E. Sinapis

Bio: E. Sinapis is an academic researcher from Aristotle University of Thessaloniki. The author has contributed to research in topics: Udder & Beef cattle. The author has an hindex of 2, co-authored 4 publications receiving 7 citations.

Using the choice experiment method in the design of breeding goals in dairy sheep.

Abstract: Market failures are the main cause of poor acknowledgement of the true impact of functional sheep traits on the management and economic performance of farms, which results in their omission from the breeding goal or the estimation of non-representative economic weights in the breeding goal. Consequently, stated-preference non-market valuation techniques, which recently emerged to mitigate these problems, are necessary to estimate economic weights for functional traits. The purpose of this paper is to present an example of the use of a choice experiment (CE) in the estimation of economic weights for sheep traits for the design of breeding goals. Through a questionnaire survey the preferences of sheep farmers are recorded and their marginal willingness to pay (MWTP) for 10 production and functional traits is estimated. Data are analysed using random parameter logit models. The results reveal unobserved preference heterogeneity for fertility, adaptability to grazing and resistance to disease, thus highlighting that these traits are appreciated differently by farmers, because their needs are diverse. Positive MWTP is found for Greek breeds, high milk production and lambs with low fat deposition, for which there is high demand in Greek markets. On the other hand, MWTP for the cheese-making ability of milk is negative, stemming from the fact that sheep milk prices in Greece are not formulated according to milk composition. In addition, farmers seem to understand differences between udder shapes and attribute different values to various types. This application of the CE method indicates that communication channels among farmers and breeders should be established in order to enhance market performance and to provide orientation to the design of breeding programmes. Non-market valuation can be used complementarily to market valuation techniques, in order to provide accurate estimates for production and functional traits.

Genetic and Environmental Trends for Milk Production Traits in Sheep Estimated with Test-day Model

Abstract: Data from milk performance testing were used to analyze genetic and environmental trends for purebred Tsigai, Improved Valachian and Lacaune sheep. 103,715 (Tsigai), 212,962 (Improved Valachian) and 2,196 (Lacaune) test-day records gathered by the State Breeding Institute of the Slovak Republic entered the analyses. The respective pedigree data comprised 23,724 (Tsigai), 51,401 (Improved Valachian) and 438 (Lacaune) records. The multiple-trait, mixed model methodology was used to predict the breeding values for daily milk yield, fat and protein content and to estimate the fixed and remaining random effects assumed to affect the above mentioned traits, separately for each breed. The breeding values for daily milk yield were adjusted for 150-day standardized lactation length by multiplying with the constant 150, as the breeding goal of the selection scheme in Slovakian sheep is to increase 150-day milk production and constant heritability throughout the whole lactation is assumed. The genetic trends were expressed as changes in averages of breeding values across birth years of animals. For Tsigai and Lacaune breeds, cumulative genetic changes over the analyzed period were 3.8 and 5.1 kg for 150-day milk, 0 and -0.16% for fat content and 0 and -0.12% for protein content. For Improved Valachian breed, either a low (1.6 kg for 150-day milk yield) or zero (fat and protein content) cumulative genetic change was found. The environmental trends were calculated as averages of solutions for flock-test day effect across years and months in which measurements were taken. A distinctive cyclical pattern which reflected short-time variation in milk production traits was found. Possible explanations for this phenomenon are given and discussed.

An experimental comparison of methods for somatic cell count determination in milk of various species of mammals

Abstract: Somatic cell count (SCC) is important foodstuff, hygienic and health indicator of milk and animal mammary gland. The goal of this paper was to evaluate an ability of chosen methods to reach the SCC reliable results in various biological kinds (species) of milk. The various methods of SCC determination were compared in cow (CM), goat (GM), sheep (SM) and human (HM) milk: direct microscopy (DM); fluoro-opto-electronic (Fossomatic 90; Foss); fluorescent (DCC; De Laval). Used methods had cow milk calibration basically. The DM, Foss and DCC result relations about SCC were very close, mostly > 0.92 (P < 0.001) for CM, GM and SM. In CM the regression equations between methods were near ideal form y = 1x + 0. The mean differences SCC data sets between mentioned methods were small for CM, larger for SM and HM and the largest for GM. It is possible to convert all DCC results in SM, HM and GM to DM or Foss method. The conversion equations were stated from DCC: to DM in cow milk y = 1.1293x - 5.5029; to Foss in goat milk y = 3.603x - 3171.4; to Foss in sheep milk y = 1.3805x - 18.149; to Foss in human milk y = 2.6246x + 158.63. Assesment of conversion equations should be individual laboratory event. Results had relatively good correspondence among DM, Foss and DCC for SCC determination in CM, GM, SM and HM for milk quality control. DCC had lower results in small ruminants as compared to Foss calibrated on CM using DM. DCC in HM had lower results as Foss adjusted by CM at good correlation (0.84; P < 0.001).