Delayed implantation in the Lynton Goat – an amazing discovery

It is now nearly two decades since Eric and I had the privilege of meeting Ray Werner for the first time and together with him founding the Lynton Friends of the Goats. .

We were very active members of the society until the traumas of Foot and Mouth disease in 2002 which led us to a decision to move away from the area and have only recently returned. But having read in Rupert Kirby's news update that the contraception programme has not so far led up to expectations it has occurred to me that evidence of delayed implantation which Eric and I discovered whilst working with the goats may have some bearing on this. I have researched the net and whilst delayed implantation is known to exist in many mammal species there is nothing whatsoever about it in goats.

So what is delayed implantation (also known as embrionic diapause). Very simply it is a survival strategy, a way in which certain species can hold a fertilised ovum in a state of dormancy before it implants into the uterine wall and develops.

The gestation period for a goat is approximately 5 months and I had always assumed that a successful mating would produce one or more kids five months later – not so, or at least, not necessarily so in the Lynton goat.

Eric and I witnessed the birth of a kid late one cold drizzly afternoon in the valley. We were alone in the valley and sat in our car by the roundabout to watch. The female was encircled by crows and on the hillside above her a group of billes were observing the process. As soon as the kid emerged everything sprang into action, the billies chased down from the hillside, the crows dived in to grab the pickings and the poor female jumped up to try to escape with her membranes trailing out behind her. She was pinned against the side of our car by the billy group and repeatedly mated while her newborn kid which was lucky not to have been trampled to death bleated pathetically up on the hillside. In my ignorance at the time I assumed that this was just to ensure that if the kid died another would be born 5 months later and in fact there is still something I wrote which I have found on the society webpage  to this effect. What I didn't know was that the mating could produce a kid long after the normal 5 month gestation period.

So how did we find this out and why is it not generally known. I assume that so far no-one has been able to determine the exact time between mating and subsequent birth in feral goat herds simply because they not monitored in the same way as domesticated stock.  Eric and I only found out by accident following the round up of 1998. This was the very first round up ever attempted. The valley goats at that time were mostly brown – as you can see from the photo of the round up on the link entitled  'The Goats' and opposite a photo of the relocated goats in their new habitat at Ash Ranges in Surrey. The use of feral goats in conservation grazing projects was just gaining momentum and a number of organisations were keen to take Lynton's surplus goats. With Ray Werner's expert advice and guidance we took the opportunity of rehoming all goats we could manage to catch which were displaying signs of crossbreeding. There were goats with long legs, short coats, large ears and generally poor body conformation and one particularly badly shaped billy which Ray named Grotty Spotty who was vasectomised by the vet before going to Surrey as they were willing to take him but didn't want him to breed on.. He was given pain relief and bedded down comfortably for the journey after his operation which was done under local anaesthetic and apparently walked out of the trailer on arrival and immediately started grazing. I  personally selected the goats to go to each organisation retaining the best animals for what we hoped would eventually become a gene bank of pure primitive goats in Lynton. One particular organisation and to the best of my memory I believe it was Thorndon Country Park in Essex,  asked for females only which they wanted as a permanently non-breeding group. The round up took place in early autumn before the annual rut and I carefully selected two females which had summer born female kids at foot and two other females which I knew had kidded earlier that year. I was absolutely convinced at the time that there was no possibility of them being pregnant so when I received a phone call the following year to say all but one of the adult females had produced kids I was gobsmacked. Not only that the kids arrived much later than 5 months after leaving Lynton and had no contact with billies in their new home. Hence the only possible explanation was delayed implantation.

Thankfully the birth of these kids was a great success with visitors to the Country Park and everyone was delighted. The introduction of goats from Lynton at Thorndon has also been a great success and the initial trials in the Country Park have expanded into a county wide grazing service using a combination of primitive goats and Red Poll cattle which they describe as a “conservation dream team”.

Joyce Salter March 2016