Nutrition for gilt rearing

When rearing gilts, it is essential they are fed correctly. Read our information on nutrient recommendations to help maximise the lifetime productivity of your gilts.

Nutrition

The primary objectives of gilt rearing, whether the pigs are home-reared or bought in, is to ensure that gilts are fed correctly to ensure optimal lifetime productivity.

Nutrition is important in the development of gilts and can help to improve post-farrowing condition in the first parity, improve litter size and reduce the number of empty days.

Reproductive failure is one of the most common reasons given for premature culling, so giving gilts the best possible start will help to reduce this and the associated losses in revenue. Correct nutrition can also help to reduce foot and leg problems which can cause significant problems in the breeding herd, which also reduces culling.

Rearing

When rearing gilts and finisher pigs, it is important to remember they have different nutritional requirements; therefore, ideally, they should be housed separately and fed to the required condition.

When rearing gilts, the aim is to prepare the animal for a long productive life. The nutritional strategy is largely determined by target weight, age and in some cases P2 targets suggested in the genetic companies’ guidelines. Feeds are lower in amino acids and energy than finishing feeds and higher in minerals to ensure sound skeletal development.

With genetic improvement, it is increasingly difficult to achieve targets when pigs are ad lib fed – weight for age is often too high. Some degree of feed restriction may be needed although it is not always practical.

Table 1 gives typical feed specifications for gilt rearing.

Table 1. Nutrient specifications for gilt rearing

¹Amino acids are presented as ratios to standard ileal digestible lysine 

²Digestible phosphorus level is based on diet formulation without the use of phytase. If phytase is being used, phosphorus levels must be readjusted. The addition of phytase to the diet is recommended for improved digestibility

³The maximum permitted level of copper in feed for all pigs over 8 weeks post-weaning is 25 mg/kg

In addition to the above nutrient recommendations, the following additives may be considered for gilt rearing:

• Phytase

Adding phytase to gilt rearer diets has been shown to increase the nutritional value of feed by increasing the release of phosphorus

Feed intake during rearing will depend largely on gilt weight for age.

Gilts may often be fed ad lib until a certain weight, after which they are fed restrictively to ensure the correct body condition. Broadly speaking, a feed allowance of 2.6 kg/day is sufficient, with further monitoring and adjustment to establish and maintain an average body condition score of 3.0 at entry to the farrowing house.

During rearing, gilts will be less sensitive to temperature changes than gestating or lactating sows; however, seasonal changes in feed intake can be expected – particularly for gilts reared outdoors.

During the summer months, a drop in feed intake may be observed and, if body condition is affected, a more nutrient dense feed can be considered. Conversely, during the winter, gilts may have an increased requirement for energy. Increasing feed allowance can be beneficial if a drop in body condition is seen.

Feed is available in several different forms, including pellets, meal, nuts and rolls. There are benefits of each and, ultimately, the type of production system and feeding equipment available may dictate choice.

In outdoor systems, rolls and nuts may be used. These are beneficial because the gilt will forage from the ground and, while on straw in the rearing period, will help to increase intake and reduce wastage.

Pellets have been widely reported to increase feeding efficiency and feed intake. This may be explained by the finer grist size giving improved availability of nutrients and quicker digestion leading to increased intake. The compact nature allows more feed to be consumed in the same length of time, resulting in improved growth performance.

In the UK, meal is generally a coarse grist product, which increases flowability and reduces blockages and dust. However, studies have shown that, generally, meals have a higher feed conversion ratio than pellets.

This work was written in conjunction with ABN, Primary Diets and Premier Nutrition.