Effect of dietary restriction and compensatory growth on performance, carcass characteristics, and metabolic hormone concentrations in Angus and Belgian Blue steers.

Compensatory growth (CG) is the ability of an animal to undergo accelerated growth after a period of restricted feeding. However, there is a dearth of information in relation to the effect of genotype on CG response, thus the objective of this study was to evaluate CG response in two contrasting breed types, namely Aberdeen Angus (AN) and Belgian Blue (BB). Crossbred AN × Holstein-Friesian or BB × Holstein-Friesian steers were assigned to one of two treatment groups in a two (genotypes) × two (diets) factorial design. For 99 days, one group (11 AN and 12 BB) was offered a high energy control diet (H-H) whereas the second group (11 AN and 12 BB) was offered an energy restricted diet (L-H). At the end of the differential feeding period (99 days), both groups of animals were then offered a high energy control diet for a further 200 days. All animals were then slaughtered on day-299 of the study. During feed restriction, L-H had lower DM intake (DMI), had greater feed conversion ratio (FCR) and lower plasma concentrations of insulin, IGF-1, leptin, glucose, urea, betahydroxybutyrate and smaller M. longissimus thoracis or lumborum muscle and fat depths compared to H-H steers. During realimentation, there was no difference in DMI between diets; however, L-H had greater live weight gain compared to H-H steers. Overall, H-H consumed greater quantities on a DM basis, however, had a higher FCR compared to L-H steers. By the end of the realimentation period, there was no difference in plasma metabolite or hormone concentrations, linear body measurements, ultrasonically scanned fat depths, carcass conformation, dressing percentage or fat class between H-H and L-H steers. At slaughter, carcass weights were affected by diet with greater values for H-H compared to L-H steers. Genotype affected measures associated with body composition including pelvic width and both muscle and fat depths (P < 0.05). Overall, L-H had a CG (or recovery) index of 0.52 and did not make up for the loss of gains during the differential feeding period; however, M. longissimus thoracis et lumborum, a tissue of high economic value, recovered completely making it a target of interest for further investigation.

Risk of malignancy in resected pancreatic mucinous cystic neoplasms.

BACKGROUND: Pancreatic mucinous cystic neoplasms (MCNs) are rare mucin-producing cystic tumours defined by the presence of ovarian-type stroma. MCNs have a malignant potential and thus surgery is frequently performed. The aim of this cohort study was to define better the criteria for surgical resection in patients with MCN. METHODS: This multicentre retrospective study included all resected MCNs between 2003 and 2015 in participating centres. Lesions without ovarian-type stroma were excluded. Patient characteristics, preoperative findings, histopathology findings and follow-up data were recorded. RESULTS: The study included 211 patients; their median age was 53 (range 18-82) years, and 202 (95·7 per cent) were women. Median preoperative tumour size was 55 (range 12-230) mm. Thirty-four of the 211 (16·1 per cent) were malignant, and high-grade dysplasia (HGD) was found in a further 13 (6·2 per cent). One-third of MCNs in men were associated with invasive cancer, compared with 15·3 per cent in women. Five cases of malignant transformation occurred in MCNs smaller than 4 cm. All cases of malignancy or HGD were associated with symptoms or features of concern on preoperative cross-sectional imaging. In multivariable analysis, raised carbohydrate antigen 19-9 (odds ratio (OR) 10·54, 95 per cent c.i. 2·85 to 218·23; P < 0·001), tumour size (OR 4·23, 3·02 to 11·03; P = 0·001), mural nodules (OR 3·55, 1·31 to 20·55; P = 0·002) and weight loss (OR 3·40, 2·34 to 12·34; P = 0·034) were independent factors predictive of malignant transformation. CONCLUSIONS: Small indeterminate MCNs with no symptoms or features of concern may safely be observed as they have a low risk of malignant transformation.

Compensatory growth in crossbred Aberdeen Angus and Belgian Blue steers: Effects on the colour, shear force and sensory characteristics of longissimus muscle.

The effect of feed restriction (99days) followed by compensatory growth during a 200day re-alimentation period on the colour and sensory characteristics of meat from Aberdeen Angus×Holstein-Friesian (AN) and Belgian Blue×Holstein-Friesian (BB) steers was examined. Compensatory growth had no effect on muscle pH and temperature decline, chemical composition, drip loss, fat colour, or juiciness, but increased (P=0.009) Warner-Bratzler shear force and decreased tenderness (P=0.08) and overall liking (P=0.09). Compared to meat from BB steers, meat from AN steers had a higher intramuscular fat concentration and was rated similarly for tenderness, but higher for many of the flavour characteristics examined. While adjustment for intramuscular fat concentration removed some of these differences, genotype-specific flavour differences remained. It is concluded that genotype had greater effects on meat quality than the compensatory growth feeding regime imposed in this study.

A case-control study comparing the incidence of early symptoms in pancreatic and biliary tract cancer.

OBJECTIVES: Pancreatic ductal adenocarcinoma (PDAC) and biliary tract cancers (BTC) are often diagnosed late and at an advanced stage. Population-based screening programmes do not exist and diagnosis is primarily dependent on symptom recognition. Recently symptom-based cancer decision support tools (CDSTs) have been introduced into primary care practices throughout the UK to support general practitioners (GPs) in identifying patients with suspected PDAC. However, future refinement of these tools to improve their diagnostic accuracy is likely to be necessary. SETTING: The Health Improvement Network (THIN) is a primary care database, which includes more than 11 million electronic patient records, from 562 GP practices in the UK. PARTICIPANTS: All patients with a diagnosis of PDAC or BTC between 2000 and 2010 were included in the study along with six matched controls; 2773 patients with PDAC, 848 patients with BTC and 15,395 controls. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary aim of this study was to determine the early symptom profiles of PDAC and BTC. Secondary aims included comparing early symptom trends between BTC and PDAC, defining symptom onset in PDAC and evaluating trends in routine blood tests nearest to the time of diagnosis. RESULTS: In the year prior to diagnosis, patients with PDAC visited their GP on a median of 18 (IQR 11-27) occasions. PDAC was associated with 11 alarm symptoms and BTC with 8. Back pain (OR 1.33 (95% CI 1.18 to 1.49) p<0.001), lethargy (1.42 (95% CI 1.25 to 1.62) p<0.001) and new onset diabetes (OR 2.46 (95% CI 2.16 to 2.80)) were identified as unique features of PDAC. CONCLUSIONS: PDAC and BTC are associated with numerous early alarm symptoms. CDSTs are therefore likely to be useful in identifying these tumours at an early stage. Inclusion of unique symptoms, symptoms with an early onset and routinely performed blood tests is likely to further improve the sensitivity of these tools.

Update on the management of cholangiocarcinoma.

Cholangiocarcinoma (CC) is a rare cancer arising from the epithelium of the biliary tree, anywhere from the small peripheral hepatic ducts to the distal common bile duct. Classification systems for CC typically group tumours by anatomical location into intrahepatic, hilar or extrahepatic subtypes. Surgical resection or liver transplantation remains the only curative therapy for CC, but up to 80% of patients present with advanced, irresectable disease. Unresectable CC remains resistant to many chemotherapeutic agents, although gemcitabine, particularly in combination with other agents, has been shown to improve overall survival. Ongoing investigation of biological agents has also yielded some promising results. Several novel interventional and endoscopic techniques for the diagnosis and management of non-operable CC have been developed: initial results show improvements in symptoms and progression-free survival, but further randomised studies are required to establish their role in the management of CC.

Proteomic profiling of bovine M. longissimus lumborum from Crossbred Aberdeen Angus and Belgian Blue sired steers varying in genetic merit for carcass weight.

Bovine skeletal muscle is a tissue of significant value to the beef industry and global economy. Proteomic analyses offer the opportunity to detect molecular mechanisms regulating muscle growth and intramuscular fat accumulation. The current study aimed to investigate differences in protein abundance in skeletal muscle tissue of cattle from two breeds of contrasting maturity (early vs. late maturing), adiposity, and muscle growth potential, namely, Belgian Blue (BB) × Holstein Friesian and Aberdeen Angus (AA) × Holstein Friesian. Twenty AA (n = 10) and BB (n = 10) sired steers, the progeny of sires of either high or low genetic merit, expressed as expected progeny difference for carcass weight (EPDcwt), and bred through AI, were evaluated as 4 genetic groups, BB-High, BB-Low, AA-High, and AA-Low (n = 5 per treatment). Chemical composition analysis of M. longissimus lumborum showed greater protein and moisture and decreased lipid concentrations for BB-sired compared with AA-sired steers. To investigate the effects of both sire breed and EPDcwt on M. longissimus lumborum, proteomic analysis was performed using 2-dimensional difference gel electrophoresis followed by mass spectrometry. Proteins were identified from their peptide sequences, using the National Center for Biotechnology Information (NCBI) and Swiss-prot databases. Metabolic enzymes involved in glycolysis (glycogen phosphorylase, phosphoglycerate mutase) and the citric acid cycle (aconitase 2, oxoglutarate dehydrogenase) were increased in AA- vs. BB-sired steers. Expression of proteins involved in cell structure, such as myosin light chain isoforms and troponins I and T, were also altered due to sire breed. Furthermore, heat shock protein ß-1 and peroxiredoxin 6, involved in cell defense, had increased abundance in muscle of AA-sired relative to BB-sired steers. Protein abundance of glucose-6-phosphate isomerase, enolase-3, and pyruvate kinase was greater in AA-sired animals of High compared with Low EPDcwt. Changes in the expression of these proteins were supported by gene expression analysis using quantitative real-time PCR. This information will aid in our understanding of genetic influences controlling muscle growth and fat accumulation and could contribute to future breeding programs to increase lean tissue gain of beef cattle.

Effect of sire breed and genetic merit for carcass weight on the transcriptional regulation of the somatotropic axis in longissimus dorsi of crossbred steers.

The somatotropic axis plays an important role in postnatal growth, development, and differentiation of skeletal muscle. The aim of this study was to examine the effect of sire breed and sire EPD for carcass weight (EPD(cwt)) on the expression of components of the somatotropic axis in LM of beef cattle at slaughter. Crossbred Aberdeen Angus (AA; n = 17) and Belgian Blue (BB; n = 16) steers born to Holstein-Friesian dams and sired by bulls with either high (H) or low (L) EPD(cwt) were used in the study. Thus, there were 4 genetic groups [i.e., BBH (n = 8), BBL (n = 8), AAH (n = 8), and AAL (n = 9)]. Blood samples were collected via jugular venipuncture at regular intervals for analysis of plasma concentrations of IGF-1 and insulin. Total RNA was isolated from LM collected at slaughter, and the mRNA expression of IGF-1, IGF-2, their receptors (IGF-1R; IGF-2R), 6 IGFBP, acid labile subunit (ALS), and GH receptor (GHR) was measured by real-time reverse-transcription quantitative PCR. There was no effect of either sire breed or EPD(cwt) on concentrations of circulating IGF or insulin (P > 0.05). Gene expression of IGF-1R and IGFBP3 was upregulated in AA (P < 0.001) compared with BB, whereas IGF-1 was upregulated in H compared with L animals (P < 0.01). Correlation analysis indicated moderate positive associations between gene expression of IGFBP3 and IGF-1 (r = 0.54; P < 0.001) and IGF-1R (r = 0.48; P < 0.01). In addition, correlation analysis revealed that mRNA expression of IGFBP3 was moderately negatively associated with LM area per kilogram of carcass weight (r = -0.40; P < 0.05). Greater gene expression of IGF-1 and reduced transcript abundance of IGFBP3 in muscle may have a role in increased muscle growth potential in steers during the finishing period. These data will contribute to a better understanding of the molecular control of muscle growth at a tissue level in cattle.

Effects of genetic merit for carcass weight, breed type and slaughter weight on performance and carcass traits of beef × dairy steers.

Crossbreeding of Holstein-Friesian dairy cows with both early maturing (e.g. Aberdeen Angus (AA)) and late maturing (e.g. Belgian Blue (BB)) beef breeds is commonly practised. In Ireland, genetic merit for growth rate of beef sires is expressed as expected progeny difference for carcass weight (EPD(CWT)). The objective of this study was to compare the progeny of Holstein-Friesian cows, sired by AA and BB bulls of low (L) and high (H) EPD(CWT) for performance and carcass traits. A total of 118 spring-born male progeny from 20 (9 AA and 11 BB) sires (8 L and 12 H) were managed together from shortly after birth to about 19 months of age. They were then assigned to one of two mean slaughter weights (560 kg (light) or 620 kg (heavy)). Following slaughter, carcasses were graded for conformation class and fat class, the 6th to 10th ribs joint was dissected as an indicator of carcass composition, and samples of subcutaneous fat and musculus longissimus were subjected to Hunterlab colour measurements. A sample of m. longissimus was also chemically analysed. Slaughter and carcass weights per day of age for AAL, AAH, BBL and BBH were 747, 789, 790 and 805 (s.e. 10.5) g, and 385, 411, 427 and 443 (s.e. 4.4) g, respectively. Corresponding carcass weight, kill-out proportion, carcass conformation class (scale 1 to 5) and carcass fat class (scale 1 to 5) values were 289, 312, 320 and 333 (s.e. 4.0) kg, 516, 522, 542 and 553 (s.e. 3.5) g/kg, 2.5, 2.4, 3.0 and 3.1 (s.e. 0.10), and 3.4, 3.5, 2.9 and 2.8 (s.e. 0.11). There were few breed type × genetic merit interactions. Delaying slaughter date increased slaughter weight, carcass weight and all measures of fatness. It also reduced the proportion of carcass weight in the hind quarter and the proportions of bone and muscle in the ribs joint. None of these effects accompanied the increase in carcass weight due to higher EPD(CWT). It is concluded that BB have superior production traits to AA. Selection of sires for higher EPD(CWT) increases growth rate, kill-out proportion and carcass weight of progeny with little effect on carcass or muscle traits. The extra carcass weight due to higher EPD(CWT) is more valuable commercially than a comparable carcass weight increment from a delay in slaughter date because it comprises a higher proportion of muscle.

Predicting beef carcass meat, fat and bone proportions from carcass conformation and fat scores or hindquarter dissection.

Equations for predicting the meat, fat and bone proportions in beef carcasses using the European Union carcass classification scores for conformation and fatness, and hindquarter composition were developed and their accuracy was tested using data from 662 cattle. The animals included bulls, steers and heifers, and comprised of Holstein-Friesian, early- and late-maturing breeds × Holstein-Friesian, early-maturing × early-maturing, late-maturing × early-maturing and genotypes with 0.75 or greater late-maturing ancestry. Bulls, heifers and steers were slaughtered at 15, 20 and 24 months of age, respectively. The diet offered before slaughter includes grass silage only, grass or maize silage plus supplementary concentrates, or concentrates offered ad libitum plus 1 kg of roughage dry matter per head daily. Following the slaughter, carcasses were classified mechanically for conformation and fatness (scale 1 to 15), and the right side of each carcass was dissected into meat, fat and bone. Carcass conformation score ranged from 4.7 to 14.4, 5.4 to 10.9 and 2.0 to 12.0 for bulls, heifers and steers, respectively; the corresponding ranges for fat score were 2.7 to 11.5, 3.2 to 11.3 and 2.8 to 13.3. Prediction equations for carcass meat, fat and bone proportions were developed using multiple regression, with carcass conformation and fat score both included as continuous independent variables. In a separate series of analyses, the independent variable in the model was the proportion of the trait under investigation (meat, fat or bone) in the hindquarter. In both analyses, interactions between the independent variables and gender were tested. The predictive ability of the developed equations was assed using cross-validation on all 662 animals. Carcass classification scores accounted for 0.73, 0.67 and 0.71 of the total variation in carcass meat, fat and bone proportions, respectively, across all 662 animals. The corresponding values using hindquarter meat, fat and bone in the model were 0.93, 0.87 and 0.89, respectively. The bias of the prediction equations when applied across all animals was not different from zero, but bias did exist among some of the genotypes of animals present. In conclusion, carcass classification scores and hindquarter composition are accurate and efficient predictors of carcass meat, fat and bone proportions.

Genetic parameters for carcass cut weight in Irish beef cattle.

The objective of this study was to estimate genetic parameters for the weights of different wholesale cuts, using an experimental and a commercial data set. The experimental and commercial data sets included 413 and 635 crossbred Belgian Blue, Charolais, Limousin, Angus, Holstein, and Simmental animals, respectively. Univariate analyses using a mixed linear animal model with relationships were undertaken to estimate the heritability of cold carcass weight, carcass conformation and fat, and the cut weights, whereas a series of bivariate analyses was used to estimate the phenotypic and genetic correlations between carcass weight, carcass conformation, carcass fat, and the major primal cuts. Heritability estimates for cold carcass weight in both data sets were moderate (>0.48), whereas heritability estimates for carcass conformation and fat grading were greater in the commercial data set (>0.63) than in the experimental study (>0.33). Across both data sets, heritability estimates for wholesale cut weight in the forequarter varied from 0.03 to 0.79, whereas heritability estimates of carcass cut weight in the hindquarter varied from 0.14 to 0.86. Heritability estimates for cut weights expressed as a proportion of the entire carcass weight varied from 0.04 to 0.91. Genetic correlations were strong among the different carcass cut weights within the experimental and the commercial studies. Genetic correlations between the weights of selected carcass cuts and carcass weight were moderate to high (minimum 0.45; maximum 0.88) in both data sets. Positive genetic correlations were observed in the commercial data set between the different wholesale cut weights and carcass conformation, whereas these were positive and negative in the experimental data set. Selection for increased carcass weight will, on average, increase the weight of each cut. However, the genetic correlations were less than unity, suggesting a benefit of more direct selection on high value cuts.

Estimation of accuracy and bias in genetic evaluations with genetic groups using sampling.

Accuracy and bias of EBV are important measures of the quality of genetic evaluations. A sampling method that accounts for the uncertainty in the estimation of genetic group effects was used to calculate accuracy and bias of estimated effects. The method works by repeatedly simulating phenotypes for multiple traits for a defined data and pedigree structure. These simulated values are analyzed using BLUP with genetic groups in the relationship matrix. Accuracies and biases are then calculated as correlations among and differences between true and estimated values across all replicates, respectively. The method was applied to the Irish beef production data set for 15 traits and with 15 genetic groups to account for differences in breed means. Accuracy and bias of estimated genetic group effects, estimated comparisons between genetic group effects, EBV within genetic group, and EBV across genetic group were calculated. Small biases were detected for most estimated genetic group effects and most estimated comparisons between genetic group effects. Most of these were not important relative to the phenotypic SD of the traits involved. For example, a bias of 0.78% of the phenotypic SD was detected for carcass conformation in Aberdeen Angus. However, one trait, calf quality, which had few performance records in the data set, displayed larger bias, ranging from -10.31 to 5.85% of the phenotypic SD across the different estimated genetic group effects. Large differences were observed in the accuracies of genetic group effects, ranging from 0.02 for feed intake in Holstein, which had no data recorded, to >0.97 for carcass conformation, a trait with large amounts of data recorded in the different genetic groups. Large differences were also observed in the accuracies of the comparisons among genetic group effects. The accuracies of the EBV within genetic group and EBV across genetic group were sometimes different; for example, carcass conformation in Belgian Blue had an average accuracy within genetic group of 0.69 compared with an average accuracy across genetic group of 0.89. This suggests that the accuracy of genetic groups should be taken into account when publishing EBV across genetic groups.

Fatty acid composition of M. Longissimus dorsi from Holstein-Friesian steers of New Zealand and European/American descent and from Belgian Blue×Holstein-Friesian steers, slaughtered at two weights/ages.

Our objective was to determine the effect of breed (B) and slaughter age/weight on the fatty acid composition, particularly the conjugated linoleic acid (CLA) concentration of beef. Two strains of a dairy breed [Holstein-Friesian (HF) (n=16 steers/strain)] and a late-maturing breed [Belgian Blue×Holstein-Friesian (BB) (n=16 steers)] were used. The HF strains were either of New Zealand (NZ) or European-American (EU) descent (selected in a grazed grass or a high concentrate nutritional environment, respectively). Animals were grown from calves to either a light (L; 560kg) or heavy (H; 630kg) target slaughter weight. Samples of M. longissimus dorsi were collected post-slaughter, lipids were separated into neutral (NL) and polar (PL) fractions, and fatty acid composition determined by gas-chromatography. The total fatty acid concentration and the concentrations of cis9, trans11 CLA, total CLA, MUFA and SFA in total intramuscular lipids were lower and the P:S ratio higher for BB than NZ or EU which did not differ. These differences largely reflected the changes in NL. The C18 desaturase index was higher for NZ than EU but EU did not differ from BB. Increasing slaughter weight/age increased the total fatty acid concentration and the concentrations cis9, trans11 CLA (P=0.06), total CLA (P=0.06), trans11 C18:1, MUFA and SFA and the C18 desaturase index and decreased the P:S ratio. The n-6:n-3 PUFA ratio was similar at the lighter slaughter weight/age for the three breeds/strains but increased for NZ and EU with increasing slaughter weight/age but was not affected in BB. It is concluded that the CLA concentration largely reflected muscle fatness but that increasing slaughter weight/age differentially affected the n-6:n-3 PUFA ratio of beef from early and late-maturing cattle.

Energy supply patterns for finishing steers: Feed conversion efficiency, components of bodyweight gain and meat quality.

The objective was to determine the effect of pre-slaughter growth rate on feed efficiency, components of body growth and on the tenderness of longissimus muscle from steers reared to a common age and carcass weight. Sixty Friesian steers were group-housed and offered grass silage ad libitum and 3.5kg concentrates per animal daily for 5 months and then 5kg concentrates and 1kg grass hay for 1month before the experiment began. The animals were then weighed and in a randomised block were assigned to one of 5 groups, for slaughter at the beginning of the experiment or to be offered concentrates and hay (900 and 100g/kg total diet, respectively) to achieve target growths of: 0.72kg/day continuously for 17 weeks, 0.36kg/day for the first 8 weeks and 1.08kg/day for the final 8 weeks (low-high), 1.08kg/day for the first 8 weeks and 0.36 for the final 8 weeks (high-low) or 0.36kg/day for the first 2 weeks, 0.72kg/day during weeks 4 and 14 and 1.08kg/day for the final 2 weeks (pulse). One week was allowed for transition to the different dietary allowances within each energy supply pattern. The mean age at the beginning and end of the study was 18 and 22.5 months, respectively. After slaughter, the weight of the carcass and kidney+channel fat depot were recorded, the pistola hind quarter was dissected into fat, lean and bone and the tenderness of the m. longissimus thoracis et lumborum (LTM) muscle was measured instrumentally and using a trained taste panel after 2, 7 or 14 days ageing. The pattern of energy supply did not affect carcass weight, fat score or kidney+channel fat weight. The pistola hind quarter from animals offered the low-high energy pattern had a similar composition to the continuously-fed animals but contained more muscle than that from animals offered high-low or pulse energy patterns. After 14 days ageing, LTM from the continuously-fed animals was more tender than that from animals offered the other energy supply patterns but shear force did not differ between supply patterns. The data do not support the hypothesis that pre-slaughter growth rate increases tenderness but suggest that energy supply pattern can influence body composition of finishing cattle.

Effect of concentrate feeding pattern in a grass silage/concentrate beef finishing system on performance, selected carcass and meat quality characteristics.

Steers were offered grass silage ad libitum and 6.4 kg concentrates daily for 126 days or silage ad libitum for 35 days, followed by concentrates ad libitum (Experiment 1). Steers were offered grass silage ad libitum and 6 kg concentrates daily for 154 days, concentrates ad libitum or grass silage ad libitum for 112 days followed by concentrates ad libitum (Experiment 2). All treatments received the same total concentrate allowance. In Experiment 1, there was no difference in any measurement of meat quality. In Experiment 2, ad libitum concentrate feeding per se, decreased redness and increased shear force of muscle at 2 days post-mortem. Delaying concentrate feeding decreased fat yellowness, decreased shear force at 7 and 14 days post-mortem and increased muscle redness at 14 days post-mortem. Modifications of the beef production system examined had minor effects on beef quality which are unlikely to be of commercial significance.

The value of muscular and skeletal scores in the live animal and carcass classification scores as indicators of carcass composition in cattle.

The objective was to determine the relationship of muscular and skeletal scores taken on the live animal and carcass conformation and fat scores with carcass composition and value. Bulls (n = 48) and heifers (n = 37) of 0.75 to 1.0 late-maturing breed genotypes slaughtered at 16 and 20 months of age, respectively, were used. At 8 months of age (weaning) and immediately pre-slaughter, visual muscular scores were recorded for each animal and additionally skeletal scores were recorded pre-slaughter. Carcass weight, kidney and channel fat weight, carcass conformation and fat scores, fat depth over the longissimus dorsi muscle at the 12th (bulls) or 10th (heifers) rib and carcass length were recorded post-slaughter. Each carcass was subsequently dissected into meat, fat and bone using a commercial dissection procedure. Muscular scores taken pre-slaughter showed positive correlations with killing-out rate (r ≈ 0.65), carcass meat proportion (r ≈ 0.60), value (r ≈ 0.55) and conformation score (r ≈ 0.70), and negative correlations with carcass bone (r ≈ -0.60) and fat (r ≈ -0.4) proportions. Corresponding correlations with muscular scores at weaning were lower. Correlations of skeletal scores taken pre-slaughter, carcass length and carcass weight with killing-out rate and the various carcass traits were mainly not significant. Carcass fat depth and kidney and channel fat weight were negatively correlated with carcass meat proportion and value, and positively correlated with fat proportion. Correlations of carcass conformation score were positive (r = 0.50 to 0.68) with killing-out rate, carcass meat proportion and carcass value and negative with bone (r ≈ -0.56) and fat (r ≈ -0.40) proportions. Corresponding correlations with carcass fat score were mainly negative except for carcass fat proportion (r ≈ 0.79). A one-unit (scale 1 to 15) increase in carcass conformation score increased carcass meat proportion by 8.9 and 8.1 g/kg, decreased fat proportion by 4.0 and 2.9 g/kg and decreased bone proportion by 4.9 and 5.2 g/kg in bulls and heifers, respectively. Corresponding values per unit increase in carcass fat score were -11.9 and -9.7 g/kg, 12.4 and 9.9 g/kg, and -0.5 and -0.2 g/kg. Carcass conformation and fat scores explained 0.70 and 0.55 of the total variation in meat yield for bulls and heifers, respectively. It is concluded that live animal muscular scores, and carcass conformation and fat scores, are useful indicators of carcass meat proportion and value.

Heterogeneity of genetic parameters for calving difficulty in Holstein heifers in Ireland.

Calving difficulty is a trait that greatly affects animal welfare, herd profitability, and the amount of labor required by cattle farmers. It is influenced by direct and maternal genetic components. Selection and breeding strategies can optimize the accuracy of genetic evaluations and correctly emphasize calving difficulty in multiple-trait indices provided there are accurate estimates of genetic parameters. In Ireland, large differences exist in the age at which heifers first give birth to calves. The objective of this study was to estimate genetic parameters for calving difficulty in first-parity Holsteins and to determine whether these differed with age of the heifer at calving. Transformed calving difficulty records for 18,798 Holstein heifers, which calved between January 2002 and May 2006, were analyzed using univariate, multitrait, and random regression linear sire-maternal grandsire models. The model that 1) fitted a second-order random regression of dam age at first parity for the direct component, 2) treated the maternal component as a single trait regardless of dam age, and 3) fitted a single residual variance component was optimal. Heritabilities for direct (0.13) and maternal (0.04) calving difficulty were significantly different from zero. These 2 components were moderately negatively correlated (-0.47). Estimates of direct genetic variance and heritability were heterogeneous along the dam age trajectory, decreasing initially with dam age before subsequently increasing. Heritability estimates ranged between 0.11 and 0.37 and were higher for records with younger and older dams at parturition. Genetic correlations between the direct components of calving difficulty decreased from unity to 0.5 with increasing distance between dam ages at parturition. The results of this study indicated that heterogeneity of direct genetic variance existed for calving difficulty, depending on dam age at first parturition.

Genetic parameters for EUROP carcass traits within different groups of cattle in Ireland.

The first objective of this study was to test the ability of systems of weighing and classifying bovine carcasses used in commercial abattoirs in Ireland to provide information that can be used for the purposes of genetic evaluation of carcass weight, carcass fatness class, and carcass conformation class. Secondly, the study aimed to test whether genetic and phenotypic variances differed by breed of sire. Variance components for carcass traits were estimated for crosses between dairy cows and 8 breeds of sire commonly found in the Irish cattle population. These 8 breeds were Aberdeen Angus, Belgian Blue, Charolais, Friesian, Hereford, Holstein, Limousin, and Simmental. A multivariate animal model was used to estimate genetic parameters within the Holstein sire breed group. Univariate analyses were used to estimate variance components for the remaining 7 sire breed groups. Multivariate sire models were used to formally test differences in genetic variances in sire breed groups. Field data on 64,443 animals, which were slaughtered in commercial abattoirs between the ages of 300 and 875 d, were analyzed in 8 analyses. Carcass fat class and carcass conformation class were measured using the European Union beef carcass classification system (EUROP) scale. For all 3 traits, the sire breed group with the greatest genetic variance had a value of more than 8 times the sire breed group with least genetic variance. Heritabilities ranged from zero to moderate for carcass fatness class (0.00 to 0.40), from low to moderate for carcass conformation class (0.04 to 0.36), and from low to high for carcass weight (0.06 to 0.65). Carcass weight was the most heritable (0.26) of the 3 traits. Carcass conformation class and carcass fatness class were equally heritable (0.17). Genetic and phenotypic correlations were all positive in the Holstein sire breed group. The genetic correlations varied from 0.11 for the relationship between carcass weight and carcass fatness class to 0.44 for the relationship between carcass conformation class and carcass fatness class. Carcass weight and classification data collected in Irish abattoirs are useful for the purposes of genetic evaluation for beef traits of Irish cattle. There were significantly different variance components across the sire breed groups.

Reverse remodelling in heart failure with cardiac resynchronisation therapy.

This review examines the use of cardiac resynchronisation therapy (CRT) for chronic, severe, systolic heart failure. Left ventricular (LV) remodelling is the final common pathway of systolic heart failure and portends a poor prognosis. It is characterised by progressive LV dilatation, deterioration of ventricular contractile function and distortion of LV cavity shape. The LV remodelling process is triggered by prolonged pressure or volume overload, loss of contracting myocytes from myocardial infarction, genetic abnormalities of contractile proteins or exposure to cardiotoxic agents. Current therapeutic strategies for systolic heart failure aim to slow or halt the remodelling process. "Reverse remodelling" is a relatively new concept, where progressive LV dilatation and deterioration in contractile function are not simply arrested, but partially reversed. Cardiac resynchronisation therapy is a novel and effective treatment for systolic heart failure, and is associated with reverse remodelling of the LV.

Decreasing variation in the eating quality of beef through homogenous pre- and post-slaughter management.

The objective of this experiment was to determine the effectiveness of current "best-practise" management of steers pre- and post-slaughter in reducing variation in the eating quality of beef. Steers sired by one Belgian Blue bull from Holstein-Friesian cows were managed optimally from birth to slaughter. Animals were slaughtered at target body weights and subcutaneous fat scores of 620 kg and 4L (LH) (n=23) or 720 kg and 4H (HH) (n=24). On each slaughter occasion, commercial steers with similar carcass weights and classification scores to the homogenous steers were selected from the factory lairage; n=19 for light commercial steers (LC) and n=20 for heavy commercial steers (HC). Carcasses were hung by the pubic bone at 10 °C for 10 h and 2 °C until 24 h postmortem, when M. longissimus dorsi and M. semimembranosus muscles were excised. Following ageing for 2, 7 and/or 14 days postmortem, eating quality was assessed. Muscle from HH steers was more variable in terms of tenderness, protein, moisture and water-holding capacity compared to muscle from LH steers within LD muscle. Muscle from HC steers was more variable in terms of tenderness, redness colour, protein and intramuscular fat compared to muscle from LC steers within LD muscle. Applying best practice management to the homogenous and commercial steers in the present experiment reduced variances in Warner Bratzler shear force (25.69 and 23.9, respectively) compared to variance (154.9) of previous research carried out by the present authors.