Effect of additional herbage areas on grazing dairy cows in commercial farms: A GPS and LoRaWAN based case study on herbage intake and milk yield

Abstract

Although grazing systems are widely used for lactating dairy cattle feed intake is generally lower than in a fully housed system even when the feed quality and animal’s nutritional requirements are similar. Here we investigate whether allocating additional herbage at a time linked to the cow’s behaviour can increase productivity using long range wide area network (LoRa) technology and GPS positioning to track animal activity and position. In particular, we examined whether additional herbage allowance increases daily herbage intake and milk production without compromising grazing efficiency.  Fourteen trials were undertaken with commercial dairy herds in 2019, 2020 and 2021 with cows in mid to late lactation. The ‘GrazeMore’ additional grazing was compared to a standard daily herbage allocation.  The ‘GrazeMore’ treatment period always followed an initial control period, sometimes with a subsequent control period. The composition of the herds was largely consistent over the duration of each trial, enabling the responses to be compared directly, though with an adjustment made for stage of lactation. Responses to additional ‘GrazeMore’ pasture allocations were inconsistent. Increased intakes during day grazing periods were sometimes balanced by reduced intakes in the following night periods, suggesting that factors other than the quantity of herbage on offer and the timing of its allocation during day grazing were responsible for limiting total 24h herbage intake and milk production. Synchronising additional pasture allocation with grazing behaviour does not always increase herbage intake and milk production.