar. Digestibility of DM (DMD), OM (OMD), ADF and NDF tended to be lower and DE was decreased when ponies received the HI exercise regime. For all treatments combined, mean faecal recoveries of ADL and Ti were 87.8±1.7% and 99.3±1.7%, respectively. Ti was not detected in the urine, indicating that intestinal integrity was maintained with exercise. Dry matter digestibility estimated with the TFC, ADL and Ti for ponies subjected to LI exercise were 66.3%, 60.3% and 64.8%, respectively, while DMD for HI ponies were 64.2%, 60.3% and 65.2%, respectively. In conclusion, physical exercise has an influence on the GE digestibility of the feed in ponies provided with equivalent levels of feed intake. In addition, the two markers used for estimating apparent DMD and OMD indicate that externally supplemented Ti is a suitable marker to determine digestibility of nutrients in horses performing exercise unlike dietary ADL.

Measurements of the live weight and body condition of 105 Scottish Blackface, North Country Cheviot and South Country Cheviot male sheep (rams) per year were made at three locations over a period of 2 years.

A distinct cyclical pattern of change in live weight and body condition throughout the year was apparent in all rams. Maximum values recorded in the autumn were followed by rapid and substantial losses throughout the mating period, with recovery of both weight and condition during the spring and summer months. The amplitude of the annual live-weight curve was of the order of 20 kg (22%) and that of body condition was more than 1 unit.

The patterns of annual change in live weight and of inferred change in body composition of rams are compared with those of ewes, and some of the probable effects on production are considered.

Plasma cortisol concentrations were determined from the blood of eight mature female reindeer (Rangifer tarandus tarandus) after an intravenous injection of either saline (control) or 100, 250 or 500 μg of synthetic ACTH. Blood samples were collected at 0, 2, 4, 6, 8, 10, 15, 20, 25, 30, 45, 60, 75, 90, 120, 150, and 180 min after the injections. The aims were to determine the appropriate dose of ACTH for adrenal stimulation tests, to define the dose level of ACTH which elicited a maximal cortisol response and to describe the range of blood cortisol concentrations for reference when evaluating the stress responses of reindeer.

The mean plasma cortisol concentrations (s.e.) at the zero sample times (t0) of the control and the ACTH treatments varied between 93·4 (11·8) and 132·5 (18·1) nmol/l. The total plasma cortisol response (area under curve, AUC, nmol/l × min) increased with increasing dose of ACTH (P < 0·001). The AUC of the control treatment was significantly smaller than of the ACTH treatments (P < 0·001). The highest dose of ACTH (500 μg) gave a significantly bigger AUC than the lowest dose (100 μg) (P = 0·008). The maximal plasma cortisol concentrations (CMAX) were achieved within 60 min of the ACTH injections. The ranges of individual CMAX were 59·0 to 136·8 nmol/l for the control treatment, and 110·0 to 252·0, 152·0 to 247·5 and 135·1 to 257·1 nmol/l for 100, 250 and 500 μg ACTH, respectively. The difference in CMAX was significant between the control treatment and the ACTH treatments (P < 0·001) but not between the different doses of ACTH. The plasma cortisol concentrations at the end of the observation period at t180 were not significantly affected by the ACTH treatment (P > 0·05).

In conclusion, the 100-μg dose of ACTH was sufficient to produce a significant cortisol response compared with the control treatment. Increasing the dose did not increase the maximal response, but tended to elongate the response profile. The blood sampling frequency used in the study was found suitable for detection of the cortisol response in reindeer.

The recent war has occasioned even greater changes in agricultural production than followed World War I. Lack of man power and draught power reduced the area of cultivation : lack of fertiliser and manure reduced the yields per acre: lack of feeding stuffs reduced livestock numbers and the output of meat, milk and eggs. This was precipitated at a time in history when it was already becoming evident that, despite improvement in agricultural technique, the output of food per acre over the world was rising comparatively little.

The pre-war agricultural problem, never clearly seen until recent years, of expanding production to meet the requirements of an increasing population, has become gravely accentuated by the additional problem of agricultural recovery following the second world war.

Comparative slaughter was used to assess the body composition of Shorthorn-Hereford (SH), Africander cross (A×), Brahman cross (B×), and late castrated Brahman cross (B×(late)) steers of the F, generation with respect to their yield of carcass, gross carcass composition and offal composition. Animals were slaughtered at pre-determined weights of 315, 355, 399, 449 and 505 kg.

The B× animals had the highest carcass yield (expressed either as dressed carcass weight at the same fasted body weight or at the same empty body weight), while the A×, B×(late) and SH animals had similar carcass yield. Within a breed, rate of growth affected carcass yield, with faster growing animals having the lower carcass yield, particularly with respect to fasted body weight.

The breeds were different in carcass composition but this was dependent on both size and growth rate. Brahman cross animals had a lower proportion of bone than A× and SH animals, particularly at the higher body weights. Faster growing animals tended to contain more muscle and bone and less fat, with the exception of the SH animals.

The breeds were also significantly different in the composition of the offal components. A× were notable for high head weights and low tail weights, B× having high blood weights and low total gut tissue weights, and Bx(late) having high hide weights and low abdominal fat weights.

Rate of growth had some effect on offal composition, the general trend being that the faster growing animals were characterized by a lower proportion of heart, blood and pancreas. However there was also evidence that the rate of growth differentially affected the offal composition with respect to breeds. This effect mainly arose because the faster growing B×(late) animals had lower weights of abdominal fat. Within the other breeds, the opposite trend was observed.