Reproductive performance of northern Australia beef herds. 7. Risk factors affecting mortality rates of pregnant cows
G. Fordyce
A G , K. D. McCosker B C , D. R. Smith D , N. R. Perkins C E , P. K. O’Rourke F and M. R. McGowan C
A The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, Centre for Animal Science, Carmody Road, St Lucia, Qld 4072, Australia.
B Department of Primary Industry and Resources, PO Box 1346, Katherine, NT 0851, Australia.
C The University of Queensland, School of Veterinary Science, Warrego Highway, Gatton, Qld 4343, Australia.
D Department of Agriculture and Fisheries, Charters Towers, Qld 4820, Australia.
E Formerly AusVet Animal Health Services, PO Box 1278, Toowoomba, Qld 4350, Australia.
F Queensland Institute of Medical Research, 300 Herston Road, Herston, Qld 4029, Australia.
G Corresponding author. Email: g.fordyce@uq.edu.au
Animal Production Science - https://doi.org/10.1071/AN19431
Submitted: 30 July 2019 Accepted: 3 November 2020 Published online: 22 February 2022
Abstract
Context: There are multiple reports of high annual cow mortality rates in northern Australia, but no reports clearly indicating the overall rates and the impact of primary risk factors.
Aims: The research aimed to determine which measured region-, property-, management group- and animal-level risk factors are associated with missing pregnant females.
Methods: Risk factors for the annual rate of pregnant-cow mortality were investigated in an epidemiological study using outcomes for 21 554 cows from 52 beef herds in 2009 and 2010 in four primary country types within the mostly-dry tropical north Australian environment. Modelling of 2001–2011 Australian beef-herd statistics was used to corroborate and further quantify findings.
Key results: In the epidemiological study, the overall predicted annual mean incidence of missing pregnant cows, a surrogate for mortality, was 10.9%, including lost tags and unrecorded cow movement that were estimated to constitute up to 9% missing cows. Risk factors associated with higher pregnant-cow mortality were as follows: not having follow-up rainfall more than 30 days after the first wet-season storms (4 percentage point increase); <2 t/ha of available pasture biomass in the early dry season (2–6 percentage point increase); pasture dry-season biomass <2 t/ha interacting with less than moderate mid-dry-season body condition score (3–10 percentage point increase); and, calving between April and September (non-significant trend for a 1–2 percentage point increase). Feed-quality measures did not affect mortality rate. Population modelling of Australian beef herd statistics suggested an average annual cow mortality rate in the Northern Forest region of ~7% compared with 2% in more nutritionally endowed regions.
Conclusions: The major risk factor for cow mortality is under-nutrition, related either to generally-low soil fertility, seasonally-dry conditions, or management that exposes animals to poor nutrition. Annual mortality of pregnant cows appears 6–9 percentage points higher in the low-fertility Northern Forest region than elsewhere.
Implications: Beef cow mortality is a major business cost in northern Australia. The efficacy of targeted management to achieve high cow performance was demonstrated by losses in a third of studied businesses in the Northern Forest being kept to the same or lower levels as median loss in endowed regions.
Keywords: beef cattle, mortality, northern Australia, production systems.
References
Anon. (2012) ‘7121.0 – agricultural commodities, Australia, 2011–12: livestock.’ (Australian Bureau of Statistics) Available at http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/7121.0main+features82011-12 [Verified 17 November 2020]Anon. (2014) ‘Climate of Australia.’ Available at http://en.wikipedia.org/wiki/Climate_of_Australia [Verified 17 November 2020]
Anon. (2015) ‘Statistics database.’ (Meat and Livestock Australia: Sydney, NSW, Australia). Available at http://statistics.mla.com.au/Report/List [Verified 17 November 2020]
Anon. (2020) ‘ABS maps.’ (Australian Bureau of Statistics). Available at https://itt.abs.gov.au/itt/r.jsp?ABSMaps [Verified 17 November 2020]
Bortolussi G, McIvor JG, Hodgkinson JJ, Coffey SG, Holmes CR (2005) The northern Australian beef industry, a snapshot. 2. Breeding herd performance and management. Australian Journal of Experimental Agriculture 45, 1075–1091.
| The northern Australian beef industry, a snapshot. 2. Breeding herd performance and management.Crossref | GoogleScholarGoogle Scholar |
Chilcott CR, McCallum BS, Quirk MF, Paton CJ (2003) ‘Grazing land management education package workshop notes: Burdekin.’ (Meat and Livestock Australia: Sydney, NSW, Australia)
Dixon RM, Coates DB (2005) The use of faecal NIRS to improve nutritional management of cattle in northern Australia. Recent Advances in Animal Nutrition in Australia 15, 65–75.
Dohoo I, Martin W, Stryhn H (2009) ‘Veterinary epidemiologic research.’ (Ed. SM McPike) University of Prince Edward Island, Charlottetown, Canada.
Fordyce G, Tyler R, Anderson VJ (1990) Effect of reproductive status, body condition and age of Bos indicus cross cows early in a drought on survival and subsequent reproductive performance. Australian Journal of Experimental Agriculture 30, 315–322.
| Effect of reproductive status, body condition and age of Bos indicus cross cows early in a drought on survival and subsequent reproductive performance.Crossref | GoogleScholarGoogle Scholar |
Fordyce G, Coates R, Debney M, Haselton S, Rebgetz R, Laing AR, Cooper NJ, Hall RL, Holmes WE, Doogan VJ (2009) A systems evaluation of high-input management using fortified molasses for beef production in Australia’s dry tropics. Animal Production Science 49, 177–191.
| A systems evaluation of high-input management using fortified molasses for beef production in Australia’s dry tropics.Crossref | GoogleScholarGoogle Scholar |
Moravek T (2015) ‘Beef rough indicator calculator of key performance indicators (BRICK).’ (Department of Agriculture and Fisheries: Brisbane, Qld, Australia). Available at https://futurebeef.com.au/knowledge-centre/brick/ [Verified 17 November 2020]
Fordyce G, McCosker KD, Barnes T, Smith DR, Perkins NR, O’Rourke PK, Marquart L, Menzies D, Newsome T, Joyner D, Phillips N, Burns BM, Morton J, Jephcott S, McGowan MR (2022) Reproductive performance of northern Australia beef herds. 6. Risk factors associated with reproductive losses between confirmed pregnancy and weaning. Animal Production Science
Gaden B (2005) Final report, Project LIVE.120. Meat and Livestock Australia, Sydney, NSW, Australia. Available at https://www.mla.com.au/contentassets/c66b3ffdfe0d416f8683daa115518ae1/live.120_final_report.pdf [Verified 17 November 2020]
Henderson A, Perkins N, Banney S (2013) Determining property-level rates of breeder cow mortality in northern Australia. Final report B.NBP.0664. Meat and Livestock Australia, Sydney, NSW, Australia. Available at https://www.mla.com.au/contentassets/ec07dba1026a41619057f5d94ca05257/b.nbp.0664_literature_review_final_report.pdf [Verified 17 November 2020]
Holroyd RG, Fordyce G (2001) Cost effective strategies for improved fertility in extensive and semi-extensive management conditions in northern Australia. In ‘The 4th international symposium on animal reproduction’, Huerta Grande, Cordoba, Argentina, 22–24 June 2001. pp. 39–60. (International Congress on Animal Reproduction)
Jackson D, Rolfe J, English B, Holmes B, Matthews R, Dixon R, Smith P, MacDonald N (2012) ‘Phosphorus management of beef cattle in northern Australia.’ (Meat and Livestock Australia Limited, Sydney, Australia).
Jayawardhana GA, McCool CJ, Zuill DQ, Olm TC (1992) The effect of stocking rate on breeder productivity in the Victoria River district. In ‘Proceedings of the north west Australia pastoral conference’, Katherine, NT, Australia, 28–29 October 1992. pp. 72–80. (Department of Primary Industry and Fisheries, Northern Territory)
Jubb TF, Vassallo RL, Annand TE (1996) Estimating deaths in breeder-age female cattle in the Kimberley region of Western Australia. Australian Veterinary Journal 73, 152–153.
| Estimating deaths in breeder-age female cattle in the Kimberley region of Western Australia.Crossref | GoogleScholarGoogle Scholar | 8660231PubMed |
Kernot JC (1998) Sustainable beef production on tropical tallgrass using the local best practice (LBP) approach. Final report, Project DAQ.092/NAP3.306. Meat and Livestock Australia, Sydney, NSW, Australia. Available at https://www.mla.com.au/contentassets/e2ff6ae92d1f405a8e3087af81cc52f0/daq.092_final_report.pdf [Verified 17 November 2020]
Lane J, Jubb T, Shepherd R, Webb-Ware J, Fordyce G (2015) Priority list of endemic diseases for the red meat industries. Final report, Project B.AHE.0010. Meat and Livestock Australia, Sydney, NSW, Australia. Available at https://www.mla.com.au/contentassets/5c4a6eb332a94448b15602249c9fa6f1/b.ahe.0010_final_report.pdf [Verified 17 November 2020]
McCosker KD, O’Rourke PK, Fordyce G, Smith DR, Perkins NR, McGowan MR (2020) Reproductive performance of northern Australia beef herds. 5. Factors influencing risk of non-pregnancy. Animal Production Science
McGowan MR, McCosker K, Fordyce G, Smith D, O’Rourke PK, Perkins N, Barnes T, Marquet L, Morton J, Newsome T, Menzies D, Burns BM, Jephcott S (2014) North Australian beef fertility project: cash cow. Final report, Project B.NBP.0382. Meat and Livestock Australia, Sydney, NSW, Australia. Available at https://www.mla.com.au/research-and-development/search-rd-reports/final-report-details/productivity-on-farm/northern-australian-beef-fertility-project-cashcow/370 [Verified 17 November 2020]
McLean RW, McCown RL, Little DA, Winter WH, Dance RA (1983) An analysis of cattle live-weight changes on tropical grass pasture during the dry and early wet seasons in northern Australia. 1. The nature of weight changes. Journal of Agricultural Science 101, 17–24.
| An analysis of cattle live-weight changes on tropical grass pasture during the dry and early wet seasons in northern Australia. 1. The nature of weight changes.Crossref | GoogleScholarGoogle Scholar |
Niethe GE, Holmes WE (2008) Modelled female sale options demonstrate improved profitability in northern beef herds. Australian Veterinary Journal 86, 458–464.
| Modelled female sale options demonstrate improved profitability in northern beef herds.Crossref | GoogleScholarGoogle Scholar | 19076767PubMed |
O’Rourke PK, Winks L, Kelly AM (1992) ‘North Australia beef producer survey 1990.’ (Meat and Livestock Australia: Sydney, NSW, Australia)
Sullivan RM, O’Rourke PK (1997) A comparison of once- and twice-yearly weaning of an extensive herd in northern Australia 1. Cow liveweights, mortalities and fertility. Australian Journal of Experimental Agriculture 37, 279–286.
| A comparison of once- and twice-yearly weaning of an extensive herd in northern Australia 1. Cow liveweights, mortalities and fertility.Crossref | GoogleScholarGoogle Scholar |
Tothill JC, Gillies C (1992) ‘The pasture lands of northern Australia: their condition, productivity and sustainability. Occasional publication, no. 5.’ (Tropical Grassland Society of Australia, Meat Research Corporation)
Winks L, Laing AR, O’Rourke PK, Wright GS (1979) Factors affecting response to urea-molasses supplements by yearling cattle in tropical Queensland. Australian Journal of Experimental Agriculture and Animal Husbandry 19, 522–529.
| Factors affecting response to urea-molasses supplements by yearling cattle in tropical Queensland.Crossref | GoogleScholarGoogle Scholar |
