This study was undertaken in the framework of a larger European project dealing with the characterization of fat co- and by-products from the food chain, available for feed uses. In this study, we compare the effects, on the fatty acid (FA) and tocol composition of chicken and rabbit tissues, of the addition to feeds of a palm fatty acid distillate, very low in trans fatty acids (TFA), and two levels of the corresponding hydrogenated by-product, containing intermediate and high levels of TFA. Thus, the experimental design included three treatments, formulated for each species, containing the three levels of TFA defined above. Obviously, due to the use of hydrogenated fats, the levels of saturated fatty acids (SFA) show clear differences between the three dietary treatments. The results show that diets high in TFA (76 g/kg fat) compared with those low in TFA (4.4 g/kg fat) led to a lower content of tocopherols and tocotrienols in tissues, although these differences were not always statistically significant, and show a different pattern for rabbit and chicken. The TFA content in meat, liver and plasma increased from low-to-high TFA feeds in both chicken and rabbit. However, the transfer ratios from feed were not proportional to the TFA levels in feeds, reflecting certain differences according to the animal species. Moreover, feeds containing fats higher in TFA induced significant changes in tissue SFA, monounsaturated fatty acids and polyunsaturated fatty acids composition, but different patterns can be described for chicken and rabbit and for each type of tissue.

Three field trials were undertaken to determine the influence of feeding sugar solutions to pigs immediately prior to slaughter on carcass yield, liver weight and muscle quality. In the first, which involved 168 pigs of 85 to 95 kg live weight, provision of a glucose syrup solution in lairage (4 h) followed by water (12 h), compared with water-only (16 h) increased carcass yield (3%) and liver weight (27%) and reduced muscle ultimate pH (0·1 to 0·4 unit). When water was not made available after consumption of the sugar there was no response in carcass yield. In the second trial conducted with 169 pigs of 110 to 125 kg live weight, and involving the same treatments as in Trial I, except that sugar was provided for a longer period (6 h), corresponding responses in carcass yield, liver weight and muscle ultimate pH were +2·7%, +24% and a decrease of 0·2 to 0·3 units. In both trials responses to sugar feeding were less when compared with pigs slaughtered shortly after arrival at the abattoir. In the final trial, which also involved heavy pigs (88), access to a glucose syrup solution (9 h), but not a sucrose one, followed by water (8 h), relative to water-only in lairage, improved carcass yield (1·1%). Liver weight was increased with glucose (34·2%) and markedly so with sucrose (49·7%) and both sugars reduced muscle ultimate pH (0·1 to 0·6 units).

1. Daily allowances of 1·37 kg of concentrates, containing either 8·9 (treatment A), 13·6 (B), 19·1 (C) or 29·2% crude protein (D) were given to 40 individually-fed steers eating long barley straw to appetite over a 112-day winter feeding period. Voluntary straw intake on treatment B was 25% higher than that on treatment A. There were no signiicant differences in straw intake between treat-ments B, C, and D. Mean daily live-weight gains (kg) for the treatment groups were A, −0·22; B, 0·05; C, 0·04; D, 0·15. When the animals were turned out to pastore, group A showed very rapid compensatory growth, and it was concluded that this was mainly due to differences between the groups in their changes in alimentary tract contents. Vitamin A and D supplementation did not affect straw intake or performance.

2. When the above supplements were given to steers in metabolism crates receiving barley straw in restricted or unrestricted quantities, it was found that an increase in the crude-protein content of the supplement significantly increased the digestibility of the organic matter, crude fibre and crude protein of the whole diet when straw intake was restricted, and significantly increased the digestibility of crude fibre and crude protein when straw was unrestricted.

3. It was concluded that voluntary straw intake was limited, at the lowest level of supplementary protein, by a deficiency of absorbed protein. At the higher levels of supplementary protein, intake was probably limited by the capacity of the alimentary tract.

Flystrike costs the Australian industry $173 to 280 M per annum and 70% to 80% of Merino lambs are currently mulesed to reduce the risk of flystrike. To alleviate welfare concerns there has been widespread adoption of analgesics to mitigate the pain associated with mulesing. The objective of this experiment was to determine the effectiveness of Tri-Solfen® and meloxicam (Metacam® 20) at reducing pain-related behavioural responses to mulesing in Merino lambs. One hundred and forty Merino lambs were allocated to one of seven treatment groups: (1) non-mulesed (Control); (2) mulesed with no pain relief; (3) subcutaneous (s.c.) meloxicam administered 15 min before mulesing; (4) Tri-Solfen® administered at time of mulesing; (5) Tri-Solfen® and saline injection (s.c.) 15 min before mulesing; (6) Tri-Solfen® and meloxicam (s.c.) 15 min before mulesing; and (7) meloxicam (s.c.) at time the of mulesing. Behavioural responses such as standing, walking and lying were measured every 15 min for 6 h on the day of marking and for up to 2 h for 4 days thereafter. Standing (hunched v. normal) and walking (stiff v. normal) behaviours were then categorised into pain- and normal-related behaviours while lying remained in its own category. Mulesed lambs with no pain relief displayed significantly more pain-related behaviours than Control lambs during the 6 h post-mulesing (1.22 v. 0.22 out of a total score of 3; RSD=1.15). Lambs that received a combination of pain relief displayed significantly less pain-related behaviour than mulesed lambs with no pain relief on the day of mulesing (0.85 v. 1.22 out of a total score of 3; RSD=1.15). Administration of meloxicam or Tri-Solfen® on their own had minimal if any significant effect on pain-related behaviours on the day of mulesing. The results of this experiment support the use of pain-related behaviours to measure the efficacy of analgesics and the use of multimodal analgesia during mulesing of lambs.

The present work was planned to study the effects of different lighting regimes in both mild and hot periods of the year on New Zealand White doe rabbit traits. The light regimes used were natural daylight as control, 16 h light and 8 h darkness, 12 h light and 12 h darkness, and 8 h light and 16 h darkness. The traits studied were thermoregulatory parameters (respiration rate and temperatures of ear, rectum and skin), type of mating necessary, conception rate, gestation period, fur plucking, behavioural indicators of stress, litter size, litter weight, kit body weight, kit daily gain in weight, milk yield, kit milk intake, efficiency of conversion of milk into live-weight gain and kit mortality, at weekly intervals between birth and weaning at 35 days. Estimation of temperature-humidity index indicated that the doe rabbits were exposed to very severe heat stress, during the hot period of the year. Period of the year (heat stress) affected adversely many of the doe traits studied. The effects were significant (P < 0·001, 0·01 or 0·05) on thermoregulatory parameters (respiration rate and temperatures of ear, rectum and skin), litter weight at days 21 and 28 of age, kit body weight at birth, milk yield of the doe at day 7 of suckling and milk intake per kit at 7 and 14 days of age. Exposure of doe rabbits to a long daylight regime affected adversely many of the traits studied, while the contrary occurred with short daylight. The effects were significant (P < 0·001, 0·01 or 0·05) on litter size at all ages except at birth, litter weight at 14, 21 and 28 days of age, milk yield on all days studied, efficiency of conversion of milk into live-weight gain at days 7, 21 and 28 and mortality at birth and pre-weaning. There was no significant interaction between period of the year and light regime on any of the traits examined. Therefore, only the main factors are reported.

In 1971 the attainment of puberty in 30 early-born and 30 late-born Chin Forest female lambs was studied. The early-born lambs showed their first oestrus at a mean age of 265·4 days and a mean body weight of 41·4 kg; the late-born lambs at 222·0 days and 36·8 kg.

Marked individual variation existed in both age and body weight at puberty within the groups, largely because of differences in growth rate during rearing. Early-born singles showed their first oestrus on average 3·4 days earlier than twins while this difference between lateborn singles and twins was 17·9 days. Since early-born lambs attained puberty at a considerably higher mean age and heavier mean body weight than late-born lambs with similar growth rates it is suggested that the daylight environment experienced by the lamb may be a critical factor in regulating the onset of breeding activity.

Antioxidants have been always used to improve post-slaughter meat quality in broilers subjected to stress. Forsythia suspensa extract (FSE), a traditional Chinese herbal medicine, is generally regarded as a natural source of antioxidants. Therefore, the objective of this study was to test the hypothesis that FSE could protect post-slaughter breast muscles against oxidative injury induced by dexamethasone (DEX) mimicking chronic physiological stress in poultry production. Average daily gain and feed efficiency of poultry were suppressed by DEX and improved by FSE (P < 0.05). Dexamethasone caused the decrease in the redness value and the increase in the lightness and yellowness values and drip loss of the breast muscles (P < 0.05), and FSE had the converse effects (P < 0.05). Dietary FSE supplementation decreased monounsaturated fatty acid (FA) and increased polyunsaturated FA in breast muscles of broilers (P < 0.05). In addition, FSE decreased malondialdehyde and carbonyl content in the breast muscles of DEX-treated broilers (P < 0.05). The inhibition of 1,1-diphenyl-2-picryl-hydrazyl in the breast muscles was decreased by DEX and increased by FSE (P < 0.05). Total-antioxidant capacity and glutathione peroxidase activity in the breast muscles were decreased in birds subjected to DEX and increased in birds supplemented with FSE (P < 0.05). Totally, DEX suppressed growth performance and induced breast muscle oxidative injury in broilers, and FSE supplementation improved antioxidant capacity to attenuate these adverse effects. Therefore, FSE could be a potential natural antioxidant to alleviate oxidative injury of the breast muscles in broilers and to improve the meat quality for human consumption.

Ultrasonic measurements, using a Danscanner, were taken of the m longissimus dorsi and overlying fat at the 10th and 13th ribs, and 3rd lumbar vertebra, of 50 Hereford bulls with ages ranging from 400 to 600 days, just prior to slaughter and side dissection.

The analysis adjusted the data for live weight and day of slaughter, and the precision of carcass lean and fat prediction was examined. The standard deviations of total fat and lean in the carcass at constant live weight were 40 and 33 g/kg respectively.

The best single measurement of fat depth for predicting fat proportion was fat depth taken 125 mm from the midline at the 13th rib (residual s.d. = 21·8g/kg). The best combined predictors of both total fat and lean proportions in the side were fat depth 125 mm from the midline at the 13th rib, fat depth 75 mm from the midline at the 3rd lumbar vertebra, and fat area at the 10th and 13th ribs, and 3rd lumbar vertebra, with residual s.d. of 20·5 and 19·6 g/kg for fat and lean proportions respectively.

The results confirm that ultrasonic scanning is now able to give a useful indication of the body composition of live cattle.

Differences between Friesians and Jerseys and between progeny of high and low contemporary comparison (CC) sires were sought by examining nine blood constituent concentrations around first and second calvings and during lactation. A total of 1359 samples from animals at first lactation and 1148 samples at second lactation were collected. All animals were individually fed a complete pelleted diet ad libitum. Blood constituents analysed were free fatty acids (FFA), ketones, glucose, calcium, magnesium, copper, phosphorus, albumin and globulin. All nine constituents showed marked changes around parturition and early lactation and several constituents showed changes with age. Jerseys had higher average copper and albumin levels and lower globulin levels than Friesians at both lactations and higher FFA concentrations at second lactation. Changes in plasma concentrations of FFA, ketones and glucose around calving were consistent in suggesting that Jerseys and progeny of high CC sires had a substantially greater energy deficit in early lactation than Friesians and progeny of low CC sires at the first but not the second lactation. Predicted requirements v. recorded intakes suggested that the Jerseys and high CC progeny had the greater energy deficit at both lactations. Although the incidence of hypocalcaemia was nearly zero, changes of calcium and magnesium concentrations were consistent with reports of Jerseys being more susceptible to hypocalcaemia in later life.

Despite large differences in milk yield, differences in plasma concentrations between animals classified as either high or low achieved yielders within their genetic class were generally smaller than differences between progeny of high and low CC sires.

The accuracy of six methods to estimate carcass leanness in young rams was studied in 36 Texel-Oxford rams, measured at 5 months of age. The rams were slaughtered and dissected. Plasma non-esterified fatty acid and very low density lipoprotein concentrations, sampled before, during and after fasting, showed no relationship with carcass leanness. The same was true for food conversion efficiency measured from 6 to 16 weeks of age, and for measurements taken with the Scanogram ultrasonic machine. The Vetscan and Danscanner ultrasonic machines gave repeatable measurements of fat depth (0·41 and 0·46 respectively). The Vetscan was the best predictor of carcass leanness by proportionally reducing the residual mean square by about 0·20, corresponding to a correlation of −0·45 between ultrasonic fat depth and carcass leanness. Inclusion of average daily gain and ultrasonic fat depth in a selection index would allow appreciable improvements in both traits.

Hypotheses on total body chemical composition were tested using data from 350 Suffolk sheep grown to a wide range of live weights, and fed in a non-limiting way, or with reduced amounts of feed, or ad libitum on feeds of reduced protein content. The sheep were from an experiment where selection used an index designed to increase the lean deposition rate while restricting the fat deposition rate. Ultrasound muscle and fat depths were the only composition measurements in the index. The animals were males and females from a selection (S) line and its unselected control (C). The protein content of the lipid-free dry matter was unaffected by live weight, sex or feeding treatment with only a very small effect of genetic line (0.762 kg/kg in S and 0.753 kg/kg in C; P < 0.05). The form of the relationship between water and protein was not affected by any of the factors; in the different kinds of sheep it was consistent with no effect other than through differences in mature protein weight. The water : protein ratio at maturity was estimated as 3.45. Over the whole dataset, lipid weight (L) increased with protein weight (P) according to L = 0.3135 × P1.850. Allowing for this scaling, fatness increased on low-protein feeds, was greater in females than in males and in C than in S (P < 0.001). Lipid content (g/kg fleece-free empty body weight) was reduced by restricted feeding only in males at the highest slaughter weight (114 kg). The lines differed in lipid content (P < 0.001) with means of 265.1 g/kg for C and 237.3 g/kg for S. Importantly, there was no interaction between line and feeding treatments. A higher proportion of total body protein was in the carcass in S than in C (0.627 v. 0.610; P < 0.001). For lipid, the difference was reversed (0.736 v. 0.744; P < 0.05). The total energy content increased quadratically with slaughter weight. At a particular weight, the energy content of gain was higher in females than in males and in C than in S. Genetic selection affected body composition at a weight favouring the distribution of protein to the carcass and lipid to the non-carcass. Once allowing for effects of genetic selection, sex and feeding treatment on fatness, simple rules can be used to generate the chemical composition of sheep.

Intrauterine variations in nutrient allowance can alter body composition and tissue features of the porcine offspring around birth. This study aimed to determine the effects of fetal weight variations between littermates and of maternal dietary regimen during gestation on fetal muscle traits just before birth. Fourteen pregnant gilts were reared under a conventional (control, CTL; n=7) or an experimental (treatment, TRT; n=7) dietary regimen during gestation. The dietary treatment provided 70% of the protein and digestible energy contents of the CTL diet during the first 70 days of gestation and then, 115% of the protein and digestible energy contents up to farrowing. At 110 days of gestation, sows were sacrificed and one fetus having a low (824±140 g) and one having a normal (1218±192 g) BW per litter were sampled. Irrespective of maternal dietary regimen, the longissimus muscle of the small fetuses exhibited higher expression levels of DLK1/Pref1 and NCAM1/CD56, two genes known to be downregulated during normal skeletal muscle development. Expression levels of the embryonic isoform of the myosin heavy chain (MyHC), both at the mRNA and at the protein levels, were also higher in small fetuses. In addition, the ratios of perinatal to embryonic and of adult fast to developmental MyHC isoforms were generally lower in light fetuses compared with their medium-weight littermates. These modifications suggest a delayed myofiber development in spontaneous growth-retarded fetuses. Finally, GLUT1 was expressed to a lesser extent in the muscle of small v. normal fetuses, suggesting decreased ability for glucose uptake in muscle. Initial feed restriction and subsequent overfeeding of sows during gestation led to a lower expression of the myogenic factor MYOD1, a prerequisite for myogenic initiation in skeletal muscle. This maternal strategy was also associated with a lower expression level of insulin-like growth factor 1 receptor (IGFR) but an upregulation of IGF2. This suggests an altered susceptibility of muscle cells to IGFs’ signal in fetuses from treated sows. Altogether, intrauterine growth restriction impaired fetal muscle development, and restricted feeding followed by overfeeding of gestating sows did not allow small fetuses to recover normal contractile and metabolic characteristics.

Large efforts have been deployed in developing methods to estimate methane emissions from cattle. For large scale applications, accurate and inexpensive methane predictors are required. Within a livestock precision farming context, the objective of this work was to integrate real-time data on animal feeding behaviour with an in silico model for predicting the individual dynamic pattern of methane emission in cattle. The integration of real-time data with a mathematical model to predict variables that are not directly measured constitutes a software sensor. We developed a dynamic parsimonious grey-box model that uses as predictor variables either dry matter intake (DMI) or the intake time (IT). The model is described by ordinary differential equations.

Model building was supported by experimental data of methane emissions from respiration chambers. The data set comes from a study with finishing beef steers (cross-bred Charolais and purebred Luing finishing). Dry matter intake and IT were recorded using feed bins. For research purposes, in this work, our software sensor operated off-line. That is, the predictor variables (DMI, IT) were extracted from the recorded data (rather than from an on-line sensor). A total of 37 individual dynamic patterns of methane production were analyzed. Model performance was assessed by concordance analysis between the predicted methane output and the methane measured in respiration chambers. The model predictors DMI and IT performed similarly with a Lin’s concordance correlation coefficient (CCC) of 0.78 on average. When predicting the daily methane production, the CCC was 0.99 for both DMI and IT predictors. Consequently, on the basis of concordance analysis, our model performs very well compared with reported literature results for methane proxies and predictive models. As IT measurements are easier to obtain than DMI measurements, this study suggests that a software sensor that integrates our in silico model with a real-time sensor providing accurate IT measurements is a viable solution for predicting methane output in a large scale context.

Detailed graphic and algebraic procedures were outlined for finding the most profitable parental combination among a group of lines when genetic additivity of component traits is assumed.

Profit was expressed as a linear function of productivity and a reciprocal function of reproductivity. The non-linearity and the unequal contributions to profit of the sire and dam lines were exploited in order to minimise both reproduction and production costs.

The conventional system of estimating metabolizable protein requirement is unsuitable for defining amino acid requirements because nitrogen loss cannot be converted to amino acid loss, and because there is a lack of data on the utilization efficiencies of individual amino acids for various productive purposes. Therefore, we are proposing an alternative approach. In this review, we use methionine (Met) and cysteine (Cys) for wool production in sheep as examples, and define requirement as retention in both body and wool protein, plus the amount of obligatory oxidation that accompanies the retention. The requirements are expressed in terms of the net absorption. Mathematical models for the calculation of the requirements of both amino acids are established based on the level of absorption, endogenous contribution from body protein breakdown, oxidation rates and the amino acid composition of body and wool proteins. The flows and oxidation of Met and Cys, and Cys synthesis de novo as well are quantified using their plasma kinetics data. Wool growth rate is predicted from the amount of the amino acid available for protein retention and the partition ratio to wool growth. The estimated requirements for Met and Cys absorption for Merino sheep at maintenance are 0·45 to 0·75 g/day and 0·52 to 0·63 g/day depending on the live weight of the sheep. When wool growth rate increases to 10 g/day, the requirements increase to 0·91 to 1·24 g/day and 1·97 to 2·02 g/day respectively. The utilization efficiency for protein retention varies with the level of absorption, and is 0·02 to 0·55 for Met, and 0·09 to 0·55 for Cys. The model shows that wool growth rate is restricted by the lack of Cys supplied in conventional diets and is very sensitive to changes in oxidation of the amino acids.

Dietary chitosan (CS) supplementation could improve the growth rate, small intestinal morphology, nutrients apparent digestibility and digestive enzyme activities in pigs, broiler chickens, rats and fish, whereas no data has been reported about the effect of CS on the growing Huoyan geese. Therefore, this study was designed to investigate the effects of CS on growth rate, small intestinal morphology, nutrients apparent utilization and digestive enzyme activities of growing Huoyan geese. Three hundred and twenty (28 days of age, gender balance) Huoyan geese were randomly divided into control, CS100, CS200 and CS400 groups (based on BW) with 20 geese per pen and 4 replicates pen per group, and the feeding experiment lasted for 4 weeks. The 4 diets contained 0, 100, 200 and 400 mg CS per kg feed, respectively. The results showed that CS200 groups had higher average daily gain, final BW, apparent utilization of DM and CP, and lower feed/gain ratio compared with the control group (P < 0.05). Meanwhile, CS100 and CS200 groups had higher villus height, villus height/crypt depth ratio and lower crypt depth in duodenum and jejunum than those in the control group (P < 0.05). The geese in CS100 and CS200 groups had higher villus height, villus height/crypt depth ratio and lower crypt depth of ileum compared with those in control and CS400 groups (P < 0.05). In addition, compared with the control group, CS200 group has higher trypsin activities and lower lipase activities in duodenal, jejunal and ileal contents (P < 0.05). The results suggested that addition of 200 mg/kg CS had positive effects on growth rate, small intestinal morphology, nutrients apparent utilization and digestive enzyme activities of growing Huoyan geese.

The onset and duration of oestrous and ovulatory activity in 26 Greyface ewes receiving natural daylength changes were determined. Precise ovulation data were obtained by endoscopy and repeated observations of the ovaries of all ewes were made on 10 occasions from 15 July 1971 to 27 June 1972. The natural breeding season for these Greyface ewes was, on average, 22 September 1971 to 18 February 1972. There were significant seasonal changes in the mean ovulation rate of the ewes which appeared to be inversely related to seasonal changes in natural daylength.

An abrupt decrease in artificial daylength of 11 -43 hr applied on 22 June 1971 to 28 similar Greyface ewes advanced their mean onset of oestrous activity by 23 days. The decrease in artificial daylength also advanced the occurrence of ovulation in these ewes. The highest mean ovulation rate of the ewes receiving the decrease in artificial daylength was at least as high as the peak mean ovulation rate measured in the control ewes.

At most stages of the experiment, the plane of nutrition had no significant effect on either oestrous or ovulatory activity in the ewes.

Four diets containing 9·6 MJ metabolizable energy (ME) per kg dry matter (DM) (LMEC), and four diets containing 11·3 MJ/kg DM (HMEC) were formulated. One diet of each ME concentration contained 90 g crude protein (CP) per kg DM and served as a negative control (NC). In the three other diets of each ME concentration, the level of CP was raised to 140 g/kg DM by inclusion of poultry litter (PL), non-protein nitrogen (NPN) or fish meal (FM). These diets were examined in a digestion and N balance trial and in a feeding trial.

For the NC, PL, NPN and FM subtreatments of the LMEC diets, DM intakes were 107·1, 112·4, 100·6 and 130·2 g/kg M075 respectively; digestibility coefficients of organic matter (OM) were 0·64, 0·70, 0·67 and 0·71 respectively; and N retention 0·40, 0·76, 0·53 and 1·21 g/kg M075 respectively. For the respective subtreatments of the HMEC diets, the values were: 100·4, 119·4, 109·3, 107·5 for DM intake; 0·64, 0·73, 0·73, 0·73 for digestibility coefficients of OM and 0·40, 0·87, 1·06 and 1·03 g/kg M075 for N retention.

Daily gain on the respective diets in the first 130 days of the feeding trial was 0·85, 0·90, 0·91, 1·04 kg for the LMEC and 1·09, 1·21, 119, 1·24 kg for the HMEC diets, and from the 131st day to slaughter was 0·98, 1·02, 100, 1·08 kg for the LMEC and 1·03, 1·02, 1·07, 1·05 kg for the HMEC diets respectively. Daily carcass gain was 0·49, 0·51, 0·51, 0·53 kg for the LMEC and 0·55, 0·59, 0·59, 0·60 kg for the HMEC diets, respectively.

The relationship between ME concentration in the diet and source of CP is discussed.

1. Wilted (32% dry matter) Italian ryegrass was conserved: (A) untreated; (B) with 16·3 g/kg dry matter (4·6 1/t of fresh material) of an 85% w/w formic acid additive; (C) 12·1 g/kg dry matter (2·3 1/t fresh material) each of 85% formic acid additive and formalin (40% w/v formaldehyde); (D) 5·8 g/kg dry matter (1·3 1/t fresh material) each of 85% formic acid additive, formalin and a 96% w/v solution of propionic acid. The silages were individually fed ad libitum to 40 15-mo-old British Friesian steers of about 350 kg initial live weight.

2. Treatment with additives inhibited fermentation, resulting in silages with higher levels of water soluble carbohydrates and lower levels of organic acids than untreated material. Lower levels of ammonia N and higher levels of true protein indicated that some protein protection resulted from the formaldehyde treatment.

3. Formic acid alone (B) had little effect on digestibility but significantly (P<0·05) enhanced dry-matter intake, live-weight gain and nitrogen retention relative to the control (A)

4. Whereas the application of formaldehyde (Treatments C and D reduced the digestability in vivo of nitrogen, significant increases in nitrogen retention were recorde relative to the control (A). Dry matter intake was not affected significantly by treatment with formaldehyde, but at the higher level of application (Treatment C) daily gain was significantly reduced compared with the control (A). These effects are discussed in relation to possible changes in VFA patterns within the rumen and to the levels of formaldehyde used.

1. Six Dorset Horn lambs were reared on each of four different concentrations of reconstituted full-cream dried milk powder (10, 15, 20 and 25 % dry matter). The lambs were fed to appetite four times a day for 3 weeks.

2. The lambs consumed significantly more liquid milk at the two lower concentrations. Intake of water per se increased with increasing concentration of dry matter.

3. There were no significant differences in the consumption of milk dry matter between the treatments, although there was a significant linear trend, with dry-matter intake decreasing with decreasing concentration.

4. There were no significant differences between the treatments in live-weight gain from 0 to 3 weeks or from 0 to 10 weeks.

5. There were no significant differences in the efficiency of feed conversion between the treatments.

6. Examination of the distribution of milk intake within days showed that the proportion of milk voluntarily consumed in the first feed of the day increased with age and with concentration.

7. The incidence of scouring was high, but there was no general relationship with treatment.

8. Abrupt weaning was not satisfactory for the lambs which had been offered only liquid food for 3 weeks and they had to receive a low level of milk feeding for a further week while they became accustomed to solid food.