Replacement of corn and hay by soybean hulls in diets for small ruminants

Author(s)

Renato Shinkai Gentil

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2010-10-01

Examining board members

Ivanete Susin; Carla Maris Machado Bittar; Iran Borges; Jane Maria Bertocco Ezequiel; Maria Claudia Araripe Sucupira

• Advisor: Ivanete Susin

Abstract

The objectives of this experiment were to determine the effects of replacing corn and coastcross hay by soybean hulls (SH) on performance and ingestive behavior in lactating goats and nutrient apparent digestibility and ruminal measures in ram lambs. Experiment 1: Eight goats were housed in a tie stall and used in a two 4 x4 Latin square design conducted concurrently. Each experimental period consisted of 16 d; the first 12 d were used to adapt the goats to the treatments and the remaining 4 d were used for data collection. Animals were fed a 40:60 (concentrate:roughage ratio). Soybean hulls replaced corn by 0%, 20%, 40% or 60% on a dry matter (DM) basis. Dry matter ground intake (DMI), milk yield and ingestive behavior were not affected (P>0.05) by replacing corn by soybean hulls. However, milk fat concentration increased (P<0.05) with soybean hulls inclusion. Experiment 2: Four ram lambs were placed individually in metabolism crates and assigned to a 4 x 4 Latin square design. The experimental period consisted of 14 d; the first 10 d were used to adapt the lambs to the treatments and the remaining 4 d were used for data collection. The treatments and diets were the same as in Experiment 1. Dry matter intake and digestibility were not affected (P>0.05) by replacing ground corn by soybean hulls. Nevertheless, propionate concentration decreased (P<0.05) while neutral detergent fiber (NDF) intake and digestibility, ruminal pH and acetate concentration increased (P<0.05) with soybean hulls inclusion. Experiment 3: Thirty-six goats were assigned to a complete randomized block design and housed in a tie stall for a period of 8 weeks. Goats were fed a 50:50 (concentrate:roughage ratio) with similar amount of NDF. Soybean hulls replaced hay by 0%, 33%, 67% or 100% on a DM basis. Dry matter and NDF intake showed a quadratic response (P>0.05). Milk yield and body weight change didnt differ (P<0.05), however milk fat concentration increased (P>0.05) while time spent with rumination and chewing decreased (P>0.05), when SH were added to the diet. Experiment 4: Sixteen ram lambs were housed individually in metabolism crates and assigned to a complete randomized block design. The experimental period consisted of 14 d; the first 10 d were used to adapt the lambs to the treatments and the remaining 4 d were used for data collection. The treatments and diets were the same used in Experiment 4. DMI and NDF intake showed a quadratic effect (P<0.05) when SH were added to the diet. However, DM and NDF digestibility increased (P<0.05) while short-chain fatty acids, acetate and propionate concentration, didnt change (P>0.05) and ruminal pH decreased (P<0.05). SH can partially replace corn or coastcross hay with no detrimental effects on performance or nutrient metabolism in small ruminants. (AU)