Test-day milk yield and somatic cell count data over extended lactation (lactation to 540–600 days) were analysed considering part lactations as different traits and fitting random regression (RR) models. Data on Australian Jersey and Holstein Friesian (HF) were used to demonstrate the shape of the lactation curve and data on HF were used for genetic study. Test-day data from about 100 000 cows that calved between 1998 and 2005 were used for this study. In all analyses, a sire model was used.

When part lactations were considered as different traits, protein yield early in the lactation (e.g. first 2 months) had a genetic correlation of about 0.8 with protein yield produced after 300 days of lactation. Genetic correlations between lactation stages that are adjacent to each other were high (0.9 or more) within parity. Across parities, genetic correlations were high for both protein and milk yield if they are within the same stage of lactation. Phenotypic correlations were lower than genetic correlations. Heritability of milk-yield traits estimated from the RR model varied from 0.15 at the beginning of the lactation to as high as 0.37 by the 4th month of lactation. All genetic correlations between different days in milk were positive, with the highest correlations between adjacent days in milk and decreasing correlations with increasing time-span. The pattern of genetic correlations between milk yield in the second 300 days (301 to 600 days of lactation) do not markedly differ from the pattern in the first 300 days of lactation. The lowest estimated genetic correlation was 0.15 between milk yield on days 45 and 525 of lactation. The result from this study shows that progeny of bulls with high estimated breeding values for yield traits and those that produce at a relatively high level in the first few months are the most likely candidates for use in herds favouring extended lactations.

Milk protein genes are among the most intensively expressed and they are active only in epithelial mammary cells of lactating animals. They code for proteins which represent 30% of the proteins consumed by humans in developed countries. Mammary gland development occurs essentially during each pregnancy. This offers experimenters attractive models to study the expression mechanisms of genes controlled by known hormones and factors (prolactin, glucocorticoids, progesterone, insulin-like growth factor-1 and others) as well as extracellular matrix. In the mid-1970s, it became possible to identify and quantify mRNAs from higher living organisms using translation in reticulocyte lysate. A few years later, the use of radioactive cDNAs as probes made it possible for the quantification of mRNA in various physiological situations using hybridisation in the liquid phase. Gene cloning offered additional tools to measure milk protein mRNAs and also to identify transcription factors. Gene transfer in cultured mammary cells and in animals contributed greatly to these studies. It is now well established that most if not all genes of higher eukaryotes are under the control of multiple distal regulatory elements and that local modifications of the chromatin structure play an essential role in the mechanisms of differentiation from embryos to adults. The technique, known as ChIP (chromatin immunoprecipitation), is being implemented to identify the factors that modify chromatin structure at the milk protein gene level during embryo development, mammogenesis and lactogenesis, including the action of hormones and extracellular matrix. Transgenesis is not just a tool to study gene regulation and function, it is also currently used for various biotechnological applications including the preparation of pharmaceutical proteins in milk. This implies the design of efficient vectors capable of directing the secretion of recombinant proteins in milk at a high concentration. Milk protein gene promoters and long genomic-DNA fragments containing essentially all the regulatory elements of milk protein genes are used to optimise recombinant protein production in milk.

A large number of environmental factors affect the daily milk production of a cow. Lactation curves included in the French test-day model are modelled as a function of days in milk with semi-parametric curves (splines). The proper modelling of environmental effects in the test-day analysis was investigated using test-day records collected from the first three lactations of French Montbéliarde cows from 1988 to 2005. Four lactation-curve effects describing calving month, length of dry period, age at calving and gestation defined within parity-class were fitted. The shape of lactation curves did not depend on year of calving, which can be modelled as a constant over the whole lactation. To reduce computational requirements and time, data were pre-adjusted in a first step for fixed effects with no year interaction, and then used for genetic evaluation. Correlations for each lactation between 305-day estimates of genetic and permanent environment effects computed using pre-adjustment factors obtained at a 4-year interval were virtually one. The use of a two-step procedure had a very limited impact on the estimates of genetic and permanent environment effects. The minimum correlations with values estimated with a one-step procedure were 0.9984 and 0.9974, respectively. The knowledge of systematic environmental effects affecting the cow daily yield through lactation curves offers interesting perspectives to predict future daily milk production.

Estimates of (co)variance components were obtained for weights at birth, weaning and at 6, 9 and 12 months of age in Jamunapari goats maintained at the Central Institute for Research on Goats, Makhdoom, Mathura, India, over a period of 23 years (1982 to 2004). Records of 4301 kids descended from 204 sires and 1233 does were used in the study. Analyses were carried out by restricted maximum likelihood (REML), fitting an animal model and ignoring or including maternal genetic or permanent environmental effects. Six different animal models were fitted for all traits. The best model was chosen after testing the improvement of the log-likelihood values. Direct heritability estimates were inflated substantially for all traits when maternal effects were ignored. Heritability estimates for weights at birth, weaning and at 6, 9 and 12 months of age were 0.12, 0.18, 0.13, 0.17 and 0.21, respectively. Maternal heritability of body weight declined from 0.19 at birth to 0.08 at weaning and was near zero and not significant thereafter. Estimates of the fraction of variance due to maternal permanent environmental effects were 0.09, 0.13 and 0.10 for body weights at weaning, 6 months and 9 months of age, respectively. Results suggest that maternal additive effects were important only in the early stages of growth, whereas a permanent environmental maternal effect existed from weaning to 9 months of age. These results indicate that modest rates of genetic progress appear possible for all weights.

There is a lack of knowledge about the genetic background of eczema due to insect bite hypersensitivity, also called summer eczema, in horses. The condition is known in several horse breeds and countries and it causes reduced welfare of the horse and economic losses to the owner. The aim of this study was to estimate genetic parameters for summer eczema in Swedish-born Icelandic horses. A questionnaire was sent to owners of horses sired by stallions with more than 50 offspring born in Sweden between 1991 and 2001. Variance components of summer eczema classified as healthy, mild, moderate or severe were estimated using the threshold methodology with sire models. In addition, summer eczema was analysed as a binary trait (healthy v. affected). The analyses included 1250 horses sired by 33 stallions. The prevalence of summer eczema was 8%, with a range of 0% to 30% in different paternal half-sib groups. Offspring of dams suffering from eczema had a higher risk of developing eczema. The heritability for severity of summer eczema was estimated at 0.3 (s.d. < 0.2) with a threshold sire model. In contrast to the age of the horse, different geographic areas and gender were significantly associated with severity of the eczema. We conclude that genetic selection could decrease the prevalence of summer eczema among Swedish-born Icelandic horses. The amount and quality of data are, however, crucial for the possibility to introduce a genetic evaluation of summer eczema. The symptoms should be classified in several classes according to severity, and this classification could be made by the horse owner.

Histological intestinal villus alterations were studied in piglets fed a raw pigeon pea meal (PM) diet including a powder mixture of amorphous charcoal carbon and wood vinegar compound solution (CWVC). Twenty-eight male castrated piglets were divided into seven dietary groups of four piglets each. The control group was fed raw PM supplemented to the basal diet (178 g/kg crude protein, 4.23 kcal/g gross energy) at 0 g/kg (CONT), 200 g/kg (PM200) and 400 g/kg (PM400). The treatment groups were fed CWVC in both PM200 and PM400 diet groups at levels of 10 g/kg and 30 g/kg (PM200 + CWVC10, PM200 + CWVC30, PM400 + CWVC10 and PM400 + CWVC30). With increasing dietary PM levels, daily feed intake tended to increase. In contrast, daily body-weight gain tended to decrease, significantly in the PM400 group (P < 0.05), resulting in a significant decrease of feed efficiency in PM groups (P < 0.05). Body-weight gain and feed efficiency were higher in the CWVC groups compared with the PM groups. The duodenum and ileum were longer (P < 0.05) in the PM400 group than in CONT, but were similar to CONT in CWVC groups. The liver was heavier (P < 0.05), whereas the weights of the heart, kidney and stomach were decreased in the CWVC groups than in other groups. Most values for the intestinal villus height, cell area and cell mitosis number were lower in PM groups than those in CONT (P < 0.05) for each intestinal segment; however, these values were higher in CWVC groups than in PM groups (P < 0.05). The epithelial cells on the duodenal villus surface of the PM200 group showed cell morphology almost similar to CONT. However, the PM400 group had a smooth villus surface due to the presence of flat cells. The epithelial cells of the CWVC groups were protuberated, resulting in a much rougher surface than CONT. The current growth performance and histological intestinal alterations in piglets fed PM and PM + CWVC diets demonstrate that the intestinal features might be atrophied by feeding PM, resulting in decreased growth performance. CWVC might prevent the harmful effects of PM dietary toxins on intestinal function, resulting in a normal growth performance.

The objective was to determine the concentration of total selenium (Se) and the proportion of total Se comprised as selenomethionine (SeMet) and selenocysteine (SeCys) in post mortem tissues of lambs in the 6 weeks period following the withdrawal of a diet containing high-dose selenised yeast (HSY), derived from a specific strain of Saccharomyces cerevisae CNCM (Collection Nationale de Culture de Micro-organism) I-3060. Thirty Texel × Suffolk lambs used in this study had previously received diets (91 days) containing either HSY (6.30 mg Se per kg dry matter (DM)) or an unsupplemented control (C; 0.13 mg Se per kg DM). Following the period of supplementation, all lambs were then offered a complete pelleted diet, without additional Se (0.15 mg Se per kg DM), for 42 days. At enrolment and 21 and 42 days later, five lambs from each treatment were blood sampled, euthanased and samples of heart, liver, kidney and skeletal muscle (longissimus dorsi and psoas major) tissue were retained. Total Se concentration in whole blood and tissues was significantly (P < 0.001) higher in HSY lambs at all time points that had previously received long-term exposure to high dietary concentrations of SY. The distribution of total Se and the proportions of total Se comprised as SeMet and SeCys differed between tissues, treatment and time points. Total Se was greatest in HSY liver and kidney (22.64 and 18.96 mg Se per kg DM, respectively) and SeCys comprised the greatest proportion of total Se. Conversely, cardiac and skeletal muscle (longissimus dorsi and psoas major) tissues had lower total Se concentration (10.80, 7.02 and 7.82 mg Se per kg DM, respectively) and SeMet was the predominant selenised amino acid. Rates of Se clearance in HSY liver (307 μg Se per day) and kidney (238 μg Se per day) were higher compared with HSY cardiac tissue (120 μg Se per day) and skeletal muscle (20 μg Se per day). In conclusion, differences in Se clearance rates were different between tissue types, reflecting the relative metabolic activity of each tissue, and appear to be dependent on the proportions of total Se comprised as either SeMet or SeCys.

Alfalfa protein is poorly utilised by ruminants due to its rapid degradation in rumen. The objective of the study was to assess the influence of spraying tannic acid (TA) on chopped alfalfa hay on in vitro rumen fermentation and nitrogen (N) retention by sheep. Alfalfa hay with and without TA was fed to sheep to determine nutrient digestibility and N balance. TA was sprayed on chopped alfalfa at three concentrations to determine its effect on in vitro fermentation of dry matter (DM) and N balance in sheep. Final TA concentrations were 0, 30, 60 and 90 g TA per kg DM. The control was sprayed with the same amount of water but without TA. In vitro DM degradation and the production of gas, ammonium-N (NH4-N) and short-chain fatty acid (SCFA) were measured. TA-sprayed alfalfa and the control were fed to sheep to determine nutrient digestibility and N retention. Addition of TA had no influence on the extent and rate of gas production but significantly decreased NH4-N concentration at 30 (P < 0.05), 60 and 90 (P < 0.0001) g/kg DM. Addition of polyethylene glycol (PEG) to TA-sprayed alfalfa increased NH4-N to a level comparable to non-TA-sprayed alfalfa. Spraying of alfalfa with TA significantly decreased (P < 0.05) isovalerate but did not affect the total and individual SCFA acid production. Tannic acid significantly (P < 0.05) reduced in vitro true degradability of DM (IVTD) after 24 h incubation at levels of 60 and 90 g TA per kg DM. Neutral-detergent fibre digestibility (dNDF) after 24 h (P < 0.01), 60 and 90 (P < 0.0001) g TA per kg DM. The effect of TA on either IVTD or dNDF was not significant (P > 0.05) after 48 h of incubation. There was a strong linear relationship between percentage increase in gas production due to PEG and protein precipitation capacity (R2 = 0.94). N digestibility was significantly reduced with all three levels of TA additions. However, the proportion of urine-N to total N output was reduced by adding 60 g (P < 0.05) and 90 g (P < 0.01) TA per kg DM. Serum metabolites and liver enzymes were not affected by TA (P > 0.05). Higher faecal N as the TA level increased indicates incomplete dissociation of tannin–protein complexes post ruminally. Factors affecting dissociation of tannin–protein complexes need further study.

In the rumen, plant particles are colonised and degraded by the rumen micro-organisms. Although numerous important findings about fibre-associated bacterial community were obtained using traditional or molecular techniques, little information is available on the dynamics of bacteria associated with feed particles during incubation in the rumen. In the present study, ryegrass leaf, ryegrass stem and rice straw, representing different carbohydrate compositions, were used as substrates and placed in the rumen of goats by using nylon bags, and PCR/DGGE (denaturing gradient gel electrophoresis) with subsequent sequence analysis were used to monitor the dynamics of and identify bacteria associated with the substrates during 24 h of incubation. DGGE results showed that substrate samples collected from 10 min to 6 h had similar DGGE patterns, with up to 24 predominant bands to each sample, including 14 common bands to all samples, suggesting a rapid and stable colonisation by a highly diverse bacterial community. Substrate samples collected at 12 and 24 h showed similar DGGE patterns but had great difference in DGGE patterns from those collected at 10 min to 6 h, suggesting an apparent shift in bacterial community. Sequence analysis indicated that most substrate-associated bacteria were closely related to fibrolytic bacteria. In conclusion, a highly diverse and similar rumen bacterial community could immediately colonise to different substrates and remained stable during the initial 6 h of incubation, but experienced a marked change after 12 h of incubation. Italian ryegrass leaf, Italian ryegrass stem and rice straw were colonised with a similar bacterial community.

Administration of melatonin to advance the breeding season in sheep has been widely used, since this hormone conveys the photoperiodic signal to the reproductive neuroendocrine axis. An increased lambing percentage has been reported following such treatment during anoestrus, which could be mediated through a higher rate of embryonic survival, either by an improvement in luteal function or by a reduction in the antiluteolytic mechanisms. The aim of this article is to review the body of knowledge on the effect of melatonin on the ovine ovary, the embryo and the establishment of pregnancy. Some studies using synchronized ewes have found that melatonin treatments during anoestrus do not improve ovulation rate by modifying the timing of follicle emergence, but increasing the number of ovulatory follicles by decreasing the atresia of medium and large follicles. On the other hand, the addition of melatonin to the in vitro maturation medium does not improve oocyte maturation rate in oocytes from sheep ovaries recovered either in anoestrus or in the breeding season. However, a luteotrophic effect of melatonin at either short or medium term has been reported. We have recently observed that melatonin implants tend to improve the survival of embryos collected from ewes after superovulation in anoestrus. More specifically, melatonin induced a significant reduction of the number and rate of non-viable (degenerate and retarded) embryos. Preliminary data from our laboratory suggest that the uterine sensitivity to progesterone – in terms of progesterone receptor expression – of superovulated ewes could be reduced by melatonin treatment. It can be concluded that the success of exogenous melatonin as a means to improve lamb production of sheep is due, at least in part, to an improvement of luteal support and embryonic survival.

In farm animals, salivary cortisol has become a widely used parameter for measuring stress responses. However, only few studies have dealt with basal levels of concentration of cortisol in pigs and its circadian rhythm. The aim of this study was to examine the effects of ambient temperature and thermoregulatory behaviour on the circadian rhythm of salivary cortisol levels in fattening pigs. Subjects were 30 fattening pigs of different weight (60 to 100 kg), kept in six groups in an uninsulated building in pens with partly slatted floors. Saliva samples were taken every 2 h over periods of 24 h at different ambient temperatures at two times in winter and four times in summer. Thermoregulatory behaviour was recorded in the same 24-h time periods. The effect of time of day, body weight, ambient temperature and behaviour on the cortisol level was analysed using a mixed-effects model. Two peaks of cortisol levels per day were found. This circadian pattern became more pronounced with increasing weight and on days where thermoregulatory behaviour was shown. Mean cortisol levels per day were affected by weight but not by thermoregulatory behaviour. From our data, we conclude that long-term variations in cortisol concentration may be influenced by increasing age and weight more than by the respective experimental situation. In assessing animal welfare, it seems more reliable to consider the circadian pattern of cortisol concentration instead of only one value per day.

In the Molise region (Italy), some autochthonous populations are still bred and, between them, some wild horses named ‘Pentro horses.’ The breeding area is a natural pasture. It is 2200 ha extended including a broad plane surrounded by wooden hills. The aim of this research was to determine the nutritional characteristics of this area over a 2-year period to improve the management of the herd and to define the stocking rate in relation to the forage production in terms of production and quality. The forage samples were collected over two successive years during the grazing period (May to October) from five experimental areas and analysed for dry matter (DM), organic matter (OM), crude protein (CP), crude fibre (CF), neutral-detergent fibre (NDF), acid-detergent fibre (ADF), acid-detergent lignin (ADL) and gross energy (GE). Horse feed units (HFU) and horse-digestible crude protein (HDCP) were also predicted. Data were analysed with a one-way ANOVA test using month and area as factors. The DM, HFU and HDCP total production was determined to be compared with the total nutrient requirements of the herds from May to October. The results show that seasonal and yearly climatic variations significantly affect chemical composition and nutritive value of the pasture. The parameters most influenced were DM, CP, ADF and to a less extent NDF, while OM, ADL and GE show smaller differences during the observed period. The results show a low production per ha; nevertheless, because of the low stocking rate (0.3 to 0.6 head per ha), nutrient production meets the nutrient requirements of the horses regarding DM and energy. The differences among the areas have to be ascribed to the different botanical compositions and to the different draining capacity of the soil, and also in this case the greatest variations are for DM, CP and ADF.

The mechanisms involved in the control of growth in chickens are too complex to be explained only under univariate analysis because all related traits are biologically correlated. Therefore, we evaluated broiler chicken performance under a multivariate approach, using the canonical discriminant analysis. A total of 1920 chicks from eight treatments, defined as the combination of four broiler chicken strains (Arbor Acres, AgRoss 308, Cobb 500 and RX) from both sexes, were housed in 48 pens. Average feed intake, average live weight, feed conversion and carcass, breast and leg weights were obtained for days 1 to 42. Canonical discriminant analysis was implemented by SAS® CANDISC procedure and differences between treatments were obtained by the F-test (P < 0.05) over the squared Mahalanobis’ distances. Multivariate performance from all treatments could be easily visualised because one graph was obtained from two first canonical variables, which explained 96.49% of total variation, using a SAS® CONELIP macro. A clear distinction between sexes was found, where males were better than females. Also between strains, Arbor Acres, AgRoss 308 and Cobb 500 (commercial) were better than RX (experimental). Evaluation of broiler chicken performance was facilitated by the fact that the six original traits were reduced to only two canonical variables. Average live weight and carcass weight (first canonical variable) were the most important traits to discriminate treatments. The contrast between average feed intake and average live weight plus feed conversion (second canonical variable) were used to classify them. We suggest analysing performance data sets using canonical discriminant analysis.

A 2 × 2 factorial experiment was conducted to investigate the interaction between high and low dietary crude protein (CP) (200 v. 150 g/kg) and sugar-beet pulp (SBP) (200 v. 0 g/kg) on nutrient digestibility, nitrogen (N) excretion, intestinal fermentation and manure ammonia and odour emissions from 24 boars (n = 6, 74.0 kg live weight). The diets were formulated to contain similar concentrations of digestible energy (13.6 MJ/kg) and lysine (10.0 g/kg). Pigs offered SBP-containing diets had a reduced (P < 0.05) digestibility of dry matter, ash, N, gross energy and an increased (P < 0.001) digestibility of neutral-detergent fibre compared with pigs offered diets containing no SBP. There was an interaction between CP and SBP on urinary N excretion and the urine : faeces N ratio. Pigs offered the 200 g/kg CP SBP-based diet had reduced urine : faeces N ratio (P < 0.05) and urinary N excretion (P < 0.05) compared with those offered the 200 g/kg CP diet without SBP. However, there was no effect of SBP in pigs offered 150 g/kg CP diets. Manure ammonia emissions were reduced by 33% from 0 to 240 h (P < 0.01); however, odour emissions were increased by 41% (P < 0.05) when pigs were offered SBP diets. Decreasing dietary CP to 150 g/kg reduced total N excretion (P < 0.001) and ammonia emissions from 0 to 240 h (P < 0.05). There was an interaction between dietary CP and SBP on branched-chain fatty acids (P < 0.001) in caecal digesta. Pigs offered the 200 g/kg CP SBP-containing diet reduced branched-chain fatty acids in the caecum compared with pigs offered the 200 g/kg CP diet containing no SBP. However, there was no effect of SBP in the 150 g/kg CP diet. In conclusion, pigs offered SBP-containing diets had a reduced manure ammonia emissions and increased odour emissions compared with diets containing no SBP. Pigs offered the 200 g/kg CP SBP-containing diet had a reduced urine : faeces N ratio and urinary N excretion compared with those offered the 200 g/kg CP diet containing no SBP.

Farmers have to cope with both society and market pressures in their working practices, as well as with the enlargement of farms, off-farm opportunities and profound changes in the workforce. Expectations in terms of working duration and rhythms are increasingly expressed by farmers, meaning that working conditions and the efficiency of work organisation are critical issues nowadays. The bibliography shows that work organisation is mainly discussed by social scientists, but that livestock scientists make a significant contribution to the debate. Indeed, technical changes modify working calendars, priorities between tasks and interchangeability among workers; technical adaptations are levers to solving problems of work with equipment, buildings and the workforce. We present here French approaches to work organisation that take into account livestock management and its implications in work organisation. The ‘Work Assessment’ method represents the work organisation and evaluates work durations and time flexibility for farmers. The ATELAGE model describes and qualifies work organisation with its various regulations and time scales, integrating the other activities – economic or private – that farmers can carry on. Three principles underpin them: not all workers are interchangeable; tasks have different temporal characteristics (rhythms, postponement, etc.); and the year is a succession of work periods that differ in their daily form of organisation. We illustrate with concrete examples how these approaches contribute to helping and guiding farmers in their thoughts about change.

Different raw beef quality traits from four local Spanish cattle breeds were studied using correlation, factorial, discriminant and multiple regression analysis. The following variables were studied after 0, 5, 10 and 15 days of storage under 60% O2, 30% CO2 and 10% N2 modified atmosphere packaging (MAP): colour physical variables, meat pigments, sensory degradation of odour and colour, microbial counts, thiobarbituric acid (TBA), pH, drip loss, lipid composition and volatile compounds. The degradation of raw beef quality was related to the increase in 2,3,3-trimethylpentane, 2,2,5-trimethylhexane, 3-methyl-2-heptene, 2-octene, 3-octene, 2-propanone, Enterobacteriaceae and aerobial plate counts (APC), metmyoglobin (MMb), lightness (L*), yellowness (b*), drip loss and TBA. Among these variables, TBA, b* and MMb may be useful in evaluating raw beef quality. No variables related to fat, except for TBA, including pH were limiting factors of the colour and odour shelf-life of raw beef under MAP. Each breed had some characteristics that were unique and these differences may influence the stability of meat to oxidation depending on myoglobin concentration and the polyunsaturated fatty acid (PUFA)/saturated fatty acid (SFA) ratio.

The purpose of this study was to compare effects of finishing environment on growth performance, pork quality and lipid composition of pork. Environments compared were standard confinement (CON) and deep-bedded semi-outdoor systems. The deep-bedded method employed in the current study was the use of hoop structures. Hoops are large, tent-like shelters with cornstalks or straw for bedding. Gilts ranging in weight from 59 to 71 kg were randomly assigned to treatments of Hoop (n = 50) and CON (n = 18) environments. Gilts were fed a two-phase dietary sequence, ad libitum for 45 days. Six gilts per treatment were selected for carcass composition and quality evaluation. The experiment was replicated a total of five times. Pigs raised in the Hoop environment gained significantly less and required significantly more feed for growth than pigs raised in the CON environment. Carcasses from CON-finished pigs were significantly fatter at the 10th rib, which lowered carcass percentage fat-free lean(FFL) and they also had greater loin marbling scores compared with carcasses from Hoop-finished pigs (P < 0.05). Significant replication effects were noted on beginning weight, live weight, carcass weight, percentage FFL, backfat, lipid content and adipose firmness. Carcasses from Hoop pigs had lower proportions of palmitic acid (P < 0.05), and higher proportions of oleic and linoleic acid (P < 0.05) in the inner layer of adipose tissue. The proportion of saturated fatty acid was lower, and that of mono- and poly-unsaturated fatty acid was higher in the inner layer of the adipose tissue of Hoop pigs. Variations in fatty acid composition and lipid deposition may have been caused by environmental temperature, since decreases in environmental temperature accompanied compositional variation of the adipose, leading to higher proportions of monounsaturated fatty acid and lower proportions of saturated and polyunsaturated fatty acid in adipose tissue, regardless of treatment. Volatile profile analysis revealed that adipose tissue of Hoop pigs had significantly higher amounts of 3-butanal and heptanal compared with CON pigs, which may be related to the amount of oleic and linoleic acids composing the adipose tissue. These data indicate finishing pigs in hoop structures allows for exposure to fluctuating temperatures, which may influence the growth of pigs, as well as fatty acid composition and firmness of pork products.

The objectives of the current study were to determine the degree to which space allocation in a deep-bedded system influences swine performance and pork quality. The deep-bedded method employed was hoop structures, which are large, tent-like shelters with cornstalks or straw for bedding. One hundred gilts ranging in weight from 59 to 71 kg were randomly assigned to treatments of low (0.70 m2 per pig, n = 50) or high (1.13 m2 per pig, n = 50) space allocation. During the 45-day experimental period, gilts were ad libitum fed a two-phase diet. Six gilts per treatment were used for carcass composition and pork quality evaluation for each replication. Five replications were conducted over a period of 4 months. Pigs finished with greater space allocation had smaller longissimus muscle area and produced pork that appeared to be darker. Variations in fatty acid composition and lipid percentage of subcutaneous adipose and longissimus dorsi muscle were observed when space allocation was changed within hoop structures. Less space resulted in greater proportion of lipid present as polyunsaturated fatty acids. Greater space allocation resulted in lower total lipid in subcutaneous pork adipose tissue. Space allocation did not affect fat firmness. Replications spanned the months of August to November, with temperatures ranging from 32°C to −2°C within the hoop structure. As environmental temperature declined, the proportion of monounsaturated fatty acids increased. Providing more space during finishing in these systems had only a small affect on pig growth and pork quality. Variations observed from replication to replication at fluctuating temperatures provide insight to seasonal differences in growth and adipose tissue composition and firmness. Therefore, finishing pigs in these systems may lead to seasonal variation in lipid composition.

Forage halophytes such as saltbush (Atriplex spp.) are widely used to revegetate Australian saline land and can provide a medium-quality fodder source. An animal house experiment was conducted to investigate differences in the carcass and eating quality of sheep ingesting saltbush from saline land in combination with a barley supplement. Twenty-six merino hoggets (two groups of 13) were fed either a 60 : 40 dried saltbush (Atriplex nummularia): barley (S + B) ration or a 33 : 25 : 42 lupins : barley : oaten hay ration (C) for 10 weeks prior to commercial slaughter. After 10 weeks, all sheep were commercially slaughtered and a single loin (from 12th rib to chump) collected from each animal for taste-panel analysis. Carcass weight, total tissue depth over the 12th rib 110 mm from the midline (GR fat depth), ultimate pH and colour were determined and X-ray bone densitometry used to estimate the fat content of the carcass. Blood samples were taken to assess the hormonal response to ingesting these diets and fatty acid profiles of the subcutaneous and intramuscular fat were determined. Both groups grew at the same rate (62 g/day) and had similar hot carcass weights (P > 0.01) (17.2 ± 0.3 kg for S + B and 17.9 ± 0.3 kg for C). However, these live weights may not be high enough to be commercially viable such that saltbush and barley may only be suitable as a maintenance feed. The S + B-fed sheep had a significantly (P = 0.055) lower fat and higher lean content (P < 0.05) than the C group. This is a positive finding as fat denudation is a significant cost to processors and farmers can produce sheep that are depositing less fat or more lean per unit of live-weight gain. The decreased fat and increased lean content were attributed to the higher protein : energy ratio available for production and lower circulating insulin and higher growth hormone of the S + B-fed sheep. The lower body-fat content and lower metabolisable energy and digestible organic matter intake did correlate with the sheep fed the S + B diet, having a significantly lower percentage of unsaturated fat and equal levels of saturated fat than the C treatment. Diet had no effect on the ultimate pH or colour of the meat. Treatment had no significant effect on any of the eating-quality attributes (P > 0.1). The drying of the saltbush, the shorter length of the experimental period and the low carcass fat content were believed to have contributed to this result. Further field experiments are needed to clarify the benefits to carcass and eating quality of ingesting saltbush.