The nutritional value of dried poultry excreta was investigated by determining the apparent digestibility of dry matter, organic matter, nitrogen, energy and copper in five diets containing 0 to 100% of this feed. Dried poultry excreta supplied 20·21% apparently digestible crude protein and approximately 1·57 or 1·74 Mcal of metabolizable energy per kg dry matter.

The copper in dried poultry excreta was found to be less digestible than the copper in barley. It is concluded that, as far as copper levels are concerned, dried poultry excreta are safe for ruminants, and are a source ofcheap protein. More detailed work is needed to determine the metabolizable energy of the material accurately.

Two experiments were carried out to examine the effects on the intake and performance of calves of supplementing a diet, based on high-digestibility, well-preserved grass silage, with fish meal. The effects of fish-meal supplementation were examined at each of two amounts of concentrate intake (1·05 and 2·2 kg/day) in a 2 × 2 factorial design. Fish meal was offered at a rate of 75 g/kg silage dry-matter (DM) intake. Experiments 1 and 2 involved 36 and 40 castrated male calves, respectively, which were initially 7 weeks old and had a live weight of 70 kg. The treatments were imposed for 20 weeks. The silages used in the two experiments had mean concentrations of 22-8 g nitrogen (N) per kg DM; 524 g protein N per kg total N; 59 g ammonia N per kg total N; 0·4 g butyric acid per kg DM; and 712 g digestible organic matter per kg DM. The concentrate consisted of (g/kg) 800 ground barley, 125 soya bean meal, 50 molasses and 25 mineral and vitamin supplement, respectively, and contained 29 g N per kg DM. Silage DM intakes and live-weight gains for the low and high amounts of concentrate supplementation were 1·93 and 1·46 (s.e. 0·055) kg/day and 0·84 and 1·01 (s.e. 0·013) kg/day respectively. The supplement of fish meal did not affect silage DM intake or animal performance for either concentrate intake. Proportionately, only 0·21 of the difference in live weight at the end of the treatment periods between the two amounts of concentrate intake remained at slaughter at 18 months of age. It is concluded that the optimum growth rate for autumn-born calves during their first winter can be sustained by a diet of high-digestibility grass silage supplemented with a maximum of 1·0 kg cereal-soya bean meal concentrate and that no response in performance was obtained to supplementation of this diet with fish meal.

A concentrate containing ground barley, soya-bean meal and fish meal was compared with one containing dried molassed sugar-beet pellets, dried distillers' grains and fish meal, in its influence on lameness in housed dairy cattle. Two groups of 24 cows were offered the diets in a 60:40 concentrate dry matter: grass silage dry matter ratio during weeks 3 to 26 of lactation. The same daily amounts of metabolizable energy and crude protein were offered to the two groups. The barley-based concentrate diet significantly increased locomotion score (indicating poorer locomotion), and the number and duration of clinical cases of lameness, compared with the sugar-beet concentrate diet. Hoof growth, wear, shape and hardness were not significantly affected by the diets. There were 16/24 cows with a locomotion score of 3 or over (1 to 5 scale) for an average of 7·3 weeks on the barley concentrate compared with 10/24 cows for 3·7 weeks on the sugar-beet concentrate. There was no significant difference between treatments in milk production or live-weight gain.

Reproductive records from 1072 Large White sows (3589 litters) were used to examine the effect ofbackfat depth (Bd) and live weight (Lw) at selection on first litter and lifetime reproductive performance. The variables investigated included mating age, total piglets born, total born alive, piglet birth weight, number weaned, piglet weaning weight, weaning to remating period and number of litters produced. Using backfat depth, sows were categorized into three groups: L, 9 to 13 mm; M, 14 to 16 mm; and F, ≥17 mm. Bd had no significant effect (P > 0·05) on the measured traits for the sows grouped by fat at first parity. When lifetime reproductive data were analysed, the L group had fewer litters (P < 0·05), and weaned fewer pigs (P < 0·01) than either the M or F group. The birth weight for piglets from L sows were significantly higher (P < 0·05) than for piglets from the other groups. The data suggest that the reproductive performance of L sows is not as good as that of M or F sows.

Sheep ate significantly faster during the first 30 min after being offered fresh food when they were fed on ground, pelleted dried grass than when fed on long hay; chopped dried grass was eaten at an intermediate speed. Rate of eating of the unground diets was negatively related to mean retention time and positively related to total voluntary intake.

In a second experiment, rate of eating during the 30 min after feeding was significantly faster when hay was fed at two-thirds of the ad libitum rate than when it was fed ad libitum, irrespective of whether penning was individual or in groups of six.

In the context of assessing the impact of management and environmental factors on animal health, behaviour or performance it has become increasingly important to conduct (epidemiological) studies in the field. Hence, the number of investigated farms per study is considerably high so that numerous observers are needed for investigation. In order to maintain the quality and validity of study results calibration meetings where observers are trained and the current level of agreement is assessed have to be conducted to minimise the observer effect. When study animals were rated independently by the same observers by a categorical variable the exclusion test can be performed to identify disagreeing observers. This statistical test compares for each variable and each observer the observer-specific agreement with the overall agreement among all observers based on kappa coefficients. It accounts for two major challenges, namely the absence of a gold-standard observer and different data type comprising ordinal, nominal and binary data. The presented methods are applied on a reliability study to assess the agreement among eight observers rating welfare parameters of laying hens. The degree to which the observers agreed depended on the investigated item (global weighted kappa coefficients: 0.37 to 0.94). The proposed method and graphical description served to assess the direction and degree to which an observer deviates from the others. It is suggested to further improve studies with numerous observers by conducting calibration meetings and accounting for observer bias.

Lifetime maternal performance records of 113 Angus cows born over a 12-year period were used to estimate the relationship between cow size characters, mature size (A) and maturation rate (K), and lifetime maternal performance characters, years in the herd (YH), number of calves (NC), total calf weight (TW), average calf weight at weaning (AW) and calf weight per year in herd (kg/year). Pertinent reproductive management of the herd was: heifers were mated to calve as 2-year-olds; any heifer failing to calve or any cow failing to wean a calf a second time was culled; all matings were to purebred Angus sires. Mean cow mature size was 487 ± 5 kg with a maturation rate of 0·058 ± 0·001. Means for maternal characters were: YH, 7·4 ± 0·4; NC, 6·4 ± 0·3; TW, 1283 ± 71; AW, 200 + 1·8; and kg/year, 173 ±5·1. The correlations between maternal characters and A and K, respectively, were: YH, −0·21, 0·15; NC, −0·21, 0·15; TW, −0·16, 0·12; AW, 0·20, −0·15; and kg/year, 0·05, −004. The regression of maternal characters on mature size was quadratic in every instance with optimal cow size for each character being: YH, 468; NC, 465; TW, 471; AW, 493; and kg/year, 475. The optimal cow size for average weight of calf weaned was 18 to 25 kg heavier than the optimal size for those characters associated with fertility. Relationships between maturation rate and maternal performance were not statistically significant.

In the Proceedings of this Society two years ago, A. T. G. Macarthur (1954) presented a method for the evaluation of dairy sires under farm conditions. Since that time, considerable use has been made of this technique in the Bureau of Records of the Milk Marketing Board and in this paper we propose to discuss the method critically, in the light of the results obtained on over 1,500 bulls.

As the experience we have gained has considerable bearing on the validity of this method, it would perhaps be valuable at the beginning to view the general problem of testing dairy bulls under British conditions. What evidence have we that the use of contemporary comparisons is the best tool that we have available for the assessment of dairy bulls? We must bear in mind here that we have two distinct problems. The first is the assessment of bulls used in A.I. whose daughters have been bred and milked in many herds. The second is the assessment of bulls used in natural service.

Carotenoids are important for human health because of their provitamin A function among other biological actions. Their implication on consumer point of view of cattle products have been widely studied, but very little information is available for horse products. The aim of this study was to study the accumulation of carotenoids, retinoids and tocopherol by HPLC and HPLC-MS analysis in different horse tissues (plasma, milk, adipose tissue and liver) and compare it with that of cattle. Fat color was also studied. Four groups of animals were studied (15 animals within each group): lactating mares (709.82±23.09 kg) and cows (576.93±31.94 kg) reared outdoors; and foals (556.8±25.9 kg, 14 months old) and calves (474.7±36.2 kg, 14 months old) reared indoors. Both mares and foals were from the Hispano–Breton breed, whereas both cows and calves belonged to the commercial crossbred Limousine–Retinta. Differences in plasma and milk carotenoids (P<0.05, P<0.001) were found between mares and cows. Similar levels of vitamin A accumulation in the plasma and fat were detected in foals and calves (P>0.05). Both species showed different levels of accumulation of retinoids in the liver, with the foal having better accumulation (P<0.01, P<0.001). These results indicate that there are species-specific differences in the accumulation of carotenoids, retinol and tocopherol, but further studies are required to establish the mechanism of these differences.

Sheep were given diets containing 0, 30, 50 or 90 g/kg added free fatty acids from palm oil or from calcium soaps prepared from the same fatty acids in a three period switch-over design. Addition of free fatty acids to the diet enhanced metabolizable energy (ME) intake when added at 30 and 50 g/kg but not at 90 g/kg. On feeding 90 g/kg free fatty acids, rumen volatile fatty acid levels decreased and acid-detergent fibre and protein digestion was reduced. Calcium soaps of fatty acids enhanced ME intake at all levels added and had no effect on rumen fermentation. Addition of both free fatty acids and calcium soaps of fatty acids enhanced apparent digestibility of total fatty acids and of all fatty acids except stearic acid. The ME of free fatty acids added at 30 g/kg was 35·56 MJ/g and of calcium soaps of palm oil was approximately 33·05 MJ/g.

Shortening the dry period (DP) has been proposed as a strategy to improve energy balance (EB) in cows in early lactation. This study evaluated the effects of shortening the DP on milk yield (MY), EB and residual feed intake (RFI) in two breeds; Swedish Red (SR) and Swedish Holstein (SH). Cows were blocked by breed and parity and then randomly assigned to one of two treatments; short DP of 4 weeks (4W, n=43) or conventional DP of 8 weeks (8W, n=34). Cows were kept and fed under the same conditions, except for the 4 weeks when the 4W group were still lactating prepartum and thus kept with the lactating cows. Milk yield and BW were recorded and body condition score (BCS) was rated from 10 weeks prepartum to 12 weeks postpartum. Dry matter intake (DMI) was recorded for lactating cows postpartum. Milk yield was reduced by 6.75 kg/day during the first 12 weeks postpartum (P<0.001) for the 4W cows compared with 8W cows, but there was no significant difference in total MY (3724 kg compared with 3684 kg, P=0.7) when the milk produced prepartum was included. Protein content was higher in 4W cows (3.42%) than in 8W cows (3.27%) (P<0.001) postpartum. In the 8W group, cows lost more BCS after calving (P<0.05). Cows of SR breed had higher BCS than cows of SH breed (SR=3.7, SH=3.2, P<0.001), but no differences in BW were found between breed and treatment. Energy balance was improved for cows in the 4W group (P<0.001), while feed efficiency, expressed as RFI, was reduced for 4W cows than for 8W cows (5.91 compared with −5.39, P<0.01). Shortening the DP resulted in improved EB postpartum with no difference between the breeds and no milk losses when including the milk produced prepartum.

Two experiments were carried out to investigate the effect of restricted suckling and milking regimes on milk yield, milk composition and calf growth. Experiment 1 was carried out in temperate conditions in the United Kingdom and experiment 2 under tropical conditions in Mexico. In experiment 1 a Latin rectangle (change-over) design with 3-week periods was used with eight Holstein Friesian cows suckling their Simmental-sired calves. Saleable milk yield (SMY), sucked milk (CSM), milk composition and calf performance were studied. The treatments were: once a day milking (a.m.) with suckling immediately after (1χAM); once a day milking (a.m.) with suckling p.m. (1χPM); twice daily milking with suckling after a.m. milking (2χAM); twice daily milking with suckling after each milking (2χ2χ). The cows were offered maize silage ad libitum and 4·3 kg dry matter (DM) per day of rapeseed meal plus minerals and vitamins. The calves had ad libitum access to concentrates (165 g crude protein (CP) per kg DM) and wheat straw. In experiment 2, 11 B. indicus χ B. taurus cows, suckling their Brahman-sired calves were used in an experiment with the same treatments and experimental design. Cows were offered star grass (Cynodon nlemfuensis) hay ad libitum and 4.0 kg DM per day of concentrate (117 g CP per kg DM). The calves had ad libitum access to concentrate (151 g CP/kg DM), star grass hay and Ramon leaves. For 1χAM, 1χPM, 2χAM and 2χ2χ respectively in experiment 1, the total milk yields (TMY = SMY + CSM) were 17.9, 18.0, 16.7 and 19.5 kg/day (s.e.d. 1.11) and SMY represented 0.70, 0.45, 0.77 and 0.53 of TMY. Corresponding results for experiment 2 were 6.0, 6.2, 7.0 and 7.1 kg/day (s.e.d. 0.32) and 0.69, 0.45, 0.78 and 0.61. Effects of treatment on milk yield and composition were consistent with the feedback inhibitor of lactation theory. It was concluded that different milking and restricted suckling patterns can be used to manipulate saleable milk production and calf growth. Holstein Friesian dairy cattle in a restricted suckling system without the calf presence at milking, behaved similarly to zebu-crossbred cows by reducing milk let down at milking.

Melatonin was fed daily at 14.00 h to eight non-lactating and six lactating hinds. Feeding was begun on 27 July 1983 (day 1) and continued until 21 September (day 57). Six non-lactating hinds were used as controls. Blood samples were taken about every 10 days from day 42 until day 73. Plasma progesterone and prolactin were determined by radioimmunoassay. Progesterone values of greater than 0·63 μg/1 were taken to indicate the presence of a corpus luteum and that the animal had ovulated. In the melatonintreated, non-lactating group seven of the eight hinds showed ovarian activity compared with two of the six controls (P < 0·01). None of the lactating hinds treated with melatonin showed evidence of ovarian activity. In both the lactating and non-lactating hinds treated with melatonin, prolactin levels were never greater than the detection limit of the assay (7·4 μg/l), while, in the control hinds mean prolactin levels were elevated on all but the last sampling day. It is, therefore, possible to induce early ovarian activity in non-lactating red deer hinds by feeding melatonin. However, although melatonin treatment similarly depressed plasma prolactin levels in both lactating and non-lactating hinds, it was unable to overcome the inhibitory effect of lactation on reproduction.

Slow-release urea (SRU) can substitute dietary protein sources in the diet of feedlotting ruminant species . However, different SRU structures show varying results of productive performance. This study was conducted to investigate the effect of different sources of nitrogen on performance, blood parameter, ruminal fermentation and relative population of rumen microorganisms in male Mehraban lambs. Thirty-five male lambs with an average initial BW of 34.7 ± 1.8 kg were assigned randomly to five treatments. Diets consisted of concentrate mixture and mineral and vitamin supplements plus (1) alfalfa and soybean meal, (2) wheat straw and soybean meal, (3) wheat straw and urea, (4) wheat straw and Optigen® (a commercial SRU supplement) and (5) wheat straw and SRU produced in the laboratory. No statistical difference was observed in animal performance and DM intake among treatments. The mean value of ruminal pH and ammonia was higher (P < 0.05) for the SRU diet compared with WU diet. The difference in pH is likely to be due to the higher ammonia level as VFAs concentrations were unchanged. The level of blood urea nitrogen (BUN) was different among treatments (P = 0.065). The highest concentration of BUN was recorded in Optigen diet (183.1 mg/l), whereas the lowest value was recorded in wheat straw-soybean meal diet (147 mg/l). The amount of albumin and total protein was not affected by the treatments. The relative population of total protozoa, Fibrobacter succinogenes, Ruminococcus flavefaciens and Ruminococcus albus in the SRU treatment was higher (P < 0.01) than that in urea treatment at 3 h post-feeding. During the period of lack of high-quality forage and in order to reduce dietary costs, low-quality forage with urea sources can be used in the diet. Results of microbial populations revealed that SRU can be used as a nitrogen source which can sustainably provide nitrogen for rumen microorganism without negative effects on the performance of feedlotting lambs.

A model has been developed to predict the true metabolizable energy (ME,) concentration in forages given to ruminants.

The chemical description of forages is based on the concentrations of ash, crude protein, ether extract, sugars and α-glycans, β-glycans and lignin, volatile fatty acids and lactic acid. The model assumes complete fermentation of sugars, α-glycans and lactic acid. The extent of fermentation of β-glycans and crude protein is determined in part by rumen solid-phase outflow rate, which can itself be predicted from dry-matter intake.

The model was tested using 121 graminaceous forages whose chemical composition and concentration of metabolizable energy had been measured in the Feedingstuffs Evaluation Unit at the Rowett Research Institute. The agreement between observed and predicted ME, for all classes of forage was nearly always as good as, or better than, the best prediction from single attributes of food chemistry which could only be determined retrospectively and were not consistent even within classes of forage. The model predicts a decline in ME, with increasing rumen solid-phase outflow rate which is determined mainly by the extent of fermentation of β-glycans.

By a combination of complete and incomplete dissections a considerable increase of precision or reduction of expense may be obtained in the construction of a prediction formula for the proportion of lean meat of a carcass from objective carcass measurements. This approach, referred to as double-regression, is demonstrated on data involving dissection of pig carcasses in The Netherlands. Advantages of double-regression relative to ordinary regression with respect to precision and experimental cost are discussed. Expressions for optimal sample sizes at fixed total cost are derived.

The objectives of this study were to see if the body condition score curve during lactation could be described using a model amenable to biological interpretation, a non-linear function assuming exponential rates of change in body condition with time, and to quantify the effect of breed and parity on curves of body condition during lactation. Three breeds were represented: Danish Holstein (n = 112), Danish Red (n = 97) and Jerseys (n = 8). Cows entered the experiment at the start of first lactation and were studied during consecutive lactations (average number of lactations 2, minimum 1, maximum 3). They remained on the same dietary treatment throughout. Body condition was scored to the nearest half unit on the Danish scale (see Kristensen (1986); derived from the Lowman et al. (1976) system) from 1 to 5 on days: 2, 14, 28, 42, 56, 84, 112, 168, 224 after calving. Additionally, condition score was recorded on the day of drying off the cow, 35, 21, and 7 days before expected calving and finally on the day of calving. All condition scores were made by the trained personal on the research farm, where the same person made 92% of the scores. The temporal patterns in condition score were modelled as consisting of two underlying processes, one related to days from calving, referred to as lactation only, the other to days from (subsequent) conception, referred to as pregnancy. Both processes were assumed to be exponential functions of time. Each process was modelled separately using exponential functions, i.e. one model for lactation only and one for pregnancy, and then a combined model for both lactation only and pregnancy was fitted. The data set contained 467 lactation periods and 378 pregnancy periods. The temporal patterns in condition score of cows kept under stable and sufficient nutritional conditions were successfully described using a two component non-linear function. First lactation cows had shallower curves, they had greater condition scores at the nadir of the curve. Danish Holstein and Jersey were thinner at the end of the mobilisation period having lost more body condition than the Danish Red breed. Although the dairy breeds ended up being thinner there were no significant differences in the rate at which they lost body condition.

1. Eighteen litters of piglets were weaned at 14 days of age and reared for a further 3 weeks at environmental temperatures of 18, 23 or 28°C. At each environmental temperature three levels of feeding were used. The changes in body composition of the piglets were studied by the comparative slaughter procedure, littermates being analysed at birth, and at 14, 22 and 36 days of age. For comparison, the bodies of suckled piglets of similar weights and ages were also analysed.

2. In the 2 to 3 day period following weaning, body weight decreased, with the greatest reduction being 0·28 (s.e. 002) kg at 18°C. Following this, body weight gain was dependent on both environmental temperature and level of feeding, although at any given level of food intake there was little difference between the values at 23 or 28°C.

3. There were marked changes in the chemical composition of the carcass in relation to the different temperature/feeding level combinations. The most variable component was fat. In the period following weaning there was considerable mobilization of fat, especially at the lower temperatures and feeding levels. The fat content of the early weaned piglets at 36 days of age (68 to 103 g/kg) was significantly less than that of the suckled piglets (169 g/kg) (P < 0·01). The decreases in fat content were accompanied by increases in the dry-matter content of the carcass.

4. The protein content of the carcass remained relatively independent of the different treatments, ranging from 140 to 164 g/kg for the early-weaned piglets, compared with 139 g/kg for those that had suckled their mothers.

5. The differences in the growth and body composition of the early-weaned piglet are discussed in relation to an inadequate food intake following weaning, to changes in nutrient supply and to variations in the climatic environment.

A randomized block design experiment involving 64 lactating dairy cattle was carried out to evaluate a bacterial inoculant and two rates of formic acid as silage additives. Herbage from the primary growth of a predominantly perennial ryegrass sward was ensiled unwilted using two precision-chop harvesters. Alternate loads of herbage were either untreated (UT) or treated with formic acid applied at the rate of 2·7 l/t grass (LF) and 5·7 l/t grass (HF) or an inoculant enzyme preparation applied at the rate of 2·2 l/t grass (I). The mean dry matter (DM) and water-soluble carbohydrate (WSC) concentrations and buffering capacity of the UT herbage were 148 g/kg, 151 g/kg DM and 638 mEq/kg DM. Inoculant treatment had no effect on the rate of silage fermentation post ensiling relative to the UT silage whereas HF treatment produced a restricted fermented silage. For silages UT, LF, I and HF, pH values were 4·53, 3·89, 4·32 and 4·05 (s.e.d. = 0·061); ammonia nitrogen (N) concentrations were 179, 89, 150 and 73 g/kg total N (s.e.d. = 10·4); butyrate concentrations were 6·0,1·9, 5·1 and 2·0 g/kg DM (s.e.d. = 1·24); and WSC concentrations were 14·4, 35·2, 18·0 and 100·7 g/kg DM (s.e.d. = 1·24), respectively. The silages were offered ad libitum. The UT silage was supplemented with either 2 (UT2), 4 (UT4) or 6 (UT6) kg concentrates per head daily while the LF, I and HF silages were supplemented with 4 kg (LF4,14, HF4) of concentrates. For treatments UT4, LF4, 14 and HF4, silage DM intakes were 9·69, 10·89, 9·93 and 10·89 (average s.e.d. = 0·465) kg/day; fat plus protein yields 1·39,1·44,1·32 and 1·49 (average s.e.d. = 0·057) kg/day; protein concentrations 29·2, 31·1, 29·9 and 30·2 (average s.e.d. = 1·01) g/kg. Inoculant treatment increased N apparent digestibility (P < 0·05) of the total diets relative to UT. The apparent digestibilities of neutral-detergent fibre (P < 0·05) and hemicellulose (P < 0·01) were decreased due to HF treatment. For the production of a constant milk fat plus protein yield it was estimated that an extra 0·63 kg per head per day and 1·04 and 1·77 kg per head per day less concentrate would be required for the I, LF and HF treatments, respectively. It is concluded that relative to the UT treatment, I treatment had no beneficial effects on silage fermentation, total diet apparent digestibility (other than N apparent digestibility) or animal performance. The LF treatment improve lage fermentation and intake, and tended to increase the yield of fat plus protein (P > 0·05) whereas HF treatment restricted silage preservation and increased silage intake and the yields of protein and fat plus protein.

The velocity of sound through the limbs of living animals and through tissue excised from carcasses has been measured. The measurements are compared with calibration velocities recommended by the manufacturers of two sonar instruments used to measure the position of tissue boundaries in animals.