The Effect of Heat Treatment of Whole Cottonseed on Site and Extent of Protein Digestion in Dairy Cows1

Abstract

Six mature Holstein cows in late lactation and fitted with permanent ruminal, duodenal and ideal cannulae were used in a double 3 X 3 Latin-square design to study the effect of roasting or extruding of cottonseed on protein degradation in the rumen and availability of amino acids in the small intestine. Raw whole cottonseed (CS), extruded whole cottonseed (ECS), and roasted whole cottonseed (RCS) were fed in diets containing 17% crude protein and composed of 42% whole cottonseed, 26% corn grain and 29% hay supplemented with dry molasses, vitamins and minerals. The diets were isocaloric and contained 1.86 Mcal NEL/kg. Acid detergent lignin was used as a digesta marker, and diaminopimelic acid as a bacterial marker. Ruminal ammonia concentration was higher (P less than .05) for CS than for ECS and RCS (15.7, 12.7 and 10.2 mM). Concentrations of isobutyrate (1.3 vs 0.8 and 0.8 mM) and isovalerate (1.8 vs 1.1 and 1.1 mM) were higher (P less than .05) for CS compared with ECS and RCS. Non-ammonia nitrogen flow to the duodenum (g/d) was 248, 300 and 350 for CS, ECS, and RCS, with RCS higher (P less than .05) that in CS. Apparent absorption of total amino acids in the small intestine was .80, 1.01, and 1.24 kg/d, for CS, ECS, and RCS, respectively, with RCS higher (P less than .05) than CS. Apparent absorption of essential and non-essential amino acids was 376, 425; 458, 548;610 and 628 g/d for CS, ECS and RCS respectively, with RCS higher (P less than .05) than CS.

The effect of heating and NaOH treatments on the nutritive value of nonlinted whole cottonseeds

“…Heat treatment reduces the degradation of CP supplements in the rumen (Satter, 1986). This effect partly related to blocking of reactive sites for microbial proteolytic enzymes, and partly to reduction of protein solubility (Broderick and Craig, 1980).…”

“…This effect partly related to blocking of reactive sites for microbial proteolytic enzymes, and partly to reduction of protein solubility (Broderick and Craig, 1980). Heating of WCS has been followed by increased in vivo CP flow into the intestine and absorption of total amino acids in dairy cows (Pena et al, 1986). There is an optimal effect of heat intensity on intestinal digestion.…”

“…Thus, whereas an increase in carbohydrate digestion from WCS in the rumen may be desirable, excess ruminal crude protein (CP) degradation should be avoided. To protect the treated WCS from excessive CP degradation in the rumen heat can be applied, thereby increasing intestinal input of undegradable CP from WCS (Pena et al, 1986;Smith and Vosloo, 1994).…”

The Relationship Between Acid Detergent Insoluble Nitrogen and Nitrogen Digestibility in Lactating Dairy Cattle

“…Specifically, this is estimated by determining the amount of insoluble N in ADF residue (Firkins et al, 1984). Several sources have reported variable ADIN levels, ranging from 0.4% of CP for corn gluten feed and cottonseed meal to 31.1% of CP for dried distillers grains with solubles (DDGS) for forages and concentrates in wet and dried forms (Pena et al, 1986;Clark et al, 1987;Edionwe and Owen, 1989;Weiss et al, 1989;NRC, 2001 In the Cornell Net Carbohydrate and Protein System, the assumption is made that ADIN represents the portion of protein in a feedstuff that is unavailable for use by the animal because it is completely indigestible (Sniffen et al, 1992). Additionally, Van Soest (1994) noted that as the concentration of ADIN increased, total tract N digestibility decreased.…”

Digestion ruminale et absorption intestinale des protéines du lupin extrudé chez la vache laitière

“…Une hausse de la disparition intestinale de la MO a également été signalée par Pena et ai (1986) après addition de graines de coton extrudées à la ration. (Pena et al, 1986;Focant et al, 1990) …”