Abstract
Linear models were developed to predict the daily (24 h) and total lactation milk yield of dairy sheep from single morning (am) or evening (pm) records. A total of 22 908 individual test-day milk records of 5110 ewes of the Chios breed, raised in 46 flocks, were used. Depending on the model, different daily yield estimates were derived for each ewe accounting for lactation number, stage of lactation, season of previous lambing and interval between successive milkings. Daily milk yield was also estimated from doubling the single am or pm records. Actual and estimated milk yields were compared using the following parameters:
root mean squared error;
mean absolute difference;
an accuracy parameter; and
the product-moment correlation.
Results were validated on independent data sets. The use of linear models resulted in significantly better estimates of the daily milk yield than simply doubling the am or pin record. Root mean square errors decreased by 7-17% and the mean absolute difference was reduced by about 3% of the average daily yield. Highest accuracy and correlation were obtained from linear model application. Total lactation milk yield was predicted from actual daily (24 h) yield and compared to predictions based on estimated daily yield from am or pm records, as well as directly on single milking records. The lowest root mean square errors were observed when daily yield had been estimated with linear models; they were 26-32% lower compared to the method of doubling the am or pm records and 6-13% lower compared to the method of estimating the total lactation yield directly from single milking records. Best mean absolute difference, accuracy and correlation were also obtained from linear model application. Results suggest that the adoption of a simplified milk recording scheme of single milking (am or pm) yield and the use of linear models for the estimation of daily (24 h) and total lactation milk yield can be effective tools for the improvement of the Chios breed.
| Original language | English |
|---|---|
| Title of host publication | PERFORMANCE RECORDING OF ANIMALS: STATE OF THE ART, 2004 |
| Editors | M Guellouz, A Dimitriadou, C Mosconi |
| Place of Publication | WAGENINGEN |
| Publisher | Wageningen, The Netherlands: Wageningen Academic Publishers |
| Pages | 115-119 |
| Number of pages | 5 |
| ISBN (Print) | 90-76998-54-X |
| Publication status | Published - 2005 |
| Event | 34th Biennial Session of the International-Committee-for-Animal-Recording - Sousse, Tunisia Duration: 28 May 2004 → 3 Jun 2004 |
Publication series
| Name | EAAP EUROPEAN ASSOCIATION FOR ANIMAL PRODUCTION PUBLICATION |
|---|---|
| Publisher | WAGENINGEN ACADEMIC PUBLISHERS |
| ISSN (Print) | 0071-2477 |
Conference
| Conference | 34th Biennial Session of the International-Committee-for-Animal-Recording |
|---|---|
| Country/Territory | Tunisia |
| City | Sousse |
| Period | 28/05/04 → 3/06/04 |
Keywords / Materials (for Non-textual outputs)
- dairy sheep
- milk recording
- Chios breed
- morning-evening milking