Determination of dietary and milk electrolytes For the egyptian lactating cattle fed the summer And winter diets [electronic resource].

Includes references.

This study aimed at the dietary cation-anion difference (DeAD) and milk electrolytes determination for lactating Egyptian cows and buffaloes fed the summer and winter diets. Forty heteroparity lactating cattle, twenty cows and twenty buffaloes, at different stages of lactation were used to collect milk samples during summer (with a temperature range of 3540 Q c) and winter (with a temperature range of 18-22 °c). All animals received the diets consisted of concentrate, fodder, and rice straw as 2: 1: 1 on dry matter basis. In the summer, the fodder was Rayana com (Zea mays mexicana), while, in the winter it was berseem clover (Trifolium alexandnOnum). The results indicated that the DCAD of the summer and winter diets was 48.64 and 83.61 m Eq/IOOg DM (on the basis of the equation: Na+ + K+ - er), respectively. Slight increase (P>0.05) was noticed for 4% fat- corrected milk (FCM) of cows fed the winter diet comparing with those fed the summer diet. However, in the swnmer 4% FCM of buffaloes significantly (P<O.05) decreased by 33.8% comparing with those fed the winter diet. Concerning milk electrolytes, the results indicated that for cow's milk, Na+/K+ ratios were 3:1 and 2.6:1, while for buffaloe's milk, these ratios were 1.85:1 and 4.6:1 during the winter and summer, respectively. Milk cr content was 19.75 and 18.33 mg/lOOg for cow's milk, while, buffaloe's milk contained 17.00 and 24.00 mg/l00g during the winter and summer, respectively. This study concluded that buffaloe1s milk production was negatively more affected by heat in summer than that of cow. The DCAD of hot-stressed buffaloes should be increased in the summer diets.

Summary in Arabic.

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