Lactation in goats is associated with an insulin resistance manifested by an impairment of the ability of insulin maximally to stimulate skeletal muscle glucose utilization. The mechanism responsible for this modification is unknown. Therefore an investigation was made of the insulin-sensitive glucose transporter (GLUT-4) in three skeletal muscles from six lactating (peak of lactation) and six non-lactating goats. GLUT-4 protein content was assessed in crude membrane preparations and Triton X-100 extracts by Western-blot analysis. Lactation resulted in a decrease in GLUT-4 protein content. This decrease was more pronounced in oxidoglycolytic muscles (proportionately -0·40 to -0·60 in m. tensor fasciae latae and longissimus dorsi) than in oxidative muscles (-0·20 in masseter). Down-regulation of the insulin-sensitive glucose transporter (GLUT-4) expression in skeletal muscles from lactating goats may be responsible for the decrease in insulin responsiveness of glucose utilization previously observed in vivo.

Shearing ewes during pregnancy frequently increases the birth weight of lambs. In housed ewes, the birth weight responses are greatest when shearing occurs relatively early in pregnancy. This study examined the effects of the timing and method of shearing on foetal growth, as measured by birth weight, in ewes at pasture. Border Leicester × Romney ewes were allocated at day 50 of pregnancy to: four ‘time of shearing’ treatments — pregnancy day 70 (P70), P100, P130 (no. = 60 for each treatment) and unshorn (no. = 34); two methods of shearing (by standard comb or cover comb); and two levels of pregnancy/rearing rank All ewes had been mated over a 14-day period and grazed pasture together throughout the trial The mid-point of lambing was 17 August.

At no time during pregnancy or lactation did ewe live weight differences between the groups exceed 4 kg. Ewes shorn by cover comb were heavier prior to lambing and during lactation than standard comb-shorn ewes. Time of shearing, method of shearing and ewe rearing rank had no effect on ewe annual greasy fleece production. There was a highly significant (P < 0·001) interaction between the effects of birth rank and time of shearing on lamb birth weight. Time of shearing did not affect birth weight of single-born lambs but birth weight of twin lambs increased with earlier maternal shearing to a maximum of 0·7 kg (per lamb) in those born to ewes shorn on P70. These results imply that shearing reduced the greater extent of maternal constraint which applies to the growth of twin v. single foetuses in utero. This selective increase in birth weights of twins achieved by early pregnancy shearing may have advantages in reducing lamb mortality.

The effect of ammonia treatment of straw on both the rumen environment and the extent of its microbial fermentation was studied. Four rumen cannulated sheep were randomly given 700 g/day of untreated straw plus urea (US), ammonia-treated straw (TS) and alfalfa hay (AH) in a change-over design with three periods. Rumen pH was lower and ammonia-nitrogen and total volatile fatty acid (VFA) concentrations were higher (P < 0·001) with AH than with US or TS. With the straw diets, TS promoted a lower pH than US (P < 0·05), but differences were less than 0·3 units and the mean pH was never below 6·5. There were no differences between the straw diets in ammonia-nitrogen or VFA concentration (P > 0·05). When untreated barley straw (BS) and treated straw (TS) were incubated in situ disappearance of dry matter (dDM) at 12, 24 and 48 h (P < 0·01) and neutral-detergent fibre (dNDF) at 48 h (P < 0·001) were higher with TS. In vitro incubation showed a higher gas production with TS only after 36 h (P < 0·05) whereas gas from BS fermentation was higher up to 14 h (P < 0·05). Among diets, dDM, dNDF and gas production with US were numerically higher than with TS or AH throughout, although few significant differences were observed, except for a higher dDM at 12 (P < 0·01) and 24 (P < 0·10) h and a higher dNDF at 12 h (P < 0·10). Particle-associated enzymes were extracted from BS and TS incubated in the rumen for 4, 8, 22 and 24 h. Results ofxylanase and cellulase activities support those of straw incubation, with a drop between 4 and 8 h in TS diet. The concentration of residual phenolics per unit of incubated straws after 12 and 24 h show that phenolics release to the media was higher with the TS diet. Daily changes of phenolic concentration into rumen liquid was also higher with TS than with US (P < 0·001). The increased release of straw phenolics by ammoniation reduced the potential for rumen degradation of straw, mainly in the first hours of the fermentation period.

To avoid winter scarcity of fresh goat milk, simple methods of advancing the season of kidding would be commercially valuable. A combination of long-day light treatment followed by melatonin is successful but other aspects of seasonality including coat growth are also reset. To investigate whether effects on breeding season and coat growth can be dissociated, British Saanen dairy goats (no. = 30) were randomly allocated to one of six groups. Control goats were untreated. Goats in the other five groups received 2 months of treatment with 20 h light: 4 h darkness (20L: 4D) and were then given 3 mg melatonin orally at 16.00 hfor 2 months. The treatments started on 11 January (group 1), 29 March (group 2), 14 June (group 3), 30 August (group 4) and 8 November (group 5). Weekly blood samples were taken for the measurement of progesterone to monitor ovarian activity and prolactin. Side patches (10 cm ×10 cm) were clipped monthly from alternate sides and weighed to measure coat growth. The onset of ovarian activity was advanced from a median date of 15 November in controls to 24 May in group 1 (P < 0·01), 16 August in group 2 (P < 0·05) and 18 October in group 3 (? < 0·05). Groups 4 and 5 showed no significant change in the onset of oestrus (median onset dates 8 November and 1 November, respectively). Group 1 goats came into season again with controls in November. In all except group 5, treatment interacted with time to affect significantly the growth of the coat. The pattern of coat growth was most altered (P < 0·001) in groups 1 and 2. This was associated with effects on plasma prolactin concentrations of light stimulation and melatonin suppression. Group 1 goats resynchronized with control goats to show a coat of normal weight in the winter following treatment. Division of milking goat herds into spring and autumn kidding groups is, therefore, a practical possibility, but effects on overall milk yield require study.

This study examined the temporal relationships between behavioural activity and hormones associated with stress in gilts farrowing in two environments. Thirty-one Large White × Landrace gilts with indwelling jugular catheters were blood sampled daily (08.00 and 16.00 h) from 10 days before their expected parturition date (EPD). Five days before EPD they were moved to either a farrowing crate (C) with no bedding, or a pen (P) (2·5 m × 3·0 m) with straw provided and were blood sampled daily at 08.00, 12.00 and 16.00 h. Around 12 h before the onset of farrowing an extension was fitted to the catheter and blood samples were taken remotely at 30-min intervals. The posture of the gilts was recorded using 5-min scan samples over the 24 h pre-farrowing. The proportion of scans standing (an index of activity) was strongly affected by time (P < 0·001) with peak levels at approximately 8 h pre-farrowing in both treatments, and by treatment (0·25 v. 0·33 (s.e.d. 0·03) for C and P gilts respectively; P < 0·05). Plasma cortisol concentrations also increased before farrowing (P < 0·001) reaching a peak at 12 to 6 h pre-farrowing. Crated gilts had higher cortisol concentrations than, penned gilts (overall mean 41·5 v. 30·7 (s.e.d. 3·8) [μg/l for C and P gilts respectively; P < 0·05) at 24 to 12 (P < 0·05), 12 to 6 (P < 0·01) and 6 to 2 (P < 0·05) h pre-farrowing. Plasma ACTH concentration showed a similar pattern to cortisol over the pre-parturient period, peaking at 12 h pre-farrowing in both treatments (time: P < 0·001); crated gilts had significantly higher concentrations of ACTH at 6h pre-farrowing only (P < 0·05). Plasma β-endorphin concentrations also showed a gradual rise (P < 0·001) towards parturition; however no treatment differences were seen. These results suggest that the pituitary-adrenal (PA) axis is stimulated during pre-farrowing activity irrespective of farrowing environment. Crates, without bedding, further stimulate the PA axis over the pre-farrowing period perhaps by preventing nest-building. The rise in Q-endorphin may be involved in an endogenous defence against parturition pain.

A study was carried out to compare the fermentation parameters and kinetics of digestion of a range of different foods in the rumen of two breeds of sheep (Churra and Merino). Ten mature sheep (five Churra and five Merino), each fitted with a rumen cannula, were used in this study. In situ rumen degradability of both dry matter (DM) and cell wall was greater in Churra than in Merino sheep, the breed differences being significant for most of the foods used in the study (P < 0·05). These differences were greater when the foods had a higher cell wall concentration and this could be related to differences in the ruminal environment. However, when the foods were incubated with rumen fluid their in vitro organic matter (OM) degradability was similar in both breeds. Rumen pH was higher (P < 0·05) and ammonia concentrations were lower (P < 0·05) in Churra than in Merino sheep. Rumen volatile fatty acid concentrations tended to be higher in Merino than in Churra sheep, though differences were only significant just before feeding (P < 0·05). The ratio acetate: propionate was higher in the Churra than Merino breed before and 12 h after feeding (P < 0·05). Protozoa numbers in rumen liquid were similar for both genotypes. The greater degradation of forages in the rumen of Churra sheep is discussed in relation to the possible higher activity of fibre-degrading micro-organisms and the greater buffering capacity of the rumen contents against fermentation acids, which could result in more favourable conditions for the microbial degradation of foods in the rumen.

Evidence from studies of group-housed sows in unbedded systems indicates that hunger may be a cause of increased aggression between animals. The present study aimed to investigate the effects of food level on performance, aggression and skin damage in a deep-straw system. Sixteen groups offive gilts were introduced over 8 months to one of two dynamic groups in a deep-straw yard (2·35 m2 per sow) receiving different food levels from an electronic sow-feeding system: high (H: 3·0 kg and 38 MJ/day) and low (L: 1·6 kg and 20 MJ/day). Seventy second-parity sows were returned to the same treatments in the same subgroups. The behaviour of the animals was recorded throughout both pregnancies using a time sampling technique. Severity of skin damage was recorded as a number from 0 to 4 for each of nine areas, the average of which being the ‘damage score’. The total number of animals in each dynamic group was maintained at around 30, through the use of additional sows. As expected, H sows were heavier than L sows but no effect offood treatment was found on litter size or performance. L sows were more active (L v. H; standing: 41 v. 31% of total observation time respectively, F114 = 7·65, P < 0·05) and showed more straw manipulation than H sows (L v. H: 17 v. 10% respectively, F 3 34 = 18·4, P < 0·001). No differences between treatments were found either in number of aggressive interactions (L v. H: 3·6 v. 3·8 interactions per sow per observation day, F, u = 0·82, P > 0·05), or in damage score (L v. H: 0·24 v. 0·28; Flu = 0·27; P > 0·05).

However, introduction of new animals did influence aggression, with sows being more involved in aggressive interactions on the day they were introduced, than on other sow's introduction days and on no introduction days (Tukey, P < 0·05). Average skin lesions per experimental sow were also higher in the days immediately following introduction. It can be concluded that in a sequential feeding system with plentiful straw, aggression is not influenced by the level offeeding. In these systems, the major factor giving rise to aggression is the introduction of new sows to the resident group.

Estimates of heritabilities, common litter of birth effects and additive maternal genetic effects were produced for ultrasonic backfat depth, average daily food intake, average daily gain and food conversion ratio of Landrace boars and gilts. Boars and gilts were performance tested under different regimes. A bivariate derivative-free restricted maximum likelihood procedure was used to estimate genetic correlations between the performance test traits as recorded in the two sexes.

Heritability estimates from the analysis including the common litter of birth effect tended to be towards the low end of the range of recently published estimates. This may reflect either population specific effects, such as effects of long-term selection, or the use of an individual animal model.

Estimates of the common litter of birth effect were around 0·05, and generally had a significant effect upon the fit of the model, while additive maternal genetic effect estimates were negligible. Therefore, it is expected that omission of maternal effects from models for evaluation by best linear unbiased prediction will not hinder genetic progress. Inclusion of common litter of birth effects would be recommended, although this result may not hold for populations given food ad libitum.

The estimates of genetic correlations between performance test traits of boars and gilts indicate that the levels of genotype-environment interaction (G × E) and genotype-sex interaction were low across most traits and data sets, with all genetic correlation estimates lying between 0·8 and 1·0. The lowest estimates of the genetic correlations, which were observed in data sets where the environments appeared to differ most, indicate that G × E interactions may be a problem in populations where males and females are subject to test regimes with greater differences than those seen here.

Feeding behaviour of six sows receiving a diet with a high inclusion (500 g/kg) of sugar-beet pulp (SBP) was compared with that of six sows receiving a conventional cereal-based diet (control). The feeding rate was determined for both the rate of consumption of the daily food allowance (SBP or control diet) and of a test portion (of control diet) offered at different intervals after the daily food allowance. SBP sows consumed their daily food allowance more slowly than control sows, SBP sows also consumed the test portion more slowly than control sows, when this was offered immediately after the daily food allowance. Prolonging the time taken to eat the control diet, by presenting it in meal form, did not change the feeding rate of the test diet. Offering the test portion 2 h after the daily food allowance, increased the feeding rate of the test portion for both control and SBP sows, with a smaller but still significant treatment difference. Gastric distension appeared to be a major factor in regulating intake when feeding a diet containing SBP. The extent to which feeding rate could be used as an index of feeding motivation and the welfare consequences of using bulky diets for sows are discussed.

Individual animal model restricted maximum likelihood was used to estimate genetic parameters for number of piglets born, number born alive, total litter weight, average piglet weight and gestation length for a commercial Landrace population undergoing selection for performance test traits. Estimates of heritabilities and repeatabilities (around 0·1 and 0·2, respectively) for number born and number born alive are in line with other published results. Heritabilities around 0·2 and repeatabilities around 0·3 were observed for average piglet weight and gestation length, while for litter weight these values were between 0·11 and 0·15 for heritabilities and around 0·2 for repeatabilities. Estimates of common litter of birth effects and maternal genetic effects were very low across all traits analysed.

The present study was undertaken to determine the Heal and total tract apparent digestibility and hindgut disappearance of dietary components and energy in a barley-based diet which included either lucerne or white-clover meal (proportionately 0·10 and 0·20). The experiment was conducted as a 5 × 5 change-over design with growing pigs fitted with simple t-shaped cannulas posterior to the ileo-caecal valve. The Heal and total tract apparent digestibilities of organic matter (OM), crude protein, crude fat, nitrogen-free extractives and energy were significantly reduced ivith increasing inclusion of lucerne and white-clover meal in the diet (P < 0·05). The total tract apparent digestibility of total fibre (TF) was significantly reduced with lucerne meal inclusion (P < 0·05), while the Heal apparent digestibility of TF was unaffected by lucerne and white-clover meal inclusion. Hindgut apparent digestibility (proportion of total tract apparent digestibility) of OM and energy was approximately 0·10, 0·70 and 0·70 for barley, lucerne and white-clover meal, respectively.

Both the Heal and total tract apparent digestibility of OM and energy were significantly higher for the control diet compared with lucerne and white-clover meal (P < 0·05). There was also a significantly higher apparent digestibility of OM, TF, crude fibre and energy in the total tract for white-clover meal compared with lucerne meal (P < 0·05). For neutral- and acid-detergent fibre a similar pattern was observed, however the effect was not significant.

The dietary digestible energy content was significantly reduced (F < 0·05), both at the ileum and over the total tract, with increasing inclusion offorage meal.

Employing practical-type diets containing graded levels of all-rac-α-tocopheryl acetate (0, 5, 15, 30, 45, 60, 75 or 100 mg/kg), the quantitative requirement for a-tocopherol by juvenile African catfish (Clarias gariepinus Burchell) was investigated. Diets, defined with respect to selenium, fatty acid and ascorbate inclusion, were offered for 12 weeks during which catfish grew from 10 g to 120 g. Dietary regime had no significant effect on growth (P > 0·05), although haematocrit values increased with increasing tocopherol dose above 15 mg/kg (assayed) (R2 = 0·71, P < 0·05). Tissue accretion of the vitamin increased concomitant with dietary dose (P < 0·001). Employing a colorimetric assay for thiobarbituric acid reactive substances (TBARS) it was evident that concentration ofTBARS in muscle and liver reflected tissue oxidation status, in that elevated dietary vitamin E resulted in decreased assayed TBARS (P < 0·05). By broken-line analysis the requirement for this species to suppress lipid peroxidation was estimated as 30 to 40 mg all-rac-a-tocopheryl acetate per kg dry diet and this agrees with published requirements of many fish species.

Growing pigs fitted with simple t-shaped cannulas posterior to the ileal-caecal valve were used in a change-over design experiment (5 × 5) to determine the Heal and total tract apparent digestibility and hindgut disappearance of dietary components and energy in a barley-based diet with increasing inclusion of either red-clover or perennial ryegrass meal (proportionately 0·10 and 0·20). The total tract and Heal apparent digestibilities of organic matter (OM), crude protein (CP), nitrogen-free extractives (NFE) and energy were significantly reduced with increasing inclusion of red-clover and perennial ryegrass meal in the diet (P < 0·05). For all fibrous components (total fibre (TF), neutral-detergent fibre (NDF), acid-detergent fibre (ADF) and crude fibre (CF)), the ileal apparent digestibility was unaffected by level offibre inclusion in the diet. Also the total tract apparent digestibility of TF, NDF and CF were unaffected by red-clover meal inclusion, while in contrast the total tract apparent digestibility of TF, NDF and CF were significantly reduced with perennial ryegrass meal inclusion (P < 0·05). The hindgut disappearance of crude fat, NDF, ADF and CF was not affected by forage meal inclusion, whereas the hindgut disappearance of OM, NFE, TF and energy were significantly lower in the perennial ryegrass meal diets than in both the control diet and the red-clover meal diets (P < 0·05).

The total tract apparent digestibility of OM was higher for the control diet compared with the red-clover and perennial ryegrass meal diets. There was also a significantly higher apparent digestibility of OM in the total tract for red-clover meal compared with perennial ryegrass meal (P < 0·05). The Heal apparent digestibility of energy in a barley-based diet with forage meal inclusion decreased proportionately by about 0·014, 0·023 and 0·030 units per unit increase ofTF, NDF and CF in dry matter, respectively. Correspondingly, for the total tract energy apparent digestibility, there was a decrease proportionately by about 0·010, 0·016 and 0·022 units per unit increase of TF, NDF and CF in dry matter, respectively. Digestible energy content was significantly reduced, as measured at the ileum or over the total tract, with increasing inclusion offorage meal (P < 0·05).

Bivariate individual animal model estimates of genetic and environmental correlations between reproduction traits (number born alive and average piglet weight) and performance test traits (ultrasonic backfat depth, average daily food intake, average daily gain and food conversion ratio) of Landrace pigs were calculated. The estimates were produced using a derivative-free restricted maximum likelihood algorithm to calculate likelihoods for different combinations of covariance parameters. A quadratic approximation to the likelihood surface was used to estimate the maximum likelihood values with respect to the covariance parameters. For all combinations of performance test traits with reproduction traits the resulting genetic and residual correlation estimates were low, with a maximum absolute value of 0·233 for the genetic correlation between food conversion ratio and number born alive. Standard errors of genetic correlation estimates were between 0·11 and 0·15. There is expected to have been little effect upon reproduction traits from the rigorous selection carried out upon performance test traits over the years. When incorporating reproduction data into best linear unbiased prediction analysis procedures it should be possible to analyse performance test and reproduction traits from this population separately, thereby making savings on computer resources and time required for the analysis of all traits.

Thirty-two male pigs were used to investigate the effects of nine levels of dietary lysine ranging from 0·41 to 1·30 g lysine per MJ gross energy (GE) on the performance of pigs weaned at 1 to 2 days of age and growing between 2 and 7 kg live weight. The nine dietary lysine treatments, which contained similar levels of GE and balance of essential amino acids, were offered to the pigs at a common feeding level of 2·0 MJ GE per kg metabolic live weight (M075) per day. Growth performance and protein deposition rates increased linearly with increasing dietary lysine content up to about 0·97 g lysine per MJ GE and remained relatively constant thereafter. The response of protein deposition (PD, g/day) in the whole body of pigs to dietary lysine (L, g lysine per MJ GE) was described by three models. The respective regression equation for the quadratic function was PD = -14·23 + 87·66 L – 36·00 L2 and maximum protein deposition occurred at 1·22 g lysine per MJ GE. The rectilinear model, which had an ascending linear phase (PD = 1·49 + 40·10 L, R2 = 0·98, P < 0·001) and a horizontal component representing a mean protein deposition rate of 39·7g/day revealed that maximum protein deposition occurred at 0·95g lysine per MJ GE. Finally, application of the asymptotic model also revealed a highly significant equation: PD = 43·40 — 79·99 × 0·07111, R2 = 0·94, P < 0·001; which indicates a dietary requirement of 1·07 g lysine per MJ GE assuming that the dietary requirement was estimated at 0·90 of the asymptote maximal value. The results indicate that the dietary lysine requirement for pigs during the first 3 weeks of life appears to have changed little over the past 20 years despite substantial changes in genotype.

Three groups of does were fed respectively with three experimental diets: control (C), vegetable fat enriched (V) and animal fat enriched (A). Also their offspring were given their respective diets from weaning to slaughter. C was a standard commercial diet, V had 99 g vegetable fat per kg, and A had 114 g animal fat per kg. Sixty animals in the live-weight range 1·75 to 2·25 kg from each group were slaughtered at 9 weeks of age. The rabbits came from a commercial three-way cross. Animals on diets A and V had a better food conversion efficiency ratio, a lower drip loss and a dressing yield substantially better than those given diet C. Males had higher food conversion rate and smaller dressing yield. Carcass colour was not affected by the diet but rabbits given diet V showed less pale meat. Differences in the three colour parameters were found for the three diets for hot and chilled carcass fat colour. Muscular pH measured in the longissimus dorsi and biceps femoris were slightly higher for diets A and V and were also higher for males than for females. Water-holding capacity of raw meat from rabbits given diets A and V was higher than from rabbits given the control diet. Protein and moisture content of the meat of a hind leg was almost the same for the three diets but fat content was much higher in animals given diets A and V than in the control group.

The effect of energy supply between 45 and 100 kg body weight (BW) on the contribution of lean tissue (muscle plus intermuscular adipose tissue) to total protein mass was studied in Large White castrated males (cLW), crossbred Piétrain × Large White castrated males (cPPx) and boars (bPPx). The pigs were allocated to four energy levels (0·70, 0·80, 0·90 or 1·00 ad libitum) and kept in metabolism cages in experiment 1 or given food ad libitum and kept in individual pens in experiment 2. Daily protein supplies were calculated to be non-limiting for growth and identical for all pigs in experiment 1. Temperature was 23°C in both experiments. The pigs were slaughtered at 100 kg BW and physically dissected; the body tissues were chemically analysed. Taking into account housing conditions, the food intake of pigs in experiment 2 corresponded to 1·20 of ad libitum intake of pigs in experiment 1; data of both experiments were combined. The energy supply and the type of pig influenced significantly the protein content of empty BW (eBW) (170 g/kg on average), of lean (184g/kg on average) and non-lean compartment (eBW minus lean, 152 g/kg on average), the proportion of total protein deposited in lean (604 g/kg of total protein, on average) but not the protein content in fat-free eBW (209 g/kg on average). The fat-free eBW can be predicted as 4·8 times the body protein mass.

The growth of male red deer slows during the first winter of life before increasing again during spring. This study aimed to determine if this period of slow growth could be minimized using artificial photoperiods during autumn and winter (10 April (week 1) to 11 September (week 23), southern hemisphere). Four groups of deer (no. = 10) were housed indoors as follows. Two groups were placed on a winter solstice photoperiod (8·5 light (L): 15·5 dark (D)) and given either a natural increase in photoperiod to 11·25L: 12·75D (WSN) or held on 8·5L: 15·5D for 7 weeks followed by an abrupt increase to 11·25L: 12·75D (WSH). One group was exposed to a summer solstice photoperiod of 16L: 8D (SS) and one group exposed to a natural photoperiodic pattern (IC). A fifth group of deer (no. = 10) was maintained outside on a gravelled enclosure under natural changes in photoperiod (OC). All groups were given a diet containing 160 g protein per kg and 11·0 MJ metabolizable energy per kg dry matter (DM) ad libitum. All animals were weighed weekly and group food intake recorded daily. Metatarsal length was measured at weeks 3,17 and 22 from the start of treatments.

The major differences occurred between SS and the other groups. After a period of slower growth (weeks 1 to 5, SS = 88 g/day v. 168 g/day other groups, s.e.d. 31·2, P < 0·05), SS grew more rapidly from week 10 (P < 0·01). As a result, SS was heaviest from week 17 (P < 0·05) until the end of the experiment (P < 0·01). The mean growth rate of SS animals from weeks 10 to 23 was 346 g/day compared with 173 g/day (s.e.d. 15·3; P < 0·001) for the other groups. Over the whole experiment, SS animals gained 42·3 kg live weight, compared with 31·1 kg for WSN, 26·6 kg for WSH, 25·1 kg for OC and 23·7 kg for IC (s.e.d. 2·08 kg P < 0·01). The DM intake of SS from week 9 until the end of the experiment averaged 2·04 kg DM per head per day compared with 1·48 (s.e. 0·041) kg DM per head per day for the mean of the other groups. Metatarsal length increased more in SS than the other groups (P < 0·001) between weeks 3 and 17 and was longest in SS at weeks 17 and 22 (P < 0·01). Exposure to a 16L: 8D photoperiod during winter advanced the rapid growth of red deer calves normally associated with spring and summer. This response may be used to advance slaughter dates for venison production.