The effect of reducing the frequency of official milk recording and the number of recorded samples per test-day on the accuracy of predicting daily yield and cumulative 305-day yield was investigated. A control data set consisting of 58 210 primiparous cows with milk test-day records every 4 weeks was used to investigate the influence of reduced milk recording frequencies. The accuracy of prediction of daily yield with one milk sample per test-day was investigated using 41 874 testday records from 683 cows. Results show that five or more test-day records taken at 8-weekly intervals (A8) predicted 305-day yield with a high level of accuracy. Correlations between 305-day yield predicted from 4-weekly recording intervals (A4) and from 8-weekly intervals were 0.99, 0.98 and 0.98 for milk, fat and protein, respectively. The mean error in estimating 305-day yield from the A8 scheme was 6.8 kg (s.d. 191 kg) for milk yield, 0.3 kg (s.d. 10 kg) for fat yield, and −0.3 kg (s.d. 7 kg) for protein yield, compared with the A4 scheme. Milk yield and composition taken during either morning (AM) or evening (PM) milking predicted 24-h yield with a high degree of accuracy. Alternating between AM and PM sampling every 4 weeks predicted 305-day yield with a higher degree of accuracy than either all AM or all PM sampling. Alternate AM-PM recording every 4 weeks and AM + PM recording every 8 weeks produced very similar accuracies in predicting 305-day yield compared with the official AM + PM recording every 4 weeks.

The present study compared the performance and development of adverse behaviours of pigs with intact tails, when housed in a straw-bedded system or a part-slatted system enriched with a commercial device. The pigs had previously received different enrichment treatments (rooting box, liquid dispenser, straw bedding or none), either in the farrowing crate or with their lactating dam or post weaning. The pigs were mixed in groups at 10 weeks of age and from then on, every 2 weeks, behavioural observations were performed, focusing mainly on harmful social behaviour and enrichment use. The study showed that pigs with undocked tails can be at high risk of tail biting in part-slatted systems, whereas the straw bedding prevented the development of tail biting. The immediate effects of the environment seemed to exert a greater influence on the development of adverse behaviour than early life enrichment and adding a simple enrichment device could not compensate for the deficiencies in the barren environment of the part-slatted system. In order to prevent vice, functional design of environmental enrichment is required.

Eighty-seven Manchego sucking lambs raised exclusively on maternal milk were slaughtered. The carcasses were weighed immediately after dressing and classified according to hot carcass weight (HCW): low HCW (<5.5 kg), medium HCW (5.5 to 6.5 kg) and high HCW (≥ 6.5 kg). The effects of this classification system on carcass and meat quality were studied. Carcass conformation improved as carcass weight increased; carcasses became more compact. Carcass fatness increased (P < 0.001) as carcasses became heavier. With regard to the joints, leg (P < 0.001) and shoulder (P < 0.05) proportions decreased as carcass weight increased, whereas loin-rib (P < 0.001) and flank (P < 0.001) proportions increased. The proportion of fat in the leg clearly increased in the heavier carcasses (P < 0.001), while that of bone decreased (P < 0.001) and that of muscle was not affected. pH at 24 h in the m. longissimus dorsi and m. semitendinosus decreased as carcass weight increased. The only meat colour parameter affected by carcass weight was the yellowness index; lighter-weight carcasses displayed lower index (P < 0.05). Cooking losses were unaffected as carcass weight increased, whereas with regard to tenderness, the shear force value tended to be higher in the low carcass weight group. No differences between carcass weight groups were found in the sensory analysis. Fatty acid composition did not show any significant effect due to carcass weight except in stearic fatty acid (C18:0); C18:0 proportion decreased (P < 0.01) as carcasses became heavier. Carcass weight affected carcass quality (all carcass quality parameters studied were higher in the heavier carcasses), whereas meat quality varied little as a result the small variation between carcass weights in sucking lambs.

The influence of the physical structure level in the diet on animal performance was investigated in 52 Belgian Blue doublemuscled bulls starting from a live weight of 348 kg until slaughter at about 645 kg. Four diets with different concentrate/maize silage ratios were offered ad libitum. The structural value (SV), developed in Belgium as a measure of physical structure in the diet for dairy cows, amounted to respectively 0.63 (HSV; high SV), 0.54 (MSV; moderate SV), 0.43 (LSV; low SV) and 0.34 (VLSV; very low SV) per kg dry matter.

Growth rate, food intake and food conversion were all linearly affected by the decreasing SV of the diet. Among carcass parameters only the SEUROP conformation score showed a significant effect of the SV, with the MSV group having the highest score and VLSV the lowest. No important influence of the SV on the histological damage of the ruminal papillae or on the foot lesions was found.

Based on the lower growth rate and food intake of the LSV group versus the HSV group, a SV of the diet between 0.54 and 0.43 is considered as an absolute minimum for Belgian Blue double-muscled bulls.

Two experiments were carried out to examine the effects of the timing and duration of mineral supplementation of the ewe's diet in the final 6 weeks of gestation on immunoglobulin G (IgG) absorption by their progeny. In experiment 1, 60 single-bearing ewes were allocated to one of four dietary treatments (no. = 15) and offered a basal diet of grass silage ad libitum, containing 50 g/kg molassed sugar-beet pulp, which was supplemented with concentrates for the final 7 weeks of pregnancy and were additionally provided with a daily mineral/vitamin supplement for the final 6 weeks (W-6), 4 weeks (W-4), 2 weeks (W-2) or no mineral/vitamin supplement, (control; W-0). The supplement contained Ca, P, Na, Mg, Mn, Zn, Se, Co, I and vitamin E and was offered at the daily rate of 48 g per ewe. The ewes were milked at 1, 10 and 18 h post partum and measured quantities of colostrum, proportional to birth weight were fed back to the progeny via a stomach tube. At each milking, colostrum yield was recorded and colostrum samples taken to determine the concentration and yield of IgG. Treatment had no effect (P > 0.05) on the yields of colostrum or IgG to 18 h post partum. The efficiency of IgG absorption was lower (P < 0.001) in the progeny of ewes who received supplementary minerals (W-6, 0.069, W-4, 0.078, W-2, 0.072, W-0, 0.261; s.e. 0.0244. P < 0.001) regardless of the duration of the mineral/vitamin supplementation period and this resulted in a reduced concentration of IgG in the lamb's serum. In experiment 2, 40 twin-bearing ewes were allocated to one of four dietary treatments (no. = 10) and offered a basal diet of grass silage ad libitum which was supplemented initially with 500 g of a concentrate containing 140 g crude protein (CP) per kg from day 98 to 133 of gestation and then replaced with 700 g/day of a concentrate containing 180 g/kg CP from day 134 of gestation until lambing, in addition to one of the following mineral/vitamin supplementation treatments : no supplementary minerals, W0 (control); 48 g of supplement per ewe per day in weeks 6 and 5 pre- partum (W6–5), or weeks 4 and 3 pre-partum (W4–3), or for the final 2 weeks pre-partum (W2–1). The ewes were milked and the lambs fed as in experiment 1. Again, treatment had no effect (P > 0.05) on the yields of colostrum or IgG to 18 h post partum. When ewes were offered the mineral/vitamin supplement in the final 2 weeks of gestation their progeny had a lower (P < 0.01) serum IgG concentration (4.6 g/l) than in the control treatment (14.0 g/l) or when the supplement was offered either in weeks 3 and 4 (11.3 g/l) or weeks 5 and 6 pre-partum (14.3 g/l). IgG absorption efficiency followed the same pattern as lamb serum IgG concentration. We conclude that supplementation of the ewe's diet at the level used in these studies for the final 2 weeks of pregnancy results in the production of offspring with a reduced ability to absorb colostral IgG. Furthermore, in order for this impairment of the IgG absorptive ability of the lamb to manifest itself the supplementation must occur for the final 2 weeks of gestation and supplementation for a 2-weekly period earlier in gestation will not elicit the same effect.

The objective of this study was to examine the effect of increased maternal nutrition in early to mid gestation on changes in serum growth factors of the sow and foetuses. Furthermore, the effect of the foetal sera on in vitro proliferation and differentiation of porcine primary myoblasts was examined. Pregnant sows were either given food either in accordance to requirements (2 kg/day; C) until day 50 or 70 of gestation or given food in accordance to requirements until day 25 and then ad libitum (A) until day 50 or 70. Sows were slaughtered at the Institute's veterinary controlled slaughterhouse at day 50 or 70, respectively. Serum from sows and pools of cord-blood serum from each litter were analysed for glucose, lactate, insulin, insulin-like growth factor (IGF; IGF-1 and -2) and IGF binding proteins (IGFBPs). IGF-1 (P < 0·001) was higher in A compared with C sows, and a 28-kDa IGFBP (P < 0·05) and a 24-kDa IGFBP (P < 0·05) was higher in serum from day 70 compared with day 50 sows. There was no significant effect of food intake on growth factor concentrations in foetal serum or on serum-induced proliferation and differentiation of myoblasts. A 28 kDa IGFBP, IGFBP-2 and -3 were all higher (P < 0·06) and serum-induced proliferation (P < 0·001) and differentiation (P < 0·1) lower at day 70 than day 50. Maternal food intake did not influence the DNA and RNA concentrations and the CPK activity in the foetal longissimus dorsi muscle. The glucose concentration in the liver was higher in C than A foetuses at day 70 of gestation, but not at day 50.

In conclusion, no significant effects of maternal nutrition were found on serum growth factor concentrations in the foetuses or on serum-induced proliferation and differentiation of primary myoblasts.

The magnitude of the discrepancy between conventional regression estimates of protein retention efficiency and theoretical estimates of synthesis efficiency indicates a major contribution ascribable to protein turn-over in the generally accepted estimates. As protein turn-over is known to be influenced by diet, feeding level and degree of maturity, this suggests the development of an estimator of protein efficiency that can be adapted for such differences. Therefore, based on generally accepted formulas for growth description, a method of estimating protein retention efficiency was developed which is flexible enough to accommodate different diets, feeding levels and degrees of maturity. Moreover, a formula was derived to convert one type of estimate to the other by regarding constant efficiency as equivalent to variable efficiency at the mid point of the estimation interval. Increase in scientific depth to this descriptive approach is provided by a theoretical consideration of a possible mechanism of hormonal control of protein synthesis and breakdown, ultimately expressed as proportionalities to powers of whole body protein (P). Molecular considerations on cellular synthesis and breakdown indicate a difference between breakdown and synthesis powers equal to (2/9)Q. The factor (2/9) is indicated by an argument based on insulinlike growth factor derived activator diffusion attributes by nucleus and body tissue geometries, while Q is equal to the proportion of nuclei activated by insulin-like growth factor. This proportion is likely to be a function of the concentration of growth factor in the blood. Hence, a linear relationship between intake and blood insulin-like growth factor concentration suggests that Q can be represented by a scaled transformation of intake, 0 ≤ Q ≤ 1, such that a value of Q = 1 represents ad libitum intake on a suitable diet and Q = 0 intake at the maintenance requirement. The quantification of breakdown and synthesis power differences by (2/9)Q leads to kP = {1 + [1 − (P/α)(2/9)Q]−1/6}−1, for turn-over related protein retention efficiency (kP), with α the limit value of P at maturity, so that 0 ≤ (P/α) ≤ 1. Experimental estimates, derived from direct estimates of whole body protein synthesis and breakdown at predetermined levels of intake, are in excellent agreement with the theoretical (2/9)Q in the power associated with (P/α) in kP. Furthermore, conventional multiple regression retention efficiencies satisfactorily approximate the turn-over related retention efficiency that can be calculated at a given level of intake for the mid point of the interval covered by the regression estimates.

During winter in southern Queensland, eight rusa deer stags aged 4 years were given ad libitum lucerne (Medicago sativa) hay and confined in individual metabolism pens for 26 days. Stags ate 2·04 kg dry matter (DM) per day and drank 6·4 kg water per day, while the drinking water: food DM ratio was 3·3 l/kg. In experiment 2, seven rusa stags were given ad libitum lucerne hay or oaten (Avena spp.) hay with or without barley grain supplementation (200 g/day) for 56 days (four periods). This experiment was conducted from 26 July to 19 September 2001, when the stags were exhibiting the behaviour characteristic of the rut. Rusa stags ate 1·19 and 1·17 kg DM per day of lucerne and oaten hay respectively. Rusa stags given oaten hay drank slightly more water than those that received lucerne hay (5·34 and 4·47 kg/day, respectively). The drinking water: food DM ratios were 3·81 and 4·67 kg/kg for lucerne and oaten hay, respectively. Barley grain supplementation (200 g/day) had no influence on total food or water intakes of the rusa stags.

Approximately 5% of pigs slaughtered in the UK have been tail-bitten, leading to welfare and production issues. Tail biting is sporadic and not all pigs tail bite. The aim of this study was to identify factors that are common in pigs that perform tail-biting behaviour, and that might be used in a predictive way to identify such animals.

The behaviour of 159 pigs was observed in the post-weaning period. Pigs were weaned at 4 weeks of age. In the week prior to weaning and at 6 weeks of age each pig was individually tested in a tail chew test (tail chew test 1 and 2, respectively). The tail chew test involved recording the pig's behaviour directed towards two ropes, one of which had been soaked in saline solution and the other not. The production performance of the pigs was recorded from birth to 7 weeks of age. Time spent performing tail-biting behaviour correlated positively with time in contact with the rope in tail chew test 2 (r = 0·224, P < 0·05), and time spent ear biting correlated positively with time spent in rope directed behaviour in tail chew test 1 (r = 0·248, P < 0·01). Pigs that spent as much as 1·5% of their time of more performing tail-biting behaviour were lighter at weaning (26 days) and tended to be lighter at 7 weeks of age compared with pigs that spent less than 1·5% of their time performing tail-biting behaviour (weaning weight: ≥1·5% tail biting 8·96 kg, <1·5% tail biting 9·67 kg, P < 0·05; 7-week weight: ≥1·5% tail biting 15·75 kg, <1·5% tail biting 17·09 kg, P < 0·08). There was no significant difference in birth weight between pigs that spent ≥ or <1·5% of their time performing tail-biting behaviour. Pigs that spent 1·5% of their time or more performing tail-biting behaviour showed significantly lower growth rates between birth and weaning (≥1·5% tail biting 260 g/day, <1·5% tail biting 285 g/day, P < 0·05) but not between weaning and 7 weeks of age (≥1·5% tail biting 343 g/day, <1·5% tail biting 365 g/day, P > 0·05).

The results suggest that pigs that tail bite have some nutritional deficiency that results in performance of foraging behaviour that is expressed in intensive housing as ear/tail biting.

The effect of site of starch digestion on glucose metabolism in dairy cows was studied. Four multiparous Israeli-Holstein cows in mid lactation were used in a 4 × 4 Latin-square design. Average body weight of cows was 580 ± 38 kg, and average milk yield was 28 ± 3 kg/day. The cows were fitted with ruminal cannula and flexible T-cannulae in abomasum and ileum. Treatments were as follows : CON (control) : water was infused to the rumen. SR (starch-rumen) : 1.5 kg/day of maize starch solution was infused into the rumen. SA (starch-abomasum) : 1.5 kg/day of maize starch solution was infused into the abomasum. SCA (starch-casein-abomasum) : 500 g/day sodium caseinate and 1.5 kg/day of maize starch solution was infused into the abomasum. Total intake of dry matter (DM), was similar in all treatments and averaged 19.9 kg/day. Total non-structural carbohydrate (TNC) intake averaged in 6.8 kg/day. The average TNC digested in the rumen was 4.95 kg/day for CON and SR cows and 3.34 kg/day for the SA and the SCA cows. The average TNC digestion in the small intestine was 1.18 kg/day for CON and SR cows and 2.41 kg/day for the SA and SCA cows. TNC digestibility in the small intestine was highest for the SCA cows at 0.83 as compared with other treatments. Concentrations of plasma glucose and insulin were similar between treatments. No difference between treatments in total volatile fatty acid (VFA) concentration in ruminal fluids was observed. However, propionate proportion in total VFA was higher in the SR cows than in other treatments (P < 0.04). Milk yield and composition were not affected by treatments in the present study. It was concluded that the amount of dietary protein in the small intestine has a considerable effect on TNC digestibility. Under conditions of high milk production and high rumen-by-pass TNC flow, efficiency of TNC utilization might be greater since TNC is digested in the small intestine rather than in the rumen.

The nutritional cost of both the acquisition and maintenance of immunity to gastro-intestinal nematodes was investigated using immunologically naïve 5-month-old lambs and immunologically competent 17-month-old ewes. Within each age cohort, animals were either infected with the equivalent of 80 L3 Trichostrongylus colubriformis larvae per kg live weight (LW) per day (IF), similarly infected and concurrently immuno-suppressed with weekly injections of 1·3 mg/kg LW of the glucocorticoid methylprednisolone acetate (ISIF), immuno-suppressed only (IS) or remained as controls (C). Body composition of all animals was estimated using X-ray computer tomography on days -14 and 76 relative to the start of infection. Body weight and faecal nematode egg counts (FEC; eggs per gram of fresh faeces (e.p.g.)) were taken weekly and blood samples for serum proteins and antibodies were obtained every 2 weeks. FEC in IF lambs peaked at 1250 e.p.g. before a typical decline as immunity developed to less than 100 e.p.g. by day 75. FEC of less than 100 e.p.g. in IF ewes indicated immunity was maintained. Successful immuno-suppression in ISIF lambs and ewes was indicated by FEC of 4000 e.p.g. on day 75 and was confirmed by comparative worm burdens and serum antibody titres. The typical reduction in voluntary food intake (VFI) as a consequence of infection was observed in IF lambs (proportionately 0·30, P < 0·001) but not in IF ewes, ISIF lambs or ISIF ewes. Gross efficiency of use of metabolizable energy for net energy deposition was reduced by proportionately 0·20 in lambs during acquisition of immunity and by 0·16 in ewes maintaining an established immunity. Infection in immuno-suppressed animals reduced efficiency by 0·05 and 0·15 for lambs and ewes, respectively. These findings allowed the hypothesis that the reduction in VFI and loss in performance in young parasitised sheep is caused by physiological signalling associated with the acquisition phase of the host immune response to infection, rather than simply the damage caused by the parasite per se.

Three experiments were carried out to evaluate the effects of varying levels of mineral and iodine supplements when offered to ewes in late pregnancy on lamb serum immunoglobulin G (IgG) concentrations. In experiment 1, 44 individually housed ewes were allocated to one of four treatments (no. = 11) and offered a basal diet of grass silage ad libitum which was supplemented with 500 g/day of a concentrate (190 g/kg of crude protein (CP)), in addition to mineral/vitamin fortification at the rate of 0 g (C), 17.3 g (LM), 34.6 g (MM) or 52.0 g (HM) per day for the final 7 weeks of pregnancy. The mineral/vitamin supplement contained Ca, P, Na, Mg, Mn, Se, I, Co, Mn and vitamin E. The ewes were milked at 1 h, 10 h and 18 h post partum and measured quantities of colostrum, proportional to lamb birth weight, were fed back to the lambs via a stomach tube. Treatment had no effect on total colostrum yield or total IgG yield to 18 h post partum (P > 0.05). There was a linear decrease in serum IgG concentration and IgG absorption efficiency as mineral supplementation increased (P < 0.001). In experiment 2, which was carried out in conjunction with experiment 1, 44 ewes were allocated to four treatments (no. = 11) and offered the same basal silage/concentrate diet as in experiment 1, in addition to receiving one of the following supplements : (C) control, as in experiment 1; (HM), as in experiment 1; (−I), ewes offered the same mineral/vitamin supplement as HM but with iodine excluded; (I0), ewes offered a daily mineral supplement of iodine only at a level of 40 mg per ewe, equivalent to the iodine inclusion in the 52 g of minerals offered in HM. The iodine-supplemented progeny (HM and IO) had lower (P < 0.001) serum IgG concentrations and higher soil scores (P < 0.05) than the C and −I progeny. In experiment 3, the effects of varying levels of iodine supplementation when offered to ewes during the final 6 weeks of pregnancy on lamb serum IgG values were examined. Forty-eight individually housed ewes were allocated to one of four treatments (no. = 12) and offered grass silage ad libitum, which was supplemented initially with 500 g of a concentrate (140 g/kg of CP) from days 99 to 130 of gestation and then replaced with 700 g/day of a concentrate (180 g/kg of CP) from day 131 of gestation until lambing. In addition, the diet of each ewe was supplemented on a daily basis with iodine at the rate of 0 mg (C), 8.9 mg (LI), 17.7 mg (MI) or 26.6 mg (HI). There was a negative linear reduction in serum IgG concentration and IgG absorption efficiency as maternal dietary iodine supplementation increased (P < 0.001). We conclude that supplementation of the ewe's diet in late pregnancy with 17.3 g of a mineral supplement as formulated in the current experiment lowers the lamb's ability to absorb colostral IgG, and offering only the iodine component of this mineral supplement, at a level which approximates to about one third of currently quoted toxicity levels, will result in reduced serum IgG concentration in the lamb. These findings suggest the need to re-examine current toxicity values for iodine.

One hundred and eighty piglets (24 days old, 6·0 kg live weight) were used to investigate interactions between lactose, avilamycin and inulin on growth performance and nutrient digestibility in weaned piglets. The piglets were blocked on the basis of live weight and within each block assigned to one of six dietary treatments (six replicates (pens) per treatment). The piglets were offered diets containing either a low (175 g/kg) or high (295 g/kg) lactose levels with one of the following food additives (1) 0 supplementation (2) avilamycin (60 mg/kg) or (3) inulin (15 g/kg) in a 2 × 3 factorial arrangement. The starter diets were offered for 21 days and all diets contained chromium III oxide at 150 p. p. m. There was an interaction (P < 0·05) between lactose level and both avilamycin and inulin on average daily gain (ADG) during the starter period (days 0 to 21). The pigs receiving 295 g/kg lactose level had a higher overall ADG than pigs receiving 175 g/kg lactose level. However, there was no difference between 295 g/kg lactose and 175 g/kg lactose in ADG when the diets were supplemented with avilamycin or inulin. There was an interaction between lactose level and inulin in the apparent digestibility of gross energy (GE) and nitrogen (N) (P < 0·05). The inclusion of inulin with 175 g/kg lactose increased GE digestibility compared with the 175 g/kg lactose only diet. However, the inclusion of inulin with 295 g/kg lactose had no effect on GE digestibility. The inclusion of inulin with 295 g/kg lactose reduced N digestibility compared with the inclusion of inulin at 175 g/kg lactose. However, there was no difference in N digestibility between 175 and 295 g/kg lactose only diets. In conclusion, there was no benefit in terms of pig growth rate to supplementing diets high in lactose with either inulin or avilamycin. However, the inclusion of inulin improved the energy digestibility of diets low in lactose.

Digestibility and nitrogen (N) balance studies were carried out on the leaves of short-term (ST) and long-term (LT) varieties of cassava, preserved by sun-drying and grinding into a meal or by ensiling. The cassava leaf meal and ensiled leaves (471 and 373 g/kg total diet dry matter, respectively) were mixed with palm syrup and palm oil, to give the experimental diets CLM and CLS, respectively. Four Mong Cai (MC) (17·2 (s.e. 2·61) kg) and four Landrace × Yorkshire (L×Y) (41·5 (s.e. 2·12) kg) male castrate pigs were used. The experiment was designed as a 2 × 2 × 2 factorial, with breed, cassava variety and processing method as factors.

The hydrogen cyanide (HCN) levels of the fresh cassava leaves of ST (545 mg/kg dry matter (DM)) and LT (408 mg/kg DM) varieties were reduced by proportionately 0·63 and 0·33, respectively, after sun-drying and by 0·78 and 0·77, respectively, after ensiling. Intake was higher for DM, crude protein (CP) and organic matter (OM) (P < 0·001) and neutral- and aciddetergent fibre (NDF and ADF) and crude fibre (CF) (P <0·01) in CLM than in CLS. There was a breed by processing method interaction for CF intake (P < 0·05). The coefficient of total tract apparent digestibility (CTTAD) was higher in CLS than in CLM for DM, CP, OM and CF (P < 0·001) and NDF and ADF (P < 0·01). The MC pigs digested ADF (P < 0·01) and CF (P < 0·001) more effectively than L×Y pigs but there was no difference (P > 0·05) in the digestibility of other nutrients or DM. There was a breed by cassava variety interaction for ADF digestibility and breed by processing method for CF digestibility (P < 0·01). Daily N intake and faecal N were higher (P < 0·001) in CLM than in CLS. Urinary N was lower in CLS than in CLM (P < 0·05) and in L×Y than in MC pigs (P < 0·001). N utilization (N retained per unit intake) was higher for CLS than CLM (P < 0·001) and in L×Y than in MC pigs (P < 0·001). It is concluded that ensiling is a more effective method than sun-drying for reducing HCN in cassava leaves after 60 days re-growth, and also results in higher digestibility of DM and dietary components than sun-drying. However, the bulkiness of the silage limits intake. The MC pigs digested dietary fibre more efficiently than the L×Y pigs, whereas the L×Y pigs utilized N more efficiently than the MC pigs.

The lactation cycle of the dairy cow induces large changes in body fat and protein pools, which can be monitored through loin backfat (BF) and longissimus dorsi (LD) measurements. Data from two experiments (exp) using Holstein-Friesian dairy cows (no. = 40 and 32 respectively) were used to study the association of body weight (BW), BF and LD depth with body condition score (BCS) for the last 6 weeks of the dry period (DP) and the first 8 weeks of lactation. Loin and tail BCS were manually assessed (0 to 5 scale) and BF and LD depth were measured by ultrasound at the fifth lumbar process. The BCS data ranged from 1.3 to 3.0 units in the DP, and from about 1.1 to 3.1 units during early lactation in both experiments. Data were analysed by two models: BW, LD or BF = exp + period (DP or lactation) + BCS + interactions + cow + error (model 1); and BCS = exp + period + LD + BF + LD2 + BF2 + exp × LD + exp × BF + exp × LD2 + exp BF2 + period × LD + period × BF + period × LD2 + period × BF2 BF2 + cow + error (model 2).

A first-order autoregressive (AR(1)) covariance structure was employed for the error terms to account for the correlation among repeated measures within cow. Regressions of BW and LD on BCS (model 1) found pre- to post-calving differences (P < 0.001) in intercept for BW and LD, and slope coefficients of 35 (DP) and 21 (lactation) kg BW, and 5.8 mm LD per BCS unit. Regression of BF on BCS (model 1) showed an exp × period interaction (P < 0.001), with 0.4 mm BF (exp 1; P < 0.05) and 2.0 mm BF (exp 2; P < 0.001) per BCS unit. Regression of BCS on LD and BF (model 2) showed intercepts not equal to 0 (P < 0.06), and differences (P < 0.001) between DP and lactation; BCS increased (P < 0.001) by 0.027 units per mm BF and 0.05 units per mm LD, but LD had a quadratic term −0.0004 (P = 0.02). It is concluded that at BCS lower than 3, LD contributes to BCS following a quadratic function, whereas BF causes BCS to increase linearly. Each unit of BCS equated to about 35 and 20 kg BW for DP and lactation periods respectively, to 5.8 mm LD, and to between 0.4 and 2.0 mm BF.

An experiment was carried out to investigate the effects of increasing the digestible undegradable protein (DUP) concentration of concentrates on colostrum production and lamb output from prolific ewe breed types. Sixty triplet-bearing ewes with a mean condition score of 3.75 were allocated to one of five treatments (no. =; 12) for the final 6 weeks of pregnancy. Four of the treatments were offered a restricted grass diet (0.6 kg dry matter (DM) per day) plus one of four isoenergetic and isonitrogenous concentrates (0.56 kg DM per day) that were formulated to provide 25 (P25); 40 (P40); 75 (P75) and 95 (P95) g DUP/kg DM. Control ewes were offered a grass-only diet with the aim of achieving an equivalent total DM intake (1.16 kg DM per day). Concentrate composition had no effect on total diet DM, crude protein or metabolizable energy intakes, but the intake of DUP increased with increasing concentrate DUP level (P < 0.001). Supplementing grass with concentrates led to significant reductions in plasma β-hydroxybutyrate (P < 0.05) and non-esterified fatty acids(P < 0.001) concentrations. Plasma urea concentration tended to be negatively and linearly related to the concentrate DUP level (P < 0.1). Colostrum production and composition were not affected by concentrate type, except for the concentration of gross energy which was highest for P40 ewes. Concentrate feeding led to significant (P < 0.05) increases in colostrum yield 18 h post lambing and colostral outputs of ash, crude protein, total solids and gross energy but resulted in a lower (P < 0.05) colostral immunoglobulin G concentration. Lamb birth weight and total litter weight were not affected by late pregnancy feeding regime. However lamb survival to weaning was reduced significantly (P < 0.05) for P25 and control ewes, resulting in lower levels of lamb output at weaning. The results from this study indicate that offering rumen undegradable rather than rumen degradable protein has no effect on colostrum production and lamb performance when ewes are offered high quality grass-based diets in late pregnancy.

Based on the potential benefits of cis-9, trans-11 conjugated linoleic acid (CLA) for human health there is a need to develop effective strategies for enhancing milk fat CLA concentrations. In this experiment, the effect of forage type and level of concentrate in the diet on milk fatty acid composition was examined in cows given a mixture of fish oil and sunflower oil. Four late lactation Holstein-British Friesian cows were used in a 4 × 4 Latin-square experiment with a 2 × 2 factorial arrangement of treatments and 21-day experimental periods. Treatments consisted of grass (G) or maize (M) silage supplemented with low (L) or high (H) levels of concentrates (65 : 35 and 35 : 65; forage : concentrate ratio, on a dry matter (DM) basis, respectively) offered as a total mixed ration at a restricted level of intake (20 kg DM per day). Lipid supplements (30 g/kg DM) containing fish oil and sunflower oil (2 : 3 w/w) were offered during the last 14 days of each experimental period. Treatments had no effect on total DM intake, milk yield, milk constituent output or milk fat content, but milk protein concentrations were lower (P < 0.05) for G than M diets (mean 43.0 and 47.3 g/kg, respectively). Compared with grass silage, milk fat contained higher (P < 0.05) amounts of C12:0, C14:0, trans C18:1 and long chain ≥ C20 (n-3) polyunsaturated fatty acids (PUFA) and lower (P < 0.05) levels of C18:0 and trans C18:2 when maize silage was offered. Increases in the proportion of concentrate in the diet elevated (P < 0.05) C18:2 (n-6) and long chain ≥ C20 (n-3) PUFA content, but reduced (P < 0.05) the amount of C18:3 (n-3). Concentrations of trans-11 C18:1 in milk were independent of forage type, but tended (P < 0.10) to be lower for high concentrate diets (mean 7.2 and 4.0 g/100 g fatty acids, for L and H respectively). Concentrations of trans-10 C18:1 were higher (P < 0.05) in milk from maize compared with grass silage (mean 10.3 and 4.1 g/100 g fatty acids, respectively) and increased in response to high levels of concentrates in the diet (mean 4.1 and 10.3 g/100 g fatty acids, for L and H, respectively). Forage type had no effect (P > 0.05) on total milk conjugated linoleic acid (CLA) (2.7 and 2.8 g/100 g fatty acids, for M and G, respectively) or cis-9, trans-11 CLA content (2.2 and 2.4 g/100 g fatty acids). Feeding high concentrate diets tended (P < 0.10) to decrease total CLA (3.3 and 2.2 g/100 g fatty acids, for L and H, respectively) and cis-9, trans-11 CLA (2.9 and 1.7 g/100 g fatty acids) concentrations and increase milk trans-9, cis-11 CLA and trans-10, cis-12 CLA content. In conclusion, the basal diet is an important determinant of milk fatty acid composition when a supplement of fish oil and sunflower oil is given.

Two isonitrogenous, isocaloric and isofibrous diets for finishing beef cattle differing only in their roughage constituents were compared in a feeding trial with Limousin bulls. A control maize silage (chop length = 9 mm) and wheat straw were the roughage sources of the former diet representing 0·23 and 0·09 of the dietary dry matter (DM) respectively. These roughage sources were fully replaced in the latter by the inclusion of a coarsely chopped maize silage (19 mm) at a level of 0·45 of the total dietary DM. Two balanced groups of 20 Limousin bulls (425·8 ± 20·3 kg live weight) each allotted in four pens were given the two diets ad libitum for a finishing period of 138 days. The different dietary roughages did not affect either bull growth performance (average daily gain = 1·39 ± 0·25 kg/day) or food conversion ratio. However, the diet containing the coarse silage significantly (P < 0·05) reduced the intake of both DM (8·30 v. 9·02 kg/day) and neutral-detergent fibre (NDF) (2·64 v. 2·92 kg/day). Although total ruminating time was similar for both diets, bulls given the coarse maize silage diet spent more time ruminating 1 kg of DM or NDF, probably due to the higher percentage of dietary forage NDF. No food selection activity towards specific chemical constituents was observed in either diet. Slaughter measurements and meat quality were satisfactory and unaffected by the type of dietary roughage. Based on cattle growth performance, feeding behaviour, and meat quality, the use of coarse maize silage as a dietary source of roughage can be considered a feasible alternative in beef cattle finishing.

Abstract The study evaluates the effects of two dietary Ca: P ratios (1·5: 1 v. 2·5: 1) and metabolizable energy (ME) contents (17·3 MJ/kg dry matter (DM) v. 19·2 MJ/kg DM) on the development of osteochondrosis, foot bending and performance in juvenile male blue foxes (Alopex lagopus). Four experimental groups (no. = 10 per group) were formed : (1) low energy, lagopus). low Ca: P (LELC); (2) normal energy, low Ca: P (NELC); (3) low energy, normal Ca: P (LENC); and (4) normal energy, normal Ca: P (NENC). The experiment started at weaning in mid July and finished in early October. From mid August onwards, animals on the normal energy diets (NELC, NENC) grew significantly faster (P < 0·001) than animals on the low energy diets (LELC, LENC). The final body weights of the normal energy groups were 1·5 kg higher than those of the low energy groups (P < 0·001). The dietary Ca: P ratio did not affect live-weight gain. Foot bending increased significantly from summer to autumn (P < 0·001). Changes in foot bending between initial and final evaluations showed that bending was significantly greater (P < 0·05) in animals on normal energy (NELC, NENC) than on low energy diets (LELC, LENC). Significant differences were not found in the mean degree of damage in foot and cartilage between the groups. Ulna breaking strength was significantly higher (P < 0·05) in normal energy (NELC, NENC) than in low energy (LELC, LENC) animals. Ulna calcium and phosphorus concentrations of the normal Ca: P (LENC, NENC) groups were significantly higher (P < 0·001, P < 0·05) than those of the lower Ca: P (LELC, NELC) groups. The bone (ulna) calcium and phosphorus concentrations tended to be higher in the normal energy (NELC, NENC) than in the low energy (LELC, LENC) groups (calcium P = 0·07; phosphorus P = 0·06). The bone Ca: P ratio was higher (P < 0·001) in the normal (LENC, NENC) than in the low Ca: P diet (LELC, NELC) animals. The carcass weights of normal energy animals (NELC, NENC) were significantly higher (P < 0·001) than those of low energy (LELC, LENC) animals. The fat : dry matter ratio was higher (P < 0·05) in normal (NELC, NENC) than in low energy (LELC, LENC) carcasses. We conclude that the Ca: P ratio of the diet has no effect on the development of osteochondrosis or bending of the foot. The higher body weight caused by normal as opposed to low metabolizable energy content seems, however, to increase the incidence of foot bending.

Abstract Visible (VIS) and near infrared (NIR) reflectance spectroscopy combined with multivariate data analysis were explored to predict fibre diameter in both clean and greasy Merino wool samples. Fifty clean and 400 greasy wool samples were analysed. Samples were scanned in a large cuvette using a NIRSystems 6500 monochromator instrument by reflectance in the VIS and NIR regions (400 to 2500 nm). Partial least square (PLS) regression was used to develop a number of calibration models between the spectral and reference data. Different mathematical treatments were used during model development. Cross validation was used to assess the performance and avoid overfitting of the models. The NIR calibration models gave a coefficient of determination in calibration (R2) > 0·90 for clean wool samples and a R2 < 0·50 for greasy wool samples. The values for the residual predictive value, RPD (ratio of standard deviation (s. d.) to the root mean square of the standard error of cross validation (RMSECV)) were 3 for clean and 0·6 for greasy wool samples, respectively. The results indicated that fibre diameter in greasy wool samples was poorly predicted with NIR, while clean wool showed good relationships.

More research is required to improve the calibration on greasy wool samples if the technology is to be used for rapid analysis to assist in the selection of animals in breeding programmes.