Evaluation of activity meters for estrus detection: A stochastic bioeconomic modeling approach

摘要

Although estrus detection makes a relevant contributionto the reproductive performance of dairy cattle,studies on the economic evaluation of automatic estrusdetection systems are rare. The objective of the presentstudy is to provide an economic evaluation of activitymeters used for estrus detection. The effect of differentestrus detection rates on gross margins was modeledwith SimHerd (SimHerd A/S, Viborg, Denmark). Theanalysis considers all costs associated with the investmentin activity meters. The economic evaluation wascarried out through simulation of Simmental herds withyearly milk yields of 7,000 or 9,000 kg and HolsteinFriesian herds with yearly milk yields of 9,000 or 11,000kg, each with herd sizes of 70 or 210 cows. Furthermore,we distinguished between 2 investment scenarios. Inscenario 1, only cows are equipped with activity metersfor estrus detection, whereas scenario 2 assumesthat cows and heifers are equipped with activity meters.Because existing empirical information for somevariables shows significant variability (estrus detectionrates, time for estrus detection), they were modeledwith distributions using the Monte Carlo method in @RISK (Palisade Corporation, Ithaca, NY), allowing usto model a probability distribution of net returns (NR)of investment in activity meters for estrus detection.The simulation results show that the average NR ofinvestment in activity meters for estrus detection overall scenarios ranges from +€7 to +€40 per cow per yearfor the Simmental breed, and from +€19 to +€46 percow per year for the Holstein Friesian breed. Generally,the NR depends on the milk production level assumed.For the Simmental breed, depending on the scenario,the simulation results show a 54 to 200% larger averageNR of investment in activity meters for estrus detectionwith a milk yield of 9,000 kg/yr compared with 7,000kg/yr. For the Holstein Friesian breed, the effect of themodeled milk yield on the NR is much less pronounced.Average NR of investment in activity meters are greaterfor larger herd sizes because of cost degression effects.An additional equipping of heifers has, on average, apositive effect on the economics of activity meters forestrus detection because of the resulting reduction inthe age at first calving. Considering all scenarios, theprobability of a positive NR of investment in activitymeters ranges between 74 and 98% for the Simmentalbreed and between 85 and 99% for the Holstein Friesianbreed.