Pasture Management – The use of fertiliser. A cautionary tale from Di Davies

Are your fields looking tired and short of grass? The simple answer is probably the lack of rain that we have been suffering in some areas of the South West while other areas have been suffering from a deluge.
However, if you are considering using fertiliser next year here is a cautionary tale. We took advice from local cattle farmers as to what they were using to improve their grazing and the unanimous answer was a chemical fertiliser caller 20:10:10 which came with the advice that once spread pastures should be left for a minimum of a week before returning the stock. This was done and being of a cautious disposition we actually left the paddocks for a full month before we did a stock rotation and moved the alpacas back onto the paddocks that had been treated with the fertiliser.
All appeared to be well until the next round of birthing – we had a female who had a perfectly normal birth, her cria was strong, she had lots of milk – indeed it was a text book birth. Next morning she was found in the field unable to stand. However, she was bright, eating and drinking. The vet arrived and was totally puzzled though felt it could be a calcium deficiency. She was advised by other vets, with greater knowledge of Camelids, not to give calcium until a blood sample had been analysed. This showed slightly low calcium levels, and the fertiliser was discussed which is high in calcium. No conclusions were reached but sadly both the cria and female were subsequently lost as despite administration of a wide range of vitamins and supplements the female never stood again.
Three days later with the next birth we had a prolapsed uterus, which was treated successfully, but we sought a cause and bloods were taken. Once again the calcium level was slightly low. The conclusion we reached with our vets was the administration of the fertiliser had increased the level of calcium in the grass and the alpacas natural calcium producing mechanism had switched off. The result of this was when they needed a boost of calcium during birthing it was not available as their systems had stopped generating calcium as they were getting it from the grass, but not storing it in their bodies.
Subsequent discussions with another alpaca breeder revealed that they too had used the fertiliser 20:10:10 and that season they had two prolapsed uterus. They have not used the fertiliser again and have had no further problems
Thus if you are thinking of using fertiliser on your fields in the Spring I would advise that you avoid 20:10:10.