NOTE: This item is not available outside the Texas A&M University network. Texas A&M affiliated users who are off campus can access the item through NetID and password authentication or by using TAMU VPN. Non-affiliated individuals should request a copy through their local library's interlibrary loan service.
Simulation of genetic and environmental interaction of sheep production in northern Kenya
dc.contributor.advisor | Cartwright, T. C. | |
dc.creator | Blackburn, H. D. | |
dc.date.accessioned | 2020-08-21T21:41:05Z | |
dc.date.available | 2020-08-21T21:41:05Z | |
dc.date.issued | 1984 | |
dc.identifier.uri | https://hdl.handle.net/1969.1/DISSERTATIONS-424508 | |
dc.description | Typescript (photocopy). | en |
dc.description.abstract | A mathematical model, programmed in FORTRAN IV, was developed to simulate flocks of sheep on an individual animal basis. Simulations can be performed for any breed where specified breed parameters are potential mature size (WMA), potential peak daily milk production (GMLKL), maturing rate, ovulation rate, seasonality of breeding and wool growth. The nutritional environment is defined by crude protein content, dry matter digestibility and availability of forages. Managerial options are flexible to allow simulation of a wide range of production scenarios. The Integrated Project in Arid Lands (IPAL) collected production data on a flock of Somali Blackhead sheep located in northern Kenya. These data were used for model validation. Simulations were performed for this area for 9 genotypic combinations with WMAs of 30, 35, and 45 kg and GMLKLs of .90, 1.30 and 1.75 kg. Four years were simulated in which 2 nutritional environments were simulated; base year, drought year, recovery years 1 and 2 which were a resumption of forage parameters used in the base year. For reproductive rate, offtake of meat and milk per ewe, and flock production efficiency, sheep with a WMA of 30 were not as productive as 35 and 45 WMA sheep. The stress of a high level of milk production causes the 30/1.75 and 35/1.75 not to recover from the drought. The 35/1.75 and 45/1.75 were the most productive genotypes tests, illustrating the necessity of matching WMA and GMLKL to enhance efficiency. Genotypes were ranked for flock efficiency for protein, energy, weight sold and dairy milk offtake. The 45/1.75 ranked first or second, and 35/1.30 ranked from first to third except for weight sold. The 35/1.75, 30/1.75 and 45/.90 always ranked the lowest. The simulations performed are being utilized by IPAL for planning the next phase of their project. Simulated results on body size and milk production level led IPAL to investigate the use of larger sheep. Before these simulations, testing a new genotype was not planned. Furthermore, simulations indicate a controlled breeding season may be counterproductive; therefore IPAL is reevaluating controlled breeding as a possible practice to increase sheep productivity. | en |
dc.format.extent | xiii, 200 leaves | en |
dc.format.medium | electronic | en |
dc.format.mimetype | application/pdf | |
dc.language.iso | eng | |
dc.rights | This thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use. | en |
dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | |
dc.subject | Animal Breeding | en |
dc.subject.classification | 1984 Dissertation B628 | |
dc.subject.lcsh | Sheep | en |
dc.subject.lcsh | Breeding | en |
dc.subject.lcsh | Data processing | en |
dc.subject.lcsh | Kenya | en |
dc.title | Simulation of genetic and environmental interaction of sheep production in northern Kenya | en |
dc.type | Thesis | en |
thesis.degree.discipline | Philosophy | en |
thesis.degree.grantor | Texas A&M University | en |
thesis.degree.name | Doctor of Philosophy | en |
thesis.degree.name | Ph. D. in Philosophy | en |
thesis.degree.level | Doctorial | en |
dc.contributor.committeeMember | Bassett, J. W. | |
dc.contributor.committeeMember | Kothman, M. M. | |
dc.contributor.committeeMember | Sanders, J. D. | |
dc.contributor.committeeMember | Smith, G. M. | |
dc.type.genre | dissertations | en |
dc.type.material | text | en |
dc.format.digitalOrigin | reformatted digital | en |
dc.publisher.digital | Texas A&M University. Libraries | |
dc.identifier.oclc | 14100838 |
Files in this item
This item appears in the following Collection(s)
-
Digitized Theses and Dissertations (1922–2004)
Texas A&M University Theses and Dissertations (1922–2004)
Request Open Access
This item and its contents are restricted. If this is your thesis or dissertation, you can make it open-access. This will allow all visitors to view the contents of the thesis.