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Monday, August 5, 2013

Dairy cattle. Estrous detection


Keywords: estrus, detection,infertility management, mounting, crowding, signs, computer, programs


Estrous detection is a major challenge for dairy farmers, especially as cows produce more milk and there are endocrine profiles are modified.

In a group of animals such as this, the farmer will spend time looking for any cows that may be allowing mounting by another cow; a sign of standing estrus. Allowing mounting is however prone to misinterpretation in a situation such as this. These cattle are crowded and even cows that are not in heat may be mounted because they are unable to move away from the cow attempting to mount them.

Additional signs of estrus in a cow include rubbing of the hair on the base of the tail, mucous discharges from the vulva, dried mucus on the tail, restlessness and mud on and animal's flanks from when others have attempted to mount it. After estrus, metestral discharges will be seen. Although metestral discharges inform the farmer that estrus has just been missed, they can be used to determine the time of onset for the next estrus period or in proactive situations, when prostaglandin should be given to shorten the luteal phase.

As shown at lower right, a farmer is consulting a 21-day estrous detection chart from this herd, to determine if mounting is real or spurious. Telemetry devices that monitor cow movement and sophisticated dairy management computer programs are also available to assist farmers in estrous detection.