Precision technologies and data have had relatively modest impacts in grass-based livestock ruminant production systems compared with other agricultural sectors such as arable. Precision technologies promise increased efficiency, reduced environmental impact, improved animal health, welfare and product quality. The benefits of precision technologies have, however, been relatively slow to be realised on pasture based farms. Though there is significant overlap with indoor systems, implementing technology in grass-based dairying brings unique opportunities and challenges. The large areas animals roam and graze in pasture based systems and the associated connectivity challenges may, in part at least, explain the comparatively lower adoption of such technologies in pasture based systems. With the exception of sensor and Bluetooth-enabled plate metres, there are thus few technologies designed specifically to increase pasture utilisation. Terrestrial and satellite-based spectral analysis of pasture biomass and quality is still in the development phase. One of the key drivers of efficiency in pasture based systems has thus only been marginally impacted by precision technologies. In contrast, technological development in the area of fertility and heat detection has been significant and offers significant potential value to dairy farmers, including those in pasture based systems. A past review of sensors in health management for dairy farms concluded that although the collection of accurate data was generally achieved, the processing, integration and presentation of the resulting information and decision-support applications were inadequate. These technologies’ value to farming systems is thus unclear. As a result, it is not certain that farm management is being sufficiently improved to justify widespread adoption of precision technologies currently. We argue for a user need-driven development of technologies and for a focus on how outputs arising from precision technologies and associated decision support applications are delivered to users to maximise their value. Further cost/benefit analysis is required to determine the efficacy of investing in specific precision technologies, potentially taking account of several yet to ascertained farm specific variables.

The aim of this work was to develop an index describing the relative intake of the total diet by dairy cows, and hence the ability to predict intake responses to changes in both forage and concentrate variables. An evaluation of concentrate factors affecting silage dry matter (DM) intake of dairy cows was conducted based on dietary treatment means from milk production experiments. The data were divided into four subsets according to concentrate treatments used within the experiments: the amount of concentrate supplementation (n = 217), protein supplementation (n = 336), carbohydrate composition (n = 114) and fat concentration of the concentrate (n = 29). The data were subjected to mixed-model regression analysis. Increased concentrate DM intake (CDMI) decreased silage DM intake (SDMI) quadratically. The substitution rate (substitution of silage DM for concentrate DM) increased with improved silage intake potential. SDMI increased quadratically with concentrate protein intake, the response being negatively related to the effective protein degradability (EPD) of concentrates. Replacement of starchy concentrate ingredients with fibrous supplements had a small positive effect on silage intake, whereas increased concentrate fat concentration slightly decreased SDMI. The outcome of concentrate factors influencing total DM intake (TDMI) was used to create a relative CDMI index as follows: CDMI index = 100 + 10 × [(CDMI − 0.1629 × CDMI − 0.01882 × CDMI2 − 5.49) + ((0.9474 × CCPI − 0.4965 × CCPI2) − 2.017 × (CEPD − 0.74)) + 0.00225 × (CNDF − 250) − 0.0103 × (40 − Cfat) − 0.00058 × (CDMI − 8.0) × (SDMI index − 100)], where CDMI = concentrate DM intake (kg/day), CCPI = supplementary concentrate CP intake (kg/day; CP>170 g/kg DM), CEPD = concentrate EPD (g/g), CNDF = concentrate NDF concentration (g/kg DM), Cfat = concentrate fat concentration (g/kg DM) and SDMI index is the relative intake potential of silage (Huhtanen, Rinne and Nousiainen 2007. Animal 1, 758–770). TDMI index was calculated as SDMI index + CDMI index − 100 to describe the relative intake potential of the total diet. For the whole data set (n = 943), one TDMI index unit was equivalent to 0.095 kg/day DM intake, i.e. close to the default value of 0.100 kg. The CDMI index explained proportionally 0.88 of the variation in TDMI within a study with a 0.27 kg/day residual mean-square error (n = 616). The corresponding values for the TDMI index were 0.81 and 0.37 kg/day (n = 943), respectively. The residual mean-square errors in cross-validation were marginally higher. The developed TDMI index can be used to estimate the intake responses to diet changes. It provides an improved basis for practical dairy cow ration formulation and economic evaluation.

The aim of the present study was to evaluate the effect of the inclusion of stoned olive cake and rolled linseed in a concentrate-based diet for lambs on the fatty-acid composition of polar and non-polar intramuscular lipids of the longissimus dorsi muscle. To achieve this objective, 32 Appenninica lambs were randomly distributed into four groups of eight lambs each and were fed conventional cereal-based concentrates (diet C); concentrates containing 20% on a dry matter (DM) basis of rolled linseed (diet L); concentrates containing 35% DM of stoned olive cake (diet OC); and concentrates containing both rolled linseed (10% DM) and stoned olive cake (17% DM; diet OCL). The concentrates were administered together with grass hay at a 20:80 forage:concentrate ratio. Growing performances and carcass traits were evaluated. The fatty-acid composition was analysed in the total intramuscular lipids, as well as in the polar and neutral lipids. The average feed intake and the growth performance of lambs were not affected by the dietary treatments, as a consequence of similar nutritional characteristics of the diets. The inclusion of rolled linseed in the L and OCL diets increased the content of C18:3 n-3 in intramuscular total lipids, which was threefold higher in meat from the L lambs and more than twofold higher in meat from the OCL lambs compared with the C and OC treatments. The n-6:n-3 ratio significantly decreased in the meat from lambs in the L and OCL groups, reaching values below 3. The L treatment resulted in the highest level of trans-18:1 fatty acids in the muscle. Regardless of the dietary treatment, the t10-18:1 was the major isomer, representing 55%, 45%, 49% and 45% of total trans-18:1 for C, L, OC and OCL treatments, respectively. Neutral lipids from the OC-fed lambs contained the highest amount of c9-18:1 (more than 36% of total fatty acids); however, the content of c9-18:1 did not differ between the OC and C lambs, suggesting an intensive biohydrogenation of dietary c9-18:1 in the case of OC treatment. The highest content of c9,t11-18:2 was detected in the intramuscular fat from the L-fed lambs, followed by the OCL treatment. A similar trend was observed in the neutral lipid fraction and, to a lower extent, in the polar lipids.

Data were available on crossbred meat lambs for 10 live-weight and growth traits (2585 lambs), 5 carcass traits (1884 lambs) and 10 dissection traits (944 lambs). These were the progeny born on an experimental farm over 5 years, from 102, 79 and 65 sires respectively for the three groups of traits. Genetic parameters were estimated from the sire components in a nested analysis of variance within breed of sire and year subclass, adjusting for sex, dam age, rearing type and other factors.

The heritabilities of the live-weight and growth traits were all low, the highest being average daily gain to slaughter (0·10, s.e. 0·06), and none was statistically significant. The heritabilities of the traits of carcass composition were much higher: percentage lean (0·41, s.e. 0·13), percentage fat (0·37, s.e. 0·13) and percentage bone (0·16, s.e. 0·10). Intermediate values were found for most other traits: killing-out percentage (0·16, s.e. 0·07), fat depth (0·21, s.e. 0·11), eye-muscle area (0·14, s.e. 0·10) and lean/bone ratio (0·13, s.e. 0·09).

Phenotypic and genetic correlations among the traits were also estimated. No major incompatibilities were found among the traits. The results are discussed in relation to the genetic improvement of lean meat production in sheep.

A closed-loop system is proposed for the control of voluntary food intake in lactating cows, and an expression is deduced relating the response of food intake to changes in milk yield and body-weight gain.

A closed-loop system necessarily involves a delay in the response to changes in production. The rate of increase of food intake is there- fore slower than the rate of increase in milk yield. The consequent deficit in energy during the rising part of the lactation curve is met by the mobilization of body reserves, which are partly accounted for by losses in body weight. During the declining part of the lactation the delay effect leads to an excess of energy intake and to the replacement of body reserves and, consequently, of body weight.

The expression deduced from the model was fitted to four different types of lactation curve corresponding to long and short lactations of Friesians and Jerseys fed ad libitum on a complete diet. The expected food intake based on the control model was contrasted with a linear regression model. The former gave a better account of the variation in food intake in all four types of lactation.

The total change in body weight during lactation was partitioned between changes in weight due to the mobilization and replacement of reserves and gain directly attributable to food intake. There was, in general, good agreement between the observed losses in weight occurring at the beginning of lactation and those predicted from the mobilization of reserves for milk production.

The physiological implications of the model and the values estimated for the parameters are discussed.

Energy and nitrogen metabolism were examined at weekly intervals during lactation weeks 1 to 8 in Holstein-Friesian cows (no. = 9) offered a diet of hay, maize pellets (whole plant) and concentrates, (barley, maize and soya bean; forage : concentrate ratio 65 : 35), with feeding levels close to ad libitum.

After calving, the cows lost body weight until week 7, with peak milk yield (35 kg/day) recorded during week 3. Dry-matter intakes increased progressively to week 4 then remained relatively constant. Apparent digestibility of dietary energy was unaffected by stage of lactation but the overall value was low (0·653) indicative of the quantity and quality of long hay in the diet. Metabolizable energy intakes ranged between 163 and 202 MJ/day, with little between-week variation after that between weeks 1 and 2 (P < 0·01). Milk energy output was relatively stable during weeks 1 to 4 but then declined progressively for each remaining week, whilst heat energy output was relatively constant throughout. Estimates of body energy retention indicated the cows were in negative energy balance at all times, being greater in week 1 (64 MJ/day, P < 0·01) than weeks 2 to 4 (mean, 35 MJ/day) or weeks 5 to 8 (22 MJ/day). Digestible nitrogen (N) intake was reduced in week 1, whilst apparent N digestibility declined significantly , with little between-week variation after that between weeks 1 and 2 < 0·05) as lactation progressed. The cows were in negative N balance (–19 g/day) during week 1, with zero (week 2) or positive balances noted thereafter.

It is concluded that during early lactation, the extent of body tissue mobilization in average yielding cows can be substantial and prolonged, whilst attainment of positive body N status occurred earlier and was not related to the energy status of the cows.

This paper describes the estimation of genetic changes in farm livestock using field data. The method proposed depends on a difference in rate of change in performance of the population and of the successive progenies of individual sires. The change in the population with time is taken as t+g, where t represents environmental change and g represents genetic change, while the within-sire change is taken as t+½g. Their difference measures half the genetic change.

This principle can be applied, with certain precautions, tofielddata where there is some spread of sires over time. The method has two advantages over other methods in that past as well as current changes can be measured and no additional facilities are required. However, selection among sires may bias the estimates of genetic change. Approximate sampling errors of the estimates of change can be obtained and hence the rate of genetic change which a certain body of data will demonstrate to be significant can be estimated.

The method was applied to a set of pig records collected over nine years by a private pig breeder. There was considerable change with time in all six traits examined and in at least three of them there appeared to have been a substantial genetic change accounting for the whole of the observed change.

It is not rare that newly hatched chicks remain without feed for about 24 to 48 h before they are placed on farms due to a series of logistic operations. Furthermore, the spread in hatching time can also mount up to 30 to 48 h for late v. early hatchers. In other words, the practice is a complex combination of spread of hatch and delayed feed access. The present study was aimed to investigate the combined effects of hatching time with a delay in feed access of 48 h, starting from their hatch-time (biological age). When chicks had access to feed immediately after hatch, late hatchers had a higher feed intake and relative growth rate up to day 5 compared with their early hatched counterparts. Feed deprivation during the first 48 h resulted in retarded early growth rate, which was further aggravated by an impaired feed intake after refeeding. In addition, the differential effects of hatching time on relative growth rate and feed intake observed in immediately fed chicks were eliminated by the 48 h feed delay. The yolk utilization after hatch was faster for the late hatchers up to biological day 2 regardless of the feeding treatments. Hatching muscle glycogen content was higher in the late hatchers compared with that of their early counterparts at hatch and at biological day 2 independent of feeding treatment. Moreover, the liver glycogen content of the late hatchers was also higher at hatch. For the immediately fed chicks, the proportional breast muscle weight of the late hatchers was higher at biological day 2 and 5. For the starved chicks, on the other hand, this effect was only observed after they had access to feed (biological day 5). The different plasma T3 levels at hatch may have contributed to the different post hatch performance. It is concluded that the spread of hatch influenced post hatch performance, especially appetite and growth at least until day 5. Moreover, the delay in feed access interacted with the hatching time and caused adverse effects on the post hatch performance.

1. Three groups of six castrated male cattle aged 6,18 and 36 months and three corresponding groups of sheep received in turn three diets consisting of high-quality dried grass (A), low-quality grass (B) or 60% of B with 40% barley (C). For one-half of each 6-week period the grass was eaten in the long form (L) and for the other half, it was ground and pelleted (P).

2. Pelleting increased intake by 45% in sheep, from 56·8 to 82·4 g dry matter per kg W-75 per day, but only by 11% in cattle, from 81·8 to 90·7. The increase was greater for diet B (44%) than for A (19%) or C (15%), and greater for the youngest animals (38%) than for the middle-aged (17%) or oldest (20%).

3. Dry-matter digestibility was reduced by pelleting from 67·2% to 58·6% in sheep and from 69·9% to 56·9% in cattle. The reduction was greater for diets A (71·2% to 56·1%) and B (65·7% to 54·1%) than for diet C (68·7% to 63·2%).

4. A hypothesis based on the importance of particle size of digesta leaving the rumen provides a possible explanation ofthese interactions between form of roughage on the one hand, and species and age of animal or diet composition on the other.

1. Total anatomical dissection data from 62 half carcasses of steers representing 6 breed groups differing in age and nutritional history, were examined with a view to establishing a basis for comparison of carcass composition of breed groups or of cattle from various treatments.

2. The results indicate that total muscular tissue might be used for comparative purposes in certain instances. Muscle weight differences could be examined independently of general size by adjusting to common muscle plus bone weights.

3. It is proposed that relative carcass composition is best assessed by use of two measures: muscle: bone ratio and percentage fat tissue in the carcass.

4. Muscle: bone ratio was shown to increase with carcass weight and after the effects of carcass weight had been statistically removed the influence of percentage fat on this ratio was negligible. The required adjustment to muscle: bone ratio for differences in carcass weight was estimated at 0·03 per 10 kg. increase in carcass weight.

5. Percentage fat in a carcass is proposed as an index of acceptability. The requirements of different markets in terms of this index would need to be established. Adjustment factors for percentage fat based on carcass weight would need to be established on a within group basis.

6. Relative growth coefficients for muscle, bone and fat, based on a logarithmic relationship with total muscle plus bone, are presented and were found to agree closely with those for swine and sheep. The magnitude of differential growth in body tissues indicated by the growth coefficients accentuates the necessity of making carcass composition comparisons at standard weights or following suitable statistical adjustments.

7. The implications of carcass composition assessment in beef breeding programmes are discussed.

One hundred and twenty pigs were used in a 3 × 8 factorial design. The factors were sex, 40 trios of littermate boars, castrated males and gilts, and dietary lysine, eight concentrations from 7×5 to 14×5 g/kg diet with 1 g/kg diet intervals of lysine with corresponding crude protein (CP) concentrations from 114 to 226 g/kg diet. Increases in dietary lysine were associated with concomitant increases in the other essential amino acids so as to provide an ideal protein. All diets had similar digestible energy values (13·65 MJ/kg). Pigs were fed once daily on a restricted scale from 25 to 55 kg live weight. For growth and carcass characteristics there was a range of linear response followed by a plateau. The inflexion points of dietary lysine for growth characteristics were at 11·1, 10·2 and 10·9 g/kg diet (171, 157 and 168 g CP per kg diet) together with daily intakes of 18·0, 16·7 and 17·6 g (daily intake of 277, 257 and 271 g CP) for boars, castrated males and gilts respectively. The equivalent points for carcass characteristics were 10·4, 9·7 and 10·1 g/kg (160, 149 and 156 g CP per kg diet) with daily intakes of 16·9, 15·9 and 16·4 g lysine (daily intakes of 260, 245 and 252 g CP). Blood urea data gave good support for these observations.

Health in relation to tail-biting behaviour was investigated on a problem farm. Quartets (n = 16) of age- and gender-matched fattening pigs including a tail biter (TB, n = 16), a victim (V, n = 16), a control in the same pen (Ctb, n = 10) and a control in a pen where no tail biting was observed (Cno, n = 14) were chosen by direct behavioural observation. Haematological and clinicochemical analyses, autopsy and histological examination of 16 different tissues were carried out. Tail lesion severity was evaluated both macroscopically, on the basis of inspection, and histologically, in the sagittally cut tail. Category effects were tested using Friedman's ANOVA by Ranks, Cochran's Q or a repeated-measure GLM and, if significant, pair-wise tests were conducted using Wilcoxon Signed Ranks or McNemar's Test. The number of received tail bites correlated better with histological than with macroscopic tail lesion scoring because of deep inflammation beneath healthy skin in some cases. Most individuals had mild inflammatory lesions in internal organs suggestive of generalized activation of the immune system, and 30% of the animals were anaemic, possibly because of systemic spread of infectious agents. V had more severe respiratory organ lesions and higher serum protein concentrations than all other categories of pigs. Liver- and muscle-specific enzymes (alanine aminotransferase, alkaline phosphatase and creatine kinase) differed between categories. In conclusion, most animals had signs of generalized activation of the immune system, possibly because of systemic spread of infectious agents. V pigs suffered from more severe inflammatory lesions than TB, Ctb or Cno. Deep infections may exist under healthy skin in the tail of bitten pigs.

Monthly coat and skin samples were taken from three goats for one year in Australia, and from six others for two years in Scotland. The coat appeared to have a simple cycle of active growth in summer followed by inactivity in winter.

The kemp fibres of the outer coat formed brush ends at about the time of the autumn equinox and remained dormant until late spring. Follicles developed first in the foetus formed a brush first. No moult was obvious because new kemps grew before all the old ones had shed, the only manifestation of shedding being a shortening of the coat. The old wool tended to be lost before growth of the new, so that wool was completely lacking in the coat during summer.

Observations on skin sections showed that the majority of both kemp (primary) and under-wool (secondary) follicles become active immediately after the longest day, although there was a tendency for re-growth of wool fibres to be delayed, particularly in females.

Whereas the proportion of kemps with brush ends during winter reached 100%, the proportion among wool fibres was as low as 50%. A complete explanation for this is not yet evident. The bad winter of 1963 apparently caused a greater proportion of secondaries to form brush-ends earlier and to remain inactive longer.

Details are given of some of the histological features of brush formation.

A nutritional hypothesis for the occurrence of the periparturient relaxation of immunity (PPRI) to gastrointestinal nematodes was tested within the bounds of a nutrient partitioning framework. It was hypothesized that at times of a scarce supply of metabolizable protein (MP), an increase in MP supply or a reduction in MP demand (having singles instead of twins) should lower the extent of PPRI in sheep. Twenty-one single- and 21 twin-bearing and -rearing Finn-Dorset ewes, 2 to 7 years old, and repeatedly infected with Teladorsagia circumcincta, were given one of three pelleted foods (no. = 7). The foods were formulated to supply 0·8 (L), 1·0 (M) and 1·2 (H) times the MP requirements during lactation, and were offered ad libitum from d–21 to d35 (d0 is day of parturition). Faecal egg counts (FEC) were assessed twice weekly as an indicator for host resistance. Dry-matter intake (DMI) during late pregnancy was higher than expected, and MP supply did not limit performance at this stage. In accordance with the hypothesis, there were no indications of a breakdown of immunity to T. circumcincta during late pregnancy. DMI during lactation did not differ between the single- and twin-rearing ewes. Calculated milk production was lower for the L than for the M and H ewes, especially for the twin-rearing ewes. A temporarily elevated FEC was observed during the first few days in lactation, which was probably mainly due to changes in faecal output rather than to PPRI. The FEC returned to low, late pregnancy levels at d12 and remained low for the single- but not for the twin-rearing ewes (P < 0·001). Overall, the L ewes had higher FEC than the M and H ewes from d19 onwards; this effect was more pronounced for the twin- than for the single-rearing ewes. It was postulated that DMI achieved overcame MP scarcity and thus prevented breakdown in immunity in the single-rearing ewes. The data support the view that, at times of MP scarcity, an increase in MP supply and reduction in MP demand can lower the extent of the breakdown in immunity towards T. circumcincta.

A trial was carried out to examine some of the factors involved in the possible deterioration in pig meat quality associated with the trend towards leaner carcasses. Five batches of pigs, each one as far as possible from the same producer, were identified at each of 10 abattoirs. Three gilts and three entire males were selected from each batch to show a range of fatness. Overall mean fat thickness measurements over the m, longissimus at the last rib (P2, mm) for lean, average and fat carcasses were 8·8, 11·6, and 16·9 (gilts) and 8·4, 11·7 and 15·5 (entire males). The overall mean carcass weight was 58 kg. Loin and leg joints were assessed for cutting and presentational characteristics by a panel of 45 butchers. Loin chops and shoulder and leg joints were assessed for eating characteristics by consumer panels involving a total of 500 families. Butchers judged the fat of lean carcasses to be softer and the meat to be floppier and with more tissue separation. Entire males also had slight disadvantages in these respects. Consumers found the chops of lean carcasses to be less juicy on average (0·16 lean carcasses were judged to have dry chops compared with 0·09 for fat carcasses) with a tendency towards toughness and less flavour. There were no differences in overall acceptability. Meat from the two sexes did not differ in eating quality or overall acceptability to consumers. The butchers were more critical of overlean carcasses than were consumers. The trial indicates that the trend towards leaner carcasses is likely to create butchery problems but not consumer dissatisfaction.

One hundred and twenty-six twin-bearing ewes were given either formic acid (FA) treated grass silage or grass/ molassed sugar-beet pulp (MSBP) silage in order to investigate factors affecting colostrum yield and quality and the efficiency of immunoglobulin (IgG) absorption. The experiment commenced on day 91 of pregnancy and the diets consisted ofFA-treated silage (Tl), FA-treated silage + soya-bean meal (SB) (72), MSBP silage (T3), MSBP silage + SB (T4), FA-treated silage + MSBP (T5), FA-treated silage + MSBP + SB (T6) or FA-treated silage + 150 g/kg of a crude protein concentrate (T7). Soya-bean meal was offered only in the last 3 weeks of pregnancy aiming for a total crude protein intake of220 g per ewe per day. Blood samples were taken from lambs in order to measure serum Ig concentrations. Ewes were milked at 1 h,10h and 18 h post lambing. Daily metabolizable energy intakes of 6·8, 11·4, 9·6, 12·8, 10·5, 13·7 and 14·7 (s.e. 0·58) M] per ewe were recorded for Tl to T7 respectively over the last 3 weeks of pregnancy. Respective crude protein intakes of 72, 213, 110, 225, 109, 215 and 175 (s.e. 5·64) g per ewe per day were recorded for Tl to T7 over the last 3 weeks of pregnancy. The addition of protein increased colostrum yield at 1 h (P < 0·01), 10 h (P < 0·01) and 18 h (P < 0·01) post lambing and total yield of colostrum to 18 h (P < 0·001). There was no significant response (P > 0·05) in colostrum production during the first 18 h following protein supplementation when the basic diet was FA-treated silage. There was no difference (P > 0·05) in colostrum production during the first 18 h between ewes offered MSBP treated silage or MSBP supplemented silage. Ewes offered FA-treated silage produced less colostrum during the first 18 h compared with ewes offered either MSBP treated or supplemented silage (P < 0·05). The production of colostral IgG during the first 18 h after parturition was related to the amount of colostrum produced; the greater the colostrum production the greater the Ig production. There was a significant quadratic relationship between the total amount of IgG ingested per kg lamb birth weight during the first 18 h and lamb serum IgG at 24 h (R2 = 0·4005; P < 0·0001). Lamb serum Ig level increased linearly with increasing colostrum IgG consumption up to 15 g/kg lamb birth weight. Proportionately about 0·17 of the IgG ingested was present in the lamb's circulation at 24 h. Ewe protein supplementation pre-lambing increased the lamb's efficiency to absorb colostral IgG (P < 0·05) during the first 24 h. In conclusion, the data show positive relationships between feeding regimes, colostrum production and IgG transfer.

This paper presents an analysis of the economic implications of alternative methods to surgical castration without anaesthesia. Detailed research results on the economic implications of four different alternatives are reported: castration with local anaesthesia, castration with general anaesthesia, immunocastration and raising entire males. The first three alternatives have been assessed for their impact on pig production costs in the most important pig-producing Member States of the EU. The findings on castration with anaesthesia show that cost differences among farms increase if the anaesthesia cannot be administered by farmers and when the veterinarian has to be called to perform it. The cost of veterinarian service largely affects the total average costs, making this solution economically less feasible in small-scale pig farms. In all other farms, the impact on production costs of local anaesthesia is however limited and does not exceed 1 €ct per kg. General anaesthesia administered by inhalation or injection of Ketamin in combination with a sedative (Azaperone, Midazolan) is more expensive. These costs depend heavily on farm size, as the inhalation equipment has to be depreciated on the largest number of pigs possible. The overall costs of immunocastration – including the cost of the work load for the farmer – has to be evaluated against the potential benefits derived from higher daily weight gain and feed efficiency in comparison with surgical castrates. The economic feasibility of this practice will finally depend on the price of the vaccine and on consumer acceptance of immunocastration. The improvement in feed efficiency may compensate almost entirely for the cost of vaccination. The main advantages linked to raising entire males are due to the higher efficiency of feed conversion, to the better growth rate and to the higher leanness of carcass. A higher risk of boar taint on the slaughter line has to be accounted for. Raising entire males should not generate more than 2.5% of boar taint among slaughter pigs, in order to maintain the considerable economic benefits of better feed efficiency of entire males with respect to castrates.

High dietary threonine extraction by the digestive tract suggests that threonine contributes to maintain gut integrity. The aims of this study were to investigate the intestine development and the growth performance of early-weaned piglets pair-fed either a control well-balanced (C: 9.3 g threonine/kg diet) or a low-threonine diet (LT: 6.5 g threonine/kg diet) for 2 weeks. As expected, LT piglets presented lower plasma free threonine compared with C piglets (118 v. 356 ± 12 μmol/l, P < 0.001). Dietary threonine supply altered neither growth performance nor growth of the intestine and of the other portal-drained viscera (stomach, spleen and pancreas). Nevertheless, villus height was reduced in the ileum of the LT piglets compared with C piglets (446 v. 714 ± 74 μm, P < 0.05). This was also associated with a decrease in crypt width (P < 0.05) and villus height-to-crypt depth ratio (P < 0.05). Whereas maltase and lactase activities did not change between the two groups, aminopeptidase nitrogen activity was decreased in the ileum of LT piglets (269 v. 374 ± 27 IU/mg protein, P < 0.05). The number of mucin-containing goblet cells was not modified in the ileum and in the proximal part of the large intestine of the LT piglets compared with the C piglets. In conclusion, despite no alteration of intestinal growth, villus hypotrophy associated with a reduction of aminopeptidase nitrogen activity suggest an alteration of the structure of the ileum in early-weaned piglets fed a diet supplying inadequate dietary threonine.

Individual food intake characteristics and indicators of gut physiology of group-housed weanling pigs were measured in relation to pre-weaning consumption of creep food. Additionally, the effects of creep food consumption on pre-weaning body weight and gain were assessed. A total of 48 litters was used in two trials. From 11 days of age until weaning (day 28), all 48 litters were given a creep food (12·7 MJ net energy (NE) per kg, 15·2 g lysine per kg) supplemented with 10 g chromium III oxide per kg. Piglets showing green-coloured faeces on three sampling days were designated as good eaters, whereas piglets that never showed green faeces were labelled as non-eaters. Piglets having green faeces once or twice were designated as moderate eaters. Based on availability, body weight, litter origin, genotype and gender 29 good eaters, 32 moderate eaters and 29 non-eaters were selected in the first trial. In the second trial there were 30 good eaters, 33 moderate eaters, and 27 non-eaters. In each trial eight piglets of each creep-food eating type were immediately killed to serve as a reference group. The remaining piglets of each eating type were weaned and placed in pens equipped with computerized feeding stations so that distributions of body weight, litter origin, and gender were similar within pens. In each trial, eight pigs of each eating type were killed 5 days after weaning in order to determine villous heights and crypt depths in the proximal small intestine and volatile fatty acid (VFA) concentrations in the colon. While being suckled, body weight was not related to the pre-weaning consumption of creep food (P > 0·1) whereas average daily gain of the good eaters during the creep feeding period was higher (P 0·05) than that of the moderate and non-eaters. Both morphology measures and VFA concentrations on the day of weaning were unaffected (P > 0·1) by the pre-weaning food consumption. After weaning, food intake and gain of the total group of good eaters were higher (P 0·05) than that of the non-eaters, whereas villous height and villous height: crypt depth ratios did not differ (P > 0·1). Neither total VFA concentration nor the proportion of branched-chain VFA were affected by creep food consumption while being suckled. Total VFA concentration in the colon was positively associated with body-weight gain (P 0·001). This study confirms earlier findings that consumption of creep food while being suckled stimulates food intake and growth after weaning. However, the beneficial effects were not associated with a prevention of damage to morphology of the small intestine.

The pig industry faces many animal welfare issues. Among these, biting behaviour has a high incidence. It is indicative of an existing problem in biters and is a source of physical damage and psychological stress for the victims. We categorize this behaviour into aggressive and non-aggressive biting, the latter often being directed towards the tail. This review focusses specifically on predisposing factors in early life, comprising the prenatal and postnatal periods up to weaning, for the expression of aggressive and non-aggressive biting later in life. The influence of personality and coping style has been examined in a few studies. It varies according to these studies and, thus, further evaluation is needed. Regarding the effect of environmental factors, the number of scientific papers is low (less than five papers for most factors). No clear influence of prenatal factors has been identified to date. Aggressive biting is reduced by undernutrition, cross-fostering and socialization before weaning. Non-aggressive biting is increased by undernutrition, social stress due to competition and cross-fostering. These latter three factors are highly dependent on litter size at birth. The use of familiar odours may contribute to reducing biting when pigs are moved from one environment to another by alleviating the level of stress associated with novelty. Even though the current environment in which pigs are expressing biting behaviours is of major importance, the pre-weaning environment should be optimized to reduce the likelihood of this problem.