In the current global economic downturn, it's vital that pig producers have genotypes that are highly productive and produce pigs that grow fast on minimum feed. Because of genetic improvements, many DanBred producers in Denmark are rearing over 30 pigs per sow on a regular basis and this is weaning at four weeks, not at three weeks as is common in Asia. That's the view of Henrik Boholm, international area manager for DanBred International, who spoke at a recent seminar in Bangkok, Thailand.
Also remember that labour is expensive in Denmark and producers can't afford the luxury of staffing farrowing houses 24/7 as is commonplace in Asia. Pig numbers are not everything they have to grow efficiently and have a high lean meat content, too.
Genetic potential is important but unhealthy pigs will never realise their full potential a bit like expecting a car with a slipping clutch to go fast. Denmark is free from all exotic diseases the last recorded case of hog cholera was in 1933 plus there is a major research programme in place to control endemic and new diseases such as PRRS and PMWS.
Claus Holmgaard is AI manager with Danish equipment company Kruuse and he described how producers could achieve the magical 30 pigs/sow/year. He listed the following key areas:
- Top genetic breeding stock,
- Optimal housing & production facilities,
- Optimal vet support and,
- Optimal sow feeding to ensure output is maximised.
The key area though, for maximising breeding herd output, is the service house. If sows come on heat routinely and are inseminated correctly and hold in-pig, then everything else seems to follow in an orderly manner. Staff must be well-trained in all aspects of insemination techniques and the latest technology applied. Good, accurate records must be kept and the information used, not left gathering dust in the office, to target problem areas.
Semen must be stored at 16-18, ideally in a temperature-controlled semen storage unit. It's vital, added Holmgaard, that semen not be exposed to sunlight quite likely in Thailand or exposed to sudden changes in temperature. Naturally, semen should be used within the lifetime of the diluent, usually 3-8 days after collection.
Heat detection
Detecting sows on heat and, critically, not missing any is a key factor in achieving the 30 P/S/Y target. Sows should be checked twice daily for signs of heat. The service house should be well lit, with high-intensity lighting, for 16 hours per day. Snout contact with an old, smelly boar will stimulate the sow.
The technician should:
- Apply fist or knee pressure to the sow's flank,
- Grab and lift the fold of skin in the groin area and massage the udder, and
- Apply pressure to the vulva.
These techniques mimic how the boar would stimulate the sow if natural mating was to take place.
Heat detection is completed by carrying out the "standing test". If the sow willingly accepts the weight of the technician on her back, she is ready for insemination.
Insemination
The boar, which should be housed well away from the weaned sows, should be brought into the insemination area, positioned in front of the sows and allowed to make positive snout to snout contact with the sows. Be mindful of limiting the boar contact to five to six sows at one time, or the number of sows which can be inseminated within 30 minutes.
Clean the vulva with a dry, clean single-use paper towel. Catheter gel may be needed, especially with gilts. Gently insert the catheter forwards and upwards into the vagina, rotating it anticlockwise until it locks in the folds of the cervix. Do not squeeze the semen as this increases the risk of back flow. During the insemination, which should last 3-5 minutes, continue to stimulate the sow by sitting on her back or by leaning on her, to ensure semen transport. When the sow has sucked in all the semen, wait a couple of minutes before removing the catheter to prevent semen leakage. Alternatively, break the catheter and fold back on itself.
Note: leave the catheter in the sow for a couple of minutes only. It takes 20-25 minutes for the semen to reach the point of fertilisation, so continue to stimulate the sow, leave her in contact with the boar and importantly, do not stress her in the next one to two hours.
Normally sows are inseminated 24 hours apart, although sows with long heats may be inseminated three times. Sows do vary in terms of the length of heat short, normal and long, hence the number of inseminations may vary.
In order to obtain a good farrowing index, it's essential to pick up any returns to service. Ultrasound scanners are commonplace these days.
Maximising numbers weaned
First of all it's essential that all the piglets get a good drink of colostrum. With big litters, the smaller piglets may miss out, so observation is vital to check that all the piglets do suckle straight after birth, helping them manually if need be.
If sows can't adequately suckle their litters, fostering is necessary. The cheapest and easiest way is to use nurse or foster sows. The one-step nurse system involves taking three-week-old piglets off a sow and replacing them with two or three piglets of four or five newly farrowed sows, after first ensuring that they all have had that vital colostrum.
An alternative, but more time consuming option, is the two-step nurse system. As the name implies, two sows are involved in this technique. As before, sow A is weaned at 21 days. Then a sow which is milking well and which has been farrowed for a week is chosen. Her piglets get transferred to sow A and sow B's litter is replaced by piglets of newly farrowed sows. Though more complicated, the two-step option is more beneficial. Trial data indicates that the two-step system resulted in less mortality (6% versus 18%) and higher weaning weights (6.4kg versus 5.5kg) than the one-step nurse option.
Dr Sermsak Jiebna of ABCO, who represents DanBred International, said that to get maximum productivity from DanBred stock it's essential that pigs are fed well-formulated feeds with the correct nutrient levels. He stated that "performance can nearly replicate Danish levels, given that nutrition is adequate in terms of ration formulation and quality ingredients and the pigs do not suffer heat stress". Dr Jiebna also emphasised the need for good cooling systems large fans and dripper systems.
New units have a raised, slatted floor design whereby air for cooling is drawn up through the slats. On older units, modifications were having to be made in the gestation houses as the DanBred sows grow much larger than other hybrids.
