In order to understand the complex changes associated with lactation in the dairy cow it is necessary to assess the contribution of the non-carcass components. It has been shown with sheep (Cowan, Robinson, Greenhalgh and McHattie, 1979) that a number of tissues may be mobilised during lactation with a redistribution of tissues particularly towards the gut and udder, and that diet may have a significant effect. Butler-Hogg, Wood and Bines (1985), using Friesian dairy cows showed changes in the weights of guts, internal fat depots (omental, mesenteric and perinephric) and liver with stage of lactation although the number of stages examined was somewhat limited. The present experiment investigates changes in non-carcass component weights at 9 points over the first 29 weeks of lactation and with 3 levels of concentrate supplementation.

Some reports have suggested differential tissue deposition of dietary trace minerals such as Zinc (Zn) when supplied to farm animals either chelated to amino acids or as inorganic salts. To test this hypothesis, an experiment was conducted to determine the ultimate tissue distribution of Zinc in rats fed either a radioactively-labeled 65Zn-chelate or 65ZnSO4. The 65Zn-chelate was prepared by heating a solution of 65ZnSO4 and an equimolar mixture of glycine and methionine for 5 minutes at 90°C. The resulting chelate was then separated from unincorporated 65ZnSO4 by gel filtration chromatography. Ten 25-d old male wistar rats (mean weight 34.5 g) were randomized by weight into two groups (n = 5/group), fasted for 18 hours and given 0.4 ml (8 μg Zn, 1 μCi65Zn) of one or other labelled solution by gavage. Four hours later, animals were returned to their normal diet for the duration of the experiment. The 65Zn activity of the animals was determined two hours after administration and daily thereafter for 7 days.

Conditions exist in Ghana which could implicate vitamin A deficiency as a factor in causing the poor growth and breeding difficulties observed in local cattle. Lansbury (1960) reviewed some of the limiting factors in the nutrition of cattle on the Accra plains, and stated ‘the bleached dried up appearance of the Accra plains over much of the year is due to the fact that most of the grassland is little more than standing hay from which most, if not all, of the vitamin A or its precursors are likely to have been lost’. Northern Ghana, with its longer dry season, presents such an appearance for a more extended period.

Sires from British breeds are less likely to cause calving difficulties than sires from Continental breeds. Consequently, heifers have usually been mated to Aberdeen-Angus, Beef Shorthorn or Hereford sires although Continental sires produce bigger, faster growing calves which mature at heavier weights. However, information is available on calving difficulties for sires used in AI and this enables easy calving Continental sires to be selected.

A group of 70 Hereford x British Friesian heifers were allocated at random to be mated, using AI, to a progeny tested high performance easy calving Aberdeen-Angus or to an easy calving sire of the Blonde d'Aquitaine, Limousin and Simmental breeds.

Only one sire from each breed was involved. The heifers were mated to commence calving in mid August 1985. A combined PRID/PG (PRID, CEVA; prostaglandin ICI Estrumate) technique was used to synchronise oestrus in the heifers and they were served by AI at 72 and 96 hours after the PG injection.

Ensiled ear maize was compared with rolled barley as the cereal in a finishing diet for cattle weighing about 400 kg. The diets resulted in similar gains of about 1·2 kg/day.

This study aimed to identify genetic evaluation models (GEM) to accurately select cattle for milk production when only limited data are available. It is based on a data set from the Pakistani Sahiwal progeny testing programme which includes records from five government herds, each consisting of 100 to 350 animals, with lactation records dating back to 1968. Different types of GEM were compared, namely: (1) multivariate v. repeatability model when using the first three lactations, (2) an animal v. a sire model, (3) different fixed effects models to account for effects such as herd, year and season; and (4) fitting a model with genetic parameters fixed v. estimating the genetic parameters as part of the model fitting process. Two methods were used for the comparison of models. The first method used simulated data based on the Pakistani progeny testing system and compared estimated breeding values with true breeding values. The second method used cross-validation to determine the best model in subsets of actual Australian herd-recorded data. Subsets were chosen to reflect the Pakistani data in terms of herd size and number of herds. Based on the simulation and the cross-validation method, the multivariate animal model using fixed genetic parameters was generally the superior GEM, but problems arise in determining suitable values for fixing the parameters. Using mean square error of prediction, the best fixed effects structure could not be conclusively determined. The simulation method indicated the simplest fixed effects structure to be superior whereas in contrast, the cross-validation method on actual data concluded that the most complex one was the best. In conclusion it is difficult to propose a universally best GEM that can be used in any data set of this size. However, some general recommendations are that it is more appropriate to estimate the genetic parameters when evaluating for selection purposes, the animal model was superior to the sire model and that in the Pakistani situation the repeatability model is more suitable than a multivariate.

The effect of melatonin treatment on fur maturation period and hair follicle cycle in 4-month-old male and female chinchillas, kept under conditions of natural photoperiod, was studied. The animals were treated with continuous-release implants of melatonin (18 mg, group M, no. = 56), while no treatment was given to the control (group C, no. = 69). The effect on hair follicle activity cycle under conditions of normal hair growth (no. = 8) and after defleecing (no. = 8) and on number of hair fibres per follicle bundle (no. = 27) were measured by taking skin samples for histological examination once a month. The age at fur priming was reduced by 31 days (P < 0001) in the melatonin-treated chinchillas. When moulting began during the short-day period, the fur reached maturity 13 days (P < 005) sooner than when the moult began during the long-day period. Melatonin administration proved to be effective in these two periods. Melatonin treatment led to hair follicle activity decreasing at a faster rate, and the differences between treated and control groups from day 60 were significant (P < 005). The primary and secondary hair follicles reached the telogen phase 30 days earlier. Due to melatonin administration more fibres per follicle bundle were observed on the matured pelt (P < 005). At 4 months of age, following the removal of hair by defleecing, the growth of the first adult hair was studied without the presence of young-age hairs. No influence of defleecing as opposed to normal hair development on age at fur maturation or on the number of fibres per hair follicle bundle was observed. Within groups M and C the number of fibres per hair follicle bundle proved to be independent of age at first fur priming. No substantial differences between the groups were observed with respect to either body weight or pelt length at the time of pelting. According to these results, melatonin administration is effective in shortening the coat maturation period in growing chinchillas and causing corresponding changes in the hair follicle cycle.

Three experiments were carried out to determine plasma amino acids concentrations in circulating, portal and hepatic blood of growing male Wistar rats given diets containing lactalbumin, faba beans or chickpeas as the only protein source. Diets contained the same amount of digestible energy (15·5 kJ/g) and protein (lactalbumin in controls or legume proteins in the experimental diets; 100 g/kg). Appropriate amounts of essential synthetic amino acids were also added to legume-based diets taking into account their amino acid composition to equalize them to control (lactalbumin) diets. Portal blood flow (8·7±0·3 ml/min) was measured by using a transit-time ultrasound flow probe. Higher (P < 001) plasma concentrations of methionine than of controls were determined in hepatic veins of legume-fed rats. In contrast, lower (P < 001) concentrations of threonine, proline, valine, leucine, phenylalanine and lysine than those of controls were found in faba bean- and chickpea-fed rats. The same result as hepatic was obtained for portal and circulating plasma samples except that alanine and histidine values of legume-fed rats were also lower (P < 001) than controls. Calculated net afferent appearance rates of amino acids to the liver were lower (P < 001) than controls in rats given faba bean and chickpea diets for threonine, alanine, proline, valine, leucine, phenylalanine and lysine. This lower contribution of amino acids to the liver mainly via the portal vein in faba bean or chickpea-fed rats might explain previously reported differences in protein utilization and growth in comparison with animals given other protein sources (lactalbumin).

The use of biological feed additives in animal production systems is becoming widespread, largely in response to consumer pressure and legislation concerning the use of antibiotics and hormone implants. Howewver, published data on their efficacy are limited. Yea-sacc,a high strength yeast culture, is one such product. A yeast-culture is a dry product composed of yeast and the media on which it was grown, dried in such a manner as to preserve the fermenting capacity of the yeast. The yeast used in Yea-sacc is a selected strain of Saccharomyces cerevisiae, and the yeast culture is produced using a high density fermentation technique. A trial was conducted to examine the effect of including Yea-sacc in the diet, on the performance of early-weaned calves.

1. Three groups, each comprising four Hereford-cross and four Friesian half-sib male calves, were fed milk substitute and offered grass cut from autumn pastures. Two of the groups received meal supplements of similar energy value but differing in protein content. The third group received no meal supplement.

2. As the consumption of meal rose the intake of herbage dry matter decreased but total dry matter intake increased.

3. The effects of the two meals on the progress of the calves were similar but not apparent until after the first 6 weeks. The lack of response to the high protein content of one meal suggests that energy may be the limiting factor to growth of calves reared on autumn pasture.

4. Hereford-cross calves which did not receive a meal supplement tended to make the best live-weight gains during the subsequent grazing season, but no such recovery was made by the Friesians.

Correct diagnosis of cause of death is necessary to suggest the most effective management interventions to reduce perinatal lamb mortality. Haemorrhage on the surface of the brain has been used as a field diagnostic tool to allocate lambs to a cause of death category, but the usefulness of this method was unclear. This study aimed to evaluate whether gross pathology was related to neuronal death and whether haemorrhage of the central nervous system (CNS) was distinct between differing causes of death, enabling indicators to be used in field diagnoses. Lambs dying from natural causes (n = 64) and from euthanasia (n = 7) underwent postmortem examination, then the brain and spinal cord were extracted and examined histologically. Histological changes consistent with neuronal death were not detected in any lamb. Haemorrhage of the meninges and/or parenchyma of the CNS occurred in all lambs. The age of the haemorrhage indicated that it occurred near the time of death in most lambs. Dilation of blood vessels varied in severity but appeared to be unrelated to causal diagnosis, severity of subcutaneous oedema, breathing or milk status. Moderate or severe dilation of blood vessels and haemorrhage of the CNS did not occur in all lambs with alternative clear indicators of dystocia and occurred in all death classifications, so it could not be used as diagnostic indicators for classification of cause of death. Dilation and haemorrhage were unrelated to neuronal damage and may have been artefactual. In conclusion, haemorrhage of the CNS was not indicative of neuronal damage and could not be used to distinguish between lambs with clear indicators of differing causes of death, so it is not recommended as a field diagnostic tool.

The effects of diets containing variable percentages of roughage and moisture on depot fats were studied. Treatments were 25 and 45% roughage in the complete fattening diet, and 10, 50 and 75% moisture content of the diets. Depot fats collected post-slaughter from kidney, pelvic, ruminal, cod and trim fats in the carcass (mostly subcutaneous and some intermuscular) were weighed and analysed for their fatty acid composition.

Increasing the quantity of roughage in the diet (from 25 to 45%) significantly decreased ruminal fat deposition. Moistening the feed significantly increased the deposition of kidney, pelvic and cod fat, and significantly reduced the deposition of fat trim in the carcass. The content of unsaturated triglyceride fatty acids was significantly greater in calves fed on the 25% roughage diet. Calves fed on the soaked diets had significantly higher contents of unsaturated fatty acids than the controls.

The content of unsaturated acids was greater in cod fat and carcass trim than in kidney, pelvic or ruminal fat.

Hydrogenation in vitro of fatty acids by ruminal micro-organisms decreased with increasing level of moisture in the diet.

It is suggested that the increased unsaturated fatty acid content of the depot fats of animals fed on soaked diets might be due to a reduction in the hydrogenation of dietary lipid by rumen micro-organisms.

A study was made of the behaviour of young calves at two Scottish auction markets, Lanark and Stirling, and an experiment was conducted to assess the effect of an auction market on the behaviour of calves less than 1 week old.

Several features of the marketing procedure were identified as causing the calves distress, mainly because the calves were unable to lie down and rest. Crowding of calves in the pens, movement to different pens, and penning of very young calves with older calves were the three main reasons why calves could not rest. The older calves (approx. > 10 weeks) were more active, running and jumping around the pens and disturbing the very young animals which stood up in response to being trodden on.

Crowding was severe in some pens although there was no clear evidence to show that small groups of calves (6 to 10 calves) in small pens rested more than calves in large groups (20 to 50 calves) in larger pens.

Calves showed their distress initially by calling loudly, looking wildly around their new environment and sometimes by running around the pen and calling. As time passed behavioural signs of distress were less prominent and calves assumed a ‘depressed’ posture with their heads low, ears held back, tails clamped down and with their weight distributed more on their hindlegs than on their forelegs.

Calves subjected to an experimental market showed similar signs of distress to those calves in the real markets, whereas control calves rested for more than 0·74 of the same time. Experimental calves which were subjected to a journey of 2.5 h were less easily disturbed from the lying posture at the experimental market than calves which had undergone a journey of 15 min only.

The results of a previous experiment suggested that a scale of feeding at about 60% of full-feed level from weaning onwards could result in a high incidence of infertility in gilts, but numbers were insufficient to confirm this. The present trial was carried out, therefore, with 18 Large White gilts per treatment fed to scales rising from either 1·4 lb. meal per day at 36 lb. live-weight to 5·0 lb. at 200 lb. live-weight, or from 1·9 lb. to 6·5 lb. over the same weight range. Average growth rate of the low-plane gilts was 76·5% of that of the medium-plane group but none of the low-plane gilts failed to conceive.

The inheritance of the time taken to react to halothane anaesthesia was examined as a possible quantitative measure of penetrance, which might allow the advantage of the halothane gene in lean content to be separated from its disadvantage of stress susceptibility. Restricted maximum-likelihood analyses were conducted on a total of 2207 pigs from 118 sire families in British Landrace and Pietrain-Hampshire lines selected for a high frequency of positive halothane reaction over 6 years. Reaction time averaged 94 s with a CV of 0·53, and was significantly influenced by line, season and live weight, but not sex. Estimated heritabilities averaged 0·07 (s.e. 0·06) and 0·16 (s.e. 0·12) in the two lines respectively, giving a pooled estimate of 0·09 (s.e. 0·05). Due to the high CV, family selection with a heritability of around 0-1 could be expected to give a rapid genetic change in reaction time. It is therefore concluded that selection for slower reaction to halothane could provide a means for reducing the incidence of stress susceptibility while retaining the advantage of the gene in lean content. However, further evidence is required on the correlation of reaction time with stress susceptibility and lean content.

Records of milking rate, milk yield and milk composition were collected over 12 yr from 123 Ayrshire heifers in their first lactation in one herd. Three direct measures of milking rate, i.e. peak flow rate, machine rate and overall rate were closely correlated and each was also correlated with total lactation yield of milk. Milking rate accounted for only a very small part of the variation in fat and total solids percentages. The mean yield of milk per milking in early lactation was a better predictor of total lactation yield than was milking rate but, among animals giving the same early lactation yield of milk, the faster milkers gave higher lactation yields than the slower milkers.

To reduce competition with human-edible feed resources, it is of interest to incorporate by-products from the food industry in animal feeds. The current research investigated the effect of including increasing amounts of tofu by-product (TF) in practical pig diets on animal performance, nitrogen balance and ammonia emissions from manure. Two experiments were conducted including a control diet without TF, containing 160 g/kg dietary non-starch polysaccharides (NSPs) and three diets including 122, 246 and 360 g TF/kg DM (TF122, TF246 and TF360, respectively) to reach 220, 280 and 360 g/kg NSP. All diets had the same level of CP and protein digestible in the small intestine which particularly was realized by replacing rice bran with TF. Animal performance was assessed in a first experiment with 40 growing barrows with initial BW of 26.6 ± 1.80 kg (M ± SD) being allocated to the 4 treatments, during 2 growth phases (i.e. until 50 kg BW and from 50 to 80 kg BW). In the growth phase until 50 kg, feed intake and average daily gain (ADG) were linearly reduced by dietary TF inclusion, while this negative impact disappeared during the second growth phase (50 to 80 kg BW). Tofu by-product inclusion even positively affected the feed conversion ratio during this second growth phase (3.4 to 2.7 kg feed/kg ADG for 0 to 360 g/kg dietary TF). Over the entire growth period, performance and feed intake were negatively affected at the highest dietary TF level. Experiment 2 was conducted to assess digestibility, nitrogen balance and ammonia emission from manure. For this purpose, 16 pigs with BW of 62.8 ± 3.6 kg (M ± SD) were assigned to either 1 of the 4 treatments. There was no difference in total tract apparent digestibility of dietary organic matter or CP, while NDF digestibility increased with increasing TF level, suggesting increasing importance of the hindgut fermentation when digesting diets with increasing TF levels. Nevertheless, this was not reflected in increasing levels of faecal volatile fatty acids or purines, nor in reduced manure pH. As a result, ammonia emission from slurry was not reduced through dietary TF inclusion, despite the linear decrease in urinary nitrogen. In conclusion, TF can be included in pigs’ diets up to an inclusion rate of 25% without risk of impaired animal performance; however, this dietary strategy fails to mitigate ammonia emission from slurry.

1. An experiment is described in which 194 pairs of piglets on 10 commercial farms were reared out of doors with access to soil, either on free range or in field pens. One piglet from each pair received 200 mg. of iron as a parenterally administered iron dextrin complex. The soil type and the iron content of the soil were determined on each farm.

2. During the first 8 weeks of life, the treated piglets showed a small but significant positive growth response of 1–2 lb. (3·0%). The response was greater (2·1 lb.) in piglets reared in field pens, but was non-significant in those reared on free range.

3. Differences in blood haemoglobin levels, mortality and the incidence of runt piglets were not significant.

4. Total body iron increased during the first 3 weeks of life by a mean of 339 mg., of which approximately 295 mg. appeared to be derived from the soil.