Mean daily milk yield, fat percentage and protein percentage were recorded monthly, from August 1978 to July 1979. for 579 303 British Friesian, 6 608 Shorthorn, 27 374 Ayrshire, 19 529 Jersey, and 19 760 Guernsey cattle and classified by breed, parity and stage of lactation. Parameters of the function y(n) = anb ecn were estimated for each breed/parity group for yield, fat percentage and yield, protein percentage and yield, and energy (MJ) output as milk (b and c describe the shape of the curve, a is a scalar, n the week of lactation and e the base of natural logarithms). In the mature cows of each breed (parity 4 or more), the shape constants (b, c) for milk, fat and protein production in kg respectively were:

Generally, cows of all five breeds which calved in the winter produced about 4% more milk, fat and protein than average, and those that calved in the summer produced about 4% less. After allowing for that, and removing the effect of the calving pattern, a seasonal variation in production occurred to produce a peak in June 1979 nearly 12% above average for liquid milk, in July 1979 about 4% for fat and in June 1979 about 12% for protein production (not percentage). Trough month was January 1979 for all three characters: —8%; —4% and — 9% respectively.

A consideration of the theory of metabolizable energy suggested that the peak of energy output which occurred about week 4 of lactation in all breeds and parities, expressed as a fraction of the live weight of the animal, had a critical bearing on the need to mobilize body reserves.

The effects of four diets differing in their for age: concentrate ratio (80:20, 60:40, 40: 60 and 20:80; g/100 g fresh matter) on rumen characteristics, digestibility and digesta flow kinetics were investigated. Alfalfa hay was used as forage and concentrate was composed of barley, soya-bean meal and maize. Diets were prepared by mixing all ingredients and offered to the animals as complete diets. Eight mature Merino sheep, each fitted with a rumen cannula, were offered 1·055 kg dry matter per day of the corresponding diet over two experimental periods. The daily evolution of ruminai pH, volatile fatty acids (VFA) and ammonia nitrogen (N) concentrations were measured. Digestibility was determined by total faecal collection and Cr and Co were used as markers to estimate digesta passage rates. Microbial nitrogen flow at the duodenum (MNDF) was estimated from the urinary excretion of purine derivatives (PD). The apparent digestibility of organic matter increased (P < 0·001) whereas that of all fibrous fractions decreased linearly (P < 0·05) as the proportion of concentrate in the diet increased. Rumen pH decreased linearly (P < 0·001) with increasing proportions of concentrate but total VFA concentrations were unaffected by changes in the diet (P > 0·05). Both liquid and solid digesta outflow rates from the rumen decreased quadratically (P < 0·01) as the proportion of concentrate in the diet increased. The urinary excretion of total N, urea-N and ammonia-N was unaffected (P > 0·05) by changes in the diet. In contrast, the daily urinary excretion of both allantoin and total PD increased quadratically (P < 0·05) with increasing proportions of concentrate. Consequently, the estimated MNDF increased linearly (P < 0·001) from 9·9 g/day on the high forage diet to 14·5 g/day on the high concentrate diet.

Fasting heat production (FHP) is used for characterizing the basal metabolic rate of animals and the corresponding maintenance energy requirements and in the calculation of net energy value of feeds. In broilers, the most recent FHP estimates were obtained in the 1980s in slow-growing and fatter birds than nowadays. The FHP values (n=73; six experiments) measured in 3 to 6-week-old modern lines of broilers weighing 0.6 to 2.8 kg and growing at 80 to 100 g/day were used to update these literature values. Each measurement was obtained in a group of fasting broilers (5 to 14 birds) kept in a respiration chamber for at least 24 h. The FHP estimate corresponds to the asymptotic heat production corrected for zero physical activity obtained by modeling the decrease in heat production during the fasting day. The compilation of these data indicates that FHP was linearly related to the BW0.70 (in kg), which can be considered as the metabolic BW of modern broilers. The 0.70 exponent differs from the conventional value of 0.75 used for mature animals. The FHP per kg of BW0.70 ranged between 410 and 460 kJ/day according to the experiment (P<0.01). An experiment conducted with a shorter duration of fasting (16 h) indicated that FHP values are higher than those obtained over at least 24 h of fasting. Our values are similar to those obtained previously on fatter and slow-growing birds, even though the comparison is difficult since measurement conditions and methodologies have changed during the last 30 years. The FHP values obtained in our trials represent a basis for energy nutrition of modern broilers.

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.

Feeding costs represent one of the highest expenditures in animal production systems. Breeding efficient animals that express their growth potential while eating less is therefore a major objective for breeders. We estimated the genetic parameters for feed intake, feed efficiency traits (residual feed intake (RFI) and feed conversion ratio (FCR)), growth and body composition traits in the Romane meat sheep breed. In these traits, selection responses to single-generation divergent selection on RFI were evaluated. From 2009 to 2016, a total of 951 male lambs were tested for 8 weeks starting from 3 months of age. They were weighed at the beginning and at the end of the testing period. Backfat thickness and muscle depth were recorded at the end of the testing period through ultrasound measurements. Feed intake was continuously recorded over the testing period using the automatic concentrate feeders. The heritability of RFI was estimated at 0.45 ± 0.08, which was higher than the heritability of FCR (0.30 ± 0.08). No significant genetic correlations were observed between RFI and growth traits. A favourable low negative genetic correlation was estimated between RFI and muscle depth (−0.30 ± 0.15), though additional data are needed to confirm these results. The selection of low RFI sires based on their breeding values led to the production of lambs eating significantly less concentrate (3% decrease in the average daily feed intake), but with the same growth as lambs from sires selected based on high RFI breeding values. We concluded that in meat sheep, RFI is a heritable trait that is genetically independent of post-weaning growth and body composition traits. A one-generation divergent selection based on RFI breeding values highlighted that substantial gains in feeding costs can be expected in selection schemes for meat sheep breeds.

Little is known about pig gene expressions related to dietary fatty acids (FAs) and most work have been conducted in rodents. The aim of this study was to investigate how dietary fats regulate fat metabolism of pigs in different tissues. Fifty-six crossbred gilts (62 ± 5.2 kg BW) were fed one of seven dietary treatments (eight animals per treatment): a semi-synthetic diet containing a very low level of fat (no fat (NF)) and six fat-supplemented diets (ca. 10%) based on barley and soybean meal. The supplemental fat sources were tallow (T), high-oleic sunflower oil (HOSF), sunflower oil (SFO), linseed oil (LO), blend (FB) (55% T, 35% SFO and 10% LO) and fish oil (FO) blend (40% FO and 60% LO). Pigs were slaughtered at 100 kg BW and autopsies from liver, adipose tissue and muscle semimembranousus were collected for qPCR. The messenger ribonucleic acid (mRNA) abundances of genes related to lipogenesis were modified due to dietary treatments in both liver (sterol regulatory element-binding protein-1 (SREBP-1), acetyl CoA carboxylase (ACACA) and stearoyl CoA desaturase (SCD)) and adipose tissue (fatty acid synthase (FASN), ACACA and SCD), but were not affected in semimembranousus muscle. In the liver, the mRNA abundances of genes encoding lipogenic enzymes were highest in pigs fed HOSF and lowest in pigs fed FO. In adipose tissue, the mRNA abundances were highest in pigs fed the NF diet and lowest in pigs fed T. The study demonstrated that dietary FAs stimulate lipogenic enzyme gene expression differently in liver, fat and muscles tissues.

To reduce mortality among suckling piglets, lactating sows are traditionally housed in farrowing crates. Alternatively, lactating sows can be housed in farrowing pens where the sow is loose to ensure more behavioural freedom and consequently a better welfare for the sow, although under commercial conditions, farrowing pens have been associated with increased piglet mortality. Most suckling piglets that die do so within the first week of life, so potentially lactating sows do not have to be restrained during the entire lactation period. Therefore, the aim of the current study was to investigate whether confinement of the sow for a limited number of days after farrowing would affect piglet mortality. A total of 210 sows (Danish Landrace × Danish Yorkshire) were farrowed in specially designed swing-aside combination farrowing pens measuring 2.6 m × 1.8 m (combi-pen), where the sows could be kept loose or in a crate. The sows were either: (a) loose during the entire experimental period, (b) crated from days 0 to 4 postpartum, (c) crated from days 0 to 7 postpartum or (d) crated from introduction to the farrowing pen to day 7 postpartum. The sows and their subsequent litters were studied from introduction to the combi-pen ∼1 week before expected farrowing and until 10 days postpartum. Confinement period of the sow failed to affect the number of stillborn piglets; however, sows that were crated after farrowing had fewer live-born mortality deaths (P < 0.001) compared with the sows that were loose during the experimental period. The increased piglet mortality among the loose sows was because of higher mortality in the first 4 days after farrowing. In conclusion, the current study demonstrated that crating the sow for 4 days postpartum was sufficient to reduce piglet mortality.

1. Twelve blocks of six enzootic-pneumonia-free Large White litter-mate pigs were individually fed, wet, from 20 to 92 kg live weight on six different levels of feed intake. Four groups were fed according to scales based on live weight and two were fed on a ‘semi-ad libitum’ system. One of the scales used was based on the ARC (1967) recommendations.

2. Pigs on ‘semi-ad libitum’ feeding grew significantly faster than those on scale feeding although the feed: gain ratios were similar. Differences in performance between the four scale-fed groups were relatively small.

3. Although treatment differences in carcass measurements were in the main small, the commercial grading results favoured the carcasses from the scale-fed pigs. The firmness of backfat assessed by thumb pressure was reduced as the level of feeding was increased.

4. The results were compared with those obtained in a similar trial carried out at Shinfield in 1957 using pigs of a completely different genetic background. The general conclusions reached were similar in the two trials, that to obtain the most satisfactory overall results some form of controlled scale-feeding was necessary.

Behaviour observations and measurements were carried out on three classes of beef steers kept in yards under drought feeding conditions. The classes were (i) 2-year-old Brahman × Hereford crossbreds, (ii) 2-year-old Herefords and (iii) 3-year-old Herefords.

Animals of each class were placed in two groups and fed on low quality bush hay, one group ad lib. and the other on a restricted basis. An intermingled group comprised two animals from each class and was fed ad lib.

Fairly stable linear social orders were observed in each yard, social success depending mainly upon height. In the intermingled group, the crossbreds dominated the 3-year-old Herefords, which in turn dominated the 2-year-old Herefords.

Crossbreds bunted more actively and were more often disturbed at feeding during the day. They consequently consumed proportionately more feed at night than the Herefords.

Although high social ranking animals had priority at the feed trough there was no relationship between social rank and growth.

The orders in which the 2-year-old Herefords and crossbreds entered a crush were non-random. These orders appeared not to be related to social rank.

Changes affecting livestock farming systems have made farm work a central concern for both the sector and for farmers themselves. Increased pressure on farms to be competitive and productive together with farmers’ demand for greater autonomy, holidays or time to spend on private activities and the family converge to underline the two key dimensions of work – productivity and flexibility – required for the assessment of work organization. This paper proposes a method called the QuaeWork (QUAlification and Evaluation of Work in livestock farms) to assess work productivity and flexibility on a farm, and its use to identify how livestock management can contribute to work organization on dairy farms. The QuaeWork method was set up through an iterative process combining surveys conducted with farmers in two regions of France, discussions with different experts and literature review. The QuaeWork was applied on a sample of seven dairy farms in the southern Massif Central in France to identify patterns of how livestock management contributes to work organization. The QuaeWork was used to analyse work organization over the year through a systemic approach to the farm, integrating interactions between herd and land management, workforce composition, equipment facilities and combinations of activities through a characterization of ‘who does what, when and for how long’. The criteria for assessing work productivity were work duration (routine work, seasonal work) and work efficiency (per livestock unit or hectare of utilized agricultural area). The criteria for assessing work flexibility were room for manoeuvre and adjustments to internal and external events. The three main patterns of livestock management practices to work organization were identified. In pattern-1, farmers used indoor stable feeding practices with delegated work, with moderate room for manoeuvre and efficiency. In pattern-3, farmers used simplified milking, reproduction and breeding practices to seasonalize work and make it efficient with consistent room for manoeuvre. The method suggests social sustainability criteria to assess work productivity and flexibility, which are important for making reasoned decisions on livestock farm changes, especially innovations. Researchers could usefully exploit the QuaeWork to integrate work objectives (productivity, flexibility) into technical and economic goals.

In pig production, piglets are tail docked at birth in order to prevent tail biting later in life. In order to examine the effects of tail docking and docking length on the formation of neuromas, we used 65 pigs and the following four treatments: intact tails (n=18); leaving 75% (n=17); leaving 50% (n=19); or leaving 25% (n=11) of the tail length on the pigs. The piglets were docked between day 2 and 4 after birth using a gas-heated apparatus, and were kept under conventional conditions until slaughter at 22 weeks of age, where tails were removed and examined macroscopically and histologically. The tail lengths and diameters differed at slaughter (lengths: 30.6±0.6; 24.9±0.4; 19.8±0.6; 8.7±0.6 cm; P<0.001; tail diameter: 0.5±0.03; 0.8±0.02; 1.0±0.03; 1.4±0.04 cm; P<0.001, respectively). Docking resulted in a higher proportion of tails with neuromas (64 v. 0%; P<0.001), number of neuromas per tail (1.0±0.2 v. 0; P<0.001) and size of neuromas (1023±592 v. 0 μm; P<0.001). The results show that tail docking piglets using hot-iron cautery causes formation of neuromas in the outermost part of the tail tip. The presence of neuromas might lead to altered nociceptive thresholds, which need to be confirmed in future studies.

Two randomized-block experiments have been carried out to examine the effects of increasing the digestibility of grass silage offered to beef cattle by harvesting three crops of grass after shorter growth intervals rather than two crops after longer growth intervals. In experiment 1 early-cut silages were harvested on 1 June, 16 July and 24 August, and late-cut silages on 20 June and 22 August 1979. In experiment 2 the early-cut silages were harvested on 19 May, 2 July and 20 August, and the late-cut silages on 5 June and 12 August 1980. Early- and late-cut silages were made from each of two cultivars of perennial ryegrass (cultivars Cropper and Talbot). The silages were unwilted and had formic acid applied at 2.5 1/t fresh crop.

In experiment 1 the silages were offered ad libitum, both unsupplemented and supplemented with 2·2 kg concentrates per head daily, to 88 cattle of mixed beef breeds and mean initial live weight 337 kg, in a 2 × 2 × 2 factorial design. In experiment 2 the silages were offered ad libitum and supplemented with 2·4 kg of concentrates per head daily to 56 Charolais × (Aberdeen Angus × Friesian) cattle of mean initial live weight 351 kg, in a 2 × 2 factorial design. Grass cultivar did not significantly affect silage intake or animal performance but intake, live-weight gain and carcass gain were significantly higher for the early-cut than for the late-cut silages in both experiments. In experiment 1 silage dry-matter intakes were 6·33, 5·12, 5·80 and 4·67 (s.e. 0·124) kg/day; live-weight gains were 0·72, 0·89, 0·47 and 0·76 (s.e. 0·029) kg/day; and carcass gains were 0·46, 0·60, 0·27 and 0·48 (s.e. 0·016) kg/day, for the unsupplemented and supplemented early-cut silages, and the unsupplemented and supplemented late-cut silages, respectively. In experiment 2 silage dry-matter intakes were 5·49 and 4·95 (s.e. 0·056) kg/day; live-weight gains Were 0·95 and 0·76 (s.e. 0·033) kg/day; and carcass gains were 0·67 and 0·50 (s.e. 0·17) kg/day, for the early- and late-cut silages, respectively.

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 impact of parasites on domestic livestock is well known. It is also clear that parasites have the potential to reduce reproductive success and survival at the individual level in wild animal populations (often through effects on body condition). However, the degree to which these impacts can regulate populations is difficult to determine because of the logistics of conducting the necessary experimental manipulations of either hosts or parasites. In addition, the relative importance of this mechanism compared to other regulatory factors such as predation and competition for food resources has not been quantified. Studies that have investigated the impact of parasites on wild mammals are reviewed and the merits of cross-sectional sampling and experimental approaches are presented. Finally, evidence for parasite mediated population regulation in wild mammals is examined and the need to develop experimental approaches that address this mechanism and its interaction with other regulatory processes is discussed.

Little is known about cheese-making efficiency at the individual cow level, so our objective was to study the effects of herd productivity, individual herd within productivity class and breed of cow within herd by producing, then analyzing, 508 model cheeses from the milk of 508 cows of six different breeds reared in 41 multi-breed herds classified into two productivity classes (high v. low). For each cow we obtained six milk composition traits; four milk nutrient (fat, protein, solids and energy) recovery traits (REC) in curd; three actual % cheese yield traits (%CY); two theoretical %CYs (fresh cheese and cheese solids) calculated from milk composition; two overall cheese-making efficiencies (% ratio of actual to theoretical %CYs); daily milk yield (dMY); and three actual daily cheese yield traits (dCY). The aforementioned phenotypes were analyzed using a mixed model which included the fixed effects of herd productivity, parity, days in milk (DIM) and breed; the random effects were the water bath, vat, herd and residual. Cows reared in high-productivity herds yielded more milk with higher nutrient contents and more cheese per day, had greater theoretical %CY, and lower cheese-making efficiency than low-productivity herds, but there were no differences between them in terms of REC traits. Individual herd within productivity class was an intermediate source of total variation in REC, %CY and efficiency traits (10.0% to 17.2%), and a major source of variation in milk yield and dCY traits (43.1% to 46.3%). Parity of cows was an important source of variation for productivity traits, whereas DIM affected almost all traits. Breed within herd greatly affected all traits. Holsteins produced more milk, but Brown Swiss cows produced milk with higher actual and theoretical %CYs and cheese-making efficiency, so that the two large-framed breeds had the same dCY. Compared with the two large-framed breeds, the small Jersey cows produced much less milk, but with greater actual and theoretical %CYs, similar efficiencies and a slightly lower dCY. Compared with the average of the specialized dairy breeds, the three dual-purpose breeds (Simmental and the local Rendena and Alpine Grey) had, on average, similar dMY, lower actual and theoretical %CY, similar fat and protein REC, and slightly greater cheese-making efficiency.

Subacute ruminal acidosis (SARA) is usually characterized by abnormal and intermittent drops in rumen pH. Nevertheless, high individual animal variability in rumen pH and the difference in measurement methods for pH data acquisition decrease the sensitivity and accuracy of pH indicators for detecting SARA in ruminants. The aim of this study was to refine rumen pH indicators in long-term SARA based on individual dairy cow reticulo-rumen pH kinetics. Animal performances and rumen parameters were studied weekly in order to validate SARA syndrome and rumen pH was continuously measured using reticulo-rumen sensors. In total, 11 primiparous dairy cows were consecutively fed two different diets for 12 successive weeks: a control diet as low-starch diet (LSD; 13% starch for 4 weeks in period 1), an acidotic diet as high-starch diet (HSD; 32% starch for 4 weeks in period 2), and again the LSD diet (3 weeks in period 3). There was a 1-week dietary transition between LSD and HSD. Commonly used absolute SARA pH indicators such as daily average, area under the curve (AUC) and time spent below pH<5.8 and pH<6 were processed from absolute (raw) daily kinetics. Then signal processing was applied to raw pH values in order to calculate relative pH indicators by filtering and normalizing data to remove inter-individual variability, sensor drift and sensor noise. Normalized AUC, times spent below NpH<−0.3 and NpH<−0.5, NpH range and NpH standard deviation were calculated. Those relative pH indicators were compared with commonly used pH indicators to assess their ability to detect SARA. This syndrome induced by HSD was confirmed by consistent expected changes in milk quality, dry matter intake and acetate : propionate ratio in the rumen, whereas the ruminal concentration of lipopolysaccharide was increased. Commonly used pH SARA indicators were not able to discriminate SARA syndrome due to high animal variability and sensor drift and noise, whereas relative pH indicators developed in this study appeared more relevant for SARA detection as assessed by receiver operating characteristic tests. This work shows that absolute pH kinetics should be corrected for drift, noise and animal variability to produce relative pH indicators that are more robust for SARA detection. These relative pH indicators could be more relevant for identifying affected animals in a herd and also for comparing SARA risk among studies.

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.

Recent studies indicate that early postnatal period is a critical window for gut microbiota manipulation to optimise the immunity and body growth. This study investigated the effects of maternal faecal microbiota orally administered to neonatal piglets after birth on growth performance, selected microbial populations, intestinal permeability and the development of intestinal mucosal immune system. In total, 12 litters of crossbred newborn piglets were selected in this study. Litter size was standardised to 10 piglets. On day 1, 10 piglets in each litter were randomly allotted to the faecal microbiota transplantation (FMT) and control groups. Piglets in the FMT group were orally administrated with 2ml faecal suspension of their nursing sow per day from the age of 1 to 3 days; piglets in the control group were treated with the same dose of a placebo (0.1M potassium phosphate buffer containing 10% glycerol (vol/vol)) inoculant. The experiment lasted 21 days. On days 7, 14 and 21, plasma and faecal samples were collected for the analysis of growth-related hormones and cytokines in plasma and lipocalin-2, secretory immunoglobulin A (sIgA), selected microbiota and short-chain fatty acids (SCFAs) in faeces. Faecal microbiota transplantation increased the average daily gain of piglets during week 3 and the whole experiment period. Compared with the control group, the FMT group had increased concentrations of plasma growth hormone and IGF-1 on days 14 and 21. Faecal microbiota transplantation also reduced the incidence of diarrhoea during weeks 1 and 3 and plasma concentrations of zonulin, endotoxin and diamine oxidase activities in piglets on days 7 and 14. The populations of Lactobacillus spp. and Faecalibacterium prausnitzii and the concentrations of faecal and plasma acetate, butyrate and total SCFAs in FMT group were higher than those in the control group on day 21. Moreover, the FMT piglets have higher concentrations of plasma transforming growth factor-β and immunoglobulin G, and faecal sIgA than the control piglets on day 21. These findings indicate that early intervention with maternal faecal microbiota improves growth performance, decreases intestinal permeability, stimulates sIgA secretion, and modulates gut microbiota composition and metabolism in suckling piglets.

1. A comparison of the performance of Scottish Blackface ewe hoggets with and without an exteriorised flow to the duodenum was carried out while the animals were fed on hay with a low nitrogen content and added salt. No evidence was found from the food and water consumed, from the weight changes or from a comparison of the organic matter, nitrogen and ash contents of the food and the faeces that the operation caused any permanent disturbance to digestion.

2. Regular measurements of the flow of abomasal contents to the duodenum established a pattern of flow that was influenced by feeding. A relationship between the quantities passed per hour from the abomasum and the time devoted to rumination was found, but the relationship appeared to be dissociated in time so that increased rumination preceded the increased passage of contents.

3. The mean quantity of abomasal contents passed from four animals was 398 ml./hour. According to the quantities of chromium sesquioxide administered by mouth, passed from the abomasum, and excreted in the faeces this value represents not more than 90% and not less than 86% of the flow that can normally be expected.

4. The quantities of organic matter that disappear in the stomach were calculated and represent about half or more of the total disappearance in the alimentary tract.

5. Substantially more nitrogen left the abomasum than was eaten in the food daily. Of the nitrogen passing to the duodenum the greater part disappeared in the intestines.

6. About twice as much ash left the stomach as was present in the food and about two-thirds of the ash entering the duodenum disappeared in the intestines.

During many pathological conditions, the tryptophan concentration in blood may be reduced. However, the effects of oxidative stress on tryptophan metabolism remain unknown. In this study, we investigated the effects of oxidative stress on growth performance and tryptophan metabolism in weaned pigs. A total of 24 weaned pigs were assigned to one of three treatments that included pigs fed ad libitum (control), pigs challenged with diquat at a dose of 10 mg/kg BW and fed ad libitum (oxidative stress) or pigs pair-fed to receive the same amount of feed as the diquat-challenged pigs. The trial lasted for 7 days. The growth performance and activities of antioxidant enzymes were declined in diquat-challenged pigs. The diquat challenge decreased the tryptophan concentration in serum and the 5-hydroxytryptamine concentration in the hypothalamus, and increased large neutral amino acids, kynurenine (Kyn) and malondialdehyde in serum. The 544-bp porcine partial mRNA sequence of the tryptophan 2,3-dioxygenase (TDO) gene was obtained according to the conserved region in the human gene sequence. In addition, the oxidative stress induced by the diquat challenge stimulated TDO-relative mRNA abundance in the liver and γ-glutamyl transpeptidase activity in intestinal mucosa, but did not affect the mRNA levels of Na+-neutral amino acid transporter B0. These results suggested that oxidative stress induced by diquat depressed growth performance and increased metabolism of tryptophan via Kyn pathway that upregulated TDO mRNA expression in weaned pigs.