The errors associated with estimations of the reproductive efficiency of bulls based on non-return data
| dc.contributor.author | Finkel, Peter William | en |
| dc.contributor.department | Dairy Husbandry | en |
| dc.date.accessioned | 2015-06-26T20:54:38Z | en |
| dc.date.available | 2015-06-26T20:54:38Z | en |
| dc.date.issued | 1953 | en |
| dc.description.abstract | Three statistical methods - multiple and linear regression, and analysis of variance - were used to interpret the data in this study. The results of a preliminary study indicated that there were several major sources of variation in the non-returns of bulls. These were seasonal differences, possible breed differences, and differences between bulls within a breed. In addition, there were differences in breeds in different seasons. Upon consideration of these data a regression study of 33 bulls was undertaken to ascertain the degree of relationship between the changes in the early and late non-returns to first services. Statistically, it was found that when both the 60-90 day and 30-60 day non-returns are available, the latter are of little practical value in predicting the changes in the 150-180 day non-returns. When only the 30-60 day figures are available they may be used with reasonable accuracy to “estimate” the final changes in the 150-180 day non-returns. An analysis of variance of the errors of estimate from the regression studies indicated that there are several assignable causes of variation in non-return estimates. These include differences between breeds as to the effect of season on reproductive efficiency, differences between bulls within a breed, and a significant difference in seasonal effect in different stations. The use of non-return data in estimating the reproductive efficiency of a bull is of value only when all factors that affect this reproductive efficiency are considered. This investigation shows the significance of some of the various factors to be considered. | en |
| dc.description.degree | Master of Science | en |
| dc.format.extent | 91 leaves | en |
| dc.format.mimetype | application/pdf | en |
| dc.identifier.uri | http://hdl.handle.net/10919/53772 | en |
| dc.language.iso | en_US | en |
| dc.publisher | Virginia Polytechnic Institute | en |
| dc.relation.isformatof | OCLC# 24817589 | en |
| dc.rights | In Copyright | en |
| dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
| dc.subject.lcc | LD5655.V855 1953.F565 | en |
| dc.subject.lcsh | Bulls -- Reproduction | en |
| dc.title | The errors associated with estimations of the reproductive efficiency of bulls based on non-return data | en |
| dc.type | Thesis | en |
| dc.type.dcmitype | Text | en |
| thesis.degree.discipline | Dairy Husbandry | en |
| thesis.degree.grantor | Virginia Polytechnic Institute | en |
| thesis.degree.level | masters | en |
| thesis.degree.name | Master of Science | en |
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