engleski

The effect of crossbreeding on yield and quality of sheep milk

The aim of the research was to determine the effect of crossbreeding on production and quality of sheep milk. A total of 129 sheep (46 autochthonous Cres sheep ; 23 crosses with 75% Cres sheep and 25% Awassi, CA ; 60 crosses with 50% Cres sheep, 25% Awassi and 25% East Friesian, CAEF) were used in the experiment. The animals were kept in a single flock on the island of Cres (Croatia) under semi-intensive management and machine milked twice a day during lactation. Milk was sampled by hand milking and daily milk yield was recorded once monthly during the evening and morning milking through the lactation period of 6 months (from February to July). On a total 572 milk samples, contents of fat, protein, lactose, total solids and solids-non-fat, somatic cell count (SCC), pH and freezing point were determined. The effect of crossing autochthonous Cres sheep with Awassi and East Friesian sheep resulted in a significant increase in milk yield and lactation length. Also, the effect of crossing was significant for milk chemical composition. Cres sheep had the lowest lactation milk yield (50.48 l) with the shortest lactation period (172 days), but with the highest average values of chemical composition. CA crosses had significantly lower milk yield (80.6 l) and shorter lactation period (184 days) than CAEF crosses (133.8 l and 195 days, respectively). Significant positive correlations were determined between total solids and fat, protein and solids-non-fat, fat and protein, SCC and protein, milk yield and lactose, milk yield and pH value, respectively. Significant negative correlations were detected between milk yield and total solids, milk yield and solids-non-fat, milk yield and fat, milk yield and protein, total solids and lactose, fat and lactose, protein and lactose, respectively.

Cres sheep; Crosses; Lactation; Milk yield; Milk quality

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