Three questions on heat detection

Author: Maarten Crivits (ILVO) - July 3, 2017

Managing the period of insemination is a complex affair because a lot of information needs to be taken into account. You don’t know when exactly the cow will be in heat, and often one needs to work within a limited timeframe. Furthermore, heat detection takes skill and time (at least two times half an hour/day). Due to this complexity, it is good to consider the insemination as a separate period, following the period of ‘starting up’. Starting up means: providing an animal at about day 55 that has remained healthy in its first month of lactation without passing through any negative energy balance. Also, an it has been shown that when a cow loses less than 0.5 point BCS, pregnancy rate increases considerably.

A question we like to answer in this project is how activity sensors can support dairy farmers in managing a desirable insemination period and the attainment of a good pregnancy rate. In September we will organize a meeting focusing on the profitability of investing in activity meters. Activity meters cannot replace the vet but can they function a certain additional trustee of the farm?

 But for now we would like to put three questions in the ether:

1. Are you using activity meters for heat detection as a selection criterion for culling? When an activity meter consistently tells you a cow does not become in heat when will you decide to cull? Will you wait until day 100 and discuss things with your vet or will you take action earlier on?  

2. When you use an activity meter will you still inseminate one of the first times possible (e.g. after 40 days) or will you rather take the comfort to wait somewhat longer and wait for ideal conditions (e.g. after 60 days, when the cow has fully restored from calving, yet still aiming for an optimal calving interval)?

3.Do you use your activity meter in a flexible way? There are quit some farmer that use, say, 50 sensors for 100 cows. After a cow is detected to be pregnant do you switch sensors to another cow? When do you put it back on? When the voluntary waiting period is over? Or, earlier on in the transition period? But if you want to follow up the health in transition period, wouldn’t you need to invest in rumination sensors, and are they worth it?