Belgian Blue Research Articles

Dermatosparaxis in two Limousin calves.

BackgroundAn unusual presentation of skin disease was identified in two related neonatal Pedigree Limousin calves presented to University Veterinary Hospital, University College Dublin, following detailed post mortem examination a diagnosis of dermatosparaxis was made. Dermatosparaxis in animals or Ehlers Danlos Syndrome, which is the analogous condition seen in humans, is a connective tissue disorder characterised by extreme skin fragility. To the authors’ knowledge this is the first report of such a diagnosis in the Limousin breed and the features of this lethal phenotype were severe in comparison to previous reports of the condition.Case presentationTwo calves, which were full siblings, a pedigree Limousin bull (Calf A) and pedigree Limousin heifer (Calf B) were examined clinically after presenting collapsed since birth, both had grossly abnormal skin with multiple skin fissures visible and both calves were subsequently euthanised. Both calves underwent gross post mortem examination, after which histological samples were reviewed and electron microscopical examination of selected skin samples was carried out. Histological features of dysplastic dermal collagen were identified. The diagnosis of dermatosparaxis in the Limousin breed was confirmed. Genetic testing was conducted to determine if the current cases had the same mutation as has previously been described in Belgian Blue cattle. Some common parentage was traced but genetic testing did not show a similar mutation to that previously described in cattle. The specific genetic cause in this case is unknown.ConclusionsThis is the first report of dermatosparaxis in the Limousin and the presentation of the dermatosparaxis phenotype has some noteworthy features thus further genetic testing is required to pinpoint the causative mutation or other genetic defect. Given the popularity of the breed and the lethal nature of the phenotype in this case it is important to raise awareness of the condition.

1305 Effect of phytogenic compounds fed to preweaned calves

Maximizing early muscle growth is important in lifetime muscle development. Additionally, growth promoting antibiotics that have been typically used in the past may not be available in the future. Phytogenic (herbal) compounds may represent a potential to replace growth promoting antibiotics. A trial was conducted using Belgian Blue and Simmental bull calves in which mixed phytogenic products included in milk replacer and calf starter. Calves were separated into group based on breed and initial weight. (Control calves weighed 93 kg, Treatment calves weighed 94 kg) Calves were fed for 52 d. Control calves received a diet of calf milk replacer, for the first 3 wk. Cereal grains and a “calf starter feed” were offered from the first week on. Hay was made available throughout the trial and corn silage was offered from Day 21 to 52. Treatment calves received the same diet as control with the exception of Digestarom Milk (phytogenic product) added to the milk replacer at a rate of 500 gm/MT of calf milk replacer. The treatment calves also received Digestarom Calf in the calf starter at a rate of 300 gm/MT. Feed intake for calves was measured throughout the trial period. Calves were weighed on Days 21, 42, and 56. Data was analyzed via independent t test (SPSS). Control calves consumed numerically, but not statistically (P > 0.10) less average intake per day through out the total period, Days 1 to 56, than did treatment calves, 2.41 vs. 2.46 kg, respectively. Calves receiving Digestarom products improved in average daily gain throughout the trial at each weighing, and for the 56 d period demonstrated and increase of 0.10 kg in average daily gain (P < 0.05). Control calves gained 1.23 kg per day, while treatment calves gained at 1.33 kg per day (P < 0.05). Feed conversion improved numerically from 1.97 for control calves to 1.86 for treatment calves (P > 0.10). This work supports previous work with these and similar phytogenic products that have demonstrated a positive effect on the growth rate of neonatal and young ruminants. As such these and similar products represent a potential replacement of alternative growth promoting technologies.

0314 Introgression of the Belgian Blue Myostatin variant into Nellore cattle: Effects of double muscling on birth weight and calving ease

0314 Introgression of the Belgian Blue Myostatin variant into Nellore cattle: Effects of double muscling on birth weight and calving ease

Breed differences of bull frozen-thawed semen.

The objective of this study was to investigate the quality of frozen-thawed semen from different bull breeds. Commercial frozen-thawed bull semen samples (26 per breed, 130 totally) of five breeds (Holstein [Η], Brown Swiss [BS], Limousin [L], Belgian Blue [BB], Blonde d' Aquitaine [BA]) were used. After thawing, each semen sample was subjected to thermal resistance test (TR) for 0.5 and 1hr at 38°C and hypo-osmotic swelling test (HOST) for 1hr at 150mOsm at 37°C. Additionally, all samples were evaluated at times 0hr (thawing), 0.5hr (TR), 1hr (TR) for kinetics by CASA [progressive, immotile, rapid, medium, slow moving spermatozoa, curvilinear velocity (VCL), average path velocity (VAP), straight line velocity (VSL), linearity (LIN), straightness (STR), beat cross-frequency (BCF), amplitude of lateral head displacement (ALH), wobble (WOB)]. Moreover, directly after thawing, all semen samples were evaluated for morphometry, morphology, viability and DNA fragmentation. Statistical analysis was conducted using a mixed model for repeated measures. The results showed (a) higher VCL after thawing in H, L breeds compared to BB and BA, (b) higher VAP after thawing in L compared to BB, BA, (c) higher values of progressive spermatozoa after TR in H, BS compared to BB, BA, (d) higher values of rapid spermatozoa after thawing and 0.5hr of TR in H, BS, L compared to BB, BA, (e) lower viability in BA after thawing compared to H, BS, BB, (f) lower morphological abnormalities in H compared to L, BB, (g) higher head length in Η compared to BB. No significant differences were observed in the results from HOST and DNA fragmentation between breeds. In conclusion, quality characteristics of frozen-thawed bull semen are dependent on the breed. Frozen semen from BB and BA breeds should be handled more carefully after thawing, as it is more sensitive to stress.

P6038 Tackling the itch: GWAS-based candidate genes for psoroptic mange sensitivity in Belgian Blue cattle

P6038 Tackling the itch: GWAS-based candidate genes for psoroptic mange sensitivity in Belgian Blue cattle

MYOSTATIN GENE ANALYSIS IN THE FIRST GENERATION OF THE BELGIAN BLUE CATTLE IN INDONESIA

A study was conducted to identify the variations of the myostatin and also to evaluate the existence of genetic marker for “double muscling” (11-bp deletion in the third exon of the myostatin gene) in the first generation of Belgian Blue cattle in Indonesia using the Single Strand Conformation Polymorphism (SSCP) and the sequencing analysis. A total of 8 DNA samples belonged to Karya Anugerah Rumpin (KAR) Farm were used in the Single Strand Conformation Polymorphism (SSCP) and the sequencing analysis. There were 3 allele types of myostatin gene based on the SSCP analysis. The Belgian Blue sire has type A allele. The Simmental, Wagyu, SO x BX, Charolais, and the PO cattle have the type B allele, while the Belgian Blue x FH and the Belgian Blue x SO have the type C allele (heterozygous). There are 11-bp deletion in the third exon myostatin gene for the Belgian Blue sire based on the sequencing analysis. The myostatin gene in the Belgian Blue F1 generation individual was heterozygous. This study provides scientific evidence that the 11-bp deletion in the third exon of myostatin gene in the Belgian Blue sire was inherited to its F1 generation (male and female).

A new predilection site of Mycoplasma bovis: Postsurgical seromas in beef cattle

Mycoplasma bovis is a highly contagious bacterium, which predominantly causes chronic pneumonia, otitis and arthritis in calves and mastitis in adult cattle. In humans, Mycoplasma species have been associated with post-surgical infections. The present study aimed to identify the bacteria associated with three outbreaks of infected seromas after caesarian section in Belgian Blue beef cattle. A total of 10 cases occurred in three herds which were in close proximity of each other and shared the same veterinary practice. M. bovis could be cultured from seroma fluid in five of the six referred animals, mostly in pure culture and was isolated from multiple chronic sites of infection (arthritis and mastitis) as well. DNA fingerprinting of the isolates targeting two insertion sequence elements suggested spread of M. bovis from chronic sites of infection (udder and joints) to the postsurgical seromas. Identical genetic profiles were demonstrated in two animals from two separate farms, suggesting spread between farms. Mortality rate in the referred animals positive for M. bovis in a seroma was 80% (4/5), despite intensive treatment. A massive increase in antimicrobial use was observed in every affected farm. These observations demonstrate involvement of mycoplasmas in outbreaks of postsurgical seromas in cattle.

Evidence for placental compensation in cattle

Prenatal development is known to be extremely sensitive to maternal and environmental challenges. In this study, we hypothesize that body growth and lactation during gestation in cattle reduce nutrient availability for the pregnant uterus, with consequences for placental development. Fetal membranes of 16 growing heifers and 27 fully grown cows of the Belgian Blue (BB) breed were compared to determine the effect of body growth on placental development. Furthermore, the fetal membranes of 49 lactating Holstein Friesian (HF) cows and 27 HF heifers were compared to study the impact of dam lactation compared to dam body growth. After parturition, calf birth weight and body measurements of dam and calf were recorded, as well as weight of total fetal membranes, cotyledons and intercotyledonary membranes. All cotyledons were individually measured to calculate both the surface of each individual cotyledon and the total cotyledonary surface per placenta. Total cotyledonary surface was unaffected by breed or the breed×parity interaction. Besides a 0.3 kg lower cotyledonary weight (P=0.007), heifer placentas had a smaller total cotyledonary surface compared with placentas of cows (0.48±0.017 v. 0.54±0.014 m2, respectively, P<0.001). Within the BB breed, fetal membranes of heifers had a 1.5 kg lower total weight and 1.0 kg lower intercotyledonary membrane weight (P<0.005) compared with cows. A cotyledon number of only 91±5.4 was found in multiparous BB dams, while growing BB heifers had a higher cotyledon number (126±6.7, P<0.001), but a greater proportion of smaller cotyledons (<40 cm2). Within the HF breed, no parity effect on intercotyledonary membrane weight, cotyledon number and individual cotyledonary surface was found. Placental efficiency (calf weight/total cotyledonary surface) was similar in HF and BB heifers but significantly higher in multiparous BB compared with multiparous HF dams (106.0±20.45 v. 74.3±12.27 kg/m2, respectively, P<0.001). Furthermore, a seasonal effect on placental development was found, with winter and spring placentas having smaller cotyledons than summer and fall placentas (P<0.001). Main findings of the present study are that lactation and maternal growth during gestation entail a comparable nutrient diverting constraint, which might alter placental development. However, results suggest that the placenta is able to manage this situation through two potential compensation mechanisms. In early pregnancy the placenta might cope by establishing a higher number of cotyledons, while in late gestation a compensatory expansion of the cotyledonary surface is suggested to meet the nutrient demand of the fetus.

Variation of greenhouse gas emissions and identification of their drivers during the fattening of Belgian Blue White bulls based on a LCA approach

Greenhouse gas emission intensity (GHGI; kilograms carbon dioxide equivalents/kilograms liveweight gain) have to be reduced so as to limit the impact of human activities on global warming while furnishing food to human. In this respect, performances of 654 Belgian Blue double-muscled bulls (BBdm) during their fattening phase were recorded. On this basis, their greenhouse gas emissions were modelled to estimate variation in GHGI and investigate mitigation options at that level. The relevance of theses option is discussed, taking into account the whole life and production system scales. Large variations (mean (s.d.)) were observed (from 7.2 (0.4) to 10.0 (0.7) kg carbon dioxide equivalents/kg liveweight gain) for, respectively, the 1st- and 4th-quantile groups defined for GHGI. Early culling, low liveweight and age at start of the fattening phase of the bulls would lead to a reduction of GHGI. Nevertheless, more than 32% of the variation remained unexplained. However, decision leading to reduction of GHG intensity at this stage of the life may be compensated in the early stage of BBdm. Attention is drawn on the necessity to encompass the whole life of BBdm for investigating mitigation options and on the sensitivity of the results on models and methodological choices.

Evaluatie van twee intensieve behandelingsschema’s tegen Psoroptes ovis-schurft bij Belgisch witblauwe runderen op negen Vlaamse rundveebedrijven

Schurft veroorzaakt door Psoroptes ovis komt voor op de meeste Vlaamse bedrijven met Belgisch witblauw vleesvee. In deze studie werden twee intensieve behandelingsschema’s geëvalueerd op negen Vlaamse vleesveebedrijven met een persisterend schurftprobleem. Op bedrijf 1 tot en met 7 werden alle dieren tweemaal behandeld (met een interval van zeven à tien dagen) met een injecteerbaar macrocyclisch lacton (ML). Op de twee laatste bedrijven werd een eenmalige injectie gegeven met de ‘long acting’-formulatie (LA) van moxidectine (10%). Na behandeling werden huidafkrabsels genomen en bij de aanwezigheid van levende mijten bij ten minste één dier werden alle dieren (bedrijven 1 tot en met 7) of enkel de positieve dieren (bedrijf 8 en 9) verder behandeld met een injecteerbaar ML. Op alle bedrijven waren de dieren klinisch genezen en schijnbaar vrij van mijten na twee tot negen behandelingsrondes (twee injecties met zeven à tien dagen interval of één LA-injectie). Hoewel er op de eerste zeven bedrijven na het daaropvolgende weideseizoen opnieuw tekenen van schurft te zien waren, was dit in mindere mate en de schurft was gemakkelijker onder controle te houden.

Comparative immune responses against Psoroptes ovis in two cattle breeds with different susceptibility to mange.

The sheep scab mite, Psoroptes ovis, is a major problem in the beef cattle industry, especially in Belgian Blue (BB) cattle. This breed is naturally more predisposed to psoroptic mange but reasons for this high susceptibility remain unknown. Different immune responses could be a potential cause; thus in this study, the cutaneous immune response and in vitro cellular immune response after antigen re-stimulation were examined in naturally infested BB. Cytokine production in the skin and in circulating re-stimulated peripheral blood mononuclear cells (PBMC) demonstrated a mixed pro-inflammatory Th2/Th17 profile, with transcription of IL-4, IL-13, IL-6 and IL-17. Strong IL-17 up-regulation in the skin of BB was associated with an influx of eosinophils and other immune cells, potentially leading towards more severe symptoms. Virtually no changes in cutaneous IFN-γ transcription were detected, while there was substantial IFN-γ up-regulation in re-stimulated PBMC from infested and uninfested animals, potentially indicating a role of this pro-inflammatory cytokine in the innate immune response. In Holstein–Friesian (HF) cattle, generally more resistant to P. ovis infection, a largely similar immunologic response was observed. Differences between HF and BB were the lack of cutaneous IL-17 response in infested HF and low transcription levels of IFN-γ and high IL-10 transcription in re-stimulated PBMC from both infested and uninfested animals. Further research is needed to identify potential cell sources and biological functions for these cytokines and to fully unravel the basis of this different breed susceptibility to P. ovis.

Reverse genetic screen for loss-of-function mutations uncovers a frameshifting deletion in the melanophilin gene accountable for a distinctive coat color in Belgian Blue cattle.

In the course of a reverse genetic screen in the Belgian Blue cattle breed, we uncovered a 10-bp deletion (c.87_96del) in the first coding exon of the melanophilin gene (MLPH), which introduces a premature stop codon (p.Glu32Aspfs*1) in the same exon, truncating 94% of the protein. Recessive damaging mutations in the MLPH gene are well known to cause skin, hair, coat or plumage color dilution phenotypes in numerous species, including human, mice, dog, cat, mink, rabbit, chicken and quail. Large-scale array genotyping undertaken to identify p.Glu32Aspfs*1 homozygous mutant animals revealed a mutation frequency of 5% in the breed and allowed for the identification of 10 homozygous mutants. As expression of a colored coat requires at least one wild-type allele at the co-dominant Roan locus encoded by the KIT ligand gene (KITLG), homozygous mutants for p.Ala227Asp corresponding with the missense mutation were excluded. The six remaining colored calves displayed a distinctive dilution phenotype as anticipated. This new coat color was named 'cool gray'. It is the first damaging mutation in the MLPH gene described in cattle and extends the already long list of species with diluted color due to recessive mutations in MLPH and broadens the color palette of gray in this breed.

A stop-gain in the laminin, alpha 3 gene causes recessive junctional epidermolysis bullosa in Belgian Blue cattle.

Four newborn purebred Belgian Blue calves presenting a severe form of epidermolysis bullosa were recently referred to our heredo-surveillance platform. SNP array genotyping followed by autozygosity mapping located the causative gene in a 8.3-Mb interval on bovine chromosome 24. Combining information from (i) whole-genome sequencing of an affected calf, (ii) transcriptomic data from a panel of tissues and (iii) a list of functionally ranked positional candidates pinpointed a private G to A nucleotide substitution in the LAMA3 gene that creates a premature stop codon (p.Arg2609*) in exon 60, truncating 22% of the corresponding protein. The LAMA3 gene encodes the alpha 3 subunit of the heterotrimeric laminin-332, a key constituent of the lamina lucida that is part of the skin basement membrane connecting epidermis and dermis layers. Homozygous loss-of-function mutations in this gene are known to cause severe junctional epidermolysis bullosa in human, mice, horse, sheep and dog. Overall, our data strongly support the causality of the identified gene and mutation.

Fast-twitch skeletal muscle fiber adaptation to SERCA1 deficiency in a Dutch Improved Red and White calf pseudomyotonia case

Missense mutations in ATP2A1 gene, encoding SERCA1 protein, cause a muscle disorder designed as congenital pseudomyotonia (PMT) in Chianina and Romagnola cattle or congenital muscular dystonia1 (CMD1) in Belgian Blue cattle. Although PMT is not life-threatening, CMD1 affected calves usually die within a few weeks of age as a result of respiratory complication. We have recently described a muscular disorder in a double muscle Dutch Improved Red and White cross-breed calf. Mutation analysis revealed an ATP2A1 mutation identical to that described in CMD1, even though clinical phenotype was quite similar to that of PMT. Here, we provide evidence for a deficiency of mutated SERCA1 in PMT affected muscles of Dutch Improved Red and White calf, but not of its mRNA. The reduced expression of SERCA1 is selective and not compensated by the SERCA2 isoform. By contrast, pathological muscles are characterized by a broad distribution of mitochondrial markers in all fiber types, not related to intrinsic features of double muscle phenotype and by an increased expression of sarcolemmal calcium extrusion pump. Calcium removal mechanisms, operating in muscle fibers as compensatory response aimed at lowering excessive cytoplasmic calcium concentration caused by SERCA1 deficiency, could explain the difference in severity of clinical signs.

Non-haemolytic Mannheimia haemolytica as a cause of pleuropneumonia and septicemia in a calf

Pure cultures of non-haemolytic Mannheimia haemolytica, were cultivated from pleural effusion fluid and blood from a 1-month old Belgian Blue bull calf that was presented with apathy and anorexia. The isolates were identified as M. haemolytica by 16S rRNA gene sequencing and MALDI-TOF-MS. Since haemolysis on blood agar plates is considered a hallmark of M. haemolytica we wanted to elucidate the unusual phenotype of the isolated strain. Therefore the leukotoxin operon (lktCABD), responsible for the haemolytic phenotype of M. haemolytica and regarded as the most important virulence factor, was completely sequenced. The leukotoxin operon of the isolated strain showed a deletion in the lktA gene, resulting in a truncated LktA protein. The absence of a complete LktA protein is responsible for the non-haemolytic phenotype of the strain. To the best of our knowledge, this is the first report of a well-characterized non-haemolytic M. haemolytica isolate causing disease in cattle.

Detection of selection signatures in dairy and beef cattle using high-density genomic information.

BackgroundArtificial selection for economically important traits in cattle is expected to have left distinctive selection signatures on the genome. Access to high-density genotypes facilitates the accurate identification of genomic regions that have undergone positive selection. These findings help to better elucidate the mechanisms of selection and to identify candidate genes of interest to breeding programs.ResultsInformation on 705 243 autosomal single nucleotide polymorphisms (SNPs) in 3122 dairy and beef male animals from seven cattle breeds (Angus, Belgian Blue, Charolais, Hereford, Holstein-Friesian, Limousin and Simmental) were used to detect selection signatures by applying two complementary methods, integrated haplotype score (iHS) and global fixation index (FST). To control for false positive results, we used false discovery rate (FDR) adjustment to calculate adjusted iHS within each breed and the genome-wide significance level was about 0.003. Using the iHS method, 83, 92, 91, 101, 85, 101 and 86 significant genomic regions were detected for Angus, Belgian Blue, Charolais, Hereford, Holstein-Friesian, Limousin and Simmental cattle, respectively. None of these regions was common to all seven breeds. Using the FST approach, 704 individual SNPs were detected across breeds. Annotation of the regions of the genome that showed selection signatures revealed several interesting candidate genes i.e. DGAT1, ABCG2, MSTN, CAPN3, FABP3, CHCHD7, PLAG1, JAZF1, PRKG2, ACTC1, TBC1D1, GHR, BMP2, TSG1, LYN, KIT and MC1R that play a role in milk production, reproduction, body size, muscle formation or coat color. Fifty-seven common candidate genes were found by both the iHS and global FST methods across the seven breeds. Moreover, many novel genomic regions and genes were detected within the regions that showed selection signatures; for some candidate genes, signatures of positive selection exist in the human genome. Multilevel bioinformatic analyses of the detected candidate genes suggested that the PPAR pathway may have been subjected to positive selection.ConclusionsThis study provides a high-resolution bovine genomic map of positive selection signatures that are either specific to one breed or common to a subset of the seven breeds analyzed. Our results will contribute to the detection of functional candidate genes that have undergone positive selection in future studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12711-015-0127-3) contains supplementary material, which is available to authorized users.

Genome-wide next-generation DNA and RNA sequencing reveals a mutation that perturbs splicing of the phosphatidylinositol glycan anchor biosynthesis class H gene (PIGH) and causes arthrogryposis in Belgian Blue cattle.

BackgroundCattle populations are characterized by regular outburst of genetic defects as a result of the extensive use of elite sires. The causative genes and mutations can nowadays be rapidly identified by means of genome-wide association studies combined with next generation DNA sequencing, provided that the causative mutations are conventional loss-of-function variants. We show in this work how the combined use of next generation DNA and RNA sequencing allows for the rapid identification of otherwise difficult to identify splice-site variants.ResultsWe report the use of haplotype-based association mapping to identify a locus on bovine chromosome 10 that underlies autosomal recessive arthrogryposis in Belgian Blue Cattle. We identify 31 candidate mutations by resequencing the genome of four cases and 15 controls at ~10-fold depth. By analyzing RNA-Seq data from a carrier fetus, we observe skipping of the second exon of the PIGH gene, which we confirm by RT-PCR to be fully penetrant in tissues from affected calves. We identify - amongst the 31 candidate variants - a C-to-G transversion in the first intron of the PIGH gene (c211-10C > G) that is predicted to affect its acceptor splice-site. The resulting PIGH protein is likely to be non-functional as it lacks essential domains, and hence to cause arthrogryposis.ConclusionsThis work illustrates how the growing arsenal of genome exploration tools continues to accelerate the identification of an even broader range of disease causing mutations, therefore improving the management and control of genetic defects in livestock.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1528-y) contains supplementary material, which is available to authorized users.

Meat composition and quality of young growing Belgian Blue bulls offered a fattening diet with selenium enriched cereals

Mehdi, Y., Clinquart, A., Hornick, J.-L., Cabaraux, J.-F., Istasse, L. and Dufrasne, I. 2015. Meat composition and quality of young growing Belgian Blue bulls offered a fattening diet with selenium enriched cereals. Can. J. Anim. Sci. 95: 465–473. The objective of this study was to evaluate the effects of selenium (Se) enrichment of cereals on the performance of Belgian Blue bulls, meat quality and chemical composition. Twenty-three bulls were used in the present study. Twelve bulls were offered a control diet containing Se at a basal concentration of 58 µg kg−1of dry matter (DM) and the other 11 bulls were given a diet containing 173 µg kg−1DM of Se by means of Se-enriched spelt and barley. The Se enrichment of the diet did not affect the growth performance, the slaughter data or meat quality (P &gt; 0.05). There were no effects of Se on tenderness, oxidative rancidity and water losses. However, there were some effects of Se enrichment on the meat chemical composition. The ether extract was decreased from 2.1 to 1.7% DM (P&lt;0.05). There was also significant Se enrichment (P&lt;0.001) in the longissimus thoracis muscle (177 vs. 477 ng g−1DM) and organs: liver (474 vs. 1126 ng g−1DM) and kidney (4956 vs. 5655 ng g−1DM), Under such conditions, the human consumption of a piece of such meat or liver can provide a large part of the recommended daily Se intake, estimated between 30 and 57%.

Effect of crossbreeding with Limousine, Rubia Gallega and Belgium Blue on meat quality and fatty acid profile of Holstein calves.

The object of this work was to study the effects of crossbreeding on meat quality and fatty acid profile of Holstein calves. Samples were taken from Longissimus thoracis (LT) muscle of 36 calves of three different groups (Holstein crossed with Rubia Gallega (HF×RG), Holstein crossed with Limousine (HF×LI) and Holstein crossed with Belgian Blue (HF×BB)). Significant differences were observed in carcass weight and killing out percentage (P < 0.001) among, groups reaching the highest values in the HF×BB group (228 kg and 59.4%, respectively), while the cross with Limousine presented the lowest values for carcass weight (191 kg) and the cross with Rubia Gallega showed the lowest killing out percentages (54.9%). Meat from HF×RG animals was redder (a* 13.31) and lightest (L* 39.55) than meat from HF×LI and HF×BB groups. With regard to fatty acid profile, the saturated fatty acids were the most abundant fatty acid, followed by monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids in the three groups. Crossbreeding did not affect the proportion of fatty acid. Finally, live weight, cold carcass weight, killing out, shear force, L* from LT, b*from LT, a* from fat, b* from fat, C14:0, C15:0, C16:0, C18:0, C18:3n-6, MUFA and price-to-sales ratio were the selected variables from discriminant analysis to classify the types of crossbreeding.

Effect of summer conditions and shade on behavioural indicators of thermal discomfort in Holstein dairy and Belgian Blue beef cattle on pasture

Using behavioural indicators of thermal discomfort, that is, shade seeking, panting scores (PS) and respiration rate (RR), we evaluated the effect of hot summer conditions and shade, for a herd of adult Holstein dairy cows and a herd of Belgian Blue beef cows kept on pasture in a temperate area (Belgium). During the summer of 2012, both herds were kept on pasture without access to shade (NS). During the summers of 2011 and 2013 each herd was divided into one group with (S) and one without (NS) access to shade. Shade was provided by young trees with shade cloth (80% reduction in solar radiation) hung between them. For S cows, we investigated how shade use was related to hot conditions as quantified by six climatic indices. The heat load index (HLI), which incorporates air temperature and humidity, solar radiation and wind speed, was the best predictor of the six indices tested. In 2011, there was a relatively high threshold for use of shade. When HLI=90, shade use probability reached 17% for dairy cows and 27% for beef cows. In 2013, however, at HLI=90, shade use probability reached 48% for dairy cows and 41% for beef cows. For animals from the NS treatment we determined the effect of hot summer conditions on RR and PS (with 0=no panting and 4.5=extreme panting). In both types of cattle, an increase in black globe temperature was the best predictor for increasing RR and PS. Furthermore, we determined how the effect of hot summer conditions on RR and PS was affected by the use of shade. Under hot conditions (black globe temperature ⩾30°C), >50% of the animals under shade retained normal PS and RR (PS<1 and RR<90 breaths per minute), whereas normal RR and PS were significantly less prevalent for animals outside shade. Our findings suggest that, even in temperate summers, heat can induce thermal discomfort in cattle, as evidenced by increases in shade use, RR and PS, and that shade increases thermal comfort.