1. In two experiments the nutritive value for the growing pig of wheat which had been micronized at temperatures of 155°, 190° or 220°C, flaked (rolled) and then ground was compared with wheat which had either been ground, or rolled and then ground.

2. In the first experiment 60 pigs offered individually, restricted amounts of feed were used in a growth and efficiency of conversion study. In the second experiment 15 pigs were used in digestibility and nitrogen retention studies.

3. The highest micronization temperature gave a significant depression in growth rate and in efficiency of conversion of dietary dry matter as compared with the other treatments for which there were no significant differences.

The effect of lambing date on the subsequent onset and duration of ovarian cyclicity in Mule (Bluefaced Leicester × Scottish Blackface) ewes was investigated. Nineteen ewes which had lambed in January (16 January 1993 (s.e. 3 days)) and been weaned in February-March and 22 comparable ewes which had lambed in May (14 May 1993 (s.e. 2 days)) and been weaned on 23 August were maintained at pasture as two isolated groups. A raddled vasectomized ram was continually present with each group from 14 July 1993 to 26 May 1994 and marked (oestrous) ewes were recorded twice weekly. Ovarian activity was assessed by measuring peripheral progesterone concentrations in blood samples collected twice weekly and by laparoscopic viewing of the ovaries of all ewes during October, January and March. The onset and duration of ovarian activity were significantly affected by the previous lambing date. For January and May lambing ewes, mean dates of onset were 5 September 1993 (s.e. 2 days) v. 25 September 1993 (s.e. 4 days) (P < 0·001) and of cessation were 5 April 1994 (s.e. 5 days) v. 10 April 1994 (s.e. 3 days). Mean durations of ovarian activity were 212 (s.e. 6) and 195 (s.e. 5) days (P < 0·05) during which 12·4 (s.e. 0·29) and 11·5 (s.e. 0·38) ovarian cycles respectively were recorded. Ovulation rate was not affected by previous lambing date but was significantly lower in March compared with October (January lambing ewes 1·7 (s.e. 0·1) v. 2·3 (s.e. 0·1) (P < 0·001); May lambing ewes 1·6 (s.e. 0·1) v. 2·1 (s.e. 0·1) (P < 0·01)). Results demonstrate that (i) Mule ewes have a potential breeding season of up to 8 months duration; (ii) the onset and duration of ovarian activity can be influenced by previous lambing date; and (Hi) a seasonal decline in ovulation rate may, in practical terms, result in a lower lambing percentage for animals bred towards the end of their natural breeding period.

Genetic analyses were carried out on 935 Large White and 767 Land-race boars performance-tested from 25 kg to 80 kg live weight under individual andad libitumfeeding conditions. Traits analysed were daily weight gain (GR), feed conversion ratio (FCR), daily feed intake (FI) and subcutaneous fat depth (F). Genetic parameters were estimated from sire components obtained by conventional hierarchical analyses of variance and covariance.

Large White pigs grew faster, had higher intakes of feed and utilized it more efficiently than Landrace. There was no breed difference in fat depth. Heritabilities, pooled over both breeds, were 0·36 ± 0·10, 0·27±0·08, 0·62±0·13 and 0·47±0·11 for GR, FCR, FI and F respectively. Noteworthy among the correlation estimates were strong and positive correlations between FI and the other three traits. A positive genetic correlation between GR and FCR arose from a very high coefficient of genetic variation for FI.

Selection indexes emphasising efficiency of lean growth were constructed using some or all of the 4 traits as measured variables. Their use is expected to reduce FI and GR on feeding ad libitum. The results indicate the need to select pigs on the same level of feeding as that used in production.

Two experiments with lambs given food indoors and individually penned were designed to study the effects of different levels of ground maize and citrus pulp as supplements of a diet based on urea-treated straw (5 kg urea per 100 kg straw) offered ad libitum over a period of 16 weeks (experiment 1) or 10 weeks (experiment 2). The voluntary intake, live-weight gain (LWG), organic matter digestibility (OMD), urinary allantoin-nitrogen (UAN) excretion and acetate clearance rate were measured. The lambs were blocked on weight and randomly assigned to the treatments described below. Ruminal outflow rate of the solid and liquid phases from the rumen were also measured in experiment 2.

In experiment 1, 20 female lambs from the Ile-de-France breed, with an initial live weight (LW) of 43 (s.e. 3·3) kg were used. Wheat straw (WS) was supplemented with 50 g/kg of fish meal (FM) and with 0, 100, 200 or 300 g/kg of ground maize on a dry-matter (DM) basis (M0, M1, M2 and M3, respectively). In experiment 2, 25 female lambs from the Portuguese breed Churra-da-Terra-Quente, with an initial LW of 24·2 (s.e. 4·3) kg were used. The straw was offered ad libitum during 10 weeks and supplemented with 50 g/kg of FM and 0, 100, 200, 300, or 400 g/kg of dried citrus pulp on a DM basis (CP0, CP1, CP2, CP3 and CP4, respectively).

During the experiments, all animals were moved to metabolism cages to measure OMD and UAN excretion. Two additional incubation studies were carried out with rumen fistulated rams (experiment 1) or cows (experiment 2) given the diets described above close to the maintenance feeding level.

In experiment 1 daily straw DM intake linearly decreased (P < 0·05) from 21·6 to 17·7 g/kg LW and LWG linearly increased (P < 0·05) from 51 to 154 g/day for treatments M0, M1, M2 and M3, respectively. The rate of straw DM degradation was significantly decreased (P < 0·01) by maize supplementation. Straw OMD (kg/kg) was 0·562, 0·583, 0·547 and 0·520 and UAN (mg/day) was 620, 790, 854 and 859 for treatments M0, M1, M2 and M3, respectively. Acetate clearance rate, increased (P < 0·05) as the level of maize inclusion increased.

In experiment 2 daily straw DM intake was 23·3, 25·8, 24·7, 23·5 and 18·6 g/kg LW per day and LWG was –9, 28, 44, 64 and 67 g/day for treatments CP0, CP1, CP2, CP3 and CP4, respectively. Supplementation significantly increased LWG (P < 0·001) but at the 400 g/kg level depressed straw DM intake. Straw OMD linearly decreased (P < 0·05) from 0·484 (CP0) to 0·428 (CP4) g/kg and UAN (mg/day) was 181, 303, 363, 384 and 392 for treatments CP0, CP1, CP2, CP3 and CP4, respectively. Rumen outflow rate of fibre particles was unaffected by supplementation while the outflow of liquid phase tended to be increased (P < 0·10). The rate of DM degradation was significantly reduced (P < 0·01) by citrus-pulp inclusion. Acetate clearance rate was unaffected (P > 0·05) by citrus-pulp supplementation.

The results of these experiments demonstrate that supplementation of urea-treated straw with ground maize up to 200 g/kg or with citrus pulp up to 300 g/kg of the diet DM increased or did not depress straw intake, increased the supply of microbial protein and have no significant effect on straw digestibility. The efficiency of utilization of absorbed energy was apparently improved by maize but not by citrus-pulp supplementation.

Operant methods were used to measure the responsiveness to earth of five groups of seven weaner piglets held in a flat-deck cage. Lifts on a lever produced access to an earth trough, an empty trough, or had no effect. Group lever lifting performance was unaffected by earth in the trough, but at least one individual, the ‘worker piglet’, operated the lever more than the others to gain access to earth. Once the lid of the trough was opened other piglets were attracted to the earth and spent more time using the earth trough than the empty trough. Previous experience of earth appeared to modify lever lifting behaviour. In one group, a worker piglet did not emerge, and in another the worker operated the lever for earth at a reduced rate. The number of piglets using the earth trough and the amount of time spent utilizing it was reduced by prior exposure to earth. It is concluded that earth is a mild reinforcer to weaner piglets, that it will sustain a low rate of responding on an operant schedule, and that a component of its reinforcement value is its novelty.

Fifty-one cattle were allocated into five groups varying in time of starvation (0, 17, 24, 41 and 48 h). Most of the loss in fasted live weight, stomach and intestinal contents occurred within 24 h. Weights of water, dry matter and potassium present in the stomach showed a significant decrease in the first 24 h, although the percentage of water in the stomach contents rose slowly over a 48-h period. It is suggested that cattle from pasture need be starved for no more than 24 h to minimize the effect of gut fill for body composition studies.

British Friesian and Jersey cows were mated either to high contemporary comparison (CC) bulls for their first pregnancy and to low bulls for their second pregnancy, or vice versa. Sixteen proven bulls were used, four ‘high’ and four ‘low’ in each breed. Least squares analysis of data on 175 lactations gave estimates of each bull's effect on his mates' milk yield in the ensuing lactation, but there were no significant differences between bulls for this ‘mate effect’. The high bulls tended to depress their mates' milk yield in the subsequent lactation and the low bulls tended to increase it. Weighted regressions of the ‘mate effect’ on breeding value had negative slopes for both breeds and for first and second lactations, separately or combined. The high CC bulls appeared to depress their mates' milk yield by at least 10% of the amount by which their daughters' yield was expected to increase.

1. Four groups of 20 ewes were individually fed in late pregnancy on: (1) silage ad libitum, (2) silage ad libitum and 12 kg rolled barley, (3) silage ad libitum and 23 kg rolled barley, (4) pelleted milled dried grass ad libitum. The concentrate was offered on a rising plane over the last 6 weeks of pregnancy. After parturition the ewes and lambs were put on spring pasture.

2. The intake of silage by twin-bearing ewes fell slightly but nonsignificantly during week 16 of pregnancy but thereafter remained steady up to lambing. There was no other decline in intake on any of the treatments. Barley, however, significantly depressed silage intake when the quantity was increased above 282 g per day.

3. Single-bearing ewes, except those on treatment 1, gained in net body weight during late pregnancy. Twin-bearing ewes on treatment 4 gained in net body weight while those on the other treatments lost weight.

4. Birth weights of single lambs from ewes on treatment 1 were significantly lower than those from treatment 3. This was the only significant difference in birth weight or subsequent growth rates of single lambs. Birth weights of twin lambs on treatment 1 were significantly lower than those on the other treatments.

5. The birth weight of twin lambs appeared to be an important determinant of subsequent performance, and may thus be a valuable criterion of the adequacy of the ewe's diet in late pregnancy.

6. With medium-quality autumn silages, 12 kg of barley given during late pregnancy is sufficient to ensure good reproductive performance in ewes.

The behavioral consequences of pregnancy in goats were studied to test the hypothesis that pregnant females on rangeland select a diet richer in nutrients once the demands of gestation increase, and that nutrient content in goat diets changes with the grazing season. A total of 12 mature mixed breed goats either pregnant (n = 6) or non-pregnant (n = 6) were used during the dry period (February to May). Dietary samples obtained from the oral cavity of grazing goats (restrained with a short light rope permanently tightened around their neck) were used for chemical analyses. Across months, pregnant goats selected diets higher (P < 0.01) in crude protein (CP) than non-pregnant goats; this nutrient did not meet the requirements of late gestating goats. Pregnant goats made use of less (P < 0.01) fibrous feeds than non-pregnant goats. In order to cope with changing nutrient demands for pregnancy, goats adjusted their diet by increasing the selection of plants with 32% higher calcium content compared to forages selected by non-pregnant goats. The physiological state of goats did not alter the levels of phosphorus (P), magnesium (Mg) and sodium (Na) in their diets; these minerals were adequate to meet the demands of pregnancy. There were no effects of physiological state on concentrations of copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe) in the goat diets during the dry season, with levels adequate for sustainability of pregnancy. Pregnant goats did not seek forages lower in tannins, alkaloids, saponins and terpenes. It was concluded that to cope with increasing pregnancy costs, goats adjusted their diets increasing selection of forages or plant parts with high nutritional value to maximize their net nutrient budget.

Blood groups were determined for eight loci in a total of 742 sheep and for the Tf (transferrin) locus of 512 sheep comprising the Scottish Blackface, the Cheviot and the Welsh Mountain breeds and their crosses. Each breed and cross was represented by a non-inbred F2 generation and by three stages of inbreeding (25, 37½ and 50%). The loci for which all genotypes were distinguished were Hb, M, and Tf, and those for which partial description (including the recessive homozygote) was made were A, B, C, D, R and i.

There were large differences among the three pure breeds only for the frequencies at the Hb and Tf loci. The homozygote frequencies of the Blackface-Welsh and Cheviot-Welsh crosses were approximately half-way between their respective pure breeds. For the Blackface-Cheviot cross the homozygote frequency was considerably lower than either parental breed, suggesting that over all loci there were greater differences in gene frequencies between these two breeds than between the Blackface and Welsh or Cheviot and Welsh.

On average over all loci (except Tf) inbreeding had the effect of decreasing heterozygosity roughly in relation to expectation. Individually this effect was statistically significant only for ii, MbMb, HbAHbA and HbbHbb. For the Tf locus there was no average decrease in heterozygosity as a result of 25% inbreeding but thereafter there was a greater decrease in the purebreds than in the crosses.

There were small (< 0·20) but significant residual correlations between R-O-ii blood types and genotypes at several other loci, and between dd and the M system genotypes.

The expected higher global demand for animal proteins and the competition for starch and sugars between food, fuel and feed seem to favour herbivores that convert solar energy captured in fibrous plants into animal products. However, the required higher production level of herbivores questions the sustainability of this conversion. An increase in herbivore production can be achieved by increasing the number of animals associated with the increasing demand of plant biomass or by improving the efficiency with which plant biomass is converted into meat and milk. The potential to increase food production by cattle, the main food-producing herbivore in the temperate zones outside China, was considered in three production systems: grassland-based, mixed rain-fed and mixed irrigated systems. The potential to increase plant biomass production in grassland-based systems seems limited, unless fertiliser is imported in large quantities and crop production is increased, sacrificing valuable, high-quality grasslands, which often conflicts with sustainable production methods. Also, in mixed systems with high inputs of fertiliser or water, improvements in plant biomass production seem marginal and the main challenges for these systems are in breeding high-quality plant biomass at lower levels of fertiliser and the use of new co-products from food processing and bio-based economies. Consequently, the main challenge in herbivore nutrition management is to improve the efficiency of plant biomass utilisation. Stocking rate management along with seasonal variation in the grazing capacity of grasslands and moderate use of fertiliser may increase meat production in grassland-based systems by 400%. Improving plant biomass utilisation in the more industrialised mixed rain-fed systems seems possible by better feed storage technologies and for dairy cattle by improving animal health and lifetime production level. Managing the transition period seems crucial to achieve more sustainable mixed rain-fed and mixed irrigated dairy production systems. Whether sustainable production methods will be implemented also depends on macro-economic conditions and awareness of regional and global environmental concerns.

Muscle fiber characteristics comprise a set of complex traits that influence the meat quality and lean meat production of livestock. However, the genetic and biological mechanisms regulating muscle fiber characteristics are largely unknown in pigs. Based on a genome-wide association study (GWAS) performed on 421 Large White × Min pig F2 individuals presenting well-characterized phenotypes, this work aimed to detect genome variations and candidate genes for five muscle fiber characteristics: percentage of type I fibers (FIB1P), percentage of type IIA fibers (FIB2AP), percentage of type IIB fibers (FIB2BP), diameter of muscle fibers (DIAMF) and number of muscle fibers per unit area (NUMMF). The GWAS used the Illumina Porcine SNP60K genotypic data, which were analyzed by a mixed model. Seven and 10 single nucleotide polymorphisms (SNPs) were significantly associated with DIAMF and NUMMF, respectively (P < 1.10E-06); no SNP was significantly associated with FIB1P, FIB2AP or FIB2B. For DIAMF, the significant SNPs on chromosome 4 were located in the previously reported quantitative trait loci (QTL) interval. Because the significant SNPs on chromosome 6 were not mapped in the previously reported QTL interval, a putative novel QTL was suggested for this locus. None of the previously reported QTL intervals on chromosomes 6 and 14 harbored significant SNPs for NUMMF; thus, new potential QTLs on these two chromosomes are suggested in the present work. The most significant SNPs associated with DIAMF (ALGA0025682) and NUMMF (MARC0046984) explained 12.02% and 11.59% of the phenotypic variation of these traits, respectively. In addition, both SNPs were validated as associated with DIAMF and NUMMF in Beijing Black pigs (P < 0.01). Some candidate genes or non-coding RNAs, such as solute carrier family 44 member 5 and miR-124a-1 for DIAMF, and coiled-coil serine rich protein 2 for NUMMF, were identified based on their close location to the significant SNPs. This study revealed some genome-wide association variants for muscle fiber characteristics, and it provides valuable information to discover the genetic mechanisms controlling these traits in pigs.

In this study, we investigate the extent to which the incidence of Escherichia coli O157:H7 can be predicted in human faeces, from human intake and infection via water contaminated by livestock and carrying this zoonotic pathogen in North-East (NE) and South-West (SW) regions of Scotland. In SW Scotland, there is a risk of coastal recreational waters failing EU standards for faecal indicator organisms, and this is assumed to be the main potential waterborne route of infection. In NE Scotland, the main waterborne route is assumed to be the many private drinking water supplies; these are mainly derived from shallow groundwater and surveys show that there is potential for significant levels of microbial contamination from livestock. The risk to human health from these sources has been assessed using a combination of process models, epidemiological risk-assessment methods and survey data. A key assumption in the calculations is the amount of mixing of pathogenic and non-pathogenic E. coli between animal faecal sources and contaminated water intake by humans. Using the probability distributions of the E. coli O157 content of individual faecal pat material (which would imply no mixing between source and human intake), based on three recent surveys of animal faeces in Scotland, led to predicted annual risks of infection slightly higher than observed human infection incidence. Using the geometric mean to represent partial mixing (which theoretically may over- or underestimate incidence with a concave dose–response curve) gave infection rates similar to those observed for two of the three faecal surveys. Using the arithmetic mean led to over-prediction of risk. This is to be expected if the true dose–response curve is (such as the Beta-Poisson curve used here) concave. Other factors that may lead to over-prediction of incidence are discussed, including under-reporting, loss of infectivity as a result of environmental exposure, immunity and the appropriateness of the Beta-Poisson curve. It is concluded that better epidemiological data for calibration of the dose–response curve, better knowledge of the degree of mixing and understanding of immunity are key requirements for progress in process model-based predictions of infection rate. The paper also explores the potential of improved farm and catchment scale management to deliver cost-effective mitigation of pollution of bathing and drinking water by livestock zoonoses.

Antibiotics are designed to affect gut microbiota and subsequently gut homeostasis. However, limited information exists about short- and long-term effects of early antibiotic intervention (EAI) on gut homeostasis (especially for the small intestine) of pigs following antibiotic withdrawal. We investigated the impact of EAI on specific bacterial communities, microbial metabolites and mucosal immune parameters in the small intestine of later-growth-stage pigs fed with diets differing in CP levels. Eighteen litters of piglets were fed creep feed with or without antibiotics from day 7 to day 42. At day 42, pigs within each group were offered a normal- or low-CP diet. Five pigs per group were slaughtered at days 77 and 120. At day 77, EAI increased Enterobacteriaceae counts in the jejunum and ileum and decreased Bifidobacterium counts in the jejunum and ileum (P < 0.05). Moreover, tryptamine, putrescine, secretory immunoglobulin (Ig) A and IgG concentrations in the ileum and interleukin-10 (IL-10) mRNA and protein levels in the jejunum and ileum were decreased in pigs with EAI (P < 0.05). At day 120, EAI only suppressed Clostridium cluster XIVa counts in the jejunum and ileum (P < 0.05). These results suggest that EAI has a short-term effect on specific bacterial communities, amino acid decarboxylation and mucosal immune parameters in the small intestine (particularly in the ileum). At days 77 and 120, feeding a low-CP diet affected Bifidobacterium, Clostridium cluster IV, Clostridium cluster XIVa and Enterobacteriaceae counts in the jejunum or ileum (P < 0.05). Moreover, feeding a low-CP diet increased the concentrations of Igs in the jejunum and decreased pro-inflammatory cytokines levels in the jejunum and ileum (P < 0.05). At day 120, feeding a low-CP diet increased short-chain fatty acid concentrations, reduced ammonia and spermidine concentrations and up-regulated genes related to barrier function in the jejunum and ileum (P < 0.05). These results suggest that feeding a low-CP diet changes specific bacterial communities and intestinal metabolite concentrations and modifies mucosal immune parameters. These findings contribute to our understanding on the duration of the impact of EAI on gut homeostasis and may provide basis data for nutritional modification in young pigs after antibiotic treatment.

In the first experiment there were significant correlations between the average product of the length and width of the boar's testicles and the sperm output of the boar under a high collection frequency over two 6-h periods and over a 6-week period (r = +0·80, d.f. = 4, P < 0·05 and r = +0·77, d.f. = 7, P < 0·05, respectively). In the second experiment there were no significant differences in the fertility or fecundity of mature boars that had either two or six copulations per week over a 25-week period. However, there was a significant correlation between the average width of the boar's testicles and the fertility of the boar under the high mating frequency (r = +0·74, d.f. = 8, P < 0·05). There were also significant correlations between the number of copulations achieved in two mating tests and the number of copulations achieved and the refusal rate to mate under the high mating frequency (r = +0·86, and r = –0·89, respectively, d.f. = 6, P < 0·01). The implication of these results to the development of tests to predict mating performance of boars is discussed

Feed conversion into milk, nutrient excretion in manure and subsequent environment impacts of manure management are highly influenced by the diets that farmers feed their lactating cows (Bos taurus). On confinement-based dairy farms, determinations of diet composition are relatively straightforward because the types, amounts and nutrients contained in stored feeds are often well known. However, on grazing-based dairy farms, diet composition is more difficult to determine because forage intake during grazing must be estimated. The objectives of this study were to determine relationships between (1) feed N intake (NI), milk production, milk urea N (MUN), feed N use efficiency (FNUE) and excreted manure N (ExN); and (2) between feed P intake (PI), dung P concentrations (g/kg dry matter (DM)) and excreted manure P (ExP) for grazing-based lactating cows having a very wide range of diets and milk production. An additional objective was to evaluate how well these relationships compare with similar relationships based on more direct measurement of feed–milk–manure on confinement-based dairy farms. Four dairy farms located in southeastern Australia were visited during autumn and spring, and data were collected on feed, milk and dung of 18 cows on each farm. Estimated dry matter intake (DMI) from pasture comprised 12% to 75% of total diet DMI, and the crude protein (CP) concentrations in the total diets ranged from 167 to 248 g/kg. During spring, as diet CP increased FNUE declined. Total diet DMI and NI provided the best predictors of ExN, and PI provided the most accurate prediction of ExP. These results indicated accuracy in the study's indirect estimates of pasture DMI. Likely due to high levels and great variability in dietary CP and P concentrations associated with use of diet supplements, MUN did not appear to be a good indicator of dietary CP, and P in dung was not a good indicator of dietary P.

A method for performance testing beef bulls on a high-energy diet from 90 days of age to 400 kg is described. Test results for 81 bulls showed that both in weight-for-age at 400 kg and feed conversion on test there were significant differences between breeds in favour of the Charolais followed by Santa Gertrudis, Criollo and Zebu in that order. Results for 8 Holstein bulls reared artificially were similar to those for Santa Gertrudis.

Comparative data on birth weights, weaning weights and pre-weaning mortality indicate that the Zebu was inferior to the other beef breeds in all these traits.

Of 60 bulls slaughtered, liver abscesses were encountered in only 2 animals, both of which had been reared artificially from birth.

Commercial carcass grading measurements and sample joint dissection were evaluated as predictors of carcass lean concentration using a data set of 1320 pig carcasses from four breeding companies. Entire males, castrated males and gilts from White-type and Meat-type populations were reared on ad libitum or restricted feeding regimens and slaughtered to achieve a carcass weight of either 52·5 kg or 72·5 kg. A model was fitted which examined the accuracy and stability of regression equations for different populations, sexes and feeding regimens, and different values of P2 and carcass weight. The regression slope of lean concentration on P2 differed by sex and population. Lean concentration decreased faster with increases in P2 among gilts than among entire or castrated males. At the same level of P2 and carcass weight, pigs fed ad libitum contained 5 g/kg less lean in the carcass than pigs fed at a restricted level. Biases among populations, sexes and feeding regimens were also found when carcass lean concentration was predicted from additional measurements: muscle depth at P2, fat thickness and muscle depth at 3/4 last ribs, and eye-muscle area. The regression slope of lean concentration on sample joints showed little evidence of variation among populations (except for the hand joint), sexes or feeding regimens. There were important differences in the intercept for different populations. The ham was the most accurate (residual s.d. = 11 g/kg) and least biased joint.

Stereotypies are used as indicators of poor animal welfare and it is, therefore, important to understand underlying factors mediating their development. In calves, two oral stereotypies, that is, tongue playing and object manipulation, result mostly from insufficient structure in the diet. Three hypotheses were studied: (1) oral stereotypies in calves are one of two alternative strategies, the alternative being hypo-activity; (2) stereotyping and non-stereotyping calves differ in terms of cortisol secretion; (3) oral stereotypy development in calves rests on a gene by environment interaction. Eight-week-old bull calves (n=48) were assigned to one of four solid feed allowances (0, 9, 18 or 27 g dry matter/kg metabolic weight per day) with the following composition: 50% concentrate, 25% maize silage and 25% straw on dry matter basis. The calves received milk replacer in buckets, the provision of which was adjusted to achieve equal growth rates. At 14 to 18 weeks of age, calves were exposed to a challenge, that is, tethering inside cages. Oral stereotypies and inactivity were recorded in the home pens in the 4 weeks before the challenge using instantaneous scan sampling. Salivary cortisol levels were measured at −120, +40, +80, +120 min and +48 h relative to the challenge. Individual differences in behaviour were recorded in the first 30 min after challenge implementation using focal animal sampling and continuous recording, and these elements were entered into a principal component (PC) analysis to extract PCs. Regression analyses were performed to find relationships between stereotypies and inactivity, stereotypies and cortisol, and stereotypies and PCs (individual differences, genes) and solid feed (environment). Relationships between PCs and cortisol were also investigated to help with the interpretation of PCs. Hypotheses 1 and 2 were rejected. Hypothesis 3, however, was supported: calves with a zero solid feed allowance, that is, in the most barren environment, showed links between stereotypies and two of the PCs. Calves that displayed high levels of idle and rapid locomotion and low levels of oral contact with the cage during the challenge also displayed high levels of object manipulation in the home pens. Calves that displayed low levels of stepping and turning attempts during the challenge also displayed high levels of tongue playing in the home pens. This study corroborates the gene by environment interaction on the development of oral stereotypies in calves.

Riboflavin (vitamin B2) is essential for monogastric animals. It is mainly produced by recombinant microorganisms (Candida famata, Bacillus subtilis and Ashbya gossypii). The availability of genetically modified organism (GMO)-free riboflavin, obligatory in European organic agriculture, is a major issue. Besides, requirements for organic livestock might differ from conventional production because other genotypes and feed formulations are used. The effects of a fermentation suspension with a high native content of riboflavin produced with unmodified A. gossypii by fermentation were investigated at graded dosages as an alternative to conventional (GMO-based) riboflavin in slow-growing broilers on performance traits and health and welfare indicators. In 2 runs with 800 animals each, Ranger Gold™ broilers were fed with 4 dietary treatments. For starter diets (day 1 to 18), treatments included a basal diet (1) without any riboflavin supplementation (negative control, N-C), (2) with conventional riboflavin supplementation (Cuxavit B2 80% riboflavin) at 9.6 mg/kg (positive control, P-C), (3) with riboflavin supplementation from the alternative source at 3.5 mg/kg (A-low) and (4) with riboflavin supplementation from the alternative source at 9.6 mg/kg (A-high). For the finisher diet (day 29 until slaughtering), P-C and A-high were supplemented with 8.0 mg/kg and A-low with 3.5 mg/kg. Diets were formulated according to organic regulations. Animals were kept in floor pens with 20 chickens per pen. Weekly, BW, feed and water consumption were recorded. Every second week, animal-based health and welfare indicators (feather score and footpad dermatitis) were scored. Slaughter traits were assessed for five males and females per pen at 62/63 days of age. Final body weight of A-high differed from N-C and A-low, but not from P-C. From week 2 until six years of age, A-high had a higher daily weight gain when compared to all other groups. With 74.4%, dressing percentage was higher in A-high compared with all other groups (73.3%). Breast percentage of A-low was lower than that of both control groups but did not differ from A-high. The highest frequency of liver scores indicating fatty liver syndrome was found in P-C, followed by N-C and A-low. Feather scores did not respond to treatment; the highest frequency of mild footpad dermatitis was observed in A-high, however at a low prevalence. In conclusion, the tested fermentation suspension with a high native content of riboflavin derived from fermentation of A. gossypii can be used at levels of commercial recommendations as alternative to riboflavin produced from GMO in broiler feeding. Further studies must verify whether riboflavin can be reduced without inducing riboflavin deficiency in slow-growing broilers.