Ngoc Hieu Vu, Christine Große-Brinkhaus, Karl Schellander, Ernst Tholen:
Productive Performance of Holstein Friesian Cows under Tropical Conditions in Viet Nam

NGOC HIEU VU, CHRISTINE GROSSE-BRINKHAUS, KARL SCHELLANDER, ERNST THOLEN
University of Bonn, Institute of Animal Science, Animal Breeding and Husbandry Group, Germany

The Holstein Friesian (HF) is one of the most common breed in the world. In Viet Nam, milk production is relatively low compared to other tropical countries. Therefore, the Vietnamese government has imported large number of HF cows from Australia and USA to improve the local milk production.

The objective of the present study is to evaluate productive performance traits of HF cows in Viet Nam. The study was based on the analyses of 3242 HF cows, including imported and farm born (breed groups). Performance of these cows was tested with respect to lactation milk yield, lactation length and birth weight of calves. The statistical model comprised the fixed effects of breed groups, calving season, parity and the random effect of sire using SAS 9.2 PROC MIXED. Covariance components were estimated through the restricted maximum likelihood (REML) procedure.

The overall least squares means for lactation milk yield, 305-day milk yield, lactation length and birth weight of calves were 4619kg, 4416kg, 271.5 days and 32kg, respectively. Performance traits of imported HF cows were significantly higher than those of farm born HF. These differences could be explained by various genetic and physiological factors. However, the superiority of the imported cows indicates the high adaptability of the HF breed also under tropical conditions. Effects of season of calving and parity were significant. The highest milk yield was observed during autumn, whereas maximum lactation length and birth weight were observed in cows calving during winter. Milk yield of HF cows was higher in the fourth and fifth parity. Interactions between breed groups with season of calving and parity were also significant, but imported cows showed higher performance than farm born cows in each season and parity. The pooled estimates of heritability for the investigated production traits ranged from 0.50 to 0.65.

In conclusion, imported cattle in general performed better than farm born HF, and dairy HF cows were well adapted to the feeding and management systems as well as the environmental conditions in Viet Nam.

Keywords: HF cows, lactation length, lactation milk yield, parity, season of calving

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Contact Address: Ngoc Hieu Vu, University of Bonn, Agricultural Science and Resource Management in the Tropics and Subtropics (ARTS)Loebestr. 3, 53173 Bonn, Germany, e-mail: vungochieuyahoo.com