Clarence Froese, M.Sc., P.Ag., Director of Nutrition, Genesus Inc.
Managing feeding levels in the dry sow herd is of critical importance to pork producers. Not only do feeding levels directly impact sow body condition and her lifetime reproductive performance; they also have a significant influence on overall herd feeding costs. With today’s high cost of feed ingredients, proper management of feeding levels becomes even more important. Table 1 illustrates the variation in dry sow feeding costs from a cross section of herds in western Canada, all fed similar diets formulated by the same nutrition consultant.
TABLE 1. ANNUAL DRY SOW FEEDING COSTS FOR 15 WESTERN CANADIAN HERDS 1
|HERD RANKING, low to high usage||DRY SOW FEED USAGE, kg (lbs.)/sow||ANNUAL FEED COST, $US/sow 2|
|TOP THIRD||660 (1455)||2.10 (4.6)||218.25|
|MIDDLE THIRD||740 (1630)||2.35 (5.2)||244.50|
|BOTTOM THIRD||820 (1800)||2.60 (5.7)||270.00|
- Gowans Feed Consulting, personal communication, 2017
- Assumes dry sow diet cost of $US300/ton
Average productivity levels were very similar for each herd category; meaning that herds in the bottom third incurred an extra $51.75/sow/year in dry sow feeding costs compared to herds in the top third, for no extra benefit!
The overall goal of a successful feeding management strategy in gestation is to meet the nutrient demands of both the sow and her developing litter, while controlling her bodyweight gain over successive parities. Table 2 compares target maternal weight gains (sow weight gain net of litter) to those achieved in a Genesus reference herd collecting detailed sow and litter data.
TABLE 2. GESTATION FEEDING STRATEGY TARGET MATERNAL WEIGHT GAINS
|PARITY||SOW MATERNAL BODYWEIGHT GAIN, kg (lbs.)|
|TARGET 1||GENESUS 2|
|1-2||45-50 (100-110)||50 (110)|
|2-5||35-40 (75-90)||40 (90)|
|>5||30 (65)||34 (75)|
1. Gestating Swine Nutrient Recommendations and Feeding Management, National Swine Nutrition Guide, 2010
2. Genesus, personal communication, 2021
As shown in the above table, the feeding of Genesus sows can be successfully managed to conform to target recommendations, thereby avoiding excessive weight gains and premature culling from the herd.
To control maternal weight gains, daily feeding (energy) intakes must be limited. The daily feeding allowance must account for the sow’s body maintenance requirement and the needs of her developing litter and accompanying fluids, as well as mammary tissue growth. Any surplus energy supplied beyond these needs is directed to recovery of body reserves (fat and muscle) lost during lactation, and subsequent weight gain. Of these components, sow body maintenance and subsequent weight gain after weaning account for over 95% of her daily energy requirements. An effective feeding program should therefore be based on an assessment of these two needs for each sow in the herd.
A sow’s body maintenance requirement is best determined by obtaining her bodyweight, but in the absence of an actual weight, parity can be a reasonable estimate of this parameter. Body reserves lost in lactation and subsequent maternal weight gain are more difficult to assess without a weigh scale. Many farms use a sow body condition score which entails a visual and subjective assessment of the sow’s body shape and fat cover. While this method is quick and easily applicable on any farm, it has proven to be unreliable and inconsistent in determining sow back fat levels and estimating weight gains.
A recently introduced tool which is an improvement over the body condition scoring system is the sow body condition caliper developed at North Carolina State University (Figure 1).
FIGURE 1. SOW BODY CONDITION CALIPER 1
1. Knauer et al., www.Porkbusiness.com,Mar., 2021
The sow body condition caliper measures the angularity of the sow’s back profile and provides a reading which is correlated to the animal’s back fat thickness. Readings are grouped into thin, ideal, and fat categories on the caliper face. It takes less than 10 seconds per sow to perform this measurement. These readings together with the sow’s parity (weight estimate) can be used to construct a practical feeding chart (Table 3) that forms the basis of an effective feeding program.
TABLE 3. RECOMMENDED GESTATION FEEDING LEVELS FOR GENESUS FEMALES
|P2 Back fat, mm:||<13||13-18||>18|
|Diet energy level:||Low 1||High 2||Low 1||High 2||Low 1||High 2|
|Parity||Daily Feed Allowance, kg (lbs.)/female|
- Diet net energy level of 9.62 MJ/kg or 1045 kcal/lb.
- Diet net energy level of 10.45 MJ/kg or 1135 kcal/lb.
To use Table 3 effectively:
- Perform a caliper measurement on all sows at weaning and set her initial gestation feeding allowance to the appropriate figure indicated in the table.
- Repeat the measurement at days 60 and 90 of gestation and adjust feeding allowances accordingly. If time is scarce, measuring a representative cross section of sows (30%) at these stages will suffice.
- Establish a target of 80% or more of sows to be in ideal body condition by day 90 of gestation.
Practiced consistently, this feeding program will minimize dry sow feeding costs and facilitate maximum sow longevity in the herd.
For further details on feeding guidelines for Genesus sows please consult www.genesus.com/nutrition
This post was written by Genesus