Carroll, Andrew Gerard (1984) Studies on reproductive performance of beef cattle in Central Queensland. Masters (Research) thesis, James Cook University.

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Abstract

Reproductive rates in beef cattle observed during a five year study (1979-1983) in the Central Highlands of Queensland were shown to be comparable with rates obtained in coastal areas. Conception rates as high as 88.8% (mean 82.6%) and branding rates as high as 84.1 % (mean 76.6%) were recorded. An effect of the 1982 drought was to decrease mean branding percentage for thirteen properties surveyed in 1983. The 1983 mean branding percentage was 61% which was significantly below the 72% obtained in 1981 (p < 0.05) and the 74% obtained in 1984 (p < 0.01). This is consistent with results obtained elsewhere.

Of 27 properties experiencing poor reproductive performance tested for vibriosis using the Campylobacter vaginal mucus agglutination test, twelve were found to be infected with a cow prevalence of 28.9% (201 cows tested and 58 infected). Only one property was found to be infected with trichomoniasis.

The 13 properties in the major survey were sampled before and after the wet season for a two year period (November 1980 to November 1982). Serovar hardjo was significantly (p < 0.01) more prevalent (13%) than serovar pomona (4.1 %) in this area. When the properties were divided into two groups on the basis of water holding capacities (WHC) of their predominant soil types, serovar hardjo was significantly (p < 0.05) more prevalent (18%) on properties with high (> 30%) WHC soils than on properties with low (< 20%) WHC soils (7.3%). Such differences in prevalence were not detected for serovar pomona.

Graphical display of monthly rainfall and hardjo prevalence demonstrated a cyclic pattern for both. Hardjo peaks tended to follow the rainfall peaks by 2 to 3 months. Similar effects were not demonstrable for pomona. As this area frequently has a midyear rainfall peak, hardjo prevalence may often peak when the majority of the area's beef cows are in the last half of pregnancy when they are most susceptible to leptospiral infection.

Twenty-six stock horses sampled were shown to have high hardjo (30%) and pomona (40%) prevalence in this area. This could have been due to local husbandry practices which may increase the exposure of these horses to young cattle and household dairy cattle and their urine under conditions of high stocking rates. Forty-two feral pigs sampled in this area were found to be virtually free of hardjo and pomona. Stock horses may therefore play a part in disseminating leptospirosis in this area.

In a single herd study, a group of pregnant cows (177) was tested before and after the last trimester of pregnancy for both serovars. Those cows with rising titres (34) had a significantly (p < 0.05) lower branding rate (64.7%) than those with steady or declining titres (83.2%). Thus leptospiral infection has been shown to correlate with branding percentage.

Item ID:	12035
Item Type:	Thesis (Masters (Research))
Keywords:	beef cattle, bovine reproduction, reproductive rates, conception rates, branding rates, fertility, infertility, environmental factors, disease, drought, seasonal rainfall, venereal diseases, vibriosis, trichomoniasis, leptospirosis, leptospira, serovar pomona, serovar hardjo, prevalence, epidemiology, soil groups, Queensland, Central Highlands
Additional Information:	Andrew Carroll received a JCU Outstanding Alumni Award in 2010.
Date Deposited:	14 Oct 2010 05:00
FoR Codes:	07 AGRICULTURAL AND VETERINARY SCIENCES > 0702 Animal Production > 070206 Animal Reproduction @ 60% 07 AGRICULTURAL AND VETERINARY SCIENCES > 0702 Animal Production > 070205 Animal Protection (Pests and Pathogens) @ 40%
SEO Codes:	83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8303 Livestock Raising > 830301 Beef Cattle @ 100%
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