The effect of lactation week and milking time on physiological and productive performance of holstein cows

الملخص EN

The present study was carried out using eight Holstein cows at the experimental research station, College of Agriculture, Fayoum University.

This work included four cows in the first parity and four cows in the second one.

Milk samples were taken from each cow in the evening and the morning milking, starting from the 3rd week to the 27th week and analyzed for butterfat, protein, lactose, solids not-fat, total solids, ash, calcium, and phosphorus.

The effects of week of lactation and milking time on milk yield and composition have been investigated.

Blood samples were taken from cows weekly after evening and morning milking.

Whole blood samples were analyzed for serum total protein, albumin, globulin, albumin / globulin ratio, glucose, cholesterol, triglycerides, calcium, phosphorus and calcium / phosphorus ratio was also calculated.

The effects of week of lactation and milking time on blood serum constituents of Holstein cows have been also investigated.

Milk yield (kg) and milk lactose reach its maximum level in the 7th week of lactation, and reach its minimum level at the 27th week of lactation.

Milk fat and total protein, decreased in the first 7 and 8 weeks of lactation.

Ash, g % gradually decreased and reached its minimum level in the 9th week of lactation.

Calcium decreased in the first 12 weeks of lactation.

The content of T.S., S.N.F., fat, total protein, lactose, ash, Ca, and P.

g% were greater in (p.m).

Milking and were 12.52, 9.05, 3.47, 3.45, 4.84, 0.76, 0.14 and 0.09 g %, respectively.

Blood serum total protein g / dl, albumin g / dl, globulin g / dl and albumin / globulin ratio were higher in morning (a.m.) (7.74, 3.57, 4.15 g / dl and 0.90 respectively) than p.m.