Ground cottonseed fed to feedlot lambs

Author(s)

Rodrigo Araujo de Souza

• Document type: Master's Dissertation
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2013-12-04

Examining board members

Ivanete Susin; Renato Shinkai Gentil; Marco Antonio Trindade

• Advisor: Ivanete Susin

Abstract

The effects of feeding ground linted cottonseed (GCS) to feedlot lambs were determined in three trials. The diets were isonitrogenous (16% CP) and composed of 90% concentrate and 10% hay \"coastcross\". Experiment 1: Forty-five ram lambs, Dorper x Santa Inês (initial BW of 21.3±3.7 kg and 79±6 days) were distributed in a randomized complete block design. Experimental treatments were defined according to the level of GCS in the diet: 0, 7, 14, 21 or 28% in the DM. In the 3rd and 6th weeks of the feedlot was evaluated the ingestive behavior of the lambs. L. dorsi muscle samples were used for the evaluation of meat and determination of fatty acid profile. There was a linear decrease in final weight of the animals and in DMI. There was a linear decrease in rumination Min/g of NDF. With the reduction in final weight, carcass characteristics also decreased linearly. There was a change in fatty acid profile with a linear reduction of palmitoleic acid, oleic and monounsaturated fatty acids, while linoleic acid increased. There was a quadratic effect for stearic, vaccenic, linolenic acid and total unsaturated. The inclusion of GCS negatively affected the performance and carcass characteristics and demonstrated low capacity to stimulate rumination. Experiment 2: Five ram lambs, Dorper x Santa Inês (45.2 ± 0.8 kg at the beginning of the trial), cannulated in the rumen, were distributed in a 5x5 Latin square design to determine the effects of adding GCS in the diet digestibility, nitrogen metabolism and rumen constituents. Each experimental period lasted 22 days, 17 days for adaptation and 5 days for sampling. The treatments were the same of Exp. 1. The digestibility of dry matter, organic matter, crude protein and non-fiber carbohydrates decrease linearly. However, the digestibility of EE had a quadratic effect and NDF was not affected. There was a quadratic effect for total SCFA and propionate, and a linear decrease for acetate. Ruminal pH increased linearly. Ammonia nitrogen was not affected. Experiment 3: The objective of this experiment was to determine the effects of feeding high-concentrate diets with whole or ground cottonseed on growth, carcass characteristics, sensory evaluation and meat quality of ewe lambs. Twenty-one White Dorper x Santa Inês ewe lambs (initial BW = 23.6 ± 1.2 kg and 87.7± 4.5 days) were used in a randomized complete block design according to initial BW and age. The experimental diets were: 1) CS0: control, without cottonseed; 2) WCS21: with 21% of whole cottonseed; and 3) GCS21: with 21% of ground cottonseed. Samples of longissimus muscle were used for meat quality analysis and sensory evaluation. Sensory test was performed by 80 untrained panelists. Color was different when the control diet was compared with the cottonseed (CS21=WC21+GC21) groups (L:29.6vs36.7; a*:9.0vs7.5; b*:11.0vs8.7). The control group had greater tenderness (6.5vs5.9), succulence (6.8vs6.1), acceptability (6.2vs5.6), and flavor (6.0vs5.5) values compared with CS21. In conclusion, whole or ground cottonseed fed to feedlot ewe lambs had a detrimental effect on sensory evaluation showing that its use should be restricted. (AU)

• FAPESP's process: 11/14968-1 - Utilization of whole cottonseed in diets with high proportion of concentrate in feedlot lambs: performance, carcass characteristics and meat, ingestive behavior and digestibility of diets.
• Grantee: Rodrigo Araújo de Souza
• Support Opportunities: Scholarships in Brazil - Master