Impact of Propylene Glycol on some Nutritional, Chemical and Technological Properties of Dairy Zaraibi Goats

Abstract

To evaluate the effects of propylene glycol (PG as powder) on some nutrition parameters (digestion coefficient and nutritive values) and some productive parameters (milk yield and composition) and its effects on the quality of milk processing forDomiatti cheese). An experiment was conducted by eighteen lactating Zaraibi goats in 3rd lactation season with an average body weight of 36±5.46 Kg and aged 39 months. In this experiment, three treatments were employed as six does in each treatment. The treatments done up to 21 weeks during lactation season and included: (1) control without PG (PG0), (2) 10g PG /doe/day (PG1) and (3) 20 g PG/doe/day. All treated goats were received basal ration contained 50% concentrate feed mixture (CFM) + 50% roughage (as berseem hay and rice straws) through lactation period up to 21 weeks. Apparent digestibility of CP, TDN and DCP was affected (P<0.05) by PG administration. Acetate and propionate were increased by using PG, but level of butyrate has increase significant for PG0. Moreover, the results could be showed that milk yield and milk compositions were affected (P<0.05) by the PG addition compared to control. Also, increasing PG levels from 10 to 20 g /does/day did not have any significant effect on milk yield, milk composition and other nutrition parameters. The cheese sample yield was slightly decreased particularly within PG1 and PG2 compared to PG0 cheese. The total solids and titratable acidity were slightly increased and pH values were slightly decreased by using PG milk. The PG cheese samples had significant (P<0.05) differences in TN/DM%, FA/DM% during the ripening period. The cheese made from PG1 and PG2 had the higher (P<0.05) score points for organoleptic properties than PG0 after continually storage period for 60 days. The results indicate that PG is an appropriate alternative for goats to prevent energy deficiency in the lactation period, while increasing the daily PG dose from 10 to 20 g has no significant but observed beneficial effect.