Modern production sows are burdened with an enormous task. Giving birth to and suckling a litter of piglets already takes a lot out of them, but then modern animal husbandry ups the ante with improved genetics resulting in an increased number of piglets per partus. And we are not stopping there! In addition to optimizing the number of piglets per farrowing we are also looking for ways to improve the number of parti per sow per year. One tool that we can use to make our sow’s life a little bit easier is making sure that gestation and lactation feeds have optimized dietary electrolyte balance (dEB) to ensure optimal calcium availability.
About one week before farrowing a sow will receive lactation feed in preparation for birth. At the time of birth feed intake is lower and therefore less calcium is absorbed. Calcium is needed for colostrum production and for uterus contractions. After the partus sows have to produce colostrum which immediately results in a strongly increased need for calcium. An ever-increasing number of piglets per litter also means that farrowing takes longer and more calcium is needed for the uterus contractions. It is thought that a calcium shortage in the blood can result in a longer partus and a delayed start of milk production. This negatively affects piglet survivability.
A balanced composition of the gestation and lactation feed establishes an easier transition towards the lactation period. The gestation feed should contain more fiber and the lactation feed should contain more protein. In practice both of the feeds show about the same ratio of raw materials. This not only results in unbalanced protein, fat and fiber composition, but also in a negative or too small difference in dietary electrolyte balance of the feeds (gestation vs lactation).
Dietary electrolyte balance
A lower dEB in lactation feed compared to gestation feed results in a higher bone mobilization of calcium in favor of partus and milk production. The dEB is the balance between the anions and the cations in the feed. The optimal difference in dEB is 50-100 mEq; gestation feed should have a higher dEB compared to lactation feed: gestating sows need to store calcium in their bones while lactating sows need to mobilize calcium from their bones. Gestation feed should contain more cations than anions, therefore the pH of the blood has a tendency to rise. However, blood pH is always between 7,3-7,4 and can only move minimally. An increase or decrease of the blood outside these levels can cause death. The pituitary gland reacts by stimulating uptake of calcium into the bones resulting in normalization of the blood pH. The lactation feed should contain less cations than anions, therefore the pH of the blood has a tendency to drop. The pituitary gland reacts by stimulating mobilization of calcium from the bones resulting in normalization of the blood pH. The correct balance is important for the farrowing process; milk production starts better and oxytocine works more effectively, resulting in improved piglet survivability.
Using sodium formate to optimize the dEB
A way to optimize the dEB is the use of feed additives. Sodium formate for example contains sodium but no chloride (unlike salt). Sodium formate increases the dEB with about 15 mEq for each kilogram added to feed. Two years ago Perstorps business unit Feed & Food started a trial that put dEB optimization to the test, using its own feed additive: ProPhorce™ AC 299 (sodium formate). The trial took place at four swine farms and in close cooperation with the Landwirtschaftskammer in Nordrhein Westfalen (Chamber of Agriculture for a district in Germany).
At the start of the trial the lactation and gestation feeds were analyzed for dEB (see table). The optimal difference should be 50-100 mEq/kg in favor of gestation feed. The test results actually showed a difference in favor of lactation feed.
The gestation feeds were optimized by adding 5 kg sodium formate on top of the diet. At the end of the two year period the data of both years was compared: the first year without dEB optimization to the second year with dEB optimization.
|dEB without optimization||dEB with optimization|
|Lactation feed||Gestation feed*||Difference||Lactation feed||Gestation feed**||Difference|
dEB-values per feed are the average of 12 analyses carried out by the LUFA (Official laboratory of the several “Landwirtschaftskammern”). * No use of feed additive ** 0,5% addition of feed additive (0,1% equals ± 15 mEq/kg)
Improvements across the board
The most important parameters checked were piglet survivability parameters, such as the number of piglets born alive, the number of piglets weaned per sow and the mortality in the first seven days. All participating farms increased the number of weaned piglets per sow per year. This can be partly explained by an increased number of piglets born alive, but also by more weaned piglets per litter. The results are shown in the table below:
|dEB optimization using sodium formate||No||Yes|
|Piglets born alive (per litter)||13.64||14.20|
|Weaned piglets (per litter)||11.24||11.72|
|Mortality in suckling piglets (%)||16.55||16.37|
|Increased number of weaned piglets (per litter)||+0.48|
|Increased number of weaned piglets per sow per year*||+1.13|
Doing the math: profitabilityIn this trial the investment in sodium formate to optimize the dEB of gestation feed was roughly one Euro per 100 kg of feed. The average sow consumes roughly 750 kg of gestation feed. Therefore the cost of using sodium formate is €7.50 per sow per year.
The increased number of weaned piglets per sow per year varied from 0.83 up to 2.17. At the time of the trial, the piglet selling price was €60 and net profit per piglet was €36. As such the following benefit can be calculated:
|Extra weaned piglets per sow per year||Net profit per piglet*||Extra profit per sow per year||Costs of Sodium Formate per sow per year||Return On Investment|
|1,13||€ 36||€ 40,68||€ 7,50||5,4|
*Selling price at that moment was €60 per piglet, after deduction of an average feeding cost per piglet of € 17 and of other costs per piglet (labor, veterinary, etc.) of € 7, a net profit of € 36 remains.
Though there were some substantial differences between farms in terms of ROI, all farms reported clearly positive figures. The return on investment varied from 1.2 to 10.4.
A practical tool for improved sow performance
It is well known that a balanced composition of the gestation and lactation feed establishes an easier transition towards the lactation period. In practice both of the feeds show about the same ratio of raw materials. This not only results in unbalanced protein, fat and fiber composition, but also in a too small or even negative difference in dietary electrolyte balance of the feeds (gestation vs lactation). This field trial has shown that optimizing dEB by using sodium formate (ProPhorce™ AC 299) is a practical tool to get more out of sows.