Effect of environmental factors and breed group, and their interactions on performance of Venezuelan dual-purpose cows

Authors

  • Lucía Vaccaro Facultades de Agronomía and Ciencias Veterinarias, Uniuersidad Central de Venezuela, Maracay, Venezuela
  • Rodolfo Vaccaro Facultades de Agronomía and Ciencias Veterinarias, Uniuersidad Central de Venezuela, Maracay, Venezuela
  • Omar Verde Facultades de Agronomía and Ciencias Veterinarias, Uniuersidad Central de Venezuela, Maracay, Venezuela
  • Humberto Humberto Mejías Facultades de Agronomía and Ciencias Veterinarias, Uniuersidad Central de Venezuela, Maracay, Venezuela
  • Leyla Rios Facultades de Agronomía and Ciencias Veterinarias, Uniuersidad Central de Venezuela, Maracay, Venezuela
  • Eva Romero Facultades de Agronomía and Ciencias Veterinarias, Uniuersidad Central de Venezuela, Maracay, Venezuela

Keywords:

Dual-purpose cattle, Genotype-environment interaction, Latin America, Lowland tropics, Zebu, Cross-breds, Milk yield, Days open, Calf weight

Abstract

Records of milk yield, days open, and 120-day calf weight were obtained from 1843 cows on four lowland tropical farms with different levels of management and mean milk yields of 678, 822, 1010, and 2461 kg per lactation. Three main breed groups were represented on each farm: zebu type (Z), medium (M), and high (H) grade European-zebu crosses. The Z cows had the fewest days open and highest calf weights. Overall, the Z and M cows performed similarly, except on the farm with the highest mean milk yield, where the milk production of the M group was 16% higher. Although the Z group was probably somewhat selected, they were the best types for environments where milk yields were about 1000 kg per lactation or less, but M cross-breds were more productive at the higher level. The H cows showed no advantage on any farm for any of the traits and their milk yield was adversely affected by calving in the rainy season.

Issue

Section

Research Papers