Fat quality, in particular, firmness is a main contributor to meat appearance, shelf life, taste, and human health. The current study was conducted to examine the fluctuation and criteria of porcine fat firmness. Several physiochemical methods were performed on 237 porcine perirenal fat samples that were obtained randomly from a commercial market. The relationship between perirenal fat and the middle subcutaneous fat layer was investigated to predict carcass fat quality. Each physiochemical property of the perirenal fat showed considerable variation as a 40-fold difference in firmness was observed between the most extreme samples. Differences between these extremes were 19°C in melting point, 0·0043 for refractive index, and 18 g per 100 g fatty acid methyl esters for saturated fatty acids (SFA) concentration. Strong curvilinear relationships were found between Instron and sensory firmness scores (R=0·90–0·96, no.=24). On the basis of these relationships, classification of the perirenal fats obtained from the commercial market was defined. Fats possessing firmness values of less than 7 N have undesirable fat quality, whereas fat samples with values greater than 16 N were not popular in the market. From these data, we conclude that fats of 7–16 N in firmness value were preferred by consumers. Firmness values of perirenal fat samples correlated significantly with the stearic acid (C18:0) and SFA concentrations of samples of the middle subcutaneous fat layer (r=0·68, 0·57, P<0·01). These results indicate that there are wide fluctuations in the porcine fat quality, and that fats ranging in Instron firmness values between 7 and 16 N are most acceptable to consumers. And, subcutaneous fat may prove to be a valuable indicator of whole body pork fat quality.

Tree leaf meals (TLM) are increasingly used in the tropics to feed pigs. The nutritive value of the TLM of cocoyam (Xanthosoma saggitifolium), mulberry (Morus alba) and Trichanthera gigantea, their effect on the digestive tract and their fermentation rate in the large intestine, were determined in adult sows given diets containing 150 or 300 g TLM per kg. The TLM contained from 8·5 to 12·0 MJ digestible energy per kg dry matter (DM) and from 60 to 125 g digestible protein per kg DM. The digestibility was not affected ( P>0·05) by their rate of incorporation in the diet. The apparent ileal protein digestibility of the diets containing 300 g TLM per kg was also determined by the slaughtering method. It reached 80% for the basal diet and 54, 70 and 74% for the Trichanthera-, mulberry- and cocoyam-based diets, respectively. No diet effect ( P>0·05) was observed on the weight and length of the gastro-intestinal tract, with the exception of a heavier caecum in sows given the Trichanthera-based diet ( P<0·01). The pH of the gastric fluid of these sows was also higher ( P<0·001). The fermentation of the dietary fibre in the large intestine was evaluated by the gas technique using syringes. The cocoyam leaves presented the highest amount of total gas produced after fibre fermentation ( P<0·001). The ranking order of gas production was identical to that observed for the digestibility coefficients: Trichanthera <mulberry <cocoyam. In conclusion, TLM can represent up to 0·3 of a diet for sows. Their use in sow nutrition may be considered in tropical regions where protein sources are scarce.

Sixteen blocks of eight littermate pigs were weaned at 3 weeks of age and each divided into four groups. Various levels of nutrition were applied to the pigs so that the four groups reached 20 kg. at 59, 68, 80 and 91 days of age, respectively.

Only small differences were observed between groups in feed conversion ratio to 20 kg.; however, Group 4 required more feed per kg. gain than the three other groups.

During the second period (20–90 kg.) the pigs in each group were divided into two sub-groups, which were on a high and a low plane of nutrition respectively. In both sub-groups the type of feeding before 20 kg. influenced the average daily gain and feed conversion ratio. The older the pigs were at 20 kg. the higher the daily gain and the lower the feed conversion ratio in the following period. There was an increase in daily feed intake with increased age at 20 kg. for pigs fed ad lib. during the second period.

An increase in age at 20 kg. caused a significant decrease in thickness of backfat, a greater area of eye muscle and a smaller area of fat overlying muscle. For pigs fed ad lib. the area of eye muscle was significantly increased by a higher age at 20 kg. live-weight.

Plasma oxytocin was measured in 11 multiparous sows for 13 h after the start of parturition to confirm the existence of early milk ejections and determine whether they were associated with pulsatile oxytocin release. The relationship between oxytocin concentrations and duration of parturition was also analysed. Oxytocin was released in pulses during and after parturition and mean concentrations reached maximum 2 to 4 h after the first birth. Discrete milk ejections occurred during parturition but only 42% of these were associated with oxytocin peaks before 4 h post partum. After this more than 80% of milk ejections occurred with oxytocin peaks. Sow grunting increased during milk ejections and peak grunt rate increased after parturition. Oxytocin peaks without milk ejections did not lead to an increased rate of grunting. Sows with prolonged parturition had lower basal and peak oxytocin concentrations. During the first 4 h only half of the piglets were born during an oxytocin peak. Discrete milk ejections with oxytocin peaks can occur before parturition is completed. However, during the first 4 h post partum, basal oxytocin concentrations may be high enough for milk ejection to occur without further oxytocin secretion. Both milk ejection and oxytocin release are necessary for the sow to increase grunt rate. Low oxytocin concentration is associated with prolonged parturition.

Crib-biting in horses is a stereotypic oral behaviour. Genetic susceptibility has been suggested on a causal basis, together with environmental factors such as stress, gastric discomfort and frustration caused by stall restrictions. This study aimed to test the associations of known or suspected stereotypic genes with equine crib-biting, including Ghrelin, Ghrelin receptor, Leptin, Dopamine receptor, μ-opioid receptor, N-cadherin, Serotonin receptor and Semaphorin. We conducted a candidate gene study with a case–control design, including 98 crib-biting and 135 control horses of two breeds, Finnhorses and half-breds. Detailed phenotypic information on crib-biting behaviour was surveyed through an owner-completed questionnaire. Control horses were more than 10 years old and without a history of crib-biting. Single nucleotide polymorphisms flanking the candidate genes were genotyped using either Sanger sequencing or Taqman assays. According to the survey, the affected horses started crib-biting at a young age, had exhibited crib-biting for more than a year, and expressed the behaviour after feeding or when stressed. Comparison of allele frequencies between the cases and controls for each breed separately did not provide evidence of an association at any of the tested loci. These results suggest that the previously known stereotypic genes are not major risk factors for crib-biting in horses, and further genome-wide studies are warranted on larger sample cohorts.

Three groups of 16 cattle each comprising three multiparous Jersey cross Holstein-Friesian cows, seven primiparous and six multiparous Holstein-Friesian cattle were offered, ad libitum, a silage-based complete diet with different concentrate ingredients following an initial 3-week covariate period. The relationship between these three diets and other parameters with lesions of the weight-bearing surface of the hoof was studied by scoring mobility weekly (locomotion score) and examining all the feet of all cows for visual lesions particularly those involving the horn of the foot. In addition hoof angle, hardness and growth and wear were also recorded. The mean locomotion score during the initial 3-week covariate period was a significant covariate for the subsequent locomotion score, milk yield, and live weight (P < 0·001). Furthermore weekly locomotion score also proved a significant covariate for weekly milk yield (P < 0·05). There were no significant differences between dietary treatment groups for locomotion score, overall lesion score (despite significantly fewer ulcers of the sole in one dietary group: P < 0·001) but a significant (P < 0·05) difference between cow ‘type’ and there was also a significant (P < 0·05) diet × breed interaction for locomotion score and milk yield. It was concluded first that initial mobility was an important factor in subsequent mobility of the cow and so experimental design; secondly that while nutrition and genotype interacted to influence mobility, visual lesions of the hoof and lameness, the mechanisms involved were far from clear; and thirdly that the simple lesion score used required some adjustment or correction factor(s) to ensure that more severe lesions were given a greater weight than a simple unitary increase.

The digestibility of the starch component of raw cereals in newly weaned piglets is highly variable. Reasons for this must be elucidated if the most suitable cereals are to be used. A novel approach was employed, which consisted of assessing the physicochemical properties (rapid visco analysis, water absorption and solubility indices, particle size distribution and in vitro amylolytic digestion) of eight raw cereals contained within piglet diets and subsequently relating this in vitro data to the biological responses of weaned piglets. Trial 1 examined soft and hard wheat, trial 2 – soft wheat, barley, rye and triticale, and trial 3 – soft wheat, naked oats, whole oats and maize. The initial observation was that in vitro testing prior to animal trials is recommended in nutritional evaluation since it indicated fundamental differences between raw cereals, such as for example the levels of endogenous amylase in wheat. Starch and nitrogen digestibility differed between cereals (apparent digestibility coefficients at the 0.5 site of the small intestine ranged from 0.10 to 0.69 for starch and from 0.17 to 0.68 for nitrogen). There is also a probable relationship between the coefficients of ileal apparent starch digestibility, at approximately halfway from the gastric pylorus to the ileocaecal valve, and the presence of endogenous amylase (mean values of 0.53 and 0.62 in trials 2 and 3, respectively, for the higher amylase wheat; 0.38 for the low-amylase wheat used in trial 1). This additional variable (i.e. the unforeseen presence of endogenous amylase) in wheat made it more difficult to draw a firm conclusion about the nutritional suitability of the different cereals. All raw-cereal diets caused atrophy of the villi during the initial week following weaning, but the soft wheat was associated with the highest comparative villi height and might therefore be considered the best of all raw cereals in minimising the post-weaning growth check. For wheat, this might also suggest a possible interaction between villus architecture and endosperm texture in the immediate post-weaning period.

Results are reported from four trials in which neonatal calves were given either whole milk or milk substitute containing the lactoperoxidase system.

Trial 1 was a pilot trial conducted in Sweden in which calves given whole milk with the lactoperoxidase system gained significantly more weight than controls (P < 0·05). Trials 2, 3 and 4 were carried out in successive years at the National Institute for Research in Dairying, using large numbers of newborn, female Friesian calves. In trial 2 a significant positive effect of the lactoperoxidase system with whole milk on live-weight gain was established by 3 weeks of age (P < 0·05) and sustained until weaning at 5 weeks. There was no significant effect of the lactoperoxidase system for the milk substitute treatment. In trial 3 the whole milk comparison from trial 2 was repeated. There was a significant positive effect of the lactoperoxidase system on the live-weight change after 2 weeks of age only (P < 0·05). In trial 4 two different methods of activating the lactoperoxidase system were compared for calves given whole milk. There was no effect of either method on the live-weight gain of the calves. However, as the levels of scouring were extremely low for all calves, a comparison of the two methods of activating the lactoperoxidase system was not justified. The combined results from trials 2, 3 and 4 confirmed that the lactoperoxidase system significantly increased the live-weight gain of calves given whole milk, despite the fact that the overall level of mortality and incidence of scouring was low in these trials.

MicroRNAs are endogenous ~22nt RNAs that negatively regulate gene expression at the posttranscriptional level via binding to the 3′-untranslated region (3′UTR) of target mRNAs. The microRNA miR-27a was reported to depress the expression of myostatin, a critical inhibitor of skeletal myogenesis, by binding to its 3′UTR in mouse. In this study, we cloned the full-length 3′UTR of porcine myostatin by rapid amplification of 3′-cDNA ends (3′-RACE) and demonstrated that the 3′UTR of porcine myostatin is targeted by miR-27a. The phenomenon that the level of myostatin inversely correlated with miR-27a was observed in fat and heart of pigs and also in proliferating porcine myoblasts. Besides, overexpression of miR-27a in porcine myoblasts promoted cell proliferation by reducing the expression of myostatin. Our data suggest that miR-27a positive regulates porcine myoblast proliferation via targeting myostatin.

Selection decisions in breeding schemes can involve choices between candidates evaluated to different accuracies. A Bayesian framework is put forward for choosing among candidates, and it is shown that attaching loss functions for estimation errors makes this process different from selecting upon best linear unbiased predictions alone. Examples are given using both linear and quadratic loss to show that when estimation errors are penalized, the selection process tends to select more unrelated and more accurately evaluated individuals. In a dairy cattle breeding scheme response was only slightly lower than that from selection on expected breeding values but with a much reduced coefficient of variation. However, if prediction errors are preferred, with the hope of selecting individuals whose breeding value are higher than expected, extra genetic progress could be obtained by favouring the selection of individuals with low accuracy. This requires consideration of more than a single generation.

With discrete generations and equal measurements on candidates the decision framework was shown to be equivalent to a single quadratic restriction on the selection scores of parents in the previous generation.

A framework based on Bayes decision theory could be simply applied to produce a flexible means for producers to select according to their individual risk preferences.

Resin acid-enriched composition (RAC) mainly containing tall oil fatty acid with an active component of resin acid (RA) can improve the microbial population in the digestive system, change the microbial fermentation, and improve the feed conversion ratio. We investigated the effects of dietary supplementation of RAC on sow colostrum yield (CY), colostrum composition and gut microbiota. Tall oil fatty acid and RA are commonly termed RAC and CLA, pinolenic, abietic, dehydrobiotic acids are characteristic components of RAC. The experiment was conducted in three trials in three respective herds. Sows were fed with a control diet and the same diet supplemented with 5 g RAC/day per sow during the last week of gestation. The 16S ribosomal RNA gene sequencing technique was used to assess sows’ faecal microbiota populations at farrowing. Colostrum nutritional composition, acute phase proteins (APPs) and immunoglobulin (Ig) content were also assessed. Individual piglets were weighed at birth and 24 h after the birth of first piglets in order to calculate CY and later at 3 to 4 weeks to calculate average daily gain. The RAC-fed sows had significantly higher IgG levels (P<0.05) in all three herds but treatment did not influence colostrum IgA and IgM concentration. There were no significant differences in colostrum protein, lactose and fat content in sows of the two diet groups (P>0.05), but those fed RAC had higher levels of colostrum serum amyloid A. Colostrum yield was significantly higher in RAC-fed sows in herds 2 and 3 with heavier piglets between 3 and 4 weeks of age (P<0.05), but not in herd 1 (P>0.05). Resin acid-enriched composition supplementation significantly increased some beneficial and fermentative bacteria (Romboutsia and Clostridium sensu stricto) than the control diet (P<0.01) while some opportunistic pathogens (Barnesiella, Sporobacter, Intestinimonas and Campylobacter), including Proteobacteria, were suppressed. Therefore, RAC added to the sow diet at late pregnancy increases colostrum IgG, colostrum availability for neonate piglets, and seems to promote better maternal intestinal microbial sources.

The main limitation for determining feed efficiency of freely grazing ruminants is measurement of daily individual feed intake. This paper describes an investigation that assessed a method for estimating intake of forage based on changes in BW of ewes. A total of 24 dry and non-pregnant Romane ewes (12 hoggets, HOG; mean±SD 51.8±2.8 kg BW; body condition score (BCS) 2.6±0.2; and 12 adults, ADU; 60.4±8.5 kg BW; BCS 2.7±0.8) were selected for the study and moved from their rangeland system to a confined pen with controlled conditions and equipped with individual automatic feeders. The experiment lasted for 28 days (21 days adaptation and 7 days feed intake measurement). Ewes were fed hay and trained to use the electronic feeders (one feeding station per ewe) in which actual daily intake (Hintake24) was measured. The pens were designed to maximize movement of trained ewes through an automated Walk-over-Weighing device, by using water and mineral salts as attractants. Total individual intake of hay measured in the automatic feeder at each meal (Hintake) was compared with indirect estimates of feed intake determined using differences in the BW of the ewes (∆BW) before and 1 h following morning and afternoon feeding at fixed times. The BW, BCS, Hintake, Hintake24, as well as plasma non-esterified fatty acids (NEFA), glucose and insulin profiles were determined. The BW was higher in ADU v. HOG but BCS was not affected by parity. The Hintake24 was affected by day of experiment as a consequence of reduced availability and intake of water on one day. Plasma glucose, NEFA and insulin were not affected by parity or day of experiment. The HIntake was and ∆BW tended to be higher in the morning in HOG, whereas Hintake was and ∆BW tended to be higher in ADU at the afternoon meal. Irrespective of parity or feeding time, there was very strong correlation (r2=0.93) between Hintake and ∆BW. This relationship confirms that our indirect method of estimating individual forage intake was reliable within the strictly controlled conditions of the present experiment. The method appears suitable for use in short-term intensive group feeding situations, and has potential to be further developed for longer-term forage intake studies, with a view to developing a method for freely grazing ruminants.

The present work was intended to analyse the chemical composition and oxidative stability of the muscle biceps femoris and adipose tissues from Iberian pigs fed different finishing diets: free-range feeding on grass and acorns in a ‘Montanera’ traditional system (MON), fed in confinement with a mixed diet containing high-oleic sunflower oil (115 g/kg of diet) and supplemented with 250 mg/kg α-tocopherol (HOVE), and fed in confinement with a tocopherol-non-supplemented control mixed diet (CON). Muscles from MON pigs contained significantly (P < 0.05) higher amounts of intramuscular fat than those from HOVE and CON pigs. Muscles from MON and HOVE pigs had significantly higher levels of α-tocopherol than muscles from CON pigs whereas free-range feeding provided significantly higher levels of γ-tocopherol to muscles from MON pigs than the experimental diets did to CON and HOVE pigs. Adipose tissues from MON and HOVE pigs contained significantly lower proportions of saturated fatty acids and significantly higher levels of oleic acid and monounsaturated fatty acids than those from CON pigs. Tissues from MON pigs contained significantly smaller levels of polyunsaturated fatty acids than those from CON and HOVE pigs. To a higher extent, feeding background affected the fatty acid composition of polar lipids from the muscle bicepsfemoris than that of neutral lipids. Tissues from MON pigs contained significantly smaller ω-6/ω-3 values than those from pigs fed mixed diets. Compared to tissues from CON pigs, those from MON and HOVE pigs exhibited a higher oxidative stability as a likely result of a most favourable fatty acid composition and the presence of higher tocopherol levels.

Diet manipulation and genetic selection are two important mitigation strategies for reducing enteric methane (CH4) emissions from ruminant livestock. The aim of this study was to assess whether the diurnal pattern of CH4 emissions from individual dairy cows changes over time when cows are fed on diets varying in forage composition. Emissions of CH4 from 36 cows were measured during milking in an automatic (robotic) milking station in three consecutive feeding periods, for a total of 84 days. In Periods 1 and 2, the 36 cows were fed a high-forage partial mixed ration (PMR) containing 75% forage, with either a high grass silage or high maize silage content. In Period 3, cows were fed a commercial PMR containing 69% forage. Cows were offered PMR ad libitum plus concentrates during milking and CH4 emitted by individual cows was sampled during 8662 milkings. A linear mixed model was used to assess differences among cows, feeding periods and time of day. Considerable variation was observed among cows in daily mean and diurnal patterns of CH4 emissions. On average, cows produced less CH4 when fed on the commercial PMR in feeding Period 3 than when the same cows were fed on high-forage diets in feeding Periods 1 and 2. The average diurnal pattern for CH4 emissions did not significantly change between feeding periods and as lactation progressed. Emissions of CH4 were positively associated with dry matter (DM) intake and forage DM intake. It is concluded that if the management of feed allocation remains constant then the diurnal pattern of CH4 emissions from dairy cows will not necessarily alter over time. A change in diet composition may bring about an increase or decrease in absolute emissions over a 24-h period without significantly changing the diurnal pattern unless management of feed allocation changes. These findings are important for CH4 monitoring techniques that involve taking measurements over short periods within a day rather than complete 24-h observations.

Age at first parturition in this environment occurs at approximately 18 months. The biggest cause of variation is flock with neither species nor any other source being significant. Parturition intervals for both species are approximatley 10·5 months: flock and season are significant on this variable and there is a decreasing, although non-significant, interval with advancing age. Litter size in goats is 1·25 and in sheep is 1·04, with parity and flock having significant effects for both species, while season also has an effect on goats. Annual reproduction rate is 1·42 kids and 1·19 lambs per breeding female per year.

The objectives of this study were to analyze whether dry matter intake (DMI), water intake (WI) and BW were influenced by estrus. A second objective was to determine whether correlations exist among these traits in non-estrous days. Data collection included 34 Holstein-Friesian cows from the research farm ‘Haus Riswick’ of the Agricultural Chamber North Rhine-Westphalia, Germany. On an individual basis, daily DMI and daily WI were measured automatically by a scale in the feeding trough and a WI monitoring system, respectively. BW was determined by a walk-through scale fitted with two gates – one in front and one behind the scale floor. Data were analyzed around cow’s estrus with day 0 (the day of artificial insemination leading to conception). Means during the reference period, defined as days −3 to −1 and 1 to 3, were compared with the means during estrus (day 0). DMI, WI and BW were affected by estrus. Of all cows, 85.3% and 66.7% had reduced DMI and WI, respectively, on day 0 compared with the reference period. Lower BW was detected in 69.2% of all cows relative to the reference period. During the reference period, average DMI, WI and BW were 23.0, 86.6 and 654.8 kg. A minimum DMI of 20.4 kg and a minimum BW of 644.2 kg were detected on the day of estrus, whereas the minimum WI occurred on the day before estrus. After estrus, DMI, WI and BW returned to baseline values. Intake of concentrated feed did not seem to be influenced by estrus. Positive correlations existed between daily DMI and daily WI (r=0.63) as well as between cows’ daily BW and daily WI (r=0.23). The results warrant further investigations to determine whether monitoring of DMI, WI and BW may assist in predicting estrus.

This study aimed to assess the interaction between different dietary vitamin A (dVitA) levels and the same concentration of vitamin E (100 IU all-rac-α-tocopheryl acetate/kg feed) in growing-finishing pigs. In the first experiment, two fat sources × two dVitA levels (0 v. 100 000 IU) were used. The supplementation of 100 000 IU dVitA induced a range of 5.13 to 30.03 μg retinol/g liver, 62.78 to 426.88 μg retinol palmitate/g liver, and 0.60 to 1.96 μg retinol/g fat. Dietary fat did not affect retinol or retinyl palmitate deposition in pigs. The high concentration of dVitA produced lower fat and liver α-tocopherol concentrations, and increased susceptibility of muscle tissue to oxidation. A second experiment was carried out to study the retinol and α-tocopherol retention at different withdrawal times prior to slaughter (two dVitA levels; 0 v. 100 000 IU). A high dose of 100 000 IU vitamin A during a short 2-week period was enough to induce α-tocopherol depletion in liver and fat to a similar extent as when 100 000 IU were administered during the whole fattening. Muscle, fat and liver α-tocopherol concentrations were not affected by dVitA in the 1300–13 000 IU/kg range, but liver α-tocopherol concentration was higher when vitamin A was removed from the vitamin mix 5 weeks prior to slaughter (experiment 3).

Aggression at regrouping is a common issue in pig farming. Skin lesions are genetically and phenotypically correlated with aggression and have been shown to have a significant heritable component. This study predicts the magnitude of reduction in complex aggressive behavioural traits when using lesion numbers on different body regions at two different time points as selection criteria, to identify the optimum skin lesion trait for selection purposes. In total, 1146 pigs were mixed into new social groups, and skin lesions were counted 24 h (SL24h) and 3 weeks (SL3wk) post-mixing, on the anterior, centre and posterior regions of the body. An animal model was used to estimate genetic parameters for skin lesion traits and 14 aggressive behavioural traits. Estimated breeding values (EBVs) and phenotypic values were scaled and standardised to allow direct comparison across multiple traits. Individuals with SL24h and SL3wk EBVs in the least aggressive 10% of the population were compared with the population mean to predict the expected genetic and phenotypic response in aggressive behaviour to selection. At mixing, selection for low anterior lesions was predicted to affect substantially more behavioural traits of aggressiveness than lesions obtained on other body parts, with EBVs between −0.21 and −1.17 SD below the population mean. Individuals with low central SL24h EBVs also had low EBVs for aggressive traits (−0.33 to −0.55). Individuals with high SL3wk EBVs had low EBVs for aggression at mixing (between −0.24 and −0.53 SD below the population mean), although this was predicted to affect fewer traits than selection against SL24h. These results suggest that selection against anterior SL24h would result in the greatest genetic and phenotypic reduction in aggressive behaviour recorded at mixing. Selection for increased SL3wk was predicted to reduce aggression at mixing; however, current understanding about aggressive behaviour under stable social conditions is insufficient to recommend using this trait for selection purposes.

Dairy cow mortality is an important animal welfare issue that also causes financial losses. The objective of this study was to identify farm characteristics and herd management practices associated with high on-farm cow mortality in Swedish dairy herds. A postal questionnaire was sent to farmers that had either high or low mortality rates for 3 consecutive years. The questionnaire consisted of five sections: ‘About the farm’, ‘Milking and housing’, ‘Feeding’, ‘Routines’ and ‘Lame and sick cows’. A total of 145 questionnaires were returned (response rate=33%). Ten of the 77 characteristics investigated met the inclusion criteria for multivariable analysis. The final logistic regression model included: herd size, breed, use of natural service bull, bedding improvement frequency and pasture system. Herds with Swedish Holstein as the predominant breed (odds ratio (OR) 22.9, 95% confidence interval (CI) 5.2 to 101.8) or with mixed breeds (OR 5.5, 95% CI 1.7 to 17.5) had a greater risk of being high mortality herds than herds that were predominantly Swedish Red (OR 1). Herds larger than 100 cows (OR 19.6, 95% CI 3.5 to 110.4) and herds with 50 to 99 cows (OR 13.8, 95% CI 3.2 to 60.6) had greater risk of mortality than herds numbering 35 to 50 cows (OR 1). Being a high mortality herd was also associated with having cows on exercise lots during the summer season (OR 3.6, 95% CI 1.3 to 9.9) compared with on pasture. A missing answer on the question of bedding improvement frequency was associated with high mortality herds. Overall, this study suggests that characteristics that are related to intensification of the dairy industry are also associated with high on-farm mortality of dairy cows.

The trans-10, cis-12 conjugated linoleic acid (CLA) causes milk fat depression by downregulating expression of genes and transcription factors involved in lipogenesis and it has been proposed that peroxisome proliferator-activated receptor gamma (PPARγ) can be inhibited by trans-10, cis-12 CLA. The PPARγ is a nuclear receptor activated by natural or synthetic ligands and promotes expression of lipogenic genes and its effect on mammary lipogenesis and the interaction with trans-10, cis-12 CLA in lactating ewes was evaluated using thiazolidinedione (TZD), a chemical PPARγ agonist. A total of 24 lactating ewes were randomly assigned to one of the following treatments for 7 days: (1) Control (5 ml/day of saline solution); (2) TZD (4 mg/kg of BW/day in 5 ml of saline solution); (3) CLA (27 g/day with 29.9% of trans-10, cis-12); (4) TZD+CLA. Compared with Control, milk fat content was not changed by TZD, but was decreased 22.3% and 20.5% by CLA and TZD+CLA treatments. In the mammary gland, TZD increased PPARγ gene expression by 174.8% and 207.8% compared with Control and TZD+CLA treatments, respectively. Conjugated linoleic acid reduced sterol regulatory element-binding transcription protein 1 (SREBP1) gene expression 89.2% and 75.3% compared with Control and TZD+CLA, respectively, demonstrating that TZD fails to overcome CLA inhibition of SREBP1 signaling. In adipose tissue, the expression of SREBP1 and stearoyl CoA desaturase 1 (SCD1) genes were increased by the TZD+CLA treatment, compared with the other treatments. Conjugated linoleic acid decreased milk fat concentration and expression of lipogenic genes, while TZD had no effect on milk fat concentration, expression of lipogenic enzymes or regulators in the mammary gland and failed to overcome the inhibition of these by CLA. Therefore, CLA inhibition of milk fat synthesis was independent of the PPARγ pathway in lactating dairy ewes.