Two groups of eives were fed to provide 1·5 × (high, H; no. = 13) or 0·5 × (low, L; no. = 12) energy requirements for maintenance of live weight from 12 days before a synchronized mating in November until slaughter at 14 days after mating and the effects on embryo survival and associated patterns of gonadotropin secretion, and ovarian follicle and corpus luteum function were investigated. Proportionately, there were more pregnant ewes in the H group than the L group (0·62 v. 0·08; %2 = 7·67; P < 0·01) at day 14 of pregnancy but there were no differences in mean LH concentrations, LH pulse frequencies or amplitudes, either before mating and ovulation (follicular phase) or at day 10 after mating (luteal phase). The mean size (mm) of the three largest follicles (H: 5·69; L: 5·65; s.e.d. = 0·21), the proportion of these follicles that were oestrogenic (secreting > 500 pg oestradiol per h; H: 0·29; L: 0·28; y) = 0·01; P > 0·05) and secretion (pg/h) in vitro of oestradiol (H, 294; L, 386; s.e.d. = 146) (pg/h) and testosterone (H: 636; L: 508; s.e.d. = 293) by these follicles were similar for both treatments. There were no treatment differences in LH receptor concentrations (pg hormone bound per mg protein) in granulosa (H: 69·02; L: 67·76; s.e.d. = 0·20) and thecal (H: 46-88; L: 50·82; s.e.d. = 0·19) tissues. However, there was a higher concentration of receptors in the thecal tissue of oestrogenic follicles ofL than H ewes (167 v. 62; s.e.d. = 18; P < 0·05). Mean weights (g) of corpora lutea (H: 0·72; L: 0·59; s.e.d. = 0·003; P = 0·09), progesterone secretion (ng/mg per h) in vitro by luteal tissue (H: 1·75; L: 1·78; s.e.d. = 0·30) and LH receptor concentrations in corpora lutea (H: 58·16; L: 54·27; s.e.d. = 25·14) were similar for both treatments. It is concluded that the reduction in embryo survival associated with a reduced level of food intake was not attributable to a reduction in LH secretion, inadequacies in follicle growth and development or in the capacity of the corpora lutea to synthesize and release progesterone.

A comparison of the patterns of LH and FSH secretion was undertaken in lines of Finn sheep selected for and against high ovulation rate. Mean ovulation rate was significantly higher in the high line ewes (mean 4·1) compared with both the control (mean 2·5) and low line (mean 2·7) ewes (P <0·01). The pre-ovulatory LH peak occurred significantly earlier in the high line ewes (mean 52·1 h) compared with both the control (mean 65·0 h) and low line (mean 59·0 h) ewes (P < 0·05). While mean LH pulse frequency and overall mean LH concentrations were both significantly higher during the follicular compared with the luteal phase of the cycle (P < 0·05), there were no consistent relationships between patterns of pulsatile LH secretion and ovulation rate among the three selection lines. Plasma FSH concentrations remained significantly higher over the entire follicular phase of the oestrous cycle in the high line ewes compared with both the control and low line ewes (P < 0·05). It is suggested that the ovulation rate achieved by high line ewes may be causally related to their higher follicular phase FSH concentrations.

The effects of fertilization (100 kg nitrogen plus 10kg phosphorus per ha per year) of Cymbopogon-Themeda veld on certain chemical components in vitro dry-matter digestibility (IVDMD), intake by either lactating cows or steers as well as daily gain of pre-weaned calves or steers, were determined in the summer rainfall area of the Republic of South Africa.

The nutritive value of fertilized veld herbage was, in terms of crude protein and acid-detergent fibre content, IVDMD and herbage intake, superior to that of unfertilized veld. Species, classified as palatable according to the literature, were more abundant on the fertilized veld than on the unfertilized veld. In spite of the fact that the stocking rate on the fertilized veld was double that of the unfertilized veld, the average daily gain (ADG) of steers on the former was higher than that of steers on the latter. There was no significant difference in the ADG of the pre-weaned calves, whose dams grazed either fertilized or unfertilized veld. It was calculated that the fertilization of veld for growing steers can (under the conditions that prevailed) be a financially viable proposition if the beef price per kg live weight amounts to at least 0·65% of the cost of fertilization per ha.

An experiment was conducted to examine the changes in colostrum secretion rate and colostrum composition in ewes over the first 24 h post partum. Sixteen mature Suffolk × Cambridge ewes, which had produced one to four lambs, were used. Colostrum yield was estimated within 1 h of parturition and colostrum secretion rate measured between 3 and 6 h, 9 and 12 h, 15 and 18 h and 21 and 24 h post partum. Samples of colostrum were taken at each milking and the composition analysed. The mean yield (g) of colostrum at 1 h was 801 (s.d. 568·9) with a range from 35 to 2450 g. Mean secretion rates, in g/h, at 3 to 6 h, 9 to 12 h, 15 to 18 h and 21 to 24 h were 120 (s.d. 67·0), 104 (s.d. 55·2), 112 (s.d. 49·8) and 109 (s.d. 41·1) respectively. At 1 h, mean concentrations, in g/l, of total solids, fat, protein, ash and IgG were 367 (s.d. 76·9), 132 (s.d. 43·7), 203 (s.d. 43·2), 9.6 (s.d. 2·4) and 116 (s.d. 30·2) respectively. Corresponding values at 24 h were 242 (s.d. 38·8), 122 (s.d. 39·5), 71 (s.d. 11·2), 6.8 (s.d. 1·0) and 15 (s.d. 12·5).

Sequential samples were taken throughout the milking process within 1 h of paturition from a further eight Dorset-cross ewes. There were no significant differences in the composition of colostrum due to stage of milking, although there was a suggestion that fat content was higher in the final sample than the first (140·1 v. 104·1 g/l, P = 0·084). It is clear that there is a large amount of variation in the secretion rate and composition of colostrum produced by ewes over the first 24 h post partum. However, a single sample taken between 3 and 12 h post partum would be a good indicator of 24 h yield (r = 0·88) and composition (total solids, r = 0·90 and IgG, r = 0·93).

The study compared using chemical components (i.e. crude protein (CP), neutral- and acid-detergent fibre or lignin (NDF, ADF and ADL) g/kg dry matter (DM), the in vitro digestibility (Tilley and Terry, 1963), the in situ (nylon bag) DM degradation (g/100 g DM) and gas production (ml/200 mg DM) techniques to predict voluntary daily intake (g DM per kg M0.75) and in vivo apparent DM digestibility (DMD) of 10 graminaceous hays individually offered ad libitum to four Merino male sheep. Gas production or DM degradation were determined after 6, 12, 24, 48, 72 or 96 h incubation and their characteristics described using the equation p = a + b (1 – e-ct). Intake and in vivo DMD of the hays were variable and poorly related (r = 0·52; P > 0·05). The in situ DM degradation was significantly (Y < 0·05) related to in vivo apparent DMD at 48 to 96 h incubation (i = 0·76 to 0·75) and to intake at 24 to 96 h (r = 0·71 to 0·75) incubation. However, fibre components, the in vitro digestibility or gas production were either related to daily intake or in vivo apparent DMD, but not to both on the same occasion. Accurate prediction of intake (r = 0·90; P < 0·05) and in vivo apparent DMD (r = 0·88; P < 0·069) were achieved using NDF, ADF, ADL and CP in a multiple regression. Using the (a + b) and the rate (c) of in situ DM degradation, both in vivo apparent DMD (r = 0·77; P < 0·05) and intake (r = 0·83; P < 0·05) were predicted with accuracy. However, using the (a + b) and (c) of gas production, only intake was predicted accurately (r = 0·87; P < 0·01). The lower performance of the gas test was attributed to the small contribution to gas production and higher buffering capacity resulting from protein fermentation. When data of the graminaceous and other data from leguminous hays were combined, the most accurate prediction of both intake and apparent digestibility was by using characteristics of in situ DM degradation followed by those of gas production. The latter was more accurate than using chemical components or the in vitro digestibility. Addition of CP in the multiple regression improved the prediction of intake and in vivo apparent DMD from characteristics of gas production. It was concluded that despite the need to overcome the problem of protein fermentation in the gas test, accurate prediction of both intake and apparent digestibility can be achieved simply from the degradation characteristics of foods.

Somatic cell counting by the Coulter Counter method, California mastitis test and bacteriological examination were performed on milk samples taken at fortnightly intervals throughout lactation from healthy primiparous and iniiltiparous ewes of the Chios and Karagouniki breeds and from healthy ewes in five grazing flocks in northern Greece.

The proportion of the bacteriologically positive milk samples was 0·22. The prevalence of subclinical mastitis ranged, between the flocks, from 29 to 43% of the ewes. Subclinical mastitis occurred more frequently in Karagouniki than in Chios eives and in multiparous than in primiparous ewes of both breeds. Coagulase-negative staphylococci and S. aureus were isolated in 44 and 33% of the bacteriologically postive samples, respectively. No parity, breed or flock differences in normal somatic cell count were noticed, but stage of lactation influenced normal somatic cell count both in primiparous and multiparous ewes. The results of this investigation also suggest that (a) ovine milk samples with somatic cell count more than 1000 × 103 cells per ml, should be tested bacteriologically, (b) somatic cell count values between 1000 and 2000 × 103 cells per ml should cause suspicion about the presence of coagulase-negative staphylococci in the milk, and (c) the presence of S. aureus in ewe's milk results in a significant increase in somatic cell count, but the wide range of the values does not permit us to suggest any threshold value. The significant correlation between the results of the Coulter Counter somatic cell count method and the Califortiia mastitis test, indicates that the latter can be used for the determination of somatic cell count in ewe's milk.

One hundred and thirty-two ewes of the Merino (M), Finn × Merino (FLXM), Border Leicester × Merino (BLXM), Bleu de Maine × Merino (BMXM), Texel × Merino (TXM), Cheviot × Merino (ChXM) and Merino Landsheep × Merino (MLXM) were evaluated for efficiency of lamb production. Individual food intakes of every ewe and also of her lamb(s) were determined over a complete production cycle. Efficiency of lamb production (kg lamb marketed at 35 kg live mass per kg food consumed by the ewe and her lamb(s)) indicated that the FLXM was the most efficient, followed by the TXM, Merino, MLXM, BLXM, ChXM and the BMXM was the least efficient. No significant differences (P < 0·05) were found between genotypes for efficiency of lamb production for ewes producing and rearing singletons until 35 kg live mass with ewe mass included as a covariate. Efficiency of wool production of the Merino was significantly (T < 0·001) higher than that of the other crosses. These results emphasize the importance of reproduction traits in improving efficiency of lamb production.

This study was aimed at evaluating (1) the dry matter (DM) and nitrogen (N) degradabilities (by sheep) of Sesbania sesban leaves, Acacia albida (Faidhabia albida), A. siberiana and A. tortiris frazfs and (2) the effect of feeding a mixture of oilseed cake and tanniferous browses on the degradability of teff (Eragrostis tef) straw and oilseed cake and on particulate and liquid passage rates. Thirteen rumen cannulated sheep in a randomized complete-block design experiment were given teff straw ad libitum supplemented (DM per day) with 155 g oilseed cake (50: 50 mixture of noug (Guizotia abyssinica) and groundnut cake; oilseed cake diet) or with 92 g oilseed cake plus either 118 g S. sesban (sesbania diet) or 179 g A. albida fruits (albida diet). Diets were formulated to supply 10·5 g supplementary N per day.

Sesbania had the highest DM washing loss, potential degradability and fastest DM degradation rate compared with the acacias. The N washing loss (g/kg) was highest for A. siberiana (500) followed by A. albida (431), A. tortilis (431) and sesbania (241). The potential N degradability (g/kg) was greater (P < 0·05) for sesbania (978) than for A. albida (848), A. tortilis (865) or A. siberiana (785). The degradation rates of oilseed cake-N and teff straw-DM, particulate and liquid passage rates, basal intake and DM digestibilities were similar among diets, but organic matter intake was highest for the albida diet. At the present levels of offer, supplementation with mixtures of oilseed cake and browses does not significantly reduce rumen degradation rates of oilseed cake-N or teff straw DM.

Information on the chemical composition of Suffolk × Blackface lambs was collected and used to predict empty body (EB) component weights from empty body weight (EBW) and non-carcass (NC) component weights. EBW accounted proportionately for 0·94, 0·89 and 0·95 of the variation in EB crude protein, fat and energy content. A combination of NC component weights accounted proportionately for 0·94, 0·95 and 0·96 of the variation in EB crude protein, fat and energy content. EBW and a combination of NC component weights together accounted proportionately for 0·97, 0·97 and 0·98 of the variation in EB crude protein, fat and energy content. Chemical analysis of NC components is cheaper and easier than whole body analysis and provides a viable alternative to sample joint or specific gravity analysis.

Two experiments were performed to monitor the stress responses of sheep to intra-uterine insemination by laparoscopy and its associated handling procedures. The results of experiment 1 indicated that both restraint alone and full laparoscopic intra-uterine insemination in animals which had been sedated with 0·2 mg/kg diazepam promoted similar, significant (P < 0·001) short-lived increase in heart rate and plasma cortisol concentrations, but there was no effect of treatment on plasma β-endorphin concentrations. Experiment 2 compared restraint and full laparoscopy, with and without sedation in a 2 × 2 factorial design. The heart rate and cortisol responses following restraint and full laparoscopy were not significantly different, although laparoscopy tended (P = 0·06) to increase the duration of the heart rate response. Sedation with diazepam significantly (P<0·05) increased the duration of the heart rate response but attenuated (P < 0·05) the amplitude of the cortisol response. These results indicate that laparoscopic intra-uterine insemination does cause sheep to mount a typical stress response, but that most of this is attributable to the restraint required to effect insemination. However, the magnitude of the stress responses recorded were much lower than those reported to follow many other husbandry procedures.

The hierarchic behaviour of 71 goats of the Verata breed from two independent flocks on two different farms (no.2 = 34 and no. 2 = 37) was studied during the milking-period of a year. Two statistical procedures: canonical correspondence analysis (CCA) and a log-linear model were used. In the CCA, the total frequencies of each goat in each of the 12 positions at the milking stalls during 210 days of lactation were computed as original variables. Canonical variables were the average values of dairy milk production, proportion of protein and proportion of fat. The first two CCA axes accounted for proportionately 0·72 of the variance. The first axis showed the effect of rank order (V1 = 0·45) and the second axis the variability between animals for the same group of hierarchy (V2 = 0·27). The first position (AC1, = 0·58; AC2 = 0·23) and the last position (AC1 = 0·11; AC2 = 0·26) of the milking stalls were in absolute contributions the most significant in the distribution of the four observed groups of hierarchy, as defined by their frequency of access to the first position. Two parameters were highly correlated with both axes: milk protein content (r1, = - 0·8; r2 = 0·9) and the day milk production (r1 = 0·6; r2 = 0·5). These results showed a direct relationship between rank order and milk production, whereas the variability in each group was best defined by the protein content. The log-linear model showed that goats of lactation numbers one, two and three have a similar behaviour with respect to their locations at the milking stalls, being distributed more randomly (â1, = 0·68 < â2 = 0·7 < â3 = 0·71) than goats of a lactation number four (â4 = 2·95). This effect could be a consequence of two different but related factors: either the animals develop a preference for a particular position over time, or that animals in their fourth lactation showed a more stable behaviour pattern which affected their body condition.

Genetic parameters were estimated for early lamb growth and ultrasonic measurements taken on Scottish Blackface lambs reared under extensive conditions on two Scottish hill farms. Measurements were taken on approximately 2000 lambs born to unselected ewes, and sired by 32 rams previously selected for divergent predicted carcass lean content. Heritabilities for birth weight, marking iveight (at approx. 6 weeks of age) and weaning weight (at 17 weeks) were 0·07 (s.e. 0·04), 0·02 (s.e. 0·03), and 0·14 (s.e. 0·05), respectively. Heritabilities for ultrasonic muscle and fat depths at weaning were 0·27 (s.e. 0·09) and 0·16 (s.e. 0·06), respectively. There was a strong maternal effect on weight which declined from birth with lamb age and was relatively unimportant for the ultrasonic measurements. The rearing environment of the lambs (hill pasture v. ‘improved’ (or ‘inbye’) pasture) was an important environmental effect on the heritability estimate for backfat thickness, with that for lambs reared on improved pasture being twice that of hill-reared lambs. The implications of the results from this work on genetic improvement of sheep in liill environments are discussed.

Eiues on grass silage-based diets were offered, during the last 6 weeks of pregnancy, an increasing allowance of a barley-soya-fish meal concentrate (400 g/day in weeks 15/16; 600 g/day in weeks 17/18; 800 g/day in weeks 19/20) as either one, two or three feeds daily or as a complete mix with silage. Silage dry-matter intake increased with concentrate feeding frequency (P < 0·01) and was greatest with the mixed diet at an average of 1·38 of that with a single daily concentrate meal. The effect on silage intake was evident even at the lowest level of concentrate supplementation during weeks 15/16 and was independent of silage quality. Ewes gained more live weight (P < 0·01), and maintained a higher live weight post partum, as a result of increasing the frequency of feeding of concentrates but mean lamb birth weight was unaffected. Maternal serum metabolites were measured in weeks 17/18 and 19/20 only. Mean [i-hydroxybutyrate was higher, but not significantly so, in weeks 19/20 despite the increased concentrate allowance and was higher overall (P < 0·05) in ewes offered concentrates once daily compared with those receiving concentrates three times daily or mixed with the silage. Insulin-like growth factor 1 (IGF-1) was higher in serum of ewes given frequent concentrate meals compared with those offered concentrate once daily (P < 0·05). Serum albumin and globulin increased as concentrate intake increased between weeks 17/18 and 19/20 (P < 0·05) and also, when concentrates were offered more than once daily (P < 0·05). Serum urea level was higher with more frequent concentrate meals (P < 0·01) and was affected by silage quality (P < 0·001).

The milk production of 63 5-year-old Merino ewes was measured over a 16-week period after lambing. The purpose was to find a suitable mathematical model to represent the lactation curve of Merino sheep and to estimate the parameters of the model for an individual ewe from a single data point in early lactation. Three models were considered, the three-parameter Wood model, yn = nb exp(a + en), the four-parameter Morant model, yn = exp(a + bn + en2 + d/n and the six-parameter Grossman model, yn = a1b1 - [tanh2 (b1n - c1))] + a2b2[1 – tanh2 (b2(n -c2,))].

The Grossman model was found to be inappropriate for the available data, while there seems to be little difference in the suitability of the other two models. The Wood and Morant models both seem adequate to represent the lactation curve. A pattern in the estimated residuals suggests possible autocorrelations in the errors, but this is inconclusive due to the limited number of data points per animal.

The correlation between the estimated parameters of the model and the daily yield measured during the 1st week of lactation enabled us to use linear regression to estimate the lactation curve of an individual animal based on the 1st week's yield. Confidence and prediction intervals for the yield during the rest of the lactation period may then also be constructed. This makes it possible to extend incomplete milk records for use in genetic evaluation, formulation of rations and economic evaluations.

The efficiency of utilization of absorbed essential amino acids (AA) was studied in wether lambs (35 to 40 kg live weight) given dried grass and dried grass: barley pelleted diets over an intake range from maintenance (M) to 2·5 M energy intake. Each animal was prepared with a duodenal and Heal simple (T-shaped) cannulafor the collection of digesta entering and leaving the small intestine and with a catheter into the abomasum for the infusion of digesta phase markers (103Ru phenanthroline and 51 Cr ethylene diamine tetra acetic acid). The efficiencies of utilization of total AA and individual essential AA (EAA) were calculated from the ratios of the regressions describing AA retention per unit nitrogen (N) intake (assessed using the N retention data obtained in the present study and the AA composition of N retention derived during an accompanying comparative slaughter experiment) and AA absorption per unit N intake. These ratios for total EAA were 0·5 for the grass diet and 0·59 for the grass plus barley diet. Values for individual EAA ranged from 0·32 for threonine in sheep given the grass diet to 0·88 for arginine in sheep given the grass: barley diet. Whilst the ratios for total and individual EAA were generally higher for the grass: barley diet the very wide 95% confidence limits associated with these derived values make any between-diet or between-EAA comparisons equivocal. The data appear to support the introduction by the Agricultural and Food Research Council (1992), of a scaling factor to reduce the high efficiency of utilization of AA used previously.

The effects of months and seasons of the year on the testis size, libido and plasma testosterone (T) concentrations were studied in 10 young sexually mature male goats over a 12-month period. Testis size was expressed in terms of scrotal circumference, testis diameter and paired testes width while the libido was measured as stimulation and reaction times,number of mounts and services, and libido index. These measurements were recorded fortnightly.

The body weight increased from 33·5 (s.e. 0·95) kg in October, to a maximum of 62·8 (s.e. 1·55) kg in July. All parameters of testis size decreased from October through January with a sharp increase noted in July and August. These parameters were significantly higher in the summer and autumn than in the winter and spring (P < 0·01). The libido in the goats increased from October to a maximum in December, declined gradually to reach the minimum in July, and then improved again in August. Thus, libido was lowest during the summer and highest in winter, the difference being significant (P < 0·01). Plasma T concentrations were high during October, with the lowest values noted in June. An increase in the T concentrations was observed in August, reaching the maximum value in September, the difference being significant (P < 0·01). The T concentrations were significantly higher during autumn than in all other seasons (P < 0·01).

As water is the major component of the pig body its accurate prediction is of importance in pig growth models. It has become conventional to predict the weight of water, WA kg, from the weight of protein, P kg. The purpose of this paper is to find how this can be done across pig genotypes of different mature size. The widely used equation to relate WA to P is of the form: WA = a.Pb. This equation is examined theoretically. It is concluded that the form of the equation is reasonable and, that while the value of the exponent b is likely to be constant across genotypes, the value of the scalar a is not. It is proposed that the value of the scalar a is best estimated as a = WAPRm Pm1·b where WAPRm is the water: protein ratio in the body at maturity and Pm is the weight of protein in the body at maturity. The value of the parameter WAPRm is assumed to be constant across genotypes with a value in the range of 3·04 to 3·20, depending on the methods used for measuring body composition. The general value of b = 0·855, taken from published work, is confirmed. A consequence of the argument quantified in the paper is that the value of a is predicted to vary from a = 4·69 for a pig with Pm = 20 kg to a = 5·36 for a pig with Pm = 50 kg. The general equation is expected to give more accurate predictions of the weight of water and, hence, of body weight, in models intended to predict pig growth, food intake, body composition and efficiency.

Reproductive records from 1072 Large White sows (3589 litters) were used to examine the effect ofbackfat depth (Bd) and live weight (Lw) at selection on first litter and lifetime reproductive performance. The variables investigated included mating age, total piglets born, total born alive, piglet birth weight, number weaned, piglet weaning weight, weaning to remating period and number of litters produced. Using backfat depth, sows were categorized into three groups: L, 9 to 13 mm; M, 14 to 16 mm; and F, ≥17 mm. Bd had no significant effect (P > 0·05) on the measured traits for the sows grouped by fat at first parity. When lifetime reproductive data were analysed, the L group had fewer litters (P < 0·05), and weaned fewer pigs (P < 0·01) than either the M or F group. The birth weight for piglets from L sows were significantly higher (P < 0·05) than for piglets from the other groups. The data suggest that the reproductive performance of L sows is not as good as that of M or F sows.

A well fermented grass silage was mixed with 9·3 g lactic acid per kg silage supplied either as the free acid (lactic acid) or partially neutralized to pH 5·2 with sodium hydroxide (sodium lactate) to give three dietary treatments. Treatment with lactic acid reduced silage pH (P < 0·05) from 4·03 to 3·80 and increased (P < 0·01) the amount of sodium hydroxide required to raise silage pH to 6·5 (neutralizing value) from 167 to 261 mmol/kg silage and osmolality (P < 0·01) from 712 to 854 mosmoljkg silage; sodium lactate treatment increased (P < 0·05) silage pH to 4·15 and osmolality (P < 0·01) to 964 mosmoljkg silage but did not change neutralizing value.

Wlien fed in a randomized-block design to either six intact lambs or to four rumen fistulated sheep lactic acid treatment reduced (P < 0·05) silage dry matter (DM) intake (g/kg weight0·75) from 34·7 to 27·8 for intact sheep and from 35·5 to 29·9 for fistulated sheep. Intakes of the sodium lactate-treated silage tended to be higher (39·2, intact and 40·1, fistulated sheep, g/kg weight0·75) than the control silage. Silage DM intake was correlated more closely with neutralizing value (r2 = 0·34) than pH (rz = 0·24).

Treatment of silage with lactic acid or sodium lactate did not change rumen pH, volatile fatty acid patterns or osmolality. Blood pH, pCO2 and bicarbonate concentrations were not changed by the diets offered and were within normal ranges. Urine acid-base balance was not affected by lactic acid treatment whereas urine pH, and bicarbonate and sodium excretion were (P < 0·01) increased by sodium lactate treatment of the silage.

There have been suggestions that positive feedback from the meal may stimulate the performance of undesirable behaviour, such as stereotypies, in the post-feeding period. The aim of this work was to measure the short-term effects of a meal on the post-feeding behaviour of the pig.

Pigs (70 kg live weight) were offered food ad libitum for 7 days and then given a restricted food allowance for 23 days (experiment 1) or 14 days (experiment 2). In experiment 1, the food allowance was given in one, two or three meals per day. In experiment 2, the food allowance was given in two meals per day and comprised ingredients which supplied glucose at different rates (starch, glucose/starch, starch/guar gum). The pigs' posture and behaviour were recorded in three 1-h periods during the day on 2 days consecutively during the ad libitum feeding period (time period 1) and on pairs of days on three (periods 2, 3 and 4: experiment 1) or two (periods 2 and 3: experiment 2) subsequent occasions during food restriction. The meal frequency or estimated rate of glucose supply had no significant effects on posture or behaviour. In both experiments activity increased with the duration of food restriction. In periods 1, 2, 3 and 4 of experiment 1 the proportions of observations spent were: standing 0·244, 0·260, 0·706 and 0·728 (s.e.d. 0·0346); nosing 0·073, 0·094, 0·229 and 0·253 (s.e.d. 0·0169); rooting 0·032, 0·037, 0·108 and 0·133 (s.e.d. 0·0133). In periods 1, 2 and 3 of experiment 2 the proportions were: standing 0·247, 0·302 and 0·446 (s.e.d. 0·0240); nosing 0·045, 0·075 and 0·138 (s.e.d. 0·0113); chewing 0·101, 0·126, 0·155 (s.e.d. 0·0121). In experiment 1 feeding rate increased with duration of restriction (P < 0·001), but was unaffected by treatment. It is concluded that post-feeding behaviour was influenced more by long-term changes in state (i.e. prolonged food restriction) than by short-term effects of the meal.