تاثير آسياب كردن و حرارت دادن پنبه دانه بر توليد و تركيب شير گاوهاي شيري هلشتاين

Effect of grinding and heat treatment of cottonseed on milk yeild and composition of lactating dairy cows

Eight multiparious lactating Holstein cows were used in a 4x 4 Latin square design to determine the effect of moisture heat treatment and grinding of cottonseed in the diets of dairy cow. Cows were allocated into four diets with 1)whole cottonseed (WCS), 2)ground cottonseed (GCS) 3)GCS heated in 140°C and steeped for 2.5 minute and 4)GCS heated in 140°C and steeped for 20 minute (GHCS2). Diets had similar in crude protein (CP), net energy for lactation and neutral detergent fiber (NDF) contents. The percentage of whole or processed cottonseed was fixed at 14%. Ruminal degradability of CP was decreased %11.09 in GHCS2. Dry matter intake was significantly (P<0.01) affected by treatment diets. The mean dry matter intake in treatments 1,2,3 and 4 were 25.97, 27.24,27.63 and 27.63 Kg/d, respectively. The inclusion of GHCS1 and GHCS2 in the rations significantly (P<0.01) decreased ruminal NH3-N compared WCS and GCS. There were significant differences (P<0.01) in blood and milk urea concentrations between treatment diets. Physical processing of WCS did not affect ruminal pH, averaging 6.6 .Actual milk (P<0.05) and 4% fat corrected milk yeild(P<0.01) were significantly increased when GHCS1 and GHCS2 were included in the diets. Milk fat and protein percentage and yield as well as yield of milk lactose were significantly (P<0.05) affected by the diets. The mean rumination times between treatment diets (min/kg NDF Intake) were significantly different (P<0.05). However, chewing activity was similar in all treatment diets, averaging 279.1:3 min/24h. Significant differences (P<0.05) were observed in plasma glucose and cholesterol concentrations in the experimental cows. It can be concluded that grinding and heat treatment of whole cottonseed can be practical in term of dairy cowʹs performance moisture.