Genetic relationship of discrete-time survival with fertility and production in dairy cattle using bivariate models

Bivariate analyses of functional longevity in dairy cattle measured as survival to next lactation (SURV) with milk yield and fertility traits were carried out. A sequential threshold-linear censored model was implemented for the analyses of SURV. Records on 96 642 lactations from 41 170 cows were used to estimate genetic parameters, using animal models, for longevity, 305 d-standardized milk production (MY305), days open (DO) and number of inseminations to conception (INS) in the Spanish Holstein population; 31% and 30% of lactations were censored for DO and INS, respectively. Heritability estimates for SURV and MY305 were 0.11 and 0.27 respectively; while heritability estimates for fertility traits were lower (0.07 for DO and 0.03 for INS). Antagonist genetic correlations were estimated between SURV and fertility (-0.78 and -0.54 for DO and INS, respectively) or production (-0.53 for MY305), suggesting reduced functional longevity with impaired fertility and increased milk production. Longer days open seems to affect survival more than increased INS. Also, high productive cows were more problematic, less functional and more liable to being culled. The results suggest that the sequential threshold model is a method that might be considered at evaluating genetic relationship between discrete-time survival and other traits, due to its flexibility

A bio-economic model to improve profitability in a large national beef cattle population

A bio-economic model was developed for estimating economic values for use in improving profitability in a large national beef cattle population from birth to slaughter. Results were divided into fattening costs, production costs and income. Economic values were derived for 17 traits for two regions, mature weight (-0.43 € and -0.38 €/+1 kg of live weight), age at first calving (-0.13 € and -0.11 €/+1d), calving interval (-1.06 € and -1.02 €/+1d), age at last calving (0.03 € and 0.03 €/+1d), mortality 0-48 h (-5.86 € and -5.63 €/1% calves per cow and year), pre-weaning mortality (-5.96 € and -5.73 €/+1% calves per cow and year), fattening mortality (-8.23 € and -7.88 €/+1% calves per cow and year), adult mortality (-8.92 € and -7.34 €/+1% adult cows per cow and year), pre-weaning average daily gain (2.56 € and 2.84 €/+10g/d), fattening young animals average daily gain (2.65 € and 3.00 €/+10g/d), culled cow in fattening average daily gain (0.25 € and 0.16 €/+10g/d), culled cow dressing carcass percentage (3.09 € and 2.42 €/+1%), culled cow price (4.59 € and 3.59 €/+0.06 €/kg), carcass conformation score (16.39 € and 15.3 €/+1 SEUROP class), dressing carcass rate of calf (18.22 € and 18.23 €/+1%), carcass growth (9.00 € and 10.09 €/+10g of carcass weight/d) and age at slaughter (0.27 € and 0.44 €/+1d). Two sample herds were used to show the economic impact of calving interval and age at first calving shortening in the profit per slaughtered young animal, which was 178 € and 111 € for Herds A and B, respectively. The economic values of functional traits were reduced and production traits were enhanced when fertility traits were improved. The model could be applied in a Spanish national program

Students' perceptions of instructional rubrics in neurological physical therapy and their effects on students' engagement and course satisfaction

One of the main challenges faced by physical therapy (PT) students is to learn the practical skills involved in neurological physical therapy (PT). To help them to acquire these skills, a set of rubrics were designed for formative purposes. This paper presents the process followed in the creation of these rubrics and their application in the classroom, noting that students perceived them as valid, reliable, and highly useful for learning. The perception of the validity and usefulness of the rubrics has different closely related dimensions, showing homogeneous values across the students´ sociodemographic and educational variables, with the exception of dedication to studying, which showed a significant relationship with schoolwork engagement and course satisfaction. The adequacy of the hypothesized structural model of the relationships among the variables was confirmed. Direct effects of the perception of the rubrics' validity and engagement on course satisfaction were found, as well as direct effects of the assessment of the usefulness of the rubrics on schoolwork engagement and indirect effects on course satisfaction through this latter variable. The results are discussed taking into account the conclusions of previous research and different instructional implications

TGFBR1 Intralocus Epistatic Interaction as a Risk Factor for Colorectal Cancer

In colorectal cancer (CRC), an inherited susceptibility risk affects about 35% of patients, whereas high-penetrance germline mutations account for <6% of cases. A considerable proportion of sporadic tumors could be explained by the coinheritance of multiple low-penetrance variants, some of which are common. We assessed the susceptibility to CRC conferred by genetic variants at the TGFBR1 locus. We analyzed 14 polymorphisms and the allele-specific expression (ASE) of TGFBR1 in 1025 individuals from the Spanish population. A case-control study was undertaken with 504 controls and 521 patients with sporadic CRC. Fourteen polymorphisms located at the TGFBR1 locus were genotyped with the iPLEX Gold (MassARRAY-Sequenom) technology. Descriptive analyses of the polymorphisms and haplotypes and association studies were performed with the SNPator workpackage. No relevant associations were detected between individual polymorphisms or haplotypes and the risk of CRC. The TGFBR1*9A/6A polymorphism was used for the ASE analysis. Heterozygous individuals were analyzed for ASE by fragment analysis using cDNA from normal tissue. The relative level of allelic expression was extrapolated from a standard curve. The cutoff value was calculated with Youden's index. ASE was found in 25.4% of patients and 16.4% of controls. Considering both bimodal and continuous types of distribution, no significant differences between the ASE values of patients and controls were identified. Interestingly, a combined analysis of the polymorphisms and ASE for the association with CRC occurrence revealed that ASE-positive individuals carrying one of the most common haplotypes (H2: 20.7%) showed remarkable susceptibility to CRC (RR: 5.25; 95% CI: 2.547–5.250; p<0.001) with a synergy factor of 3.7. In our study, 54.1% of sporadic CRC cases were attributable to the coinheritance of the H2 haplotype and TGFBR1 ASE. These results support the hypothesis that the allelic architecture of cancer genes, rather than individual polymorphisms, more accurately defines the CRC risk

Evidence for classification of c.1852_1853AA>GC in MLH1 as a neutral variant for Lynch syndrome

Background: Lynch syndrome (LS) is an autosomal dominant inherited cancer syndrome characterized by early onset cancers of the colorectum, endometrium and other tumours. A significant proportion of DNA variants in LS patients are unclassified. Reports on the pathogenicity of the c.1852_1853AA>GC (p.Lys618Ala) variant of the MLH1 gene are conflicting. In this study, we provide new evidence indicating that this variant has no significant implications for LS. Methods: The following approach was used to assess the clinical significance of the p.Lys618Ala variant: frequency in a control population, case-control comparison, co-occurrence of the p.Lys618Ala variant with a pathogenic mutation, co-segregation with the disease and microsatellite instability in tumours from carriers of the variant. We genotyped p.Lys618Ala in 1034 individuals (373 sporadic colorectal cancer [CRC] patients, 250 index subjects from families suspected of having LS [revised Bethesda guidelines] and 411 controls). Three well-characterized LS families that fulfilled the Amsterdam II Criteria and consisted of members with the p.Lys618Ala variant were included to assess co-occurrence and co-segregation. A subset of colorectal tumour DNA samples from 17 patients carrying the p.Lys618Ala variant was screened for microsatellite instability using five mononucleotide markers. Results: Twenty-seven individuals were heterozygous for the p.Lys618Ala variant; nine had sporadic CRC (2.41%), seven were suspected of having hereditary CRC (2.8%) and 11 were controls (2.68%). There were no significant associations in the case-control and case-case studies. The p.Lys618Ala variant was co-existent with pathogenic mutations in two unrelated LS families. In one family, the allele distribution of the pathogenic and unclassified variant was in trans, in the other family the pathogenic variant was detected in the MSH6 gene and only the deleterious variant co-segregated with the disease in both families. Only two positive cases of microsatellite instability (2/17, 11.8%) were detected in tumours from p.Lys618Ala carriers, indicating that this variant does not play a role in functional inactivation of MLH1 in CRC patients. Conclusions: The p.Lys618Ala variant should be considered a neutral variant for LS. These findings have implications for the clinical management of CRC probands and their relatives.Generalitat Valenciana in Spain (AP140/08) and the Biomedical Research Foundation from the Hospital of Elche, Spain (FIBElx0902). Conselleria de Educació (Generalitat Valenciana); Fundacion Juan Peran-Pikolinos; Fundacion Carolina-BBVA and Fondo Investigación Sanitaria (FI07/00303). Instituto de Salud Carlos III (INT09/208)

EFFECTIVENESS OF SELECTION FOR GROWTH TRAITS IN BEEF CATTLE

Data derived over a period of 21 years in which growth traits of animals in a herd of Angus cattle were recorded, were utilized in an analysis of the effects of selection. The primary selection criterion was weight at one year of age. In the early phase of the experiment, sire selection was wholly based on own performance and, in the later phase, some sires were selected for reuse based on the performance of their progeny. The selection objectives of the experiment were fairly constant over the 21 years. Genetic trends and parameters were estimated from data on 2576 calves. Data on calves from parents repeated in consecutive years were used to estimate genetic changes due to male and female selection. Annual genetic changes due to male selection were estimated to be .00 Kg, 2.09 Kg, 1.46 Kg and 2 gr for birth (BWT), weaning (WWT) and yearling (YWT) weights and postweaning daily gain (PWDG), respectively. Corresponding changes were .10 Kg, 1.66 Kg, 2.06 Kg and 2 gr due to female selection. Environmental trends were large and negative (-.13 Kg, -2.6 Kg, -1.85 Kg and -3 gr). Progeny mean deviations from year means were calculated for 38 sires with two or more progeny sets of twelve or more offspring and were used to calculate another estimate of genetic trend due to male selection of 0.04 Kg, 0.90 Kg, 2.00 Kg and 12 gr). Theoretical annual genetic progress was .15 Kg, 1.38 Kg, 2.87 Kg and 12 gr due to male selection and .07 Kg, .56 Kg, 1.18 Kg and 5 gr due to female selection. Heritabilities estimated by the paternal half-sib method were .58, .39, .51 and .51 BWT, WWT, YWT and PWDG in the male population and .46, .29, .28 and .45 in the female population. Estimated heritabilities by regression of offspring on parent were small. Genetic correlations of BWT with WWT, YWT and PWDG were .47, .51 and .64, of WWT with YWT and PWDG were .91 and .37 and PWDG with YWT was .93. Repeatabilities of BWT, WWT, YWT and PWDG as a trait of the dam (calculated by correlation between early and later performance) ranged from .20 to .36, .13 to .35, -.07 to .09 and .05 to .13, respectively. Repeatabilities estimated by dam variance component were .21, .24, .17 and .13 for the corresponding traits. Sire progeny sets were expressed as a deviation from the year mean. Correlations between first and later progeny sets were high for BWT. Only a few of the correlations for WWT, YWT and PWDG were statistically significant. With exception of the correlation between first and second progeny sets all correlation of first with later progeny sets were negative for WWT and YWT. Correlations of own performance and breeding value with progeny mean performance were high for BWT and small or negative for WWT, YWT and PWDG. A theoretical study was made for one and two-stage selection using own performance and progeny test with h(\u272) = .37 and genetic standard deviation = 15. With the same mating rate for bulls selected under both criteria of selection (5 to 105 cows/bull) the progeny test produced little improvement in annual genetic change (3.6% in the best case) over selection based on own performance alone. The most important factor contributing to optimal annual genetic progess is a high selection intensity for young bulls based on own performance. Low levels of bull reuse (highest own performance bulls used a second time and highest first progeny test bulls used a third time) resulted in only small increases in genetic change. Estimates of observed genetic change agreed well with theoretical expectations

Clinical mastitis in Spanish dairy cows: incidence and costs

Clinical mastitis in Spanish dairy herds has been studied. Since April 2005 up to December 2006, in 25 Spanish herds 1,054 cases registered were available. Aims were to determine mastitis incidence and factors of risk, to analyze whether yield production has been affected, and to quantify mastitis costs along 2006. The 25% lactations were infected at least once with average recurrence of 1.64. Descriptive analysis showed that 29% of cases occurred within the first month after calving. Primiparous showed higher mastitis frequency at early and late lactation while in multiparous cases number was progressively decreasing since the first month. Multiparous were statistically more liable to mastitis than primiparous. Mastitis did not show effect on yield production. Mastitis costs included treatment products and discarded milk. Individual daily production at each case onset was estimated by using monthly official milking records. An average mastitis case cost was 73.93 �, cheaper in primiparous than in multiparous because of lower milk production. Average discarded milk represented 74% of total cost per case. Mastitis costs were 117 � per infected cow and lactation. Then, annual economic losses due to mastitis were 3,190 � per average herd, showing the concern of producers on selecting resistant animals as well as the importance of the implementation of systematic recording for clinical mastitis in Spanish dairy farms.Se ha estudiado la mamitis clínica en 25 explotaciones utilizando 1.054 casos registrados desde abril de 2005 a diciembre de 2006. Los objetivos del trabajo fueron determinar la incidencia, analizar si la producción se vio afectada y calcular los costes generados en el año 2006. El 25% de las lactaciones presentaron algún episodio de mamitis, siendo la recurrencia media de 1,64. El 29% de los primeros casos se diagnosticaron en el primer mes tras el parto. Las primíparas fueron más susceptibles al principio y al final de la lactación, mientras que las multíparas presentaron menos casos según avanzaba la lactación. Sólo resultaron estadísticamente significativos el rebaño y el número de lactación, siendo las vacas con más de un parto más propensas a la mamitis. La producción de leche no se vio afectada. Los costes de mamitis incluyeron los correspondientes a medicamentos y a la leche retirada no comercializada. La producción individual diaria en el momento de la infección fue estimada utilizando el control lechero mensual oficial. El coste medio de mamitis fue de 73,93 �, siendo más caro en las multíparas debido a una mayor producción. El coste medio por media de leche retirada representó el 74% del coste por caso. El coste por vaca infectada fue de 117 � por lactación, lo que supone unas pérdidas económicas anuales por rebaño medio de 3.190 �, justificando la preocupación de los productores por seleccionar animales resistentes y la necesidad de sistematizar la recogida de mamitis clínicas en las explotaciones lechera españolas

A bio-economic model to improve profitability in a large national beef cattle population

A bio-economic model was developed for estimating economic values for use in improving profitability in a large national beef cattle population from birth to slaughter. Results were divided into fattening costs, production costs and income. Economic values were derived for 17 traits for two regions, mature weight (- 0.43 € and - 0.38 €/+1 kg of live weight), age at first calving (- 0.13 € and - 0.11 €/+1d), calving interval (-1.06 € and -1.02 €/+1d), age at last calving (0.03 € and 0.03 €/+1d), mortality 0-48 h (-5.86 € and -5.63 €/1% calves per cow and year), pre-weaning mortality (-5.96 € and -5.73 €/+1% calves per cow and year), fattening mortality (-8.23 € and -7.88 €/+1% calves per cow and year), adult mortality (-8.92 € and -7.34 €/+1% adult cows per cow and year), pre-weaning average daily gain (2.56 € and 2.84 €/+10g/d), fattening young animals average daily gain (2.65 € and 3.00 €/+10g/d), culled cow in fattening average daily gain (0.25 € and 0.16 €/+10g/d), culled cow dressing carcass percentage (3.09 € and 2.42 €/+1%), culled cow price (4.59 € and 3.59 €/+0.06 €/kg), carcass conformation score (16.39 € and 15.3 €/+1 SEUROP class), dressing carcass rate of calf (18.22 € and 18.23 €/+1%), carcass growth (9.00 € and 10.09 €/+10g of carcass weight/d) and age at slaughter (0.27 € and 0.44 €/+1d). Two sample herds were used to show the economic impact of calving interval and age at first calving shortening in the profit per slaughtered young animal, which was 178 € and 111 € for Herds A and B, respectively. The economic values of functional traits were reduced and production traits were enhanced when fertility traits were improved. The model could be applied in a Spanish national program