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Feeding Sows RIGHT All the Way Through

Author: Greg Simpson - Swine Nutritionist/OMAFRA

Creation Date: 01 March 2004

Last Reviewed: 14 July 2009

Proper nutrition of the breeding herd plays a key role in maximizing herd productivity and profit.

Traditional feeding strategies for the reproductive female have used body reserves as a bufferagainst short-term deficiencies in nutrient intake, resulting in minimal damage to the fetal or

suckling piglets. However, modern sows, with a lean genotype and higher reproductiveperformance, must be managed differently since they start their reproductive life with fewer

reserves. It is well established that the way sows are fed in one stage of the reproductive cyclewill affect productivity during subsequent stages. As a result, an integrated feeding strategy is

needed, starting with the gilt and continuing throughout each successive litter, designed tomaintain high productivity and prolong the reproductive life of the sow. The proof that a strategy

is working is not only in the longevity and productivity of the sow but also in the performance ofher offspring.

Nutrition is the key component that ensures the modern sow achieves her genetic potential forreproduction. In practical terms, the actual level of sow performance in modern herds is well

below the animal's capability. Many farms average 20-22 piglets/sow/year compared with thepotential of 30 piglets/sow/year. Table 1 highlights some of the achievable production targets for

the modern sow.

Table 1. Production targets for the modern sow

Good Excellent

Sow replacement rate (%) 40 35

Farrowing rate (%) 85 90

Litters/sow/year 2.3 2.4

Empty days/year*

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Source: Close, W.H. 2003. The role of feeding and management in enhancing sow reproductivepotential. Proceedings of the 2003 London Swine Conference.

If less than 20% of producers achieve excellent levels of performance, what is holding back the

rest? In order to achieve these targets, we need to go back to the basics of sow feeding anddevelop a strategy that makes sense from beginning to end, from the replacement gilt rightthrough gestation, lactation and re-breeding. There are a number of factors along the way that

may help to achieve this level of performance.

When it comes to nutrition, the recipe for success includes everything that replacement gilts andsows need - energy, protein (specifically essential amino acids), essential fatty acids, vitamins

and minerals. Without all of these basic building blocks, sows cannot support their requirementsfor maintenance and growth (body, mammary, and uterine tissue), let alone the requirements for

fetal growth. Can you get away with feeding low quality feed to the breeding herd? Sure, but "ifyou fail to plan, you plan to fail". The potential consequences can include a decrease in

conception rates, smaller litters and/or reduction in birth weight, lower milk production, anincrease in weaning-to-service interval, or a shortened reproductive life.

Replacement Gilts

Do NOT feed replacement gilts similar to market hogs. Since gilts selected to enter the breedingherd have superior growth rates and lower backfat levels, they will have higher nutrient

requirements than their counterparts headed for the finishing barn. A typical market hog diet willnot provide sufficient nutrients to prepare the gilt for a long, productive breeding life.

Replacement gilts need higher levels of Ca and P (0.1% above market hog requirements from 50-120 kg body weight - refer to Table 2). These levels will maximize bone mineralization to

improve longevity.

Table 2. Nutrient Requirements of Gilts

Item (%)Development Phase (kg)

22+ 45+ 70+ 115+

Protein 18 17 16 15

Lysine 1.0 0.9 0.8 0.7

Ca 0.85 0.8 0.75 0.75

Total P 0.75 0.7 0.65 0.65

Avail P 0.49 0.45 0.4 0.4

Source: Carlson, M.S. 2002. Nutritional Considerations for Breeding Swine. Proceedings of Sow

Management Short Course.

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Gestating Sows

If there was an overall guiding principle for dry sow feeding, it would be "do NOT overfeed

sows during gestation" since it lowers feed intake during lactation. During gestation, feedinglevels of 1.8 to 2.5 kg/day will be satisfactory for most dry sows assuming they are housed under

reasonable conditions, free of parasites, and are fed individually. Factors that will adjust feedinglevels include the size and body condition of the sow, the type of housing and environmentprovided, the method of feeding, and the health and productivity level of the herd.

Just like people, not all sows are created equal. The heavier the sow, the greater the maintenance

requirement and the greater the amount of feed required - for example, energy requirementsincrease by about 5% (0.1 kg of feed/day) for each 10 kg increase in body weight. Sow body

condition is also a key factor. Thin sows have less thermal insulation and are less able to adjustto lower environmental temperatures, and thin sows also require a larger increase in feed at a

lower temperature.

Temperature is an important variable to consider in a sow feeding strategy. All animals have athermoneutral zone, the range of temperatures at which they are most comfortable and their body

temperature remains constant. In sows, an environment where the temperature is 1C below theirthermoneutral temperature (20C) increases their requirement by 3 - 4% more feed.

Restricting feed intake in gestating sows is necessary to limit excessive weight gain and fatdeposition, stimulate lactation feed intake and increase overall sow productivity. However, limit

feeding does not allow the sow the chance to feel full or satisfied after eating and can lead tofrustration and, ultimately, stereotypic behaviours. Feeding fibre during gestation can help

address this issue and can also contribute to reduced constipation and over-conditioning,enhanced feed intake in lactation, increased gut capacity, reduced stress, as well as increased

litter weight gain and productivity

An important part of any feeding program is the assessment of its effectiveness. There are atleast 3 methods to assess how well sows are being fed: body condition scoring, backfat probing

and weighing. The most common method is body condition scoring. Ideally producers shouldchart the body condition score of each sow several times during the reproductive cycle. In the

interest of time, a good starting point would be to assess the average condition score for theentire dry sow herd. Armed with this information, adjustments can be made to the feeding levels

based on whether the overall average score is greater or less than "3".

Lactating Sows

It is essential that sows start eating after farrowing and continue to eat well throughout lactation.This is vital since the nutrient requirements of the lactating sow are three times higher than

during gestation and, considering current average weaning ages, there is no time to waste.Ultimately the goal is to minimize weight loss (less than 10 kg in 21 days), increase piglet

growth rate, decrease piglet mortality, and ensure re-breeding and subsequent reproductiveperformance. Table 3 lists some practical ways to enhance appetite.

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It is important that the temperature in the farrowing room is not too hot for the sow. Heat stressoccurs when an animal is unable to remove enough heat from its body. All animals produce heat

from digestion. Excess heat production must be lost to the outside environment in order tomaintain normal body temperature. Dissipating heat consumes energy, therefore taking energy

away from growth or lactation. To complicate matters, pigs that are heat stressed often eat less,

making even fewer nutrients available. So, ensure that supplemental heat is provided to thepiglets while the sows enjoy thermoneutral temperatures.

Table 3. Practical Ways to Enhance Appetite

y Feed a well-balanced ration to meet nutrient requirementsy Gradually increase daily intake then feed ad libitumy Offer fresh, palatable feedy Feed several times per day, or to appetitey

Provide 10-12 hours of lighty Feed pelleted rations instead of mealy Ensure fresh water is available at all timesy Water flow rate should be >2 L/miny Avoid exposing sow to high temperatures (

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An integrated feeding strategy that starts with the replacement gilt and supports the sow througheach successive litter is the key to maintaining high productivity and prolonging the reproductive

life of the sow.