Effects of grain sorghum planting density and processing method on nutrient digestibility and retention by ruminants.
Grain sorghum grown in 38-cm rows (high density [HD]) or 76-cm rows (normal density [ND]) was treated as follows: steam-flaked (SF), high-moisture-harvested followed by rolling and ensiling (HM), or dry-rolled (DR). Resulting grains were evaluated using lambs in two 5 x 5 Latin square digestion trials. Treatment diets contained either SF-HD, SF-ND, HM-HD, HM-ND, or DR-ND grain sorghum in two trials; a 90 or a 60% concentrate diet was fed in each trial. High-density planting increased (P < 0.10) the apparent absorption of P relative to ND planting for both 60 and 90% concentrate diets. Steam flaking decreased (P < 0.10) the apparent absorption of P in the 90% concentrate diet and decreased (P < 0.10) the apparent absorption of N in both the 90 and 60% concentrate diets. Despite differences in N digestibility, steam flaking and HM ensiling resulted in similar (P > 0.10) N retention as a percentage of N intake in both trials. However, changes in the distribution of N between feces and urine among processing methods could affect N content of manure and alter nutrient management strategies. These results indicate that both planting density and grain processing can alter the apparent absorption of grain sorghum P by ruminants. Furthermore, it seems that grain processing can alter the route of N excretion in ruminants without changing total N retention.
Defoor
P J
PJ
Division of Agriculture, West Texas A&M University, Canyon 79016, USA. paul@prattusa.com
Cole
N A
NA
Galyean
M L
ML
Jones
O R
OR
D000383:Agriculture / Q000379:methods*; D000821:Animal Feed / Q000592:standards*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004063:Digestion; D002523:Edible Grain / Q000254:growth & development*; D005243:Feces / Q000737:chemistry; D005511:Food Handling / Q000379:methods*; D007408:Intestinal Absorption; D008297:Male; D008372:Manure; D009584:Nitrogen / Q000378:metabolism; D012756:Sheep / Q000378:metabolism*
D008372:Manure; D009584:Nitrogen