Condensed tannins and nutrient utilization by lambs and goats fed low-quality diets.
In the first of two experiments, four wether lambs (BW = 26.8 kg) and four wether Angora goats (BW = 31.7 kg) were used in two simultaneous 4 x 4 Latin squares to study the influence of condensed tannins (CT) on nutrient usage and concentrations of serum urea N, somatotropin (GH), and insulin (INS) when the animals were fed low-quality diets containing mountain mahogany (MM; Cercocarpus montanus) leaves. Diets were 8% CP and contained 25% or 50% MM (with hay or straw, respectively), either untreated or treated with polyethylene glycol (PEG; molecular weight 3,350) to reduce total reactive CT. Diets treated with PEG and 25% MM diets had less (P less than .05) CT than diets without PEG or those with 50% MM. Diets containing 50% MM resulted in greater N balance and lower serum urea N (P less than .01) than 25% MM diets. Concentrations of GH and INS were similar in animals fed the 25% and 50% MM diets. Reducing CT by adding PEG did not affect N balance or improve nutrient digestion by lambs or goats fed low-quality diets. In Exp. 2, four wether lambs (BW = 28.4 kg) were used in a 4 x 4 Latin square and fed the same diets as animals in Exp. 1 to study the influence of CT on ruminal fermentation and digesta kinetics. Dietary PEG treatment did not affect digesta kinetics except for a 30% increase in ruminal volume; 50% MM diets had faster particulate passage rates (P less than .05) than 25% MM diets. Ruminal ammonia N was greater (P less than .01) in lambs fed PEG-containing or 25% MM diets; however, rate of in situ NDF disappearance was not reduced by the lower ammonia N in the latter diets.
Nuñez-Hernandez
G
G
Dept. of Anim. and Range Sci., New Mexico State University, Las Cruces 88003-0003.
Wallace
J D
JD
Holechek
J L
JL
Galyean
M L
ML
Cardenas
M
M
D000641:Ammonia / Q000032:analysis; D000821:Animal Feed; D000818:Animals; D004043:Dietary Fiber / Q000008:administration & dosage / Q000378:metabolism; D004063:Digestion; D004435:Eating; D005232:Fatty Acids, Volatile / Q000032:analysis; D006041:Goats / Q000502:physiology*; D013006:Growth Hormone / Q000097:blood; D007328:Insulin / Q000097:blood; D008297:Male; D009584:Nitrogen / Q000378:metabolism; D009753:Nutritive Value; D011092:Polyethylene Glycols / Q000494:pharmacology; D012417:Rumen / Q000737:chemistry / Q000378:metabolism; D012756:Sheep / Q000502:physiology*; D013634:Tannins / Q000378:metabolism*; D014508:Urea / Q000097:blood
D004043:Dietary Fiber; D005232:Fatty Acids, Volatile; D007328:Insulin; D013634:Tannins; D011092:Polyethylene Glycols; D000641:Ammonia; D014508:Urea; D013006:Growth Hormone; D009584:Nitrogen