Making the most of sow milking potential

Tuesday, December 8, 2015

German research indicates that top milking sows nowadays return a metabolic performance equal to that of a 45-litre-a-day dairy cow. This means that the best female lines can mostly cope with modern large litters   

by NORMAN DUNN   

Sow milk yield shows a wide variation between females, even of the same hybrid type, according to results from a recent trial at the University of Applied Sciences in Bingen, Germany.  

Differences of up to 6.1 kilograms in daily production within a small batch of hybrid females were found. Just to put this in context, an average litter of 12 piglets aiming for a viable litter daily liveweight gain of 2.5 kilograms needs 10 to 11 litres of milk daily.   

Changed days! Around 30 years ago, research into just how much milk the average hybrid sow was producing indicated a yield of six to eight litres. Mind you, the average litter at that time had only nine piglets. Now we're dealing with 11 to 14 fast-growing youngsters per litter. Has sow milk production kept up? Research at Bingen indicates that the answer is probably "yes." But only on average.

The research team, led by Prof. Georg Dusel, based its work on a modern litter of 11 to 12 piglets needing to achieve a daily weight gain of around 2.5 kilograms and one with 13 to 14 piglets aiming for three kilograms, the latter performance requiring the sow to provide as much as 12.5 kilograms of milk daily.

Of course, almost everything in such equations depends on optimum sow feeding and health. However, the Bingen work reveals that the genetic capability is there in the modern female. A batch of milk from 16 Topigs, recorded up to day 21 post-farrowing, gave an average 10.8 litres with highest performers peaking at 15 litres. Given the very high nutrient value of sow milk (average 6.5 per cent fat, 4.9 per cent protein and a lactose content way up over five per cent) the average sow producing, say 12 litres of milk daily, has the metabolic performance per kilogram liveweight of a dairy cow producing 45 litres per day!

The variability found in milk production per sow in this small trial once again underlines the importance of a close watch on piglet performance and sow body condition during suckling, warn the Bingen researchers. The results also indicate that a lot more work is maybe needed looking into lactation capacities of sows and nutritional quality of their milk.

Danish research at Aarhus University is currently trying out a two-part nursing sow feed concept aimed at optimum milk supply for the litter, while at the same time preventing undue loss of sow condition. One part of the ration is designed purely to meet sow maintenance requirements. The second part aims at ensuring top milk production. The Aarhus scientists find that amino acid requirements in the nursing sow ration change almost daily and cannot be optimally met by a standard farrow-to-weaning feed. For instance, the lysine-to-energy ratio stands at 0.38:1 on day two after farrowing, rising to 0.58:1 at typical weaning time in Denmark (day 28). Research team leader Peter Kappel Theil from the Department of Animal Science says weight loss of sows during milk production can be avoided if milk production is fed for separately – with amino acid amounts adjusted to meet milk production needs. Tests are ongoing.

Corn silage keeps hogs happy
An EU directive established 12 years ago says swine pens must include some sort of facility for occupying the animals' attention at least some of the time, hopefully stopping fighting and injuries.  Everything from old tires to retired armchairs have been thrown into hog pens since then and most ideas have worked, at least in the short term.

Time has proved that organic material is the real winner here. Give a pen of hogs some straw to chew and play around with and the occupants will be happily employed for hours. As always, though, there's manure handling to think about. In this respect, straw falling through the slats is acceptable if well chewed or short-chopped in the first place.

Now farmers in the Netherlands and Germany, who already make corn silage for dairy cattle or biogas fermenters, are finding that this can be an ideal material for keeping hogs happy if offered freely from an automatic dispenser in the pen.

The silage has to be high dry-matter to flow properly in the dispenser. At Soest Technical University in Westphalia, Germany, post-graduate student Julia Fine applied video monitoring technology to find out how attractive corn silage is for feeding hogs. In a row of slatted-floor 24-hog pens, she offered the animals daily corn silage (in addition to their complete liquid feed ration).

The typical reaction recorded by the Soest University video featured 167 to 366 visits by hogs in each pen with each animal visiting and occupied with the corn silage an average  of 10 times per day. An important point: over 110 days to slaughter time, the continuous offer of corn silage remained attractive to the hog.

The corn silage solution is proving even more useful for European hog farmers because it can be introduced with a minimum of work or expense. The Soest researcher says a simple 22-millimetre diameter drainage pipe with one end closed but incorporating two cut-out slits at one end to allow hogs to bite and tease out the silage is all that's required. The pipe is simply screwed in a vertical position against a pen wall and topped-up with corn silage daily.

Boars that better 1 kg daily weight gain
Up until this year, only 50 breeding boars were selected annually as good enough to influence the breeding framework of Norway's "Norsvin" national hybrid herd. The Landrace males involved (Duroc boars are also used in the national program) recorded in 2014 a feed conversion ratio of 1:2.15 from 40 to 120 kilograms liveweight with a daily liveweight gain over the same period of 1,071 grams. The selection to produce this top performance has also brought an average performance in the terminal breeding stage of the 60,000-sow national herd of 29.2 weaned per sow and year and 14.3 born alive per litter.

Every year in Norway, 1,800 Landrace and 1,200 Duroc male weaners from pedigree breeders have been shipped into the country's central Delta-Station testing facility at 25 kilograms liveweight to find the year's top 50 males. These chosen few are also precision-tested for lean meat content at 120 kilograms liveweight, as well as for bone structure and strength in spine, pelvis, shoulder blades and legs.

The difference between Norway and most other countries is that these animals are not slaughtered for these important tests. Instead, they are anesthetized and run through a computer tomography system to give millimeter-by-millimeter measurement of muscle formation, size of best joints as well as skeletal strength details. The latter is useful in sow breeding programs for frames helping towards a longer production life for healthier sows.

The Norwegian swine breeders actually started CT-aided selection 30 years ago when first breeding boars were secretly transported to a hospital during the night to be put through a computer tomograph – at that time officially only for humans. Now, the system is an important pillar in producing one of the world's best performing national hog herds.  

In August 2014, Norsvin and of one of the world's biggest swine breeding companies, the Dutch-based Topigs, signed a strategic agreement for long term collaboration and formed the international Topigs Norsvin concern, capable of producing more than 1.55 million hybrid sows annually and more than 8 million doses of semen.

A key to more pork from less feed?
Residual feed intake (RFI) is already recognized as a possibly better indicator of efficient weight gain in animals compared to the traditional feed conversion ratio. Researchers at the French National Institute for Agricultural Research (INRA) in Saint-Gilles now reckon that this approach offers a way of selecting for not only improved feeding efficiency, but also better health, less lameness and fewer injuries. What's more, selection for low RFI also seems to give breeding sows producing more piglets per litter with heavier weaning weights.

First of all, let's take a look at what RFI really means. This feed efficiency index was actually discovered about 60 years ago, applied in those days to beef cattle breeding by Robert M. Koch in the USA. Now, the factor is attracting more interest in the hog world. Residual feed intake is the difference between physically recorded consumption per animal and that calculated for the same performance in maintenance and weight gain using the standard equations. The lower the RFI for a hog, the nearer the animal is to an ideal textbook feed conversion efficiency, and therefore more efficient at converting feed into pork. Selecting for low RFIs over seven generations in France, and comparing the resultant hogs in the feeding barn with higher RFI hogs, indicated that the former had a lower metabolic rate.  For instance, the low RFI hogs, fed from 10 weeks of age to 100 kg liveweight in groups of 12 and videoed over 24 hours at 17 weeks of age to check behaviour, spend most of their time lying around their respective pens (for 80 per cent of the day and 89 per cent of the night). The low RFI hogs also had less health problems and spent fewer minutes of each day queuing at the automatic feeder. Calculated into metabolic energy requirement, this behavior meant the low RFI animals needed 14 per cent less energy (and less feed) than high RFI hogs.

Final advantages for the hogs selected for lower residual intake noted by the INRA researchers featured an almost complete absence of lameness and tail damage, logically attributed to the greatly decreased movement. The reaction to these results includes a lot more attention now being paid to RFI performance in the swine sector, according to the French researchers. BP