DM intake by feedlot beef cattle: factors that impact intake patterns.

DM intake (DMI) for individual pens of cattle is recorded daily or averaged across each week by most commercial feedlots as an index of performance. Numerous factors impact DMI by feedlot cattle. Some are available at the start of the feedlot period (initial BW, sex), and others become available early in the feeding period (daily DMI during adaptation) or more continuously (daily DMI from the previous week). To evaluate the relative impact of these factors on daily DMI during individual weeks within the feedlot period, we employed a dataset compiled from 2009 to 2014 from one commercial feedlot, including 4 132 pens (485 458 cattle), which were split into two fractions: 80% were used to calculate DMI regressions on these factors to develop a prediction equation for mean DMI for each week of the feeding period, and 20% were reserved to test the adequacy of these prediction equations. Correlations were used to determine the relationship between all available variables with observed DMI. These variables were then included in the generalized least squares regression models. A veracity test of the model was performed against the reserved data. Daily DMI from previous week was the factor most highly correlated with daily DMI (P < 0.10) during from week 6 to week 31, accounting for approximately 70% of the variation, followed by mean daily DMI during adaptation period (weeks 1-4), including in the prediction model from weeks 5 to 12. Initial shrunk BW (ISBW) was the third most correlated factor, which was included in prediction equations from week 5 to week 20. Sex entered the prediction model only after week 8. Daily DMI for each test week within the feeding period was predicted closely (r2 = 0.98) by these four factors (RMSE = 0.155 kg). In conclusion, the mean daily DMI during each week of the finishing period for a pen of cattle could be predicted closely based on mean daily DMI intake during the previous week plus other variables available early in a feedlot period (daily DMI during adaptation period, ISBW and sex).

Somatic cell score genetic parameter estimates of dairy cattle in Portugal using fractional polynomials.

Milk somatic cell count is an indicator trait for mastitis resistance. Genetic parameters for somatic cell score in the Portuguese Holstein-Friesian population were estimated by modeling the pattern of genetic correlation over the first 3 lactations (days in milk) with a random regression model. Data records from the first 3 lactations were from the national database of the Portuguese Holstein Association herds. Heritability estimates ranged from 0.05 at the beginning of the lactation for the 3 lactations, to 0.07 at the end of the lactation period for the first and third lactations, to 0.09 for the second lactation. This increase in the heritability values was due to an increase in the genetic variance and a decrease in the residual variances. Genetic correlations evaluated for monthly time points were high (0.65 to 0.99) for all 3 lactations, whereas phenotypic correlations were much less than the genetic correlations (0.13 to 0.62).

Diagnosis, genetic control and preventive management of canine hip dysplasia: a review.

Despite expensive screening and breeding programmes, hip dysplasia (HD) continues to be one of the most common orthopaedic diseases in dogs. The vast majority of dogs afflicted with HD show minimal to no clinical signs, but it can also be a highly debilitating condition for both working and pet dogs. Hip joint laxity is considered a major risk factor for the development of degenerative joint disease and a definitive diagnosis is made if characteristic signs are evident on a ventrodorsal view of the pelvis. Early prediction of the condition can be made using stress radiographic techniques to evaluate the passive hip laxity. The diagnosis of HD may be used for the purpose of selecting breeding stock or to decide on the best treatment approach. Breeding programmes based on individual dog phenotypes have been ineffective and a selection procedure based on breeding value (BV) estimation is recommended. Traditional conservative and surgical treatment approaches are reserved for dogs with overt clinical signs of the disease but such treatments can be expensive and aggressive, and are often ineffective in eliminating clinical signs or subluxation and in preventing the development of degenerative joint disease. The implementation of breeding programmes based on BVs and further research into early prediction/diagnosis of HD and effective preventive treatment approaches are essential.

Hip dysplasia in Estrela mountain dogs: prevalence and genetic trends 1991-2005.

Three hundred and thirteen Estrela mountain dogs were examined for hip dysplasia (HD) using the standard ventrodorsal hip extended view, and graded into five categories (A, B, C, D and E) using the Fédération Cynologique Internationale's (FCI) scoring system. The Ortolani method was performed to evaluate hip joint laxity. Pedigree information was obtained from the Portuguese Kennel Club and the genetic trend was evaluated by calculating the mean breeding values (BVs) for the last 15 years, using the threshold model. HD was found in 66% of the dogs. There was low-moderate correlation between the results of the Ortolani test and FCI hip scores (r(s)=0.386; P<0.001). Grades of hip dysplasia were equal in both males and females (P=0.14) and in the animals' right and left sides (P=0.51). The mean BVs for HD were stable in dogs born between 1991 and 2003, and showed an improvement in 2004 and 2005. The data confirm the high prevalence and severity of HD in predisposed breeds that do not have breeding programmes in place. It also confirms an initial favourable change in BVs that is a likely consequence of the voluntary radiographic hip-screening programme.

A study of Lusitano mare lactation curve with Wood's model.

Milk yield and composition data from 7 nursing Lusitano mares (450 to 580 kg of body weight and 2 to 9 parities) were used in this study (5 measurements per mare for milk yield and 8 measurements for composition). Wood's lactation model was used to describe milk fat, protein, and lactose lactation curves. Mean values for the concentration of major milk components across the lactation period (180 d) were 5.9 g/kg of fat, 18.4 g/kg of protein, and 60.8 g/kg of lactose. Milk fat and protein (g/kg) decreased and lactose (g/kg) increased during the 180 d of lactation. Curves for milk protein and lactose yields (g) were similar in shape to the milk yield curve; protein yield peaked at 307 g on d 10 and lactose peaked at 816 g on d 45. The fat (g) curve was different in shape compared with milk, protein, and lactose yields. Total production of the major milk constituents throughout the 180 d of lactation was estimated to be 12.0, 36.1, and 124 kg for fat, protein, and lactose, respectively. The algebraic model fitted by a nonlinear regression procedure to the data resulted in reasonable prediction curves for milk yield (R(a)(2) of 0.89) and the major constituents (R(a)(2) ranged from 0.89 to 0.95). The lactation curves of major milk constituents in Lusitano mares were similar, both in shape and values, to those found in other horse breeds. The established curves facilitate the estimation of milk yield and variation of milk constituents at different stages of lactation for both nursing and dairy mares, providing important information relative to weaning time and foal supplementation.

Comparison of estimates of hip dysplasia genetic parameters in Estrela Mountain Dog using linear and threshold models.

Genetic parameters, breeding values, and genetic trends of hip dysplasia in Estrela Mountain Dogs were estimated using a linear model (LM) and a threshold model (TM). A database with 313 animals was used. Right and left hip joints were individually scored, according to the Fédération Cynologic Internationale grading rules of the canine hip dysplasia system, as normal (1), borderline (2), slight (3), moderate (4), and severe (5 and 6). The estimate of repeatability was lower in LM (0.86) than in TM (0.90). The same tendency was verified with the heritability because its estimate in LM was 0.38 and in TM was 0.43. However, these results did not establish any statistical differences between the models. The genetic trend of canine hip dysplasia for LM and TM showed a similarity in shape, but considerable individual differences were found in the EBV ranking lists. Therefore, the selection of breeding animals would not be the same with the 2 methodologies. To select the best method for genetic evaluation of hip dysplasia, further studies using more data and other dog breeds are required.

Measurement of the femoral neck anteversion angle in the dog using computed tomography.

Simple and accurate limb and pelvic conformation evaluation using computed tomography (CT) can be useful in planning canine hip dysplasia (CHD) treatment and in helping to understand the pathogenesis of osteoarthritis and CHD. The objectives of this study were to describe a new method for femoral neck anteversion angle (FNA-angle) measurement in CT, and to compare it to the established radiographic standard biplanar method. The hips of 23 Estrela Mountain Dogs were evaluated using radiography and CT and their FNA-angles were determined by performing two CT examinations and with one radiographic measurement session. The intra-class correlation coefficient (ICC) was used to evaluate the repeatability (agreement between the two CT sessions, ICC=0.92) and reproducibility (agreement between each CT and radiographic session, ICC=0.91 in both cases) of the CT FNA-angle measurement method. This study suggests that CT FNA-angle measurement method is reliable and can be used in CT hip studies with confidence.

The accuracy of seven mathematical functions in modeling dairy cattle lactation curves based on test-day records from varying sample schemes.

Daily milk yield over the course of the lactation follows a curvilinear pattern, so a suitable function is required to model this curve. In this study, 7 functions (Wood, Wilmink, Ali and Schaeffer, cubic splines, and 3 Legendre polynomials) were used to model the lactation curve at the phenotypic level, using both daily observations and data from commonly used recording schemes. The number of observations per lactation varied from 4 to 11. Several criteria based on the analysis of the real error were used to compare models. The performance of models showed few discrepancies in the comparison criteria when daily or 4-weekly (with first test at days in milk 8) data by lactation were used. The performance of the Wood, Wilmink, and Ali and Schaeffer models were highly affected by the reduction of the sample dimension. The results of this work support the idea that the performance of these models depends on the sample properties but also shows considerable variation within the sampling groups.

Genetic parameter estimates of portuguese dairy cows for milk, fat, and protein using a spline test-day model.

A spline animal model was fitted to 152,103 test-day milk, fat, and protein yield records from 14,423 first-lactation cows. The models included age at calving and the herd-test-month as fixed effects. Model fitting was carried out using Restricted Maximum Likelihood with ASREML. For milk yield, the heritability at 18 d in milk was 0.19, which increased to the maximum estimated value of 0.23 at midlactation and then decreased. On average, milk, fat, and protein yield heritabilities were 0.22, 0.14, and 0.19, respectively. For milk yield, all correlations were positive and ranged from 0.54 to 0.99 for the genetic component and from 0.32 to 0.78 for the phenotypic component. Genetic correlations were higher than phenotypic ones. For fat and protein yields, all genetic correlations were positive, ranging from 0.43 to 0.99. The phenotypic correlations for fat yield had the lowest correlations of the 3 traits. Curves of estimated breeding values for milk, fat, and protein over lactation had positive deviations from mean curves for sires with high genetic merit, but there was considerable variability in the shapes of the curves for different sires. More research is needed to compare the spline function with other mathematical functions used as submodels of lactation curve.

[Immunologic and epidemiologic characterization of non-responders/low-responders to hepatitis B vaccine]. / Caracterização imunológica e epidemiológica dos não-respondedores/hipo-respondedores à vacina da hepatite B.

UNLABELLED: An important reduction in morbidity and mortality due to hepatitis B was achieved with the discovery of an effective vaccine. However, 2 to 10% of healthy adults do not respond to vaccination with the production of protective levels of antibody anti-HBs (assumed as protective, concentrations of ab. anti-HBs > 10 UI/L). Therefore, the aim of the present work was to study epidemiological (sex, age, obesity, alcoholic and smoking habits, previous diseases) and immunological factors (white cell count, immunoglobulins and sub-classes of IgG, lymphocytic populations and sub-populations) in a group of 20 healthcare workers with a low response (anti-HBs < 50 UI/L) to a genetically-engineered vaccine (Engerix B). The results were compared to the ones found in an identical sample of responders (anti-HBs > 100 UI/L) from the same population. No statistically significant differences regarding the epidemiological data, differential white cell counts and immunoglobulin quantification (IgG, IgA, IgM, IgG1, IgG2, IgG3) were detected. The mean value of IgG4 (mean = 54.53 +/- 59.8 mg/dl) in non/hyporesponders was significantly higher (p = 0.038) when compared to the same result in responders (mean = 33.76 +/- 31.30 mg/dl). A statistically significant difference (p < 0.05) in the quantification of double negative lymphocytic T sub-populations was also found, the mean value being higher in the responders (mean = 6.5 +/- 4.1% versus 4.6 +/- 2.3%). CONCLUSIONS: The effectiveness of recombinant hepatitis B vaccines is well known. However, a number of apparently healthy people are unable to achieve protective titres of anti-HBs after vaccination. As our study groups did not have a considerable number of cases, we can not establish definitive conclusions based on differences found in the quantification of IgG4 and double negative lymphocytic T sub-populations. It seems to us that an investment in future research into the eventual causes of nonprotective response and into new strategies of immunization of non/hyporesponders are appropriate. In the meantime, the occupational daily risk of exposure to infected body fluids makes adequate hepatitis B immunization of healthcare workers a priority.

Organochlorine residues in tissues of striped dolphins affected by the 1990 Mediterranean epizootic: relationships with the fatty acid composition.

A simple and rapid method was developed for the simultaneous determination of fatty acids, organochlorine pesticides, and polychlorinated biphenyl (PCB) congeners in the same sample in order to explore possible connections between levels of contaminants and fatty acid composition. The method was applied to samples of melon, cerebrum, cerebellum, lung, liver, kidneys, and skeletal muscle obtained from 5 male and 5 female striped dolphins (Stenella coeruleoalba) found stranded in 1990 in the northeastern Spanish coasts during the morbillivirus epizootic that affected this cetacean in the Mediterranean Sea. The results indicate that PCBs were dominant in all tissues, with the highest geometric mean concentration being found in melon (903 micrograms g-1 wet wt); sigma DDTs were also found at high concentrations (111 micrograms g-1 wet wt, in melon). Statistical analysis indicate that organochlorine concentration was correlated with the fatty acid composition of tissues, although some of these variations can be interpreted as a consequence of a shift in the diet produced in the striped dolphin population. However, other changes such as the negative correlation with arachidonic acid may suggest that the eicosanoid production could have been affected by the extremely high concentrations of PCBs and sigma DDTs.