Over the last decade, feed delivery technology has made great progress from traditional feed lines with drop feeders mounted above gestation stalls and hand or feed-line feeding in lactation, to a whole range of automated systems with varying options. In the past, sows were fed a single diet throughout gestation and one during lactation, and the only “tailoring” involved setting the daily feed allowance by manually altering the level of feed in the hopper. More recently, smart feeding systems are allowing much more flexibility in both gestation and lactation feeding programs (nutrient profiles and allocation).

Automatic feeders during gestation, ‘electronic sow feeders’ (ESF) as they are often called, allow producers to feed each sow individually. Although individual feeding technology in itself is no great advance beyond the era when sows were still individually stall housed, ESFs offer the flexibility of changing the feed allowance at multiple stages of gestation. Such flexibility can better meet the nutritional demands of the sow as embryo development occurs. Adjustments can be efficiently made via a computer, without physically adjusting feeder hardware settings. Every producer with an ESF will have one or more ‘feeding curves’ in place. The curves allow for changes in feed allowance in early gestation to compensate for condition lost in the preceding lactation, and also in late gestation, to match increased nutritional demands for foetal growth. In this way, theoretically every single sow can have a curve tailored to her needs, based on her parity, desired maternal and foetal gain in gestation, and on the body weight and condition at the start of gestation. Today’s ESFs enable a precision approach to feeding even in group-housing situations, which are becoming more common as production regions introduce more stringent animal welfare regulations. Such precise feeding capabilities would otherwise not be feasible without EFSs.

‘It is interesting to note that we typically offer four different diets to piglets in a window of two months, whereas we feed gestating sows the same diet for the whole four months of gestation’

Electronic feeders in gestation unlock many additional opportunities to optimize sow nutrition. For example, most producers use only one diet in gestation. A solo diet does not take into account the varying needs of the sow in various stages of gestation. It is interesting to note that we typically offer four different diets to piglets in a window of two months, whereas we feed gestating sows the same diet for the whole four months of gestation. In early gestation, nutrition needs to meet the demands for maternal gain of protein, fat and skeletal reserves, and also ensure optimal implantation of the foetuses.

Figure 1. Increase in mass of various tissues throughout gestation, and the related requirement for lysine level in the diet for gilts (dashed line) and sows (solid line).

In the middle of gestation, placenta growth accelerates and foetal growth starts to increase slowly, while in late gestation, foetal growth accelerates dramatically, and mammary tissue increases in size (Figure 1). All these phases require different levels of protein (and likely amino acid profiles) and energy. To illustrate this, the concentration of digestible lysine in the diet at a given energy level varies throughout gestation, for the reasons mentioned before. Moreover, younger parity sows typically require a higher lysine level due to their increased needs for maternal protein gain compared to older sows. A blended feeding program of two diets differing in protein profile and in energy content can partially meet these varying demands and can be precisely executed using an ESF. In this way, overfeeding of protein in early or mid-gestation is prevented. And in late gestation, a good birth weight of piglets can be ensured without jeopardizing maternal protein reserves. This approach has also been shown to have measurable impacts on sustainability: Gaillard et al. (2020) calculated that blend feeding two diets can potentially reduce nitrogen and phosphorous losses by 17% and 15% respectively, whilst at the same time saving 3.6% on feed costs.

Figure 2. Left: Relationship between colostrum intake of litters with 13 to 15 piglets and their gain during lactation. Right: Litter colostrum intake for control sows and sows that received a supplement designed to stimulate mammary gland development in the last month of gestation (P < 0.10). Trouw Nutrition data, unpublished.

“It’s especially important to measure how much back fat sows are losing in the farrowing houses as it’s also connected to weaning age,” he said. “If you wean at three weeks versus four weeks, it's a major difference. During that extra week, the sows can really lose a lot of extra back fat.”

ESFs are not a silver bullet. As ESFs can blend only so many diets, a limited number of nutrients can be integrated into the total diet. Additionally, the complexity of physiological changes occurring during gestation requires more than balancing only energy and lysine levels. A novel feature that can complement standard diets, and offer more options for nutrient delivery variation, is top dress technologies mounted on ESFs. Most brands of ESFs offer optional hardware components that allow various nutrients or supplements to be added at specific windows during gestation. These may be targeted amino acids, for various health or fetal development reasons, or nutraceuticals that are fed to assist the sow’s development during certain gestational phases. In late gestation for example, mammary tissue increases in size. The amount of secretory tissue at the end of gestation sets the quantity of colostrum that is available to the litter. Colostrum is vital to the survival and development of piglets. Many studies looking at piglet survival consider an intake of 250 g colostrum per piglet a vital threshold. However, even beyond 250g colostrum intake is still very important in that it supports development of the piglet as reflected by the relationship between colostrum intake and gain throughout lactation (Figure 2). Supplements that can specifically target mammary gland tissue growth could be key in managing litters of high prolific sows in the future. Such supplements will be made possible by providing the tools to maximize the availability of colostrum at farrowing, and thereby improving early development and health of piglets. Of course, the economics of any innovation must be considered as well. If we assume a value of € 50 for every piglet sold to market, every percent reduction in mortality equates to €7.5 per litter gained, assuming 15 piglets born alive. Using targeted nutrient delivery at precise times, instead of including supplements throughout gestation , could allow for improved ROIs, while at the same time addressing an increasingly debated welfare issue.

‘Tailored feed delivery takes sow nutrition to the next level.’

In the farrowing unit, sows will generally receive a single lactation diet from about one week before farrowing until weaning. Sometimes a transition diet may be provided to tailor the specific needs of the sow around farrowing, such as fibre to prevent constipation. Today’s and future feed delivery systems for lactating sows offer a lot more flexibility than traditional feeding times that offer a single diet 2-3 times per day. So called “self-service” systems will allow the sow to determine when she feeds and how much she eats. Internal research has demonstrated that when sows are allowed to feed ad libitum from entering the farrowing unit, they will consume 5 kg on average in the transition period, and increase feed intake in early lactation more rapidly than on a conventional lactation feed curve. The increased intake in transition and early lactation results in higher milk production and clearly heavier piglets at weaning (Langendijk & Fleuren, 2018). These kinds of studies indicate that traditional feed delivery strategies do not entirely meet the needs of the lactating sow. They also reveal an opportunity to optimize feed delivery and total diet composition to improve sow performance and piglet health/survival.

Table 1. Lactation performance in multiparous sows fed according to a traditional “step-up curve” (n=23), or fed ad libitum from entering the farrowing house and through lactation (n=25).

As with gestation, sows’ lactational demands vary with stage of lactation. Milk production, feed intake, and mobilization of maternal reserves change in a non-proportional way in the course of lactation, affecting the demands for energy, protein, and specific amino acids from the diet, and the balance between these nutrients. In a typical sow feeding program, the ratio between energy and protein deficit will be -38 MJ/d : -46 g/d protein in the first week of lactation. In the second week this may be -36 MJ/d : 107 g/d protein, and in the third week -19.1 MJ/d : 49 g/d protein. Later in lactation, development of follicles that will yield the oocytes for the next pregnancy is initiated, and requires insulinogenic properties in the diet that may not be essential in early lactation. Again, blending of diets can accommodate these changing needs more effectively than when a single diet is used.

The nutritional approaches described above are only a few examples of how advanced feeding technology can better meet the complex, dynamic and specific demands of sows going through gestation, lactation, and breeding from parity to parity. Proper application and adoption of these technologies under commercial production condition will accelerate development of targeted nutritional solutions to help optimize the reproductive performance in high prolific sows, and improve survival and development of their offspring in a sustainable and profitable way.

Author details - Pieter Langendijk, Global Nutritionist at Trouw Nutrition

Gaillard et al. Evaluation of a decision support system for precision feeding of gestating sows. Journal of Animal Science, 2020, Vol. 98, No. 9, 1–12

Langendijk P, Fleuren M. Feeding the transition sow ad libitum: a healthy start for suckling piglets. 69th Meeting of the European Federation of Animal Science, Dubrovnik 2018, pp. 116.

Ferrari CV, Sbardella PE, Bernardi ML, Coutinho ML, Vaz Jr. IS, Wentz I, Bortolozzo FP. Effect of birth weight and colostrum intake on mortality and performance of piglets after cross-fostering in sows of different parities. Preventive Veterinary Medicine 114 (2014) 259–266.