The performance of our pig herds has developed rapidly over the last two decades. At the end of the last millennium, 24 weaned piglets per sow a year were not commonplace, especially in piglet production. Today we are talking about 35 piglets and considerably more weaned piglets per sow and year. The genetic development is impressive. But we have to ask ourselves whether our management is always well prepared for this and whether our feeding strategies and feed composition meet these high performance requirements. What do we have to pay attention to, what do we have to do better? This article will answer these questions with practical recommendations.
Most important basis for high performance: condition feeding
“Body Condition Scoring (BCS)” – is not really carried out in every farm. You don’t necessarily have to measure the thickness of backfat continuously with an ultrasonic device. However, we must be able to assess the condition of our sows in the individual production cycles and classify them in the corresponding condition class (Figure 1). The illustration of the condition classes is now more than 20 years old – but it is not outdated, it‘s still up to date. Only sows that have been specifically fed for their condition are in a position to implement their genetic performance potential and to give the large number of piglets born alive sufficient birth weight. And only such sows have the possibility to produce enough milk from the very beginning – i.e. also enough colostrum milk. The sow condition should always range between at least 2.5 and not significantly higher than 3.5. The optimal condition of 3 should be reached as soon as possible after successful insemination. The feed quantity is always allocated on the basis of the breeding condition.
Figure 1: Condition classes for breeding sows („Body Condition Scoring – BCS“)
Milk yield and milk quality
Large litters need milk not only as a source of nutrients. Milk is much more important as a source of antibodies – immunoglobulins. Because piglets are born without immunoglobulins. The colostrum of the own mother is the only and most important source. The content of the important immunoglobulins IgG in the colostrum decreases significantly in the first 12 hours after the introduction of the milk shot into the teats (see Table 1). This is also confirmed by a recent scientific study carried out in the Netherlands In the first 10 hours after birth, the IgG content was reduced by 43% and 70% of the sows examined had an 80% reduced IgG content in the milk after 24 hours. Another important factor is the amount of colostrum intake. Piglets that could only absorb 200 g colostrum had a 20% lower weaning weight compared to piglets that received 350 g and more colostrum. Losing piglets also had one thing in common in this study: most of them belonged to the group of piglets who had received little colostrum.
Table 1: Immun globulin content in colostrum
Which factors have a significant influence on the production and quality of colostrum?
In addition to protein, ileal digestible amino acids and energy (evaluated on the basis of net energy),
two factors are particularly important: the mineral content and the resulting differentiation of the DCAB value (DCAB: Dietary Cation Anion Balance) between gestation and lactation feed as well as the content of insoluble fermentable structural carbohydrates.
The need of pregnant and lactating breeding sows for the important minerals calcium, phosphorus, sodium and magnesium has been investigated many times and the necessary daily supply depending on litter size and milk yield is well known. However, the storage of calcium and phosphorus in the depots during pregnancy and the rapid conversion of the metabolism to the release of these minerals from the depots (above all from the bone tissue) with incipient milk production is another important success factor. This is where the DCAB value and its differentiation between gestation and lactation feed comes into play. Through a targeted combination of different sodium sources (sodium chloride and sodium bicarbonate), the DCAB value can be adjusted to be at least 20 to 50 meq per kg higher in the gestation feed than in the lactation feed. This promotes the early release of calcium in particular from the depots with the onset of colostrum formation and thus compensates for the supply gap from absorption from the intestine. This ensures that the metabolism is supplied with minerals throughout the entire lactation period, which is also necessary for high daily milk production.
The DCAB (in meq per kg of feed) is calculated using the following equation:
DCAB (meq/kg) = 43,5 x Na (g/kg) + 25,6 x K (g/kg) – 28,2 x Cl (g/kg) – 62,4 x S (g/kg)
Fibre for breeding sows – “crude fibre” or…?
A great challenge in the feeding of high-performing breeding sows is the sufficient supply of “crude fibre”. But what is “crude fibre”, why does the sow need “fibre” and are there better characteristics than “crude fibre”?
The characteristic “crude fibre” cannot be described as a sufficient precise characteristic due to the chemically little exactly defined composition after the today’s state of knowledge, the digestion-sided need of the breeding sow at insoluble fermentable as well as insoluble, not to little fermentable structural carbohydrates. The NDF (Neutral Detergents Fibre) and ADF (Acid Detergents Fibre) quantities to be determined analytically are much more suitable. While the NDF contain all insoluble dietary fibers (insoluble hemicelluloses, cellulose and lignin), the ADF is part of the NDF and represents the cellulose and lignin (Figure 2).
Figure 2: Nutrient analysis for the differentiation of carbohydrates
Insoluble structural carbohydrates are used fermentatively in the large intestine of the breeding sow by the microbial population. The resulting short-chain fatty acids have a direct or indirect positive influence on the stability of the microbial population in the intestine. Especially gram-positive bacteria like Clostridia types are limited in their development. On the other hand, these short-chain fatty acids – acetic acid, lactic acid, propionic acid, butyrate and other metabolites from fermentation – are available as energy sources in the breeding sow’s metabolism. Scientific studies show that adult monogastric animals such as breeding sows can cover 30% or more of their energy requirements from fermentation in the large intestine.
The physical and chemical properties of the structural carbohydrates are of outstanding importance for a smooth-running faecal heel – i.e. the avoidance of any opstipation. In addition to their fermentability, they bind water in the intestinal lumen and thus facilitate faecal excretion. In addition, when the components are specifically selected, they also possess mechanical properties that are important for intestinal motility and thus the passage rate. A minimum content of ADF that is less fermentable also plays a role here. Any avoidance of opstipation is also an important health aspect for breeding sows. This is because blockages significantly increase the risk of endotoxin flooding (lipopolysaccharides – cell wall components of gram-negative bacteria such as E. coli). They can lead to inflammatory processes in the metabolism and are often jointly responsible for milk deficiency symptoms as part of the MMA complex. Their concentration can also increase in sow milk and they can thus be absorbed by the suckling piglets. This can result in a lack of vitality, reduced growth performance and increased suckling piglet losses.
Sources of NDF and ADF are components such as wheat bran, sugar beet pulp, soybean husk, sunflower husk, sunflower meal, rapeseed meal and palm expeller. Pressure hydrothermal processing of such components can further enhance the positive properties of these components in breeding sow feeding. In piglet feeding in particular, the use of such solubilised components rich in structural carbohydrates – especially special products with solubilised soybean hulls – is an important success factor in a healthy weaner as well as rearing diet and thus a very important component in significantly reducing the use of antibiotics for diarrhea treatment.
In order to implement such feeding concepts for high-yielding breeding sows with high milk production capacity in a technically correct and economically interesting way, the energy evaluation of feed raw materials and feed mixtures, which is still carried out in several countries like Germany and Austria today on the basis of metabolizable energy, must be renewed. An evaluation based on net energy, as it is done in the Netherlands, for example, assesses the energy supply from fermentation in the large intestine much more appropriately and is therefore not only the right evaluation model for breeding sow feeding. Also in the feeding of weaning and rearing piglets there is the possibility to optimally combine growth performance with intestinal stability – i.e. avoidance of dysbioses up to diarrhoea symptoms.
The nutrient contents that are to be achieved as target values in gestation, lactation and flushing feed are shown in Table 2.
Table 2: Recommendations on nutrient contents in feeding phases for high proliferic sows
What remains to be recorded?
Our current breeding sow lines have a high genetic potential. Well over 30 piglets born alive per sow and year are more and more the rule today. Whereas years ago the improvement of production performance was geared towards this, today the focus is on the question of how piglets can be reared on sows in the best possible way and with low losses. This requires new feed and feeding concepts that take more than just the purely numerical nutrient requirement into account. The special features of the digestive tract and its various compartments must be known and optimally used. The optimal support and use of fermentation in the large intestine of breeding sows is a key success factor if milk yield and milk quality are to be optimised to supply large litters.
