Resumen

GARCIA-MUNIZ, José Guadalupe et al. iables associated with milk yield of Holstein cattle in family dairy farms with different technology level. INCI [online]. 2007, vol.32, n.12, pp.841-846. ISSN 0378-1844.

The effect of environmental factors and technology level (NT) were evaluated on 305-day milk yield (PLT), peak milk yield (PP), days to peak (DPP), and persistency (PER) in Holstein cows of family dairy farms from Jalisco state, Mexico. Data analyzed (n = 4323 test-day records from 537 lactations) came from 16 dairy farms, categorized as being of low, medium or high NT. Fixed effects in the mixed model were NT, number, year, and season of calving. Similar PLT were found between seasons; however, PLT in the medium NT during the rainy season was 11% higher than during the dry season, and the opposite occurred in the high NT. A similar interaction was observed for PP. DPP in the low (68,7 days) or high (77,2 days) NT occurred later than (P<0,01) in the medium NT (47,7 days). PER in the medium or high NT was similar across seasons; however, it was higher (P<0,01) in the low NT during the dry (60%) than the rainy (44%) season. Milk production among family dairy farms differs across NT, which implies that rural development programs must take these differences into account.

Palabras clave : Bovinos Lecheros ; Curvas de Lactancia ; Lechería Familiar ; Nivel Tecnológico .