Measuring the economics of six week in-calf rates

Transcription

1 Measuring the economics of six week in-calf rates TS Brownlie 1, JM Morton 2, C Heuer 3, S McDougall 1 1 Cognosco, Anexa Animal Health, 25 Moorhouse Street, PO Box 21, Morrinsville, Jemora Pty Ltd, PO Box 2277, Geelong, Victoria 3220, Australia 3 Epicentre, Institute of Veterinary, Animal and Biomedical Sciences, Massy University, Private Bag , Palmerston North 4442 Introduction In the last few years there has been a shift in extension focus on dairy farms from affecting change through entirely animal derived solutions to understanding the drivers for change on farm and the constraints that prevent these changes occurring. In doing so, the veterinary profession has looked towards the body of research generated by agricultural extension and social scientists and have begun to adopt some of the principles from their approach toward identifying these drivers. When considering improving the reproductive performance of dairy herds it is apparent that the driver for change lies with the motivation of the herd owner (Kristensen and Jakobsen 2011). If we accept this, then we need to consider the drivers that create a tension for change on farm. Within the complex framework of decision making, we believe that individuals will often consider most solutions in terms of time, effort and money and how these impact on their personal goals. These three comprise the value proposition to the herd owner. For the veterinarian striving to improve dairy herd reproductive performance, each one of these considerations has to be addressed when proposing change. Independently, each is not sufficient to bring about change. Exploring the financial component of reproductive performance has been made achievable recently with the introduction of the InCalf reproductive extension programme and the DairyNZ Whole Farm Model (Beukes et al. 2010) in New Zealand. The programme is widely available and accessible in various levels to all herd owners and rural professionals. The programme was originally developed for the Australian dairy industry following the Australian National Dairy Herd Fertility Study (Morton 2004). As part of the package of resources and tools InCalf offers a platform to benchmark the reproductive performance of a herd against industry targets. To provide a comparable measure of reproductive performance, the proportion of cows diagnosed pregnant within six weeks of the mating start date (six-week in calf rate) is used as a principle benchmark. The proportion of cows not in calf at the end of mating (empty rate) is also considered but is always relative to the variable length of mating. The industry levy body (DairyNZ) has funded the InCalf extension programme in response to the declining herd reproductive performance nationally and to achieve ambitious industry targets of a 78% six week in-calf rate by 2015 with minimal hormonal intervention ( co.nz/file/fileid/34840). Measuring the six week in-calf rate The New Zealand National Herd Fertility Study was conceived to evaluate the effect of the InCalf programme on dairy herd reproductive performance in four dairy regions of the country between 2008 and It used a large scale multi-year random controlled study design, where farms allocated to treatment were offered enrolment in a year-long structured reproductive extension programme; the InCalf farmer action groups. The objectives and study design of the National Herd Fertility Study are discussed in greater detail earlier in the New Zealand Society for Dairy Cattle Veterinarians conference proceedings (InCalf: Preliminary outcomes on farm). Proceedings of the Epidemiology & Animal Health Management Branch of the NZVA,

2 The study used the six week in-calf rate of the herds enrolled in the study as the chief outcome measure. In order to capture this data, pregnancy diagnoses were mandated on each herd between 84 and 96 days after the mating start date. This allowed the best possible window to capture accurately aged pregnancy diagnoses from the first six weeks of mating (42 to 84 days of gestation ideally). All animals not diagnosed as pregnant at the first pregnancy test visit were considered not-diagnosed-pregnant but not not-in-calf. A second and if necessary, a third pregnancy test visit allowed those animals not diagnosed as pregnant in the first six weeks to be diagnosed and aged if appropriate. A third test was considered necessary where mating length exceeded 17 weeks and herd owners agreed to fund the additional test. All efforts were made to ensure that the subsequent pregnancy tests allowed accurate ageing of all animals. Where this was not possible and an animal was diagnosed pregnant but of a gestation length too great to allow accurate or reliable diagnosis, it was diagnosed as pregnant but not assigned a gestation length. Each pregnancy tester nominated a maximum gestation length for each herd over which any mature foetus that was unable to be accurately diagnosed was allocated. To generate the six week in-calf rate for the eligible study herds, 87,644 pregnancy tests were recorded for the 2009/2010 season. In the subsequent analysis, an animal was considered eligible for the six week in calf rate measure if she had calved on or between 130 days before and 59 days after mating start date in the herd she was pregnancy tested in and not culled before the mating start date. Conceptions were assumed to have occurred only if the cow had had a positive pregnancy diagnosis. It was assumed that all pregnancies 35 days of gestation or older at pregnancy diagnosis were detected, and that no positive pregnancy diagnoses were false positives. For each cow, her conception status (having conceived at any stage during mating or not) was then calculated. Time from mating start date to conception was also calculated for each cow. For cows that did not conceive, time from mating start date was truncated ( censored ) at 148 days (1 day after the maximum interval for conceptions to be included in not-in-calf rate). Cows culled during the mating period without having a positive pregnancy diagnosis were censored at the end of mating, or at fewer days depending on their service and pregnancy diagnosis history. Not-in-calf rate was calculated at the date the mating ceased (date the bull was removed from the herd). Industry target Using the six week in-calf rate measure, the dairy industry agreed on targets for reproductive performance based on the distribution of current performance (Burke et al. 2008). The industry elected to set the six week in-calf rate target as the mean value of the top performing quartile of herds in the country. This currently sits at 78% of animals diagnosed pregnant at six weeks after mating start date. However, this should also be considered in line with other targets, for example a maximum 15% of the herd treated for anoestrus and no calving induction treatments. Greater explanation of the decisions around all key performance indicators was presented in the Proceedings of New Zealand Society of Dairy Cattle Veterinarians (Burke et al. 2008) In the same proceedings, a case study was also presented where the DairyNZ Whole Farm Model was used to derive the incremental value of improving the six week in-calf rate (Burke CR 2008). The Whole Farm Model predicts reproductive status of individual cows through a deterministic approach based on the scientifically acceptable physiological events required for a cow to re Proceedings of the Epidemiology & Animal Health Management Branch of the NZVA, 2011

3 establish a viable pregnancy while lactating. The simulations from these InCalf Economic Benefit Models were used to predict the operating profit (effective farm surplus) in $/ha for a variety of environmental and management variables and convert this in to the dollar benefit for each percentage change in six week in-calf rate. With a $5.50 pay out and a 3 cows/ha stocking density the rounded dollar value is currently $4 for each percentage change in six week in-calf rate multiplied by the population of cows in the herd. The distribution of six week in-calf rates of herds enrolled in the National Herd Fertility Study is presented earlier in the New Zealand Society for Dairy Cattle Veterinarians conference proceedings. Figure 1 below, presents the distribution of the economic value of the study herds meeting the industry target of 78% of cows pregnant in the first six weeks of mating in Included in the distribution are the negative economic values of herds with six week in-calf rates over 78%. Only 14.6% (11/133) herds met or exceeded the industry target in At a study level, the mean economic benefit of closing this gap is $18,699 (SD = $17,045) with a maximum of potential economic benefit of over $80,000 on one large herd of 1075 animals with a 59% six week in-calf rate. Figure 1. Distribution of the economic value of meeting the InCalf target of 78% of animals diagnosed pregnant 42 days after mating start date for 133 seasonal-calving, pasture-based dairy herds from four regions in New Zealand, enrolled in the national herd fertility study during 2009 When stratified by region, the confounding effect of herd size can be seen clearly. However the value of understanding these data is to the advantage of veterinary practitioners in these regions. Proceedings of the Epidemiology & Animal Health Management Branch of the NZVA,

4 Figure 2. Box and whisker plots of the economic value of meeting the InCalf target of 78% of animals diagnosed pregnant 42 days after mating start date for 133 seasonal-calving, pasture-based dairy herds by region of New Zealand, enrolled in the National Herd Fertility Study in 2009 Results of recent baseline social interviews conducted as part of the National Herd Fertility Study found that although reproduction is a priority for the future, herd owners are in the most part satisfied to very satisfied with their reproductive performance (Brownlie et al. 2011). Our belief is that establishing dissatisfaction with this status quo is necessary to bring about the change that can improve the reproductive performance of dairy herds. If we are to address each component of the value proposition the economic benefits must be addressed. The economic value of improving the six week in-calf rate through a condensed and effective calving period is being used by the InCalf extension programme in its Economics of Reproductive Performance Tool. By aligning this measure with industry targets it identifies the gap that exists for the majority of herd owners. This benchmarking process is being used to create some of the tension for herd owners to re-examine their goals for reproductive performance. In its practical application, this benchmarking also allows more achievable farm specific targets to be used instead of the industry target and reviewed with each new season, a process central to the InCalf doctrine of measured incremental gain. The National Herd Fertility Study is very grateful to the practices and technicians that have contributed so willingly and generously to support this study; Dr Andrew Weir at the Eltham District Veterinary Services, Dr Kate Foxcroft and Jason Gill at Riverside Vets, Dr Matt O Sullivan and Jared Ovens at Oamaru Veterinary Services and Dr Steve Harness, Dr Geoff Plant, Dr Bryce Todd, Dr Katrina Roberts, Dr Katie Denholm, Dr Noelle Finlayson and technicians Laura Clausen, Cathy Yanez, Jo Niethammer at Anexa Animal Health, Waikato Proceedings of the Epidemiology & Animal Health Management Branch of the NZVA, 2011

5 Acknowledgements The National Herd Fertility Study is very grateful to the practices and technicians that have contributed so willingly and generously to support this study; Dr Andrew Weir at the Eltham District Veterinary Services, Dr Kate Foxcroft and Jason Gill at Riverside Vets, Dr Matt O Sullivan and Jared Ovens at Oamaru Veterinary Services and Dr Steve Harness, Dr Geoff Plant, Dr Bryce Todd, Dr Katrina Roberts, Dr Katie Denholm, Dr Noelle Finlayson and technicians Laura Clausen, Cathy Yanez, Jo Niethammer at Anexa Animal Health, Waikato. The National Herd Fertility Study is funded by New Zealand dairy farmers through DairyNZ ( DAIRYNZ for enquiries). References Beukes PC, Burke CR, Levy G, Tiddy RM. Using a whole farm model to determine the impacts of mating management on the profitability of pasture-based dairy farms. Animal Reproduction Science 121, 46-54, /j.anireprosci , 2010 Brownlie TS, Weir AM, Tarbotton I, Morton JM, Heuer C, McDougall S. Reproductive management of dairy herds in New Zealand: Attitudes, priorities and constraints perceived by farmers managing seasonal-calving, pasture-based herds in four regions. New Zealand Veterinary Journal 59, 28-39, / , 2011 Burke CR, Fowler C, Tiddy RM. Building towards the InCalf programme for New Zealand. Proceedings for the Society of Dairy Cattle Veterinarians of the New Zealand Veterinary Association 1-8, 2008 Burke CR TR, Beukes PC. Case studies exploring the potential impact of farm system changes on herd reproductive performance,production and profitability. Society of Dairy Cattle Veterinarians of the NZVA Annual Conference 25-34, 2008 Kristensen E, Jakobsen EB. Challenging the myth of the irrational dairy farmer; understanding decision-making related to herd health. New Zealand Veterinary Journal 59, 1-7, / , 2011 Morton JM. Determinants of reproductive performance of dairy cows in commercial herds in Australia. PhD thesis, University of Melbourne, 2004 Proceedings of the Epidemiology & Animal Health Management Branch of the NZVA,