FR 15. Biological feasibility of establishing calving seasons in dual purpose herds
In order to study the biological feasibility of establishing calving seasons in 7 dual purpose herds, 1781 records of a total production index [IPT= (milk production/lactation + 8 x calf weight corrected for sex and age at 120 days)/(calvings interval)], were used. The models included the effect of calving season (T: 5 and 7 months), farm (F) grouped by zones: Apure-Guárico (APU-GUA, n=4) and Falcón (FAL, n=3), breed group (GR:<1/2, ½ and >1/2 European), number of calvings (NP:1 or 2+), year of calving (A:1990-93) and the interactions TxF, TxGR, TxNP,TxA,GRxF, GRxNP, GRxA. T affected IPT (P<.05) en APU-GUA and FAL. TxF affected IPT (P<.05) with a range of variation between T according to F from 4.5 -14.6% and 3.08 - 4.1% over mean values ranging between F from 3.08 - 4.1 and 4.16 - 7.84 in APU-GUA and FAL, respectively. A significant effect of TxA (P<.05) was observed in APU-GUA and FAL with displacements of the best calving season across years. It was concluded that it is not possible to recommend a T either at zone or individual farm level. Climatic and management changes prevented constant patterns from manifesting themselves over the years.
| Main Authors: | , , , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Asociacion Latinoamericana de Produccion Animal
2005
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| Online Access: | https://ojs.alpa.uy/index.php/ojs_files/article/view/280 |
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