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Feeding for vitality and uniformity

Maintaining vitality and uniformity in piglets is a major challenge to overcome in the quest to maximise the number of pigs reaching market weight. Piglet feeding strategies including probiotics and enzymes can help producers overcome this challenge and stay profitable.

By Gwendolyn Jones, global technical manager, Danisco Animal Nutrition, UK

Pig unit profitability is dependent on a pig’s ability to survive to weaning, thrive through the nursery period and grow to an optimum weight with acceptable carcass quality at market. All this has to be achieved in the shortest possible time period. However, the selection for increased litter size in sows has to some extent decreased this ability in pigs, since it has resulted in litters with increased numbers of low birth weight piglets and greater variability in piglet body weights. Lower birth weight piglets generally have a decreased survival rate, experience poorer weight gains and have increased days to market. Each piglet lost prior to weaning represents a loss in income per sow and each extra day to market in the pig increases the costs of production. The lack of uniformity in body weight within litters is an important concern because it complicates the management of pigs in the later stages of production, resulting in a loss of income for the farmer. It follows that there is a need for measures which support the vitality and uniformity of piglets from hyperprolific sows to meet piglet growth and survival targets for profitable pig production.

Microbial balance for vitality
From the moment the piglet leaves the security of the uterus and enters the birth-canal it becomes exposed to and is colonised by microbes in the gut. The relative proportion of different organisms in the newborn piglet’s environment and the extent to which the piglet comes into contact with them further affects the colonisation of the gut by microorganisms. A normally functioning gut in the pig is colonised by a diverse bacterial population of more than 400 bacterial species and is characterised by a healthy balance between harmless and pathogenic bacteria within this flora. An imbalance in the gut microbiota favouring pathogenic bacteria either during its development or when matured makes the animal more susceptible to disease, which affects vitality and can cause sub-optimal production results. Feeding regimes aimed at increasing vitality and growth in piglets should consequently include strategies which support the development and maintenance of a healthy gut microbiota from birth (Figure 1).

Feeding strategies for a healthy uniform growth. 

Probiotics help
Probiotics are feed additives containing live micro-organisms and are widely recognised for their ability to help establish and maintain a balanced gut microbiota. Scientific research demonstrated that feeding a Bacillus subtilis based multi-strain probiotic supplement to sows during late pregnancy and throughout lactation can successfully transfer the probiotic from the sow’s faeces to the piglet. Supplementation of pre-weaning piglets with probiotics can therefore be achieved via the sow. A further study evaluated the effect on the gastrointestinal microbiota of piglets preweaning by feeding a multi-strain Bacillus subtilis product to sows prior to lactation. Results of this second study demonstrate that the developing gastrointestinal microflora of a neonatal piglet can be positively influenced by probiotic supplementation to the sow. The same probiotic increased piglet viability over a 21 day lactation period when fed to sows.

Digestibility for uniformity
Another critical step in the piglet’s gut life-cycle is the transition to weaning. The digestive system at this stage is not adequately developed to handle the digestion and absorption of nutrients from a typical diet based on grains and vegetable proteins. This can lead to increased amounts of undigested nutrients supporting the proliferation of pathogenic bacteria in the hindgut, which again can result in enteric disease. The supplementation of weaner piglet feed with feed enzymes, such as xylanase, amylase, protease and betaglucanase, can help the piglet to digest the feed better. This has been proven to increase energy and protein availability which will help to prevent imbalances of the gut microbiota and maintain gut health. Improved gut health will not only increase growth rates and feed efficiency in piglets; it will also reduce the variability of pig weights within pens.

Variability in piglet growth performance can also result from variability in grain nutrient value, which can be corrected by the use of appropriate enzymes. Adding xylanase-based enzyme solutions to piglet feeds has been demonstrated to reduce the variability in the energy feeding value of key cereal grains and increase pig weight uniformity by 31% on average (Figure 2).

Coefficient of variation for final weight in piglets (Partridge 2008).

Mineralisation for strength
Skeletal development, leg structure and integrity in pigs are to a large extent associated with calcium and phosphorus reserves and are directly affected by dietary levels of calcium and phosphorus. For example research has shown that the dietary level of calcium and phosphorus from weaning to 98 kg influences skeletal development in gilts. Availability of these minerals over the growth period will have a carry-over effect on bone structure and consequent lameness in the first lactation. Since lameness is one of the key reasons for culling in breeding sows, feeding for maximum bone mineralisation can have an important impact on sow longevity and hence farm profitability. More recent scientific research by Varley and others in 2010 shows that bone mineralisation in pigs at 100 kg body weight can be influenced during the early stages of growth and development (i.e. from weaning to 30 kg) through higher dietary phosphorus levels than those required for growth performance to conventional slaughter weights. At current high phosphate prices higher levels of supplemented dietary phosphorus can significantly increase the cost of piglet feed. Furthermore high inclusion rates of inorganic phosphate in the diet can lead to increased pH levels in the gut resulting n decreased digestive efficiency and imbalances in the gut microflora of the piglet, which can lead to scouring and unthriftiness. Using higher levels of phytase in the weaner diet alleviates the need for high inclusion rates of inorganic phosphorus. Therefore adding phytase at higher inclusion rates into weaner diets to maximise bone mineralisation will support skeletal strength for later production stages and optimise piglet gut health to support increased growth rates.

What about feed cost?
Margin over feed costs is a key driver of the profitability of a pig unit. However, raw material prices are becoming increasingly volatile and the ability to make smart decisions about which tools and technologies best support risk management efforts to counter raw material price volatility can be what separates high performers from the rest. The key for producers and feed companies is to increase flexibility in their feed formulations as part of their internal risk mitigation, allowing them to switch to alternative, but cheaper raw materials and thus reduce the cost of feed without compromising animal performance.

Replacing major feed ingredients to some extent with alternative, but cheaper raw materials, results in more complex diets. Increased complexity means diets can contain more antinutrients, become more fibrous, less digestible and more variable in nutrient value, which can have a negative impact on piglet performance. Fortunately, many of the factors which affect digestibility and variability in nutrient availability can be targeted by appropriate enzyme supplementation. Something that is still often overlooked in formulating diets, is the fact that phytate is a potential source of phosphorus to the animal, as well as an anti-nutrient, which can reduce the availability of dietary calcium, energy and protein to the pig. Therefore adding phytase to the diet will not only help to increase the availability of phosphorus, but also calcium, energy and protein in piglet diets, which enables even greater feed cost savings in diet formulations. Recent research confirms that new generation bacterial phytases are more effective than traditional fungal phytases against the antinutrient effect of phytate. With increasing prices for feed phosphates and other key raw materials, producers should consider increasing the inclusion rate of phytase as well as maximising nutrient availability via the use of carbohydrases in their feed to replace more inorganic phosphorus and become more flexible in the choice of alternative raw materials without compromising piglet performance.