The northern Australian beef industry, a snapshot. 2. Breeding herd performance and management

Abstract

Breeding herd performance and husbandry were surveyed on 375 northern Australian beef properties in 8 regions during 1996 and 1997. Mean branding rates ranged from 62.6% in the Northern Territory to 77.1% in the Maranoa South West regions of Queensland with considerable variation within regional herds. The proportion of herds using controlled mating was highest in the Central Coastal, Central Highlands and Maranoa South West. Mean mating period across all regions varied from 5.6 to 11.8 months. Calving was seasonal with peak activity in the August–December period. Calving commenced earlier in the south (August) than it did in northern regions (September–November). Rainfall influenced the timing of commencement of calving and peak calving activity. The use of pregnancy testing was widespread but selective and often not all females were pregnancy tested. About 97% of properties used weaning strategies with a peak in calf weaning in April–July, and a minor peak in September–October. Although mean weaner ages were similar across regions (5.9–6.9 months), mean weaner liveweight varied markedly with weaners in the more northern regions being lightest (<190 kg) while those in southern regions tended to be >200 kg. Culling criteria for cows and heifers focused on temperament, conformation and reproductive failure; age was also important for cows with a common culling age of 10 years. Bulls were more commonly culled at 7–8 years of age. In addition to age, bulls were culled for physical defects, reproductive problems, temperament and poor quality/performing calves. Four to 5 criteria were commonly used to select bulls. Structural soundness and temperament ranked highest followed by conformation, weight for age, Breedplan and colour. Producers using Breedplan tended to use structural soundness and temperament also as selection criteria. The results suggest that producers associated increasing turn-off weight or decreasing turn-off age more with pasture improvement than with bulls of higher genetic merit for growth. Supplementation of the breeding herd increased in the last half of the calendar year. Supplements containing molasses, urea, phosphate source, salt, and sulphate of ammonia were the most commonly supplied supplementary nutrients. Vaccination for botulism was quite common (>30% of regional survey groups) in all regions except Central Coastal and Maranoa South West regions of Queensland. Comparisons with previous surveys show that there have been marked improvements in breeding herd performance and management over an extended period. The results are discussed in relation to scientific developments over the last 2 decades and future development of the northern Australian beef industry.

Livestock production in a changing climate: adaptation and mitigation research in Australia

“…However, in northern Australia this is further exacerbated by poor conception and weaning rates compared with cattle in the temperate regions of southern Australia. Bortolussi et al (2005) surveyed segments of the northern industry in the 1990s and found weaning rates varied between 50 and 80%. When this is coupled with low weaning weights of <0.3 of the maternal weight, it is clear that there is major scope for improvement in both weaning rate and weight.…”

Heifer nutrient intake during early- and mid-gestation programs adult offspring adiposity and mRNA expression of growth-related genes in adipose depots

“…In northern Australia, protein supplementation of breeder herds is necessary to maintain body condition during the dry season (Bortolussi et al 2005), while in Southern Australia, breeder cattle often graze winter and spring pastures that provide greater than the recommended level of protein (Walsh & Birrell 1987). We have previously reported that male fetuses exposed to a low level of maternal nutrient intake during the first trimester were heavier throughout the postweaning period compared with their high-nutrient exposed counterparts.…”

Dehydration as a risk factor for calf mortality in northern Australia

“…This is not surprising given the high rate of foetal growth during this period compared to the first and third trimesters (Eley et al, 1978). Due to seasonal rainfall patterns and therefore pasture quality (Norman, 1963, Robinson and Sageman, 1967, Holroyd et al, 1977, McIvor, 1981, Squires and Siebert, 1983, Coates, 2000 and herd management across northern Australia (Bortolussi et al, 2005), many breeding herds are likely experiencing decreasing pasture quality as their pregnancies progress. Therefore, many breeding herds may be at high risk of nutritional deficiency during mid-and especially late-gestation and consequently at risk of producing low birth weight calves.…”

“…Therefore the majority of cows in northern Australia are experiencing dry season conditions and low quality pasture during mid-late gestation. Consequently, the majority of calves in northern Australia are born between the months of October and January, with a tendency for later peak of calving further north (Bortolussi et al, 2005).…”