Effects of dietary n-3 polyunsaturated fatty acids and ... - FINS

production of fat correctedmilk 3,5%, kg1 st WorkshopXIII International Feed Technology SymposiumFehr (16), it was established that the highest milk production was present in the systemof nutrition when the ration contained a higher quantity of concentrate compared to hay.At the same time, when compared to the other two systems of nutrition, milk yieldremained at approximately the same level during the 8 weeks of lactation.Feeding during gestation5432101 2 3 4 5 6 7 8week of lactationvknsvsnknkisGraph 1. The effect of various concentrate: fodder ratios during gestation on thequantity of milk produced in early lactation (16)RELATION BETWEEN CONCENTRATE AND FODDER IN THERATIONHowever, the fodder : concentrate ratio in goat nutrition, in addition to raising the levelof milk yield, also has an effect on changing milk fat and protein content in goat milk.Changing the relationship between concentrate and fodder can significantly influencemilk fat content, and even reduce it by 20%. If the share of concentrate in dry matter ofthe ration is raised by 50-60%, milk fat content can drop significantly due to theproduction of propionate and the lower quantity of the milk fat precursor acetate (3).However, the effect of highly concentrated rations is reduced if mixed rations are used,or if concentrate is fed in smaller portions, i.e. three or more times a day. Under suchcircumstances, conditions in the rumen remain relatively stable, and the ratio betweenthe end products of fermentation – acetate and propionate – remains relatively constant.Thus, in an experiment by Kawasa et al. (5), a reduction of the fodder : concentrate ratioto 45:55 lowered the milk fat percent, increased protein content, milk yield and weightgain, while the period goats spent feeding and ruminating decreased (Table 5). However,the potential to alter protein content in milk via nutrition is considerably lower whencompared to milk fat, for several reasons, the most significant being that their naturalvariation is low, and that all nutritional factors have not been fully studied. In addition,264