Effect of recombinant bovine somatotropin (rbST) administration on ewes milk. Influence of the nature of concentrate

Forty Comisana ewes (62 +/- 8 days in milk) were divided into four equal groups: i) HA: high starch 34.1%; NDF 20.0%; ii) HA + rbST; iii) BA: low starch 12.2%, NDF 32.7% and iv) BA + rbST. Recombinant bovine somatotropin (Somidobove fly Lilly Elanco) was injected once subcutaneously (320 mg/ewe). Milk production was increased (P < 0.01) by rbST treatment for a cycle of 28 days. High starch concentrate lowered significantly (P < 0.05) milk pH and somatic cell counts. Dietary treatment and rbST did not affect respectively, milk fat and protein percentages, rennet coagulation of milk and blood parameters.