Tup be and not tup be

Alnorthumbria Vets director John Macfarlane.
Alnorthumbria Vets director John Macfarlane.

The one and often only thing tups get prior to breeding is a dose of wormer.

Ironically this is probably the only thing they don’t need.

Tups should be assessed six weeks pre-tupping for:

1. Ability to seek and serve

2. Ability to impregnate

3. Biosecurity – are they an infectious threat to the flock?

The ability to seek and serve requires libido. If possible his interest should be tested. Sponges could be used to bring a batch of females into season and if necessary they can be aborted 10 days later. Seeking ability also requires general health and soundness – he should be bright and healthy with a body condition score of 3.5.

Too fat means lazy, while too thin could result in a loss of stamina. 3.5 may seem high but it will likely drop when the season gets under way.

The tup should walk well and his feet should check out free of problems. His sheath and brisket should be free of painful sores that would stop him for sure and his penis should be extrudable and normal in appearance.

He should have teeth good enough for the feeding system (ideally perfect teeth and perfect bite) and he should have a normal temperature.

The tups’ trace element status, liver fluke status and general metabolic health will hopefully be assessed as part of the overall flock blood profiling so any abnormalities can be corrected.

The ability to impregnate requires the production of ample fertile semen and this in turn requires two adequately sized firm testicles hanging low and free in the scrotum.

Surplus scrotal wool can be clipped off at this stage but a protective layer should be left – the aim is to stay cool but with some protection from flies, thistles, direct sun and chaffing.

Scrotal circumference is statistically linked to fecundity (number of multiple births) and to the age of puberty in the female offspring so for these reasons it may be important but perhaps not crucial in all systems. Your vet will have a table of scrotal reference ranges for different ages and breeds.

Hard testicles are usually inflamed or traumatised, soft testicles are usually degenerate.

The epididymes should feel right and be free of fluid blockages.

Despite all these checks, 70 per cent of subfertile or infertile tups will so far appear fine, so, for this reason, semen quality of all tups should be checked pre-use.

Thankfully, modern programmable pulsators (electroejaculators) make this quicker and more reliable than in the past.

The semen will be assessed for sperm richness, sperm motility and sperm shape and passed or failed accordingly. Often the assessment will be on ‘degree of subfertility’ and tup usage can then be planned more strategically using the less fertile tups with fewer females. The sterile ones will obviously need replacing. Some semen test failures are recognisable as recoverable, some not, so the decision to cull or not can often be aided.

Biosecurity testing will be very dependant on the farm in question and local veterinary knowledge will advise on which infections to test for eg Border disease, Johnes, digital dermatitis, MV, brucellosis, scrapie susceptibility, tick borne disease, CLA, scab, lice, anthelmintic resistant worms, etc.