Effects of sorghum grain processing and forage fiber source on milk production, digestibility and kinetics of passage in Holstein cows.

Persistent Link:
http://hdl.handle.net/10150/185188
Title:
Effects of sorghum grain processing and forage fiber source on milk production, digestibility and kinetics of passage in Holstein cows.
Author:
Poore, Matthew Henry.
Issue Date:
1990
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Experiments were conducted to determine effects of source of forage and starch degradability on milk production, digestibility and passage in Holstein cows. A preliminary experiment showed that sampling site, dosing time and passage model had little influence on passage parameter estimates for grain in lactating cows. Mean retention times were 17 and 25 h for duodenal and fecal sampling, respectively, and 16 and 18 h at the duodenal site and 24 and 26 h at the fecal site for doses given before rather than after feeding, respectively. In an 8 wk trial cows in early lactation were fed diets with 30% NDF with forage NDF from wheat straw or alfalfa hay in proportions of 0:3, 1:2, 2:1 or 3:0. Intake and milk yield were not influenced, but milk fat percentage, acetate to propionate ratio (C2:C3) and persistence were decreased with increasing straw, and yield of FCM decreased on all straw. Ratio of forage NDF to ruminally degradable starch (FNDF:RDS) was 1.10 1.01,.92 and.84 in 0:3, 1:2, 2:1 and 3:0 diets, respectively, and it was concluded that a ratio of <1:1 would result in low C2:C3, and poor persistence. In another 8 wk trial, cows were fed diets formulated to contain equal forage NDF from wheat straw or alfalfa hay, and steam-flaked or dry-rolled sorghum grain in a 2 x 2 factorial arrangement of treatments. All diets had FNDF:RDS >1:1. Forage source did not influence any performance parameter nor did forage source interact with grain processing. Steam-flaking grain increased milk yield 12%, milk protein yield 14% and improved efficiency and persistence. Although milk fat percentage was decreased from 3.6 to 3.2, yield of milk fat was not influenced. It was concluded that increasing starch degradability may improve performance if the ratio of FNDF:RDS is maintained > 1:1. In the last experiment, duodenally cannulated cows were fed diets similar to those in the second lactation trial, except straw was substituted for 2/3 of the alfalfa hay on an NDF basis. Substituting straw for alfalfa did not influence flow of OM, starch or any CP fraction, but resulted in decreased (54 vs 47%) ruminal cellulose digestibility. Steam-flaking sorghum grain increased ruminal digestion of starch (74 vs 48%), increased flow of non-ammonia CP (120 vs 110% of intake) and bacterial CP (2.8 vs 2.2 kg/d), and decreased ruminal digestibility of cellulose (47 vs 53%), compared to dry-rolling. Response to steam-flaking in the lactation trial was probably due to both increased energy availability and improved duodenal flow of CP.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Agriculture
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Nutritional Sciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Single, R.S.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleEffects of sorghum grain processing and forage fiber source on milk production, digestibility and kinetics of passage in Holstein cows.en_US
dc.creatorPoore, Matthew Henry.en_US
dc.contributor.authorPoore, Matthew Henry.en_US
dc.date.issued1990en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractExperiments were conducted to determine effects of source of forage and starch degradability on milk production, digestibility and passage in Holstein cows. A preliminary experiment showed that sampling site, dosing time and passage model had little influence on passage parameter estimates for grain in lactating cows. Mean retention times were 17 and 25 h for duodenal and fecal sampling, respectively, and 16 and 18 h at the duodenal site and 24 and 26 h at the fecal site for doses given before rather than after feeding, respectively. In an 8 wk trial cows in early lactation were fed diets with 30% NDF with forage NDF from wheat straw or alfalfa hay in proportions of 0:3, 1:2, 2:1 or 3:0. Intake and milk yield were not influenced, but milk fat percentage, acetate to propionate ratio (C2:C3) and persistence were decreased with increasing straw, and yield of FCM decreased on all straw. Ratio of forage NDF to ruminally degradable starch (FNDF:RDS) was 1.10 1.01,.92 and.84 in 0:3, 1:2, 2:1 and 3:0 diets, respectively, and it was concluded that a ratio of <1:1 would result in low C2:C3, and poor persistence. In another 8 wk trial, cows were fed diets formulated to contain equal forage NDF from wheat straw or alfalfa hay, and steam-flaked or dry-rolled sorghum grain in a 2 x 2 factorial arrangement of treatments. All diets had FNDF:RDS >1:1. Forage source did not influence any performance parameter nor did forage source interact with grain processing. Steam-flaking grain increased milk yield 12%, milk protein yield 14% and improved efficiency and persistence. Although milk fat percentage was decreased from 3.6 to 3.2, yield of milk fat was not influenced. It was concluded that increasing starch degradability may improve performance if the ratio of FNDF:RDS is maintained > 1:1. In the last experiment, duodenally cannulated cows were fed diets similar to those in the second lactation trial, except straw was substituted for 2/3 of the alfalfa hay on an NDF basis. Substituting straw for alfalfa did not influence flow of OM, starch or any CP fraction, but resulted in decreased (54 vs 47%) ruminal cellulose digestibility. Steam-flaking sorghum grain increased ruminal digestion of starch (74 vs 48%), increased flow of non-ammonia CP (120 vs 110% of intake) and bacterial CP (2.8 vs 2.2 kg/d), and decreased ruminal digestibility of cellulose (47 vs 53%), compared to dry-rolling. Response to steam-flaking in the lactation trial was probably due to both increased energy availability and improved duodenal flow of CP.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectAgricultureen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineNutritional Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSingle, R.S.en_US
dc.contributor.committeememberHuber, J.T.en_US
dc.contributor.committeememberTheurer, C.B.en_US
dc.contributor.committeememberBrown, W.H.en_US
dc.contributor.committeememberLei, K.Y.en_US
dc.identifier.proquest9103049en_US
dc.identifier.oclc709778206en_US
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