Graduate Thesis Or Dissertation
 

Optimum stocking rate of cattle on three tropical grasses

公开 Deposited

可下载的内容

下载PDF文件
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/2n49t541f

Descriptions

Attribute NameValues
Creator
Abstract
  • Pangola digitgrass (Digitaria decumbens), Coastcross- 1 bermudagrass (Cynodon dactylon), and Kazungula setaria (Setaria sphacelata cv Kazungula) were used in a two-year study at the C.A.M.P.A. Training Center in Tampico, Mexico. The objective of the study was to determine the optimum stocking rate during the grazing season on these species and the relationship of average daily gain (ADG) on each grass with several nutritional and environmental parameters. The grazing seasons were from June 25, 1975, to January 21, 1976; and from June 16, 1976, to January 27, 1977. The parameters measured were available dry matter (kg), ADG (kg) during the preceding 14, 28, and 42 days, percentage of soil moisture, and precipitation (mm). An area of 2.7 ha of each species was used in this trial. These areas were divided into three lots of 1.1, 0.9, and 0.7 ha. Each lot was grazed by 9 and 10 zebu steers in a rotational form during the first and second grazing season, respectively. Each grazing season was divided into 5 grazing periods of 14 days. Covariance analysis was used to estimate the optimum grazing pressure. Analysis of variance showed no difference in ADG during the two grazing season. The estimated carrying capacities in animal units (animal unit = A.U. = 450 kg liveweight)/ha were 1.962, 2.062, 2.975, and 3.291 for Pangolagrass during periods 1, 2, 4, and 5, respectively. For Coastcross-1 bermudagrass the estimated rates were 3.492, 2.755, 1.397, and 1.000 A.U./ha for periods 2, 3, 4, and 5, respectively; while with Kazungula setaria the optimum grazing pressures were 1.790, 1.917, 1.838, and 1.441 A.U./ha for periods 1, 3, 4, and 5, respectively. The optimum rates were not estimated for periods 3, 1, and 2 for Pangolagrass, Coastcross-1 bermudagrass and Kazungula setaria, respectively, because the highest grazing pressure was to low to consume pasture production. The regression equations that best estimated ADG were: ADG on Pangolagrass (kg) = 1.675 + 0.000946 available dry matter at 15 cm height or more -0.558 ADG (kg) during 28 days before -0.0262% soil moisture from 12-25 cm depth. ADG (kg) for Coastcross-1 bermudagrass = -0.740 + 0.0598% soil moisture from 12-25 cm depth. ADG (kg) for Kazungula setaria = 0.1587 - 0.648 ADG (kg) during the 28 days before + 0.00645 precipitation (mm) during the preceding 14 days.
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
权利声明
Publisher
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome) using ScandAll PRO 1.8.1 on a Fi-6670 in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces

关联

Parents:

This work has no parents.

属于 Collection:

单件

缩略图 标题 上传日期 公开度 行动
file details OrtegaRivasEligio1979.pdf 2017-08-23 公开 下载