Stefano Biffani

Fatores ambientais e genéticos sobre o crescimento ao ano e ao sobreano de bovinos Nelore, criados no Nordeste do Brasil

Data growth records relative to 2004 Nellore breed calves, from Ceara and Piaui states, were used to study the influence of environmental effects and to estimate the heritability of the weight traits at the 365 days (yearling) and 550 days (post-yearling) of age. The variance components were estimated by the restricted maximum likelihood method. In the analysis of variance a model that included the fixed effects of sex, year and season and herd of birth, and the age of dam as covariant and the random effect of sire within the herd, was used. The fixed effects of classification were significant for all evaluated traits. Least square means were 186.16 ± 2.74 kg and 244.06 ± 5.23 kg, for yearling and post-yearling weight respectively. Age of dam at calving influenced only the yearling weights, with estimated maximum weight of 187.29 kg and ages around nine years. Heritability estimates were .56 ± .09 and .64 ± .12, for yearling and post-yearling weight, respectively.

Fatores ambientais e genéticos que influenciam o desenvolvimento ponderal até o desmame de animais Nelore criados no Nordeste do Brasil

Growth records from Associacao Brasileira de Criadores de Zebu (ABCZ), correspondent to a 2977 Nellore breed calves, born from 1976 to 1994 and raised on pasture in 11 herds from Piaui and Ceara states were analyzed to study the environmental factor effects and to estimate the heritability for the traits weight at 205 days of age (weaning weight). The mathematical model included the fixed effects of sex, year, season and herd of the birth, the covariant age of the dam and the random effect of the sire. The variance components used to estimate the heritability (h2), were obtained by Derivative Free Restricted Maximum Likelihood, using MTDFREML program. The fixed effects of sex, year and herd of birth were significant, whereas the season of birth and the age of the dam at calving were not significant. Least squares means for the weaning weight was 129.06 ± 1.46 kg (CV =17.6%). Males were an average, 12 kg heavier than females and the heaviest animals were born in the year of 1982, with a mean weight of 146.54 ± 5.22 kg, while the lightest ones were born in the year of 1979, with a mean weight of 114.13 ± 4.51kg. Differences among herds were evident, and some showed high mean values in relation to the overall mean value. The heritability for weaning weight was .48 ± .08.

Rumination time as a potential predictor of common diseases in high-productive Holstein dairy cows

We examined the hypothesis that rumination time (RT) could serve as a useful predictor of various common diseases of high producing dairy cows and hence improve herd management and animal wellbeing. We measured the changes in rumination time (RT) in the days before the recording of diseases (specifically: mastitis, reproductive system diseases, locomotor system issues, and gastroenteric diseases). We built predictive models to assess the association between RT and these diseases, using the former as the outcome variable, and to study the effects of the latter on the former. The average Pseudo-R 2 of the fitted models was moderate to low, and this could be due to the fact that RT is influenced by other additional factors which have a greater effect than the predictors used here. Although remaining in a moderate-to-low range, the average Pseudo-R 2 of the models regarding locomotion issues and gastroenteric diseases was higher than the others, suggesting the greater effect of these diseases on RT. The results are encouraging, but further work is needed if these models are to become useful predictors.

Heat stress effects on Holstein dairy cows’ rumination

The objective of this study was to investigate the relationship between temperature-humidity index (THI) and rumination time (RT) in order to possibly exploit it as a useful tool for animal welfare improvement. During summer 2015 (1 June to 31 August), data from an Italian Holstein dairy farm located in the North of Italy were collected along with environmental data (i.e. ambient temperature and relative humidity) recorded with a weather station installed inside the barn. Rumination data were collected through the Heatime® HR system (SCR Engineers Ltd., Hadarim, Netanya, Israel), an automatic system composed of a neck collar with a Tag that records the RT and activity of each cow. A significant negative correlation was observed between RT and THI. Mixed linear models were fitted, including animal and test day as random effects, and parity, milk production level and date of last calving as fixed effects. A statistically significant effect of THI on RT was identified, with RT decreasing as THI increased.

Improving the stability of test day model evaluation for production traits in the Italian Holstein

Abstract Genetic evaluation for production traits in the Holstein breed in Italy is based on a Random Regression Test Day Model (RRTDM) since November 2004. More specifically the model is a multiple lactation, multiple traits RRTDM, similar to the model used in Canada for official genetic evaluation. In order to improve stability, data were pre-adjusted for number of days pregnancy at test day and fixed regression curve effects include now the effect of year of production, four calving seasons instead of two and a general effect for days in milk (DIM) was added. The changes in the model improved stability of proofs over time, thus increasing the ability of the test day to accurately predict the breeding value of both bulls and cows. Trend validation results showed also improvements and residuals were positively affected by the changes. Trends in trait residuals previously detected with respect to DIM and month of calving did show a significant reduction. The new model was officially introduced in January 2009.

Heritability and genetic correlations between rumination time and production traits in Holstein dairy cows during different lactation phases

Present address Riccardo Moretti, Associazione Nazionale Allevatori Bovini di Razza Piemontese, Carrù, Italy. Abstract So far, rumination has been used as a proxy for monitoring dairy cow health at farm level. However, investigating its genetic aspects as well as its correlation with other important productive traits may turn this management tool into a new informative selection criterion. However, scientific evidences on genetic correlation among rumination time (RT) and milk production and milk composition are still scarce. Therefore, the objective of this study was to estimate the heritability of RT across three lactation phases and its genetic correlation with milk production, milk composition and somatic cell count (SCC). Results of our study showed that heritability for RT was 0.34 and was constant across lactation. The mean genetic correlations between RT and milk production and composition traits were 0.07 (milk production), −0.07 (protein yield), −0.31 (fat yield), and −0.32 (fat/protein ratio). The mean genetic correlation between RT and the SCC was 0.05.

Body measurements from selective hunting: biometric features of red deer (Cervus elaphus) from Northern Apennine, Italy

Abstract Morphometric studies on European red deer (Cervus elaphus L.) living in sub-Mediterranean areas are rare. In this paper, we provide the first morphometric description of red deer from Apennine living in Prato Province, as well as a description of its skeletal growth pattern. We analysed 18 body, cranial and antler measurements from 905 deer carcasses, collected during 12 hunting seasons (2000–2012). The body size of red deer from Prato appeared comparable to that of other populations from Northern Apennine and Central Alps. A significant variation in weight during the hunting season was detected only in adult stags: they were estimated to lose 23% of their eviscerated body weight from the beginning of the rutting season until the end of winter. The relationship between eviscerated body weight (EW) and whole body weight (WW) was highly significant in both sexes within every age class (R2 always higher than 0.75), thus linear regressions were assessed in order to estimate EW from WW, allowing to complete datasets when such information is missing. Growth equations were utilised to describe the development of a subset of skeletal measures (height at shoulder, hind foot length, mandible length, head–trunk length) commonly collected on hunted cervids. Hind foot length was the measure which first ceased to grow and with the highest growth constant; although the relationship between cohort hind foot length and environmental, climatic and demographic variables has to be tested for red deer from Apennine, these bones appeared a suitable biological indicator for long-term monitoring of the species.

Genetic Parameters for Milk Yield and Persistency in Carora Dairy Cattle Breed Using Random Regression Model

In tropical environments, lactation curves with lower peaks and higher persistency (PS) might be desirable from both an economical and a physiological point of view. The objective of this study was to obtain genetic parameters for test day (TD) yields, and PS for the tropical breed Carora and to compare these with results from a standard 305-d-milk yield animal model. Four random regression models (RRM) were used on a dataset composed of 95,606 TD records collected in Venezuela and tested to find the best fitting the data. Estimated daily heritabilities for milk yields ranged from 0.21 to 0.30, with the lowest values around the peak of lactation. Lactation repeatabilities ranged from 0.50 to 0.56. Correlations between the breeding values obtained with the RRM and the lactation model currently used in Venezuela [single trait Animal Model (stAM)] are quite high and positive (Pearson correlation=0.71 and Spearman correlation=0.72). Correlations between PS and 305-d-milk yield estimated breeding values (EBV) ranged from -0.18 (PS as the deviation of daily productions in the interval 50-279 days in milk from a point at the end of lactation) to 0.52 (PS as EBV difference between the second and the first stage of lactation). The use of PS indexes accounting for milk yield may allow the selection of individuals able to express their potential genetic values in tropical environment, without incurring in excessive heat stress losses.