Protein supplementation, by-products and corn processing for lactating dairy cows.

Author(s)

Hugo Imaizumi

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2005-04-20

Examining board members

Flavio Augusto Portela Santos; Telma Teresinha Berchielli; Wilson Roberto Soares Mattos; Paulo Henrique Mazza Rodrigues; Ivanete Susin

• Advisor: Flavio Augusto Portela Santos

Abstract

Four studies were conducted to compare protein sources and content, corn processing method and a fibrous by-product for lactating dairy cows. Study 1: corn processing methods (fine ground, M; and popped, P) and protein sources (soybean meal, FS; urea, U; or fishmeal, FP) were compared in 4 treatments: MFS (M + FS); PFS (P + FS); PFP (P + FS + FP); PU (P + U). Compared to fine ground corn (MFS), popped corn (PFS) decreased milk fat and protein content. The 3 protein sources comparisons (PFS x PFP x PU) showed that milk yield was higher for PFS. Feeding fishmeal (PFP) decreased milk fat content, but increased milk protein content. Study 2: the cottonseed meal content in the diet (0, 15 and 30% of DM) in replacement to soybean meal were compared. Dry matter intake was not affected by treatments, but cottonseed meal supplementation had a negative linear effect on milk yield and on milk protein content and yield. Increasing cottonseed meal had a positive linear effect on milk fat content and yield. Study3: basal diet (16% CP) was compared to two diets with 17.5% CP, where crude protein content of diets were increased by feeding extra urea (U-17.5, resulting in increased rumen degradable protein content, RDP) or extra soybean and cottonseed meal (FSFA-17.5, resulting in increased metabolizable protein content, MP). Extra RDP (U-17.5) tended to increase DMI compared to basal diet. Milk yield were increased by extra MP (FSFA-17.5) but not by extra RDP (U-17.5). Milk protein content and yield were also increased by feeding extra MP. In conclusion, increasing diet MP content above National Research Council - NRC (2001) recommendations for cows producing around 29 kg/d improved milk and milk protein yields. Study 4: two trials were conducted. In trial 1, treatments were 0 (RUC-0), 10 (RUC-10) or 20% (RUC-20) wet brewers grains inclusion in diet dry matter. All 3 diets contained 1% urea on a DM basis. A fourth isonitrogenous diet, with additional urea (2% of diet DM) in partial replacement of soybean meal, without brewers grains, was compared to. Dry matter intake were not different. Milk yields and milk protein contents and yields were increased by feeding wet brewers grains and decreased by feeding 2% urea. In trial 2, weekly received fresh wet brewers grains versus wet brewers grains ensiled with ground corn were compared. Both treatments were isonitrogenous diets and contained the same proportions of ground corn and wet brewers grains on a dry matter basis. Dry matter intake, milk yield, milk fat content and yield and protein content and yield were not different. (AU)