The dry-matter (DM) intake and growth rate in male lambs were predicted from rumen degradability characteristics, rumen DM losses at different times, neutral- or acid-detergent fibre (NDF or ADF) contents and DM apparent digestibility of roughages. Four different straws consisting of wheat, barley, oat and rice were each offered ad libitum to 24 Merino male lambs with 200 glday concentrate for 4 weeks to determine DM intake and growth rate. Apparent digestibilities of the straws were measured with three Merino male sheep. Measurements were made during the last 10 days of each 20-day period. The degradation characteristics of the straws were measured by incubating samples in nylon bags for 8, 16, 24, 48, 72 and 96 h in the rumens of three Merino male sheep fitted with rumen cannulae. The exponential model p = a + b(l - er^) was fitted to the data. Potential degradabilities of DM (defined as a + b) and apparent digestibilities of DM ranged from 530 to 679 and 440 to 560 g/kg, respectively. The mean DM intake of the straws varied from 543 to 745 glday, the digestible DM intake from 236 to 417 glday and growth rate from 17 to 95 glday. Using the degradation characteristics A, B and c in a multiple regression analysis, the correlation coefficients with DM intake and growth rate were 0·79 and 0·70, respectively. NDF and ADF were related to DM intake (i = 0·65; r = 0·64) and growth rate (r = 0·55; r = 0·56). The correlation coefficient between DM apparent digestibility and DM intake was 0·76. It is concluded that the rumen degradation characteristics have potential for predicting intake of straws and growth rate in sheep.

Video image analysis (VIA), carcass shape and colour data were collected for 1211 lambs of known gender, breed type and carcass weight over a 1-week period using the VIAscan® system developed by the Australian Meat Research Corporation. Classification data (thickness of soft tissue over the 12th rib (GR measurement) and subjective conformation scores on a five-point scale of the leg, loin and shoulder) were assessed by an Agriculture and Agri-Food Canada grader after carcasses had chilled at 5°C for 3 to 6 h. Dissections into saleable meat yield (no. = 58) were performed after carcasses had chilled an additional 24 h. The timing of this study, which was dependent on availability of the VIA equipment, influenced the age and type of lambs available for analysis. The majority of lambs evaluated were wool-breed wethers, age > 10 months, of average GR (15·7 (s.d. 0·2) mm) and muscle conformation (3·0, s.d. 0·1). VIA improved the prediction of saleable meat yield (R2 = 0·71, residual s.d. = 14g/kg) compared with the current classification system (R2 = 0·52, residual s.d. = 18 g/kg). Although prediction ofGR measurement by VIA resulted in a large residual error (residual s.d. = 2·4 mm), the proportion of waste fat (perirenal and subcutaneous) and bone dissected from the carcass was accurately predicted (R2 = 0·62, residual s.d. = 11 g/kg). Proportions of leg (R2 = 0·71, residual s.d. = 7 g/kg) and shoulder (R2 = 0·62, residual s.d. = 9 g/kg) primals were also accurately predicted by VIA, although there were no significant predictors for the proportion of the loin (P > 0·15). VIA improved the prediction of saleable meat yield compared with the current classification system. However collection of additional data including some from extremely lean or well muscled animals would be required before VIA could be recommended to classify lamb carcasses

Forty first cross hybrid gilts were used to study the effect of dietary protein during lactation on free amino acid, protein and total oestrogen concentrations in colostrum and milk. The diets were formulated to contain similar levels of digestible energy (DE) but with either 236 or 186 g protein per kg and 13·3 and 8·1 g lysine per kg air-dried diet respectively. Both diets were offered at 2·5 kg/day for 1 week prior to farrowing and ad libitum throughout a 24-day lactation (no. = 20 gilts per treatment). Colostrum and milk were collected manually at 3h (colostrum), 3, 7, 14 and 22 days (milk) post partum. Free amino acid concentrations in colostrum and milk were determined by high-performance liquid chromatography following derivatization of the amino acids by 9-fluorenylmethyl chloroformate. The lysine and glutamic acid concentrations in colostrum were the most abundant free amino acids followed by tryptophan and taurine in order of decreasing abundance. Milk free taurine concentrations increased to the greatest extent among all free amino acids over the 21 days of lactation. Gilts' mature milk was rich in free taurine, glutamic acid, glycine and lysine. During the first 3 h post partum, the protein content of colostrum was unaffected by dietary protein. However, milk protein content over 7 to 21 days of lactation was significantly higher in gilts offered the higher protein diet (P < 0·001). Total solids in colostrum and milk was not significantly affected by dietary protein. At 3h and 3 days post partum the concentrations of total oestrogen in colostrum and milk, determined by radioimmunoassay, were significantly higher in gilts offered the high protein diet (P < 0·05). These finding indicate that a high protein diet in late gestation and during lactation can influence protein content, amino acid and oestrogen concentrations of milk in gilts.

A study was conducted to find early predictors of the Booroola gene in several generations of a crossbred sheep population. Merino carriers of the Booroola gene were mated with Texel sheep to improve prolificacy of the latter. Ovulation rate at 8 months of age, litter size at 1 and 2 years of age and FSH and inhibin levels at 3, 4, 5 and 6 weeks of age were determined in about 700 females.

Gibbs sampling was applied for inference in a mixed inheritance model. Estimates for the gene effect in heterozygous females were +1·5 corpora lutea and +1·3 lambs at 2 years of age. The gene effect on litter size at 1 year was small. The only significant major gene effect for hormone levels found was for lnINH4 (–0·66).

A number of hormone levels and combinations of hormone levels appeared to be useful predictors of carrier status of individual animals. In comparison with a situation where only parents' genotype is known, posterior probabilities for non-carriers were on average increased from 50 to over 95% when FSH levels were used. However, the combined posterior probabilities of carriers and non-carriers increased only up to 67%. So in general, classification with Gibbs sampling resulted in too few animals being identified as carrier. The sum of FSH levels at 3, 4, 5 and 6 weeks of age is proposed as a predictor of presence of the Booroola gene in an animal. Multivariate analysis of mixed inheritance models could help to find more effective combinations.

The study was designed to measure (i) dry-matter intake (DMT) of sheep when diets including different tannins were offered and (ii) the effect of administration of polyethylene glycol (PEG), a tannin-binding agent, on DMI of tannin-rich diets. Acacia saligna phyllodes, a potential food for sheep, quebracho powder or tannic acid were added to a concentrate diet that served as a control and were offered to 16 ewe lambs (34·6 (s.d. 3·3) kg) that is, four lambs per diet. A. saligna has high levels of tannins; quebracho is a complex mixture of phenolic compounds in which condensed tannins predominate while tannic acid is a relatively pure example of a hydrolysable tannin. Intake was measured during four periods (I to IV) of 10 days each in which PEG was offered during periods II and IV. Food and water were available ad libitum. The DMI of the concentrate diet ranged between 925 glday and 1050 glday which was higher than for the other three diets (P < 0·05). The lambs consumed approximately 600 g dry matter (DM) of the diet that included 400 g A. saligna phyllodes per kg, and 500 g DM of the diets that included 100 glkg quebracho or 150 glkg tannic acid. With the quebracho and tannic acid diets, there was a distinct increase in intake when PEG was added and a decrease without PEG. This was not so with the Acacia diet when the intake remained high in period III without PEG and increased again in period IV with PEG. Body mass of control lambs increased in all periods and the increase was greater than in the other diets (P < 0·05). With the quebracho and tannic acid diets, there was an increase in body mass when PEG was added and a decrease without PEG. With the Acacia diet, there was a decrease in body mass in period I and an increase thereafter, even without PEG in period III.

Thirty-five gilts grown between 18 and 55 kg live weight were used to examine the effects of feeding fermentable carbohydrate on voluntary food intake, performance, carcass characteristics, and large intestinal growth. Five diets were used. The first diet contained steam-flaked sorghum and a supplement based on animal protein sources and 40 g/kg soya-bean meal (diet SAP). Using this diet as a base, three other diets contained either (i) guar gum, a source of soluble non-starch polysaccharide (NSP) (diet SAP + S-NSP), (ii) Novelose™, a source of resistant starch (RS) (diet SAP + RS), and (Hi) a combination of both S-NSP and RS (diet SAP + S-NSP + RS). The final diet (diet WBL) was based on wheat, barley and Australian sweet lupins. Diets (i), (ii) and (Hi) were formulated such that the concentrations of soluble NSP, oligosaccharide and RS were similar to those contained in diet WBL. There was no relationship (F > 0·05) between voluntary food intake and indices of hind-gut fermentation, although pigs given diets SAP + S-NSP and SAP + S-NSP + RS took longer to reach the slaughter weight of 55 kg (F < 0·001) and converted food less efficiently than pigs given other diets (F < 0·001). An increased intake of S-NSP (R2 = 0·842, P < 0·05) and S-NSP + RS (R2 = 0·805, F < 0·05) was positively correlated to an increased (empty) weight of the large intestine. A significant negative relationship (R2 = 0·78, F < 0·05) existed between the daily intake of S-NSP + RS and dressing proportion, such that each gram increase caused a 0·25 g/kg decrease in the dressing proportion of pigs. No such relationships existed between the daily intake of soluble NSP, insoluble NSP, or RS (P > 0·05) with dressing proportion. These data suggest that the sources of fermentable carbohydrate used in this study, i.e. soluble NSP and RS, may not significantly depress voluntary food intake but can affect performance and have a significant effect on large intestinal growth and dressing proportion.

Genetic parameters for birth weight were estimated for two sets of spring-born and one set of autumn-born lambs of the same breed composition and genetic origin using a model that included random additive, additive maternal, permanent environmental maternal, litter and residual effects. Litter effects were significant for all data sets, indicating that within-year effects of common environment and (or) non-additive genotype were important for birth weight and should be included in genetic evaluation programmes. Estimates of variance components for autumn-born lambs differed significantly from those obtained from spring-born lambs or from the combined data. In contrast, estimates obtained for the two sets of spring-born lambs did not differ from those obtained when data on all spring-born lambs were pooled. The estimate of h2 for birth weight in spring-born lambs was over twice as large as that obtained for autumn-born lambs (0·26 v. 0·22).In contrast, the across-year repeatability of ewe effects was much larger in autumn lambs (0·41 v. 0·26) as was the full-sib littermate correlation (0·73 v. 0·49). Mean birth weights were also 0·4 to 0·6 kg less in autumn lambs. These results suggest that negative effects on birth weight that have been reported for lambs gestated during summer in equatorial and subtropical regions are also manifested (albeit at reduced levels) in less extreme climates (in this case, 37°, 15' N latitude and 654 m elevation) and that maternal variation exists in the ability of the ewe to maintain adequate lamb birth weights in autumn lambing systems.

An experiment was carried out to estimate the concentration of sodium, potassium, whey albumin and total protein of normal and experimentally infected milk from meat breed ewes. Intramammary infection significantly (P > 0·0001) increased the concentration of sodium, albumin and total protein and decreased that of potassium. The potassium decrease was not statistically significant fP = 0·08). The increase in whey albumin and total protein was followed by a significant decrease in the albumin and total protein of blood serum. The increases and decreases of sodium, potassium, albumin and total protein were significantly correlated to the rise in somatic cell count and subsided 3 to 4 days after failure to isolate the infecting micro-organisms from the milk of ewes. Changes in the concentration of albumin could be used in identifying infected mammary glands or to evaluate the virulence of the infecting micro-organism.

Two experiments involving 213 finishing lambs were carried out to examine the responses in growth rate and carcass composition to the addition ofmetabolizable energy (ME) to a mixed diet in theform ofeither grass silage concentrate. In the second experiment the performance of lambs offered silage only was also compared at equal intake with the performance of lambs given mixed diets. On average the silages contained 224 g dry matter (DM) per kg; 148 g crude protein (CP) per kg DM; 86 g ammonia-nitrogen per kg total nitrogen and 723 g digestible organic matter per kg DM. Concentrates were based on barley and soya-bean meal and contained 181 g CP per DM. Responses in carcass weight gain when additional ME was added to mixed silagelconcentrate diets in theform ofgrass silage and concentrates were 9·2 and 10·2 (s.e. 0·90) gIM] respectively in experiment 1 and 9·8 and 10-(s.e. 0·33) g/MJ respectively in experiment 2, and responses in energy retention in experiment 2 were 0·34 and 0-(s.e. 0·012) MJ/M] respectively. However carcass gain and energy retention sustained by a silage only diet were only 0·67 and 0·70 respectively of those sustained by a high-concentrate diet at the same ME intake. The diet did not significantly affect body or carcass composition.

Thirty sows were allocated at their first farrowing to five litter size treatments. Litter sizes of six, eight, 10,12 and 14 were established by cross-fostering within 48 h post partum. Milk yield (Y, kg/day) of sows was linearly related to litter size (L) and was described by the equations; Y = 5·98 (s.e. 0·48) + 0·689 (s.e. 0·046)L, R2 = 0·99; residual s.d. = 0·29; P < 0·001 and Y = 8·20 (s.e. 0·46) + 0·324 (s.e. 0·044)1, R2 = 0·95; residual s.d. = 0·28; P < 0·002 for early (day 10 to day 14) and late (day 24 to day 28) lactation, respectively. The composition of milk from sows suckling various litter sizes remained relatively stable but suckling frequency in early lactation increased linearly in response to increased litter size. Litter size significantly affected the average growth rate of individual piglets; piglet growth rate from birth to weaning at 28 days of age decreased from 283 g/day to 202 giday in response to increasing litter size from six to 14. The relationships between milk yield, average piglet growth rate and litter size indicate that the number of functional glands is the major factor influencing milk yield of sows. Increasing the number of functional glands by increasing litter size more than compensates for any decrease in milk output from individual glands.

The effect of method of blood sample collection (automatic blood sampling equipment (ABSE) v. manual) on cortisol and progesterone concentrations was investigated in 20 farmed red deer hinds and 20 domestic sheep ewes following dexamethasone and exogenous ACTH administration. Ten animals were subjected to either automatic sampling or manual sampling via jugular venipuncture in 1 week, with the treatment groups reversed in the 2nd week. The ABSE was programmed to collect a blood sample, then deliver 2 mg dexamethasone, collect a further blood sample 120 min later and then inject 100 fig ACTH. Thereafter, samples were collected at 15-min intervals during a 2·5 h period (12 samples in total). In the manual injection and sampling treatment, four samples were collected: (1) before dexamethasone administration, (2) before ACTH administration, (3) 60 min after ACTH administration, and (4) 150 min after ACTH administration. The success rate of blood sampling with ABSE was 80%. The overall mean packed cell volume (PCV) from samples collected by ABSE from both hinds and ewes was significantly lower than that from samples collected manually (P < 0·01) and PCV declined with time in manually sampled animals (P < 0·01). Plasma cortisol concentrations peaked at 45 min after ACTH administration in sheep and deer. In sheep, there was a marked fluctuation in the plasma cortisol concentrations with time. Both deer and sheep showed a reduced cortisol response to ACTH during week 2 irrespective of sampling method suggesting down-regulation of the response to ACTH. Maximum mean plasma progesterone concentration was reached at 15 to 30 min after ACTH administration. No significant differences in cortisol and progesterone responses due to blood sampling method were found in animals receiving prior dexamethasone treatment. This demonstrates that the ABSE has the ability to be used to effectively conduct ACTH stimulation tests without the need to handle the animals during the test.

The amino acid composition of cat hair was determined by conventional 24-h acid hydrolysis and non-linear least-squares extrapolation to time zero of the amino acid composition data from a series of hydrolysis intervals. Twenty-five individual samples of cat hair, consisting of four colours, were also analysed (24-h hydrolysis) to determine if there was an effect of hair colour on amino acid composition. Amino acids were determined following HCl hydrolysis (6 mol/l) with cysteine and methionine determined by performic acid oxidation of the sample prior to hydrolysis.

There was no significant (P > 0·05) effect of hair colour on the amino acid composition of cat hair. The non-linear compartmental model used to determine the amino acid composition of cat hair took into account the simultaneously occurring processes of hydrolysis and degradation of amino acids over time. The amino acids cysteic acid, methionine-sulphone, threonine and serine exhibited high loss rates during 6 molll HCl hydrolysis while the peptide bonds involving valine and leucine were slowly hydrolysed. Amino acid nitrogen accounted for 0·94 of the total nitrogen in cat hair when determined by conventional 24-h hydrolysis and 0·99 of the total nitrogen when the compartmental model was applied. The average nitrogen proportion in cat hair protein was found to be 0·175. The amino acid composition of cat hair protein is comparable with that of dog, horse, sheep and human hair although the proline content of cat hair protein appears to be lower than that in the other species.

The aim of the study was to investigate the influence of different energy levels during a 4-week lactation on the regulation of the metabolic hormones somatotropin (GH), prolactin, insulin and insulin-like growth factor-1 (IGF-1). A total of 21 crossbred sows (German Landrace × Duroc) were cannulated for daily blood collection from 3 weeks before parturition until 2 weeks after weaning and for weekly window sampling (every 20 min for 10 h). Nineteen sows were given 2·8 kg food during late gestation, 5·0 kg food during lactation and 2·8 kg food per day after weaning and two sows were given food at a restricted level (3·0 kg) during lactation. In the 19 sows, the different energy balance was induced by allocation of different numbers of sucking piglets to the respective sows. One group of sows suckled seven piglets and served as a control (C; no. = 7) and another group suckled 10 to 12 piglets and was energy deficient (D). After the study, the sows of the deficient group were, based on their litter weight gain from parturition until weaning, divided into low (D-L; no. = 6) or high (D-H; no. = 6) litter weight gain. The D-H sows lost more body weight during lactation than C and had lower glucose and higher nonesterified fatty acids levels before morning feeding. GH and prolactin increased around parturition and their secretory profiles during lactation were altered by the frequent sucking stimulus, whereby the access of the piglets to their dams was not controlled. During lactation, GH and prolactin were highest in D-H sows. The results suggest a possible role of not only GH but also of prolactin in nutrient partitioning to the mammary gland just before the start of lactation and for minimizing the adverse effects of a negative energy balance. Furthermore, insulin and IGF-1 increased around parturition in all sows. Insulin was higher before and after feeding and the highest levels were found in C and D-L sows. The regulation patterns of insulin and IGF-1 indicate that the lactating sow is able to mobilize enough energy from body reserves to prevent metabolic disorders, even during a period with deficient energy supply. This is contrary to the regulation in the dairy cow, where the negative energy balance is coupled with a severe glucose deficit during phases of high milk yield, which causes decreased levels of insulin and IGF-1. In the sow, the glucose intake with the food meets the glucose requirement for metabolic pathways also during a deficient lactational energy intake. Therefore, in sows IGF-1 can be stimulated by increased GH levels via the GH receptor in the liver during a state of nutritional energy deficiency and the fact that sows can compensate a deficient metabolic state much better than cows is also reflected in the respective endocrinology.

The effect of intake level during the milk-feeding period and dietary protein content during the post-weaning period on performance, weight of components of the digestive tract and carcass and non-carcass chemical composition was investigated in 28 Churra lambs. A 2 × 2 factorial design was used with two intake levels during the milk-feeding period (Lmilk: 0·9 and Hmilk: 1·5 MJ gross energy per kg M0·75 daily) and two concentrate supplements (Lprotein:barley grain and Hprotein: barley grain plus 200 g/kg fish meal) during the post-weaningperiod. After selecting an initial slaughter group of four 2-day-old lambs, 12 lambs were assigned randomly to each of two intake levels during a 4-week milk-feeding period and given food individually. Four lambs from each intake level were slaughtered at weaning (30 days old) and the remaining 16 were weaned between 30 and 49 days old (weaning period). Eight lambs from each nutritional regimen during the milk-feeding period were further divided into two equal groups and given food individually ad libitum with hay and the post-weaning concentrate, according to the experimental design until thefinal slaughter weight (20 kg) (post-weaning period). Lmitk lambs showed a capacity to grow as well as the Hmilk during the weaning and post-weaning period and there were no differences (P > 0·05) in dry-matter intake and food conversion ratio among treatments. Before weaning, the weight of the reticulo-rumen was not affected by the intake level during the milk-feeding period. The most affected component of the gastrointestinal tract was the small intestine as proportion of the digestive tract which was lower in Lmilk lambs (P < 0·05). At 20 kg live weight, the relative size of the reticulo-rumen was greater (P < 0·01) and the abomasum (P < 0·05) and large intestine (P < 0·01) were smaller in lambs which were given the Hprotein concentrate after weaning. The organic matter apparent digestibility (OMD, P < 0·05) and crude protein apparent digestibility (CPD, P < 0·05) of the post-weaning diets was greater in Lmilk lambs and the Hprotein post-weaning diet was associated with a greater dry-matter apparent digestibility, OMD and CPD when lambs were close to final slaughter weight. At 20 kg live weight, the proportion of protein in the carcass of Lmilk lambs was greater (P < 0·05) than in Hmilk lambs. The greater growth of the reticulo-rumen of the Lmilk lambs might have increased solid food intake after the milk-feeding period, led to greater CPD of post-weaning diets and had consequences in terms of carcass composition.

The rôle of nutrition in the periparturient breakdown of resistance to gastrointestinal parasitism in mature ewes was investigated. Host resistance around this period, as measured by faecal egg concentration and worm burden, was sensitive to protein supply and to a lesser extent energy supply and body condition. Resistance was significantly less in ewes bearing and suckling twin lambs than those with singles. Differences in larval intakes spanning the range likely to be experienced in practice did not appear to be important. In dual infection with Teladorsagia circumcincta and Trichostrongylus colubriformis, the breakdown of resistance occurred almost exclusively with T. circumcincta confirming previous evidence of parasite species specificity in the periparturient breakdown of resistance.

Genetic and phenotypic variation in post-weaning growth, food intake, efficiency and body composition of mice post weaning and at maturity, were examined to determine whether genetic variation in efficiency exists and to predict likely responses to selection for increased food efficiency in post-weaning animals. Genetic variation was found for average daily gain, mid-weight, daily food intake and proportion of body fat both post weaning and at maturity. Residual food intake calculated from phenotypic regression had a heritability of 0·27 (s.e. 0·06) post weaning and 0·24 (s.e. 0·08) at maturity, and was very similar to residual food intake calculated using genetic (co)variances, indicating genetic variation in efficiency exists in post-weaning and mature mice. Although the phenotypic correlation between residual food intake post weaning and at maturity was low (0·29), the genetic correlation was moderate (0·60). This suggests that selection for efficiency in young animals will lead to a correlated improvement in maintenance efficiency of mature animals. Genetic correlation estimates suggest that correlated responses in other traits would include a concomitant decrease in post-weaning food intake, a slight increase in weight at weaning, a slight increase in post-weaning fat proportion and little or no change in post-weaning growth. In mature animals there will be an associated decrease in daily food intake and a slight decrease in mature size and body fat proportion. The results suggest that residual food intake of young animals might be a suitable selection criteria for use in livestock species to improve efficiency in young animals and also in the breeding herd.

A 3 × 2 factorial experiment was used to investigate the influence of the breed type of gilts (Meishan synthetic 50% (M), purebred Large White (LW) and purebred Landrace (LR)) on response to insoenergetic diets of differing protein levels (180 g crude protein (CP) per kg, 9 g lysine per kg; or 240 g CP per kg, 12 g lysine per kg) offered to appetite over a 28-day lactation. Body fat reserves were adjusted during pregnancy by supplementing a set quantity of basal diet (131 g CP per kg, 12·7 MJ digestible energy (DE) per kg) with an energy source (maize starch + soya oil), to attain a backfat at P2 (6·5 mm off midline at last rib) of 25 mm at farrowing for all breeds. There were no significant diet effects or breed ×diet interactions on lactational performance. On day 1 of lactation, backfat was: M = 25·9, LW = 24·9, LR = 23·9 mm (P < 0·005). M gilts were lighter at farrowing (M = 173, LW = 192, LR = 182 kg; P < 0·001) and had more piglets than LW and LR. LR gilts had heavier piglets at birth (M = 1·13, LW = 1·18, LR = 1·38 kg, P < 0·001) than M and LW gilts. M gilts had a higher food intake (M = 6·4, LW = 5·2, LR = 5·1 kg/day; P < 0·001) but higher fat (M = 4·1, LW = 2·2, LR = 2·9 mm; P < 0·05) and weight (M = 15·9, LW = 1·0, LR = 4·7 kg; P < 0·001) loss over lactation than LW and LR gilts. LW gilts had a lower lactation output as reflected by lower litter weights at weaning than M and LR gilts (M = 73·7, LW = 59·3, LR = 75·2 kg; P < 0·002). It is concluded that lactation of gilts is not improved by provision of a very high protein diet (240 g CP per kg) and that performance still differs between breeds when backfat levels are standardized.

One hundred and twenty crossbred gilts and sows were used in an experiment with three differently composed pregnancy diets in order to study the effects on performance during three reproduction cycles. Treatments during pregnancy were: (1) a standard diet; (2) 500 g sugar-beet pulp per kg diet; (3) 500 g mixture of green grass-meal, wheat bran and oat hulls per kg diet. Sows were given similar levels of estimated daily net energy (NE). All three groups were given the same standard lactation diet semi-ad libitum in two daily meals. Recordings were made of food intake during pregnancy and lactation, body weight of sows at mating, farrowing and weaning, days until first mating, litter size, and mean piglet weight at birth and weaning. Pregnancy food intake (kg) was highest in diet 3 and lowest in diet 1 (P < 0·001). Food intake was lower for sows given diet 2 than for sows given diets 1 and 3, when measured in NEfor pigs (P < 0·001). Food intake during lactation was higher for sows given diet 2, than for sows in the two other diet groups (P < 0·01). Results were consistent during all three experimental rounds. Mean body weight of sows was the same for all diet groups both at mating, farrowing and weaning. Weight gain during pregnancy and weight loss at farrowing was significantly higher in groups 2 and 3 than in group 1 (P < 0·001). Litter size was not affected by the different pregnancy diets, neither total number live born nor weaned. Both mean piglet weight and total mean litter weight at birth were negatively influenced by diet 2 (P < 0·001) and (P < 0·05) respectively. This indicates that a diet with a high content of soluble dietary fibre and a large capacity to induce satiety may have a negative effect on piglet weight at birth. At weaning, however, the mean weights of piglets were the same for the three diet groups. It was concluded, that it is possible to feed pregnant sows very differently composed diets without detrimental effects on performance.

The voluntary intake and apparent digestibility of kleingrass (Panicum coloratum cv. Verde) were measured in seven periods, comprising one full year. The forage was offered twice a day ad libitum to seven rams, fitted with faeces collection bags; each experimental period was composed of 8 days for adaptation and 8 days for collection of data. The dry-matter (DM) intake (DMI) varied from 36·1 to 64·9 glkg M075, the digestible dry-matter intake (DDMI), from 17·4 to 41·9 glkg M0·75 and the in vivo dry matter apparent digestibility (DMD), from 0·471 to 0·667.

Daily samples of offered forage were taken and pooled subsamples from each of the seven periods were incubated in nylon bags in the rumen of three Hereford steers. The data were fitted to the exponential equation: p = a + b (1-e-ct) to estimate p (the proportionate loss of DM at time t of incubation); effective degradability (ED) and lag time (L) were also estimated.

The parameters obtained in situ were related to the in vivo results by simple and multiple regression. The correlation coefficients of the rate of degradation (c) and ED with DMI, DDMI and DMD were, respectively, 096 and 0·97; 0·97 and 0·96; 0·86 and 0·88. By including a, b, c and L into a multiple regression analysis, the coefficients of determination (R2) were: DMI: 0·99; DDMI: 0·99 and DMD: 0·91. Within the conditions of this study, the parameters obtained in situ were reasonable estimators of voluntary intake and apparent digestibility.