The aim of this work in pigs was to evaluate the effect of fermented liquid food (FLF) and the combination of FLF plus short-term addition of an antibiotic food additive zinc bacitracin (FLF + ZB) compared with fed non-pelleted dry food (NPDF), on microbial metabolism in the gut and the effects on flavour and odour attributes and profiles of pig meat as well as boar odour from entire male and female pigs.

At an average start weight of 60 kg, 108 pigs (54 males and 54 females) were equally allocated to three treatments according to pen-replicate, litter and sex. Microbial metabolism in the gut was studied in 24 pigs, eight from each treatment. For sensory profile evaluation (flavour, odour and tenderness) of pork loins from m. longissimus dorsi, 48 pigs (24 entire males and 24 females) were selected. The sensory evaluation of different qualities of flavour and odour as well as tenderness of cooked pork loins (LD) was done by a boar taint (skatole and androstenone) trained taste panel. To evaluate the odour and the flavour, a sensory profile analysis was performed which involved the following attributes: total off-odour/off-flavour, pig, urine, manure, naphthalene, rancid, sweet and sweat in the whole sample including both meat and fat.

Giving FLF to pigs significantly changed the microbiota in the gastro-intestinal tract compared with NPDF. In particular, the density of coliform bacteria was reduced in the gastro-intestinal tract of the pigs on FLF. Giving FLF demonstrated no effects on skatole concentration in caecum, colon, blood and backfat and boar odour attributes, whereas administration of FLF + ZB decreased the skatole concentrations and the typical boar odours, pig and manure odour, compared especially with the pigs on NPDF. However, meat from pigs given FLF either with or without zinc bacitracin had smaller but significantly worsened scores for three flavour attributes — pig flavour, rancid flavour and total off-flavour — compared with meat from NPDF pigs and the three flavour attributes were equally affected in both sexes. This seems to point to a significant worsening of meat flavour in pigs given FLF that is independent of sex and boar odour problems (skatole and androstenone).

Estimates of variance components for five egg traits on 26265 laying hens were obtained by restricted maximum likelihood (REML) using several models. In the DOMFS model, the effects included hatch group, additive genetic, full-sib, parental dominance and inbreeding depression. In the DOM model, the full-sib effect was eliminated. In the FS model, the parental dominance effect was eliminated. In the ADD model, both the full-sib and the dominance effects were eliminated. In the DOMFS model, the estimates of the full-sib variance were generally higher for egg production traits and lower for egg characteristics than those of the parental dominance variance. However, this model has partially failed in separating these two components. When the full-sib effect was removed from the model, almost all of its estimated variance moved to the estimated parental dominance variance. When the parental dominance effect was removed from the model, almost all of its estimated variance moved to the estimated full-sib variance. The estimates obtained with REML and the DOM model were compared with those obtained by method R and tilde-hat methodologies. The d2 (ratio of dominance variance to total variance) differed by up to 86% for method R and up to 225% for tilde-hat. The h2 differed by up to 26 and 28%, respectively. For data sets that are too large to be analysed with REML, method R is a feasible alternative. A model for estimation of dominance variance should also include the full-sib or a similar effect, provided the data set is large. Similarly, to analyse egg production traits, the model should include at least the full-sib effect.

Nose-rings are often fitted to outdoor commercial pigs to inhibit rooting and reduce consequent pasture damage. During ethological observations of the behaviour of ringed pigs at pasture, subjective impressions suggested that pigs with nose-rings picked up their normal feed, in the form of large nuts (‘roll nuts’), more tentatively than unringed pigs. The observed pigs were gestating sows under one of three treatments: unringed controls (UR), multiple wire ‘clip-rings’ through the upper rim of the snout (CR), or rigid ‘bull-rings’ through the nasal septum (BR). For formal assessment of feeding efficiency eight randomly selected pigs from each condition were timed and video-recorded, in individual feeder stalls, as they ate 20 3-cm long roll-nuts laid out in a standard rectilinear array in a steel-sided tray under each of five conditions: on a hard surface, on the surface of soil, on the surface of turf, embedded in soil, or embedded in turf. All groups took longer to eat up their test meal from the plain surface than from the surfaces of either soil or turf and longer still when the nuts were embedded. In all conditions, ringed pigs took longer to eat their 20 nuts than did controls, with BR > CR > UR (overall mean times, pooling data from the different feeding conditions: 118·6, 69·9 and 56·7 s respectively: P < 0·001). The difference between groups was greatest when nuts were embedded. Also, when nuts were embedded, ringed pigs were more reluctant to root: the latency to their first rooting action was delayed (mean latency across both embedded’ conditions: 29·6, 87·9 and 106·8 s for UR, CR and BR pigs, respectively: P < 0·01 with soil and turf conditions combined) and, even after starting, a smaller proportion of the residual trial time was spent rooting (0·11, 0·27 and 0·62 of the total time by BR, CR and UR pigs respectively; P < 0·001). It is concluded that nose-ringing depresses the efficiency with which pigs feed on solid food, especially if they have to root for it. The threat to welfare inherent in this will be greatest when ringed pigs are in direct competition with unringed pigs.

An experiment was conducted in 1995 in order to examine muscle growth, muscle histochemical properties, muscle metabolism and meat quality of two types of Danish Landrace pigs representing the growth potential of years 1976 and 1995, respectively. Danish Landrace pigs representing 1976 (slow-growing, SG) originated from a breeding station where the population was maintained without being selected for production traits such as daily gain, food conversion ratio and meat content. Pigs representing Danish Landrace of 1995 (fast-growing, FG) were bought from certified Danish pig breeders. The pigs were simultaneously tested for performance from 40 to 95 kg live weight. The daily gain, food conversion ratio and meat content of the carcass were improved proportionately by 0·43, 0·24 and 0·03 in FG pigs compared with SG pigs. In m. longissimus dorsi (LD), the cross-sectional area of muscle fibres was smaller in FG pigs compared with SG pigs indicating increased muscle fibre number. Data further suggest increased satellite cell proliferation in muscles of FG pigs. Serum from FG pigs stimulated the proliferation of C2C12 muscle cells to a greater extent than serum from SG pigs, although the serum level of insulin-like growth factor 1 did not differ between pig types. The effect of serum on protein turn-over of C2C12 myotubes did not depend on pig type. The glycogen concentration in the LD did not differ significantly between pig types, while the activity of citrate synthase, 3-OH-acyl-CoA-dehydrogenase, and lactate dehydrogenase were higher in the LD of SG pigs compared with FG pigs. Pork chop colour of FG pigs was proportionately 0·09 lighter (L⋆) and 0·13 less red (a⋆) than pork chops of SG pigs. The total muscle pigment concentration in the LD, m. biceps femoris and m. vastus intermedius was proportionately reduced by 0·17, 0·19 and 0·11, respectively, in FG pigs compared with SG pigs. In the LD, the concentration of myoglobin was proportionately reduced by 0·17 in FG pigs. The chemical composition of the LD differed between pig types such that the water content was higher and protein content lower in LD from FG pigs compared with SG pigs. The pH of the LD measured 45 min and 24 h post mortem, drip loss and thawing loss were similar for both pig types. Meat tenderness of conditioned pork chops of FG pigs was slightly reduced in accordance with a decreased intensity of the 31 kDa peptide band and increased cooking loss. The present study suggests that increased muscle fibre number and rate of muscle DNA deposition (satellite cell proliferation) have contributed to the increased muscle growth as a result of selection for performance in pigs under Danish conditions. However, the increase in growth performance was accompanied by deterioration in muscle colour and slightly reduced tenderness.

As part of an investigation of factors responsible for a previously reported lower efficiency of carcass lean gain in steers offered grass silage diets, 16 Simmental × Friesian steers (515 (s.e. 6·4) kg) were offered perennial ryegrass silage ad libitum (C0) or silage plus rolled barley at 200 (C20), 400 (C40) or 600 (C60) g/kg total diet dry matter (DM). Barley-supplemented diets were intake-restricted to provide equal DM and metabolizable energy (ME) intakes to those offered C0. Eight steers were selected at random to determine the ME contents of the diets by open-circuit respiration calorimetry. The other eight steers were offered the same diets and were blood-sampled at 20- to 60-min intervals, for 10 h, to monitor changes in the concentrations of a number of nutritionally related plasma metabolites and hormones. Estimated ME intakes in these steers were 85·7, 83·1, 84·4 and 86·2 (s.e. 0·91) MJ/day from diets C0, C20, C40 and C60 respectively. Rumen-fistulated Hereford × Friesian steers provided 24-h rumen data for the same diets offered at equal amounts of ME per kg metabolic live weight.

Mean 24-h plasma concentrations of insulin and insulin-like growth factor 1 (IGF-1) were linearly and positively related (P < 0·01 and P < 0·001 respectively) and glucagon quadratically related (P < 0·05) to the proportion of barley in the diet. Plasma insulin increased after feeding on all diets but concentrations on diets C40 and C60 were significantly higher than those on C0 and C20 at all post-feeding sampling times up to 9 h after feeding. Plasma IGF-1 concentrations increased above pre-feeding levels following feeding of the higher barley diets (C40 and C60; P = 0·053) but remained unchanged in steers offered C0 and C20. Mean plasma concentrations of glucose were unaffected by diet but those of β-hydroxybutyrate (BOHB) and urea were positively and negatively related respectively (both P < 0·001) to the proportion of barley in the diet. Plasma BOHB and urea concentrations also changed with time after feeding (P < 0·001). Amongst the rumen parameters measured (pH; ammonia and volatile fatty acid concentrations and proportions) only the mean 24-h concentrations and proportions of butyrate were positively related to the proportion of barley in the diet (P = 0·051 and P < 0·05 respectively). All rumen parameters were affected by time after feeding (acetate, P < 0·01; others, P < 0·001) but there was no interaction between treatment and time for any parameter.

The effect of two different lactation environments on the development of pig behaviour was examined at weaning and on days 1, 8, 15 and 57 post weaning. Ten focal indoor-bred pigs and 10 focal outdoor-bred pigs were weaned and mixed together into a group of 60 to 80 mixed indoor- and outdoor-bred pigs. There were six replicate groups. Scans of all focal animals were made using time sampling with a 2-min interval, for 3·0 h immediately following weaning and from 06:00 to 11:00 h on days 1, 8, 15 and 57 post weaning. All pens were straw bedded with two different types of feeder system: one seven-space ad libitum hopper and two rooting-action feeders each accommodating up to four piglets at one time.

From weaning to day 1 post weaning, outdoor-bred pigs were observed to feed more than were indoor-bred pigs (115·6 v. 97·0 observations per pen per day, P < 0·05, s.e.d. = 1·18). From days 8 to 57 post weaning, outdoor-bred pigs were observed to root more than were indoor-bred pigs (22·5 v. 14·7 observations per pen per day, P < 0·05, s.e.d. = 1·22). These findings support the hypothesis that the lactation environment has a significant effect on the behaviour of pigs in their subsequent growing environment. However, such effects appear not to lead to differences in carcass weights, rigor following dressing or carcass blemish at slaughter.

This study provides estimates of genetic parameters for various diseases, fertility and 305-day milk production traits in dairy cattle using data from a UK national milk recording scheme. The data set consisted of 63891 multiple lactation records on diseases (mastitis, lameness, milk fever, ketosis and tetany), fertility traits (calving interval, conception to first service, number of services for a conception, and number of days to first service), dystocia and 305-day milk, fat and protein yield. All traits were analysed by multi-trait repeatability linear animal models (LM). Binary diseases and fertility traits were further analysed by threshold sire models (TM). Both LM and TM analyses were based on the generalized linear mixed model framework. The LM included herd-year-season of calving (HYS), age at calving and parity as fixed effects and genetic, permanent environmental and residual effects as random. The TM analyses included the same effects as for LM, but HYS effects were treated as random to avoid convergence problems when HYS sub-classes had 0 or 100% incidence. Because HYS effects were treated as random, herd effects were fitted as fixed effects to account for effect of herds in the data. The LM estimates of heritability ranged from 0•389 to 0•399 for 305-day milk production traits, 0•010 to 0•029 for fertility traits and 0•004 to 0•038 for diseases. The LM estimates of repeatability ranged from 0•556 to 0•586 for 305-day milk production traits, 0•029 to 0•086 for fertility traits and 0•004 to 0•100 for diseases. The TM estimates of heritabilities and repeatabilities were greater than LM estimates for binary traits and were in the range 0•012 to 0•126 and 0•013 to 0•168, respectively. Genetic correlations between milk production traits and fertility and diseases were all unfavorable: they ranged from 0•07 to 0•37 for milk production and diseases, 0•31 to 0•54 for milk production and poor fertility and 0•06 to 0•41 for diseases and poor fertility. These results show that future selection programmes should include disease and fertility for genetic improvement of health and reproduction and for sustained economic growth in the dairy cattle industry.

When compared with other menadione derivatives such as menadione sodium bisulphite (MSB), menadione nicotinamide bisulphite (MNB), an organic salt combining menadione and nicotinamide, shows better stability towards physical and chemical factors once it is added to pre-mixes or foods. The present work evaluates the bioavailability of the two vitamins present in this compound and toxicity in the pig. To assess vitamin bioavailability, pigs were given small amounts of food containing MNB or equivalent amounts of MSB and nicotinamide in the free form. Menadione and nicotinamide concentrations in blood samples drawn at set times after the diets were given did not reveal any significant differences between the two modes of administration. Haematic levels of both vitamins in animals receiving MNB, or MSB and nicotinamide, were after 2, 4, 8 and 12 h higher (P < 0·001) than those of untreated animals. The tolerance level to MNB was evaluated in pigs given diets containing graded amounts of MNB (100, 500, 2500 mg/kg) for 28 days. No significant (P > 0·05) differences were recorded in live weight, food intake and gain/food ratio in pigs given these diets when compared with those given an unsupplemented diet. Haemoglobin and bilirubin levels did not differ between animals given various amounts of MNB and control animals. Plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities in pigs given 100 mg/kg of MNB did not show significant differences when compared with those observed in pigs given an unsupplemented control diet. In pigs on the diets supplemented with 500 and 2500 mg/kg of MNB there was a significant increase in the two enzymatic activities as compared with controls (P < 0·001 and P < 0·01). In the case of ALT this had disappeared by 28 weeks. MNB is a good source of vitamin K for the pig and does not appear to have any adverse effects, even when administered at levels higher than those normally used in pig food supplementation.

Forty-two multiparous Large White sows were used to investigate the effect of diurnally fluctuating temperature (T) on lactation performance and feeding behaviour. The animals were allocated to one of the four thermic treatments: constant T at 25°C (25C) and 29°C (29C) or equal-mean diurnal cyclic T varying from 21 to 29°C (25V) and from 25 to 33°C (29V). Photoperiod was fixed to 14 h of light. The sows were given food ad libitum between the 7th and the 19th day post partům. Lactation performance was measured for all sows whereas the feeding behaviour was recorded only on 28 sows. The ad libitum food intake was comparable at 25C and 25V (6•31 kg/day) as were milk production and body reserves mobilization. In contrast, food intake at 29V was higher than at 29C (4•53 v. 3•48 kg/day) with no difference in milk production between the two treatments. The increased daily food intake at 29V resulted from higher intakes over the coolest periods of the day and especially during the dark period. Neither meal size nor daily number of meals were significantly affected by T. Feeding behaviour was mainly diurnal but with differences between treatments: 0•90 of total food intake at 29C v. 0•78 at the other three T It appears that the effects of diurnally fluctuating T on lactation performance of sows depend on the mean level of T

The suckling frequency in 34 first-lactation sows and their litters in conventional farrowing pens was observed during a 35-day lactation period from birth to weaning. In order to quantify the ontogenetic development of this behaviour a non-linear regression function was used as a model. The maximum (MAX) of the curve was determined at day 8×5 (31×4 sucklings per 24-h period) and was considered as the biological beginning of the weaning process. The occurrence of MAX was shifted towards an earlier time by about 6 days earlier from small (4 to 7 piglets per litter) to large litters (11 to 14 piglets per litter). However, no significant influence of the litter size on the development of the daily suckling frequency and the average individual piglet weight was found. Nevertheless, there was a tendency for an inverse relationship between the litter size and the piglet weight during lactation and, further, for an increased daily suckling frequency during early lactation and a lower frequency during late lactation in larger litters. As a compensation for the decreasing suckling frequency piglets markedly increased their creep food consumption in the last week of the suckling period (day 28 to 35). The results indicate that the suckling behaviour in domestic pigs reflects sow-piglet relationships which are consistent with a theoretically predicted model of weaning conflict. Hence, it is suggested that modelling the suckling behaviour using well defined and comparable measures may be a suitable approach for the evaluation of the weaning process both in terms of sociobiology (e.g. weaning conflict, parent-offspring conflict) and of farm animal science (e.g. performance, housing conditions).

When modelling the effect of a changing nutrient supply to growing animals, it is important to distinguish the individual response curve of an animal from the change in this response that may occur during growth. A data analysis model is proposed where, for an individual animal, the relation between protein deposition (PD) and metabolizable energy (ME) intake above maintenance (MEp) is curvilinear, so that PD intersects the origin and reaches its maximum at the maximum protein deposition rate (PDmax). An increase of MEp beyond that required to attain PDmax would not change PD. The MEp not used for protein synthesis can be used for lipid deposition (LD). The relation between PD and LD on the one hand and ME on the other hand can then be described as a function of the maintenance energy requirement (MEm), PDmax, the level of ME required to attain PDmax (F; as a multiple of MEm) and the energetic efficiencies of PD (kp) and LD (kf). Of these statistics, only kp and kf were assumed to be independent of body weight (BW), age or genotype. Variation in PDmax was described as a Gompertz function (of age) whereas variation in F was assumed a linear function of BW. Maintenance energy requirement was expressed as a power function of BW. To evaluate the model, 145 nitrogen and energy (indirect calorimetry) balances were obtained from three types of pigs (Large White castrated males (cLW) and Piétrain × Large White castrated males (cPP× ) and males (bPP×)) ranging in BW between 45 and 100 kg and housed under thermoneutral conditions. Animals were allotted to one of four energy levels ranging from 0·70 to 1·00 of ad libitum intake. The MEm was not different between genotypes (849 kJ/kg BW0·60) whereas the kp and kf were 0·56 and 0·75, respectively. For castrated animals on ad libitum intake, PDmax started limiting PD at approximately 130 days of age (78 and 86 kg BW for cLW and cPP×, respectively). Before this age and for bPP×, PD was limited by MEp. In bPP×, the difference between PD and PDmax was small (less than proportionately 0·05). The F did not change with BW for bPP× (2·85 × MEm) whereas for the other genotypes, it decreased linearly from 4·47 at 45 kg to 2·00 at 100 kg of BW. Due to its nature, the model allows estimation of PDmax even when energy is restricting PD.

A crossbreeding experiment involving Timahdit (T), D'man (D) and improved sire breeds (M) was conducted to compare lamb production in five crossbreeding types: D ✕ D, T ✕ T, D ✕ T (DT), M ✕ T, and M ✕ DT lambs. Reproductive and production traits were analysed in 1187 litters, 1586 lambs born and 1346 lambs weaned, progeny of 605 ewes. Effects of crossbreeding type, year of birth, sex of lamb, age of dam, and type of birth were significant on the majority of traits studied. The D ✕ D and M ✕ DT crossbreeding system showed the highest litter sizes at lambing and at weaning with respective values in D ✕ D (2·17, 1·34) and M ✕ DT (1·72, 1·39). Ewes bearing the M ✕ DT cross lambs showed the highest (P < 0·05) litter weight at weaning (28·28 kg) followed by those with M ✕ T (23·14 kg), and D ✕ D (22·53 kg) lambs. M ✕ DT and M ✕ T lambs were heavier and grew faster than the other lambs. On the other hand, lamb survival rates and growth traits were the lowest in D ✕ D but those in T ✕ T and D ✕ T genetic types of lamb were intermediate. Results showed that D as a dam breed had a favourable effect on litter size (P < 0·01) but unfavourable effect on lamb survival and birth weight. The reproductive performance of DT crossbred ewes, due to their high prolificacy and lamb survival, associated with the favourable effect of an improved terminal sire (M) for growth traits, indicated that the three breed cross (M ✕ DT) could enhance lamb production in Morocco.

A 2 ✕ 2 ✕ 3 factorial arrangement of treatments used 522 boars to examine the main effects and interactions of season (spring v. summer), number of pigs per pen with a single-space feeder (13 or 16 pigs per pen with a singlespace feeder; 0·78 m2 per pig v. 0·65 m2 floor space per pig) and nutrient density of the diet (12·5 g lysine per kg and 14·0 MJ digestible energy (DE) per kg from 38 kg to slaughter (high), 12·5 g lysine per kg and 14·0 MJ DE per kg during the growing phase and 10·0 g lysine per kg and 13·6 MJ DE per kg during the finishing phase (split) and 10 g lysine per kg and 13·6 MJ DE per kg from 38 kg to slaughter (low)) on the performance and carcass characteristics of growing and finishing pigs. The smaller group of pigs had a higher food intake during the grower-finisher period than the high stocked pigs (P < 0·01). The pigs had a higher lysine intake in the spring than in the summer months (P < 0·05). Differences in daily food intake for the smaller group of pigs were reflected in increased growth rate during the grower-finisher period (P < 0·001). However these pigs had a poorer food conversion ratio during the grower-finisher period (P < 0·05) than the bigger group of pigs. The pigs offered the high specification and split-fed diets had better growth rate (P < 0·05) than the pigs given the low specification diet during the grower and finisher period. There was a significant two-way interaction in growth rate between dietary treatment and season during the finisher period (P < 0·01). The pigs given the high specification diet had a better growth rate (P < 0·001) than the pigs given the low diets during the summer months. However, the high specification diet depressed growth rate during the spring months (P < 0·05). The pigs had a lower backfat and higher lean meat in the summer than in the spring months (P < 0·05).

The effects of different dietary essential fatty acids on piglet tissue composition at birth and performance until 7 days post weaning were investigated by offering the sow diets containing (17·5 g oil per kg diet) either maize oil (MO) as a control treatment, tuna oil (TO) as a source of long chain n-3 polyunsaturated fatty acids, particularly 22:6 n-3, or a mixture of maize and linseed oils (LO) which supplied the same amount of n-3 acids as TO but in the form of 18:3 n-3. Ten sows were allocated to each treatment which was offered throughout pregnancy and lactation. Compared with MO, offering TO increased sow plasma and subcutaneous adipose tissue 22: 6 n-3 proportions whereas LO increased 18: 3 n-3 and, to a much lesser extent than TO, 22: 6 n-3. Offering TO to the sow increased the proportions of 20: 5 n-3 and 22: 6 n-3 in piglet brain and liver at birth and decreased the n-6 acids, 20: 4, 22: 4 and 22: 5. LO only increased piglet liver 20: 5 n-3 proportions but to a lesser extent than TO; however, LO also decreased the proportions of 20: 4, 22: 4 and 22: 5 n-6 in piglet tissues. Offering the pregnant sow dietary 18: 3 n-3 therefore increased deposition of 22: 6 n-3 in foetal piglet tissues to a much lesser extent than tuna oil and so it is necessary to offer the sow pre-formed 22: 6 n-3 in order to achieve maximum foetal 22: 6 n-3 deposition. By experimentally allocating piglets at birth, effects of sow nutrition during pregnancy and lactation were separated. Piglets sucking MO or TO sows were heavier than piglets sucking LO sows 7 days post weaning.

Four hundred piglets were housed in 20 pens and offered for 42 days a pre-starter and then a starter compound supplemented with trace elements given as sulphates (SULF) or proteinates (PROT) at a common level (100) or at a reduced level (20) of inclusion. The common level supplied 278, 148, 315 and 98 mg/kg and the reduced level supplied 128, 38, 135 and 50 mg/kg of iron (Fe), copper (Cu), zinc (Zn) and manganese (Mn), respectively, taking into account the natural food contents. Proteinates used in the trial were analysed and described in terms of content and quality of different potential ligands. Piglet growth was not affected by any treatment. At the end of the trial blood samples were collected from eight pigs for each treatment. These animals were slaughtered and their livers were removed, weighed and analysed. Compared with SULF, PROT increased significantly plasma levels of Fe (25·1 v. 15·7 μmol/l), haemoglobin (10·9 v. 10·4 g/dl) and the number of red blood cells (6·4 v. 6·1 millions per μl) but the liver recovery of Fe was not affected by any treatment. In piglets receiving PROT the liver content of Cu and Zn increased significantly compared with those receiving SULF. On reducing the dosage, Cu in the liver significantly decreased with SULF but not with PROT and the amount of Zn decreased more with SULF than with PROT. The results may reflect a better availability of Cu and Zn when proteinates rather than sulphates were used as mineral supplements.

This study investigated the effect of the change of diet and feeding regimen at weaning on myoelectrical activity of the intestine of piglets. For this purpose the electromyographic recordings of duodenal myoelectrical activity were carried out in relation to the different weaning status of piglets. Six piglets, in two experimental trials were surgically modified with two serosal, bipolar electrodes on the duodenum. The myoelectrical activity was recorded in the same piglets before weaning when they were sucking their sow and after weaning when the diet was changed to solid dry food (standard commercial concentrate for weaned pigs). In sucking piglets the intestinal myoelectrical activity pattern exhibited triple-phased migrating myoelectric complex (MMC), undisturbed by sow nursing. After weaning, feeding with solid food induced a long-term post-prandial pattern with higher frequency of electrical response activity (ERA) when compared with phase II of the MMC. The duration of the MMC cycles increased with time over the experiment by proportionately 0•11 and 0•14 in the periods before and after weaning. However, weaning significantly shortened MMC cycle duration by proportionately 0•21. The duration of phase II was significantly prolonged with time over the experiment by 0•07 to 0•10 and it was not affected by weaning. Phase III of MMC were of constant duration over the whole experimental period.

In summary, changes in the diet and feeding regimen have an influence on the characteristics of intestinal myoelectrical activity in piglets around weaning.

Increasing sow food intake in late gestation prevents loss of sow fatness prior to farrowing. However, this may result in reduced food intake and greater overall fat loss during lactation and has also been associated with increased incidence of agalactia. In this experiment 78 Camborough sows (parities 1 to 3) were given food at one of two levels: either 1·15 × maintenance energy (normal-N sows, 2·3 (s.e. 0·03) kg/day) or 2·00 × maintenance energy (high-H sows, 3·9 (s.e. 0·04) kg/day) from day 100 of gestation until farrowing. Lactation food intake, changes in sow live weight and backfat thickness and piglet growth rates were then measured. Diet digestibility in early lactation was measured using a chromium III oxide marker in the food. There was no change in backfat thickness in late gestation in H sows (0·2 (s.e. 0·25) mm), whereas N sows lost backfat during this period (1·6 (s.e. 0·23) mm, P <; 0·001). There was no difference in lactation food intake between the two groups (6·5 (s.e. 0·13) kg/day) and differences in backfat thickness at parturition were maintained through to weaning. H sows did not show increased incidence of agalactia compared with N sows. There was no difference in diet digestibility between the two treatment groups. Food intake level in late gestation did not affect piglet birth weights, growth rates or mortality. It is concluded that the main benefit of increasing sow food intake in late gestation was to reduce sow backfat loss during the reproductive cycle.

In the present study body condition scores (BCS), ultrasound fat thickness and ultrasound m. longissimus dorsi thickness as well as body measurements and management factors were recorded repeatedly during lactation in 71 Holstein-Friesians, 71 Jerseys and 71 Holstein-Jersey F1-crosses (first to ninth lactation) on four feeding regimens. BCS were analysed with ultrasound measurements as explanatory variables by mixed models. A compound symmetry structure for the variance components was applied. The models were also tested for an autoregressive error structure [AR(1)]. Ultrasound fat thickness and ultrasound m. longissimus dorsi thickness explained most of the variability in BCS. Coefficients of determination were between 0•84 and 0•85. Management factors such as feeding group and stage of lactation (week of taking measurements) and the breed type ✕ lactation interaction were, although significant, not relevant for the fit. Holsteins tended to have lower scores than F1-crosses and Jerseys and younger cows tended to have higher scores than older cows. Despite small differences between breeds, Edmonson’s BCS proved to be consistent within each breed type; thus BCS can be applied to various dairy breeds.

Growing pigs fitted with post-valve T-caecum cannulas were used in a change-over design experiment (5 ✕ 5) to determine the ileal and total tract apparent digestibility and hindgut disappearance of dietary components and energy in a cassava root and soya-bean meal-based diet with an inclusion rate at 0·15 of the dry matter (DM) of either cassava leaf meal, ensiled cassava leaves, groundnut foliage, or leucaena leaves.

The ileal and total tract apparent digestibilities of organic matter (OM), crude protein, nitrogen-free extractives and energy of the diets were significantly reduced with inclusion of the foliages (P < 0·05). The digestibility of neutral-detergent fibre (NDF) and crude fibre was improved when groundnut foliage was included in the diet (P < 0·05).

The dietary content of NDF was a better predictor of the total tract digestibility of OM (R2 = 0·87) and energy (R2 = 0·90) than the content of crude fibre (R2 = 0·68 for OM digestibility and R2 = 0·72 for energy digestibility).

The disappearance of OM and energy in the hindgut of the foliage diets was 0·36 (s.d. 0·02) and 0·31 (s.d. 0·02), respectively, which was significantly lower (P < 0·05) than on the control diet (0·48 and 0·46, respectively).

Ileal as well as total tract digestibilities of OM in groundnut foliage were higher than for the other leaf products (ileal, 0·55 and 0·42; and total tract, 0·64 and 0·55, respectively). For foliage products of cassava and leucaena an average digestible energy value of 11·4 MJ/kg DM was calculated, whereas for groundnut foliage the corresponding value was 10·9 MJ/kg DM.

It was concluded that, inclusion of foliages in pig diets will reduce the dietary energy content, due to a high fibre content. However, under tropical conditions foliage at low levels of inclusion may be useful in low fibre diets for growing pigs to improve the dietary protein supply.

The digestibility and voluntary intake of fibrous roughages and acorns was studied in six wild boar and five Meishan pigs. The neutral-detergent fibre (NDF) concentration of the diets ranged from 139 to 767 g/kg of the organic matter. Organic matter digestibility of acorns, mixed grass and wheat straw was higher in wild boar (P < 0·05) while voluntary food intake of the Meishan pigs was higher for mixed grass, hay and wheat straw (P < 0·05). Organic matter digestibility (P < 0·01) and NDF digestibility (P < 0·05) were both negatively related to NDF concentration of the diet. No relationship existed between voluntary food intake and NDF concentration of the diet. The apparent nitrogen (N) digestibility was positively related (P < 0·01) to dietary N while no relationship was found with dietary NDF. The negative effect of NDF on digestibility could only be partly explained by the lignin concentration of NDF. Much more important was the lower efficiency of the carbohydrate fermentation in the caecum and colon when compared with the direct absorption of glucose from the small intestine. It was estimated that digestible NDF at a maximum contributed proportionately 0·26 to the metabolizable energy intake of the animals. It was concluded that wild boar and domestic pigs should be able to maintain themselves on an all fresh grass diet when NDF concentration of the diet does not exceed about 550 g/kg and N concentration is not too low.