What about courtship. The boars testes secrete large quantities of 16-androstenes, both conjugated and unconjugated. These musk-smelling steroids accumulate in the submandibular salivary glands and serve as pheromones when dispensed with the boar’s saliva during courtship behaviour. At estrus, females recognise these pheromones, resulting in enhanced sexual receptivity.
During puberty, testicular size increases at an accelerated rate. By the age of 17 weeks (determined on breed as Meishan boars are much earlier) formation of the blood-testes barrier are complete and the testicular size correlates with total daily sperm production. EG: at 11 months – 170ml of semen is produced, with a total testicular weight of approximately 600 grams.
During insemination of the sow, semen is deposited through the cervix into the uterus. Spermatozoa move through the uterus rapidly and enter the oviducts within 15 to 30 minutes after insemination. The lower region of the oviduct serves as a storage area for spermatozoa as they await the arrival of ovulated oocytes. In this area of the oviduct, ejaculated spermatozoa undergo capacitation, removal of proteins that were acquired in the cauda epididymis. Capacitation is necessary before spermatozoa can fertilise ova.
Some of us hire, keep and bring on boars for meat but there is more to them than that. We all keep and grow on gilts and ask questions which is pertinent to them so lets discuss the boys.
The reproductive physiology of boars is intriguing because their testicular morphology and secretion of testicular steroids are distinctively different from those in other species. The testicles of boars contain a higher percentage of interstitial tissue and the volume of their ejaculate is unusually large, 50 to 400ml. Blood concentrations of estrogens in boars exceed those of estrous female pigs and their testicles produce significant quantities of the musk-smelling scent due to pheromones/hormones/testosterone.
In the scrotum, testicular temperatures are several degrees lower than the internal body temperature owing to both its anatomical position and its integrated vascular plexus that cools the blood entering the testes. The scrotum, by altering its wall thickness and varying the proximity of the testes to the body cavity, serves a critical role as elevated testicular temperature is detrimental to the production of viable spermatozoa and fertility.
Accumulation of the 16 androstenes (pheromones/hormones/testosterone) contributes to what many regards as unpleasant “boar taint” from sexually mature boars. Boars distinguish themselves with their high testicular production of androstenes and estrogens. Commercial breeds are susceptible to this. The rarer and traditional breeds do not need to be castrated as the process is slower. Generally the amount of fat is less in intact boars. With castrated boars having the most fat. Intact males are raised because they are more efficient (less food per unit gain and leaner) than castrated males; so marketed weights are around 90kg before boar taint appears.
If farrowing inside during winter: have heat lamp in creep area, with nice amount of straw. Radio is nice addition too.
If farrowing inside during summer: still have radio, heat lamp to be on day and night for the first 5 days and then reduce for just night time. Heat lamp maybe too much for summer. Perhaps a little night lamp on every night for three weeks just so everybody can see each other.
Farrowing outdoors in winter: ensure you have plastic curtains, arks are facing against the prevailing winds and you may also find that a fender (little fence for the outside of the ark) will be useful to place outside. A suitable farrowing ark size would be 8ft wide by 6ft long. Also to raise the lip of the entrance to the pig ark to prevent any piglets losing their way in the dark and accidentally falling out of the ark.
Farrowing outdoors in summer: same as above you may wish to keep the plastic curtains down to prevent predators until the piglets are say three weeks old.
Before your weaners go to new homes you may wish to ready yourself with a couple of things.
A few of days before the weaners leave ensure that you have:-
filled out the electronic movement licence for England and Wales this will be eAML2. For Scotland this will be ScotEID.
Ensure copy of movement licence is given to the new keepers on pick up of their weaners.
Ensure that any tagging or identification is done prior to the day of pick up.
Worm your pigs
Have your weaners in an area which is easy to transfer and move when new keepers pick up.
A little advice sheet may be useful showing the date of birth of the weaners, what feed they are currently on and how much you are currently feeding with how much to feed going forward. You may wish to offer some of your feed so the new keepers may integrate it with their feed, which will help settle the tummies. If indeed you are feeding a different compound feed.
Moving the sow from the litter is best as the litter will not be stressed and will be left in the area which is familiar to them.
Move sow with litter back inside (where they were born) leave sow with litter inside for a day and then move sow from pen back in field next day. Weaners will be stress free as in familiar area, radio will be on with goodies in trough and your familiar voice will make it all a very calming experience. This method makes it easier when it is time for them to go to their new homes.
Video showing sow and piglets going into the barn ready to be weaned.
Boars are quicker to finish than gilts (girls) and can be sent off at 26 weeks whereby you would expect to get an average dead weight (dw) of 70Kg. Gilts can be brought on to 9 months and will give you bigger hams.
Those that are producing charcuterie will bring on both boars and gilts to 10 months to 12 months of age.
Please do remember that boars and gilts that have been sold for meat weaners are for meat and not for breeding. If you feel that one of your meat weaners looks as if it is suitable for breeding, please consult the breeder who will gladly come and inspect the pig and confirm its eligibility for breeding purposes.
The Oxford Sandy and Black Breed Standard can be found here