• Asian-Australasian Journal of Animal Sciences
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• 제5권3호
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• pp.419-426
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• 1992

After the virtual eradication of cattle during World War II, Papua New Guinea herds were rebuilt with Shorthorn and Aberdeen Angus cattle from Australia. These, and Red Sindhi and Sahiwal, imported in 1952, were considered unsuitable breeds. In 1954, Department of Agriculture, Stock and Fisheries imported three Brahman bulls and three heifers from Texas and in 1960 began importations of Afrikaner from Queensland. In Central Province, Brahmans were crossed with Angus and at Erap (Morobe) the hottest place in Papua New Guinea, Shorthorns were crossed with Afrikaners. In 1965, Brahman and Brahman-cross were sent to Erap. Records of breeding and growth rates were collected for use in upgrading in cattle of the basis of performance, not pedigree. The data are not ideal for genetic analysis, since no control groups were maintained. Birth weights (BWT), weaning weights (WWT) and calving intervals (CI) were analysed for the period 1969-1978. After exclusion of unsatisfactory data, 2,514 calf records were used, including both breeds from 1969 to 1973, but only Brahman-cross subsequently. Breed mean BWT ranged only from 30.6 to 33.8 kg. As Brahman content increased, BWT decreased and WWT increased; within a genotype, there was a negative maternal effect of high Brahman content on BWT and a positive effect on WWT which ranged from 138 to 174 kg. Afrikaner calves had heavier BWT but lighter WWT. As expected, bulls were heaviest, heifers lightest and mature cows bore and reared heavier calves. Calving interval (405 days, equivalent to 90% calving) was unaffected by breed but 4-year old cows averaged 423 days. Breed differences in BWT and WWT are consistent with the body of literature on performance of Brahmans and Afrikaners. Since cattle tick are not present and internal parasites are insignificant at Erap, the superiority of Brahmans indicates that they were better at utilizing the mediocre quality grazing of the Markham Valley or were more heat tolerant. Performance selection over ten years resulted in the virtual elimination of Afrikaners, with the final genotype approximately 9/16 Brahman, 3/8 Shorthorn and 1/16 Afrikaner.

• Asian-Australasian Journal of Animal Sciences
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• 제22권5호
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• pp.756-764
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• 2009

Provision of an optimal environment for the calf is critical to establishing the patterns of growth and development essential to allow the heifer to express its genetic potential for milk output and reproductive capacity during its productive life. Maternal nutrition during gestation is now recognised as a key to genetic programming in utero and this influence is extended through the complexity of hormones, growth factors and immunostimulants incorporated into colostrum and milk consumed by the neonatal calf. This natural process is most often disrupted as calves are weaned abruptly to maximise milk output for commercial exploitation. The key then is to accelerate the rate of maturation of the ruminal epithelium through the provision of concentrate starter rations and high quality forage, which promote VFA production. Management systems to promote these processes in Holstein Friesian cattle are well developed, however, little is known of these processes with buffalo and Bos indicus dairy cattle such as the Sahiwal. The development of methods to program the neonate to grow faster to puberty in these species will be important to improving their productivity for the dairy industries in tropical and sub-tropical environments in the future.