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Mastitis is the most prevalent disease present in livestock species leading to economic loss. In dairy sheep, it caused mainly from bacterial infections. The aim of this work was to investigate the risk of having mastitis in Valle del Belice dairy ewes during the first lactation, due to environmental or contagious pathogens, using a survival analysis approach. All test‐day records from primiparous ewes were collected from five flocks. All test‐day were grouped in two data sets, one with mastitis due to environmental pathogens (ENV) and the other with mastitis due to contagious pathogens (CON). In this analysis the follow up period of a ewe was the lactation, consequently all the record began with lambing. Ewes without infection at the end of the first lactation were treated as right censored. The analysis was performed with the Survival kit v.6.1 (Ducrocq et al., 2010). Cox model was used: h(t; x_m,z_m )=h_0 (t)exp{x_m^' (t)┤β+z_m^i u where: h_0 (t) is the baseline hazard; β contains the time‐independent covariates: litter size (LS, 2 classes), age at first lambing (AFL, 4 classes); and timedependent covariates: milk production within flock (MK, 3 classes); somatic cell count within flock (SCC, 3 classes); EP: environmental pathogens, that was only considered when analyzing contagious pathogens (2 classes) and CP: contagious pathogens, that was considered only when analyzing environmental pathogens (2 classes); u contains the time‐independent random effect of FYS: flock‐year‐season (46 classes). For ENV and CON about 48% and 85% of the records were right censored, respectively. Chi‐square test approximations based on likelihood ratio test were calculated for all the effects in the model. For the ENV, the time‐dependent fixed effects: MK, SCC and CP were significant. A higher risk of being infected (hazard ratio, HR, 1.41) was observed for ewes with low MK compared to reference class (i.e. MK=2). Higher HRs were found for animals that had a medium and high level of SCC (1.80 and 2.23, respectively) compared to the reference class of low level of SCC. A lower HR was observed for animals that have been infected with contagious pathogens (0.08). For CON, SCC and EP were significant:. A higher HR was found for animals that had a medium (1.79) and high (3.96) level of SCC compared to the reference class of low level of SCC. A lower HR was observed for animals that have been infected with environmental pathogens (0.09). Results suggest that selection for decreased SCC may be effective to reduce mastitis incidence and the breeding goal should favor ewes with lowest observed SCC. Ducrocq, V., Solkner, J. and Meszaros G. (2010). Survival Kit v6 a Software Package for Survival Analysis. In: 9th World Cong. Genet. Appl. Livest. Prod., Leipzig, Germany.

In the Mediterranean region, goat milk production is an important economic activity. In the present study, 4 casein genes were genotyped in 5 Sicilian goat breeds to 1) identify casein haplotypes present in the Argentata dell'Etna, Girgentana, Messinese, Derivata di Siria, and Maltese goat breeds; and 2) describe the structure of the Sicilian goat breeds based on casein haplotypes and allele frequencies. In a sample of 540 dairy goats, 67 different haplotypes with frequency >or=0.01 and 27 with frequency >or=0.03 were observed. The most common CSN1S1-CSN2-CSN1S2-CSN3 haplotype for Derivata di Siria and Maltese was FCFB (0.17 and 0.22, respectively), whereas for Argentata dell'Etna, Girgentana and Messinese was ACAB (0.06, 0.23, and 0.10, respectively). According to the haplotype reconstruction, Argentata dell'Etna, Girgentana, and Messinese breeds presented the most favorable haplotype for cheese production, because the casein concentration in milk of these breeds might be greater than that in Derivata di Siria and Maltese breeds. Based on a cluster analysis, the breeds formed 2 main groups: Derivata di Siria, and Maltese in one group, and Argentata dell'Etna and Messinese in the other; the Girgentana breed was between these groups but closer to the latter.

processo civile

A deterministic static model was used to estimate the economic values (EV) of production (MY, milk yield; BW, birth weight; and ADG, average daily gain) and functional traits (ASR, adult survival rate; LSR, lamb survival rate; FE, fertility; PR, prolificacy; and LW ewe , mature weight of ewe) in Valle del Belice dairy sheep. In this study, values for the biological parameters and the production traits used in the model were taken from real data, by surveying 15 Valle del Belice farmers and reflected the production circumstances of pasture based dairy production systems. In this system feed cost accounted for 95% of total variable costs, whereas fixed costs were low and reflected traditional and small ruminants’ husbandry system. A base situation with a fixed number of animals was considered to estimate the EV for the traits considered in this study. Economic values were positive for production traits: € 0.31 (MY, kg), € 4.40 (BW, kg) and € 0.15 (ADG, g) and for functional traits: € 2.15 (ASR, %), € 0.78 (LSR, %), € 2.64 (FE, %), € 0.39 (PR, %), except for LW ewe that was negative (€ −0.08, kg). Sensitivity analysis of EV to changes in prices indicated that future economic values for traits might change dependent on output and price levels, in particular on milk and meat price level. This study suggests that genetic improvement of milk production, lamb and adult survival rate, fertility and prolificacy will have a positive effect on profitability of pasture based dairy production system.

The objectives of this study were to evaluate the effect of somatic cell count (SCC) on functional longevity and to estimate the heritability of functional longevity using survival analysis in Valle del Belice dairy sheep. A total of 4,880 lactations of 2,190 ewes from 11 flocks were used. In this study, SCC was considered as an indication of subclinical mastitis. In case of clinical cases, identified by the technicians at milking time, test-day weights and milk samples of those ewes were not considered. Somatic cells were analyzed as counts, without any transformation, and were grouped in 3 classes based on the observed SCC maximum (mxSCC). The mxSCC classes, expressed as 103 cells/mL, were classified as 1 if mxSCC ≤ 500, 2 if 500 < mxSCC < 1,000, and 3 if mxSCC ≥ 1,000. An increase in SCC was associated with an increased hazard of being culled. Ewes in the highest class of SCC on a test-day had a 20% higher hazard of being culled than those in the lowest class. Therefore, SCC played a role in culling decisions of Valle del Belice dairy sheep farmers. The heritability estimate for functional longevity was 7% on the logarithmic scale and 11% on the real scale, indicating that selection for this trait is possible in sheep. The flock-year-season effect explained 19% of the variation on the logarithmic scale and 27% of the variation on the real scale.