Standard lactations (305 days [d]) of Brown Swiss (BS, n = 54,985), Simmental (SM, n = 114,189) and Holstein (HO, n = 137,703) breeds of cow were analyzed, and their lactation curves were calculated. For the prediction of the milk yield of cows at 305 d and the prediction of lactation - curve standards (LCS), a regression equation system was developed separately for each breed and parities (1, 2, ≥3). The regression equation system was used for the estimation of Wood curve parameters for arbitrary milk yield on the basis of the first daily milk recording. An analysis, using the least power norm method(Lp), of the conformity between the calculated Wood's curves and those estimated using the regression equations on the verification data set (n = 34,374) indicated that the equations can provide a good prediction of LCS. Our results indicate that the expected milk yield in a standard lactation and the lactation curve trajectory of an individual cow in a herd may be predicted using a simple algorithm on the basis of the proposed regression equations and known daily milk yield in the initial period of lactation.
COBISS.SI-ID: 3525676
The aim of the current work was to investigate the possibility of modifying the existing Mean Stage by Weight (MSW) system for evaluating the average development stage in alfalfa. The modification was performed with the aim of providing a simplified system that may be used to evaluate the alfalfa development stage and to predict its nutritive value for ruminants. The suggested modification consists of designating an MSW value on the basis of the fresh weight of all morphological stages in a fresh green plant, as opposed to the original method which is based on weighing all morphological stages dried at 65 °C. The investigation was done on 141 samples of one alfalfa cultivar, collected from the same location during the first three growth cycles. Based on the results of this investigation the modified method appears to be a quick and accurate. It enables determination the average development stage in alfalfa and can be recommended for both scientific research and practical field use, as well as for prediction of its chemical composition and nutritive value.
COBISS.SI-ID: 4114024
The aim of this study was to predict the fatty acid (FA) composition of bulk milk using data describing farming practices collected via on-farm surveys. The FA composition of 1,248 bulk cow milk samples and the related farming practices were collected from 20 experiments led in 10 different European countries at 44° N to 60° N latitude and sea level to 2,000 m altitude. Farming practice-based FA predictions were good for C16:0, C17:0, saturated FA, polyunsaturated FA, and odd-chain FA, and very good for trans-11 C18:1, trans-10 + trans-11 C18:1, cis-9, trans-11 conjugated linoleic acid, total trans FA, C18:3n-3, n-6:n-3 ratio, and branched-chain FA. Fatty acids were predicted by cow diet composition and by the altitude at which milk was produced, whereas animal-related factors (i.e., lactation stage, breed, milk yield, and proportion of primiparous cows in the herd) were not significant in any of the models. Proportion of fresh herbage in the cow diet was the main predictor, with the highest effect in almost all FA models. However, models built solely on conserved forage-derived samples gave good predictions for odd-chain FA, branched-chain FA, trans-10 C18:1 and C18:3n-3. These prediction models could offer farmers a valuable tool to help improve the nutritional quality of the milk they produce.
COBISS.SI-ID: 4183656