Nutrition: Sow colostrum - start of a lifetime or missed opportunity?
Tuesday, December 2, 2008
Colostrum is critical in carrying the newborn piglet down the right path to rapid growth and good health. It is up to producers to ensure that each piglet gets its fair share of this rich source of nutrients
by JANICE MURPHY
Piglet survival is one of the keys to success in the pork production chain. And colostrum intake is a major determining factor of piglet survival during the early suckling period as well as later on in life. Unfortunately, colostrum production varies considerably among sows and the factors that cause this variability are not that well understood.
As with most farm animals, piglets are born with little or no energy reserves and an antibody deficit with which to fight disease. The two major roles of colostrum are to provide the piglet with energy for heat production and metabolism, and passive immunity in order to help prevent infections. Colostrum also plays an important role in the development of the gastro-intestinal tract of the piglet.
Colostrum is a rich source of highly digestible nutrients (see Table 1), which are critical in carrying the newborn piglet down the right path to rapid growth and good health.
It is vital for the well-being of each individual piglet to get colostrum early and in high enough quantities to provide the necessities of life. Although sow milk production has been widely studied, no one has specifically studied colostrum production. However, several researchers, while looking at the physiological role of colostrum, did measure its intake during the first day after birth.
They came up with a rough estimate of 2.5 to five kilograms (average 3.6 kilograms) over 24 hours for a litter of eight to 12 piglets. In comparison, milk production on day 4 of lactation varied from 4.6 to 9.6 kilograms per day (average eight kilograms per day). Based on this information, it appears that the total yield of colostrum is half that of milk in early lactation, but it is just as variable.
Colostrum production is very variable among sows, and the factors influencing its production and composition have not been thoroughly investigated. In theory, those that could influence colostrum are genotype, parity, age, endocrine status, nutrition and body weight of sows, nursing behaviour and litter characteristics of the piglets, as well as environmental factors. In practice, some of these parameters are difficult to assess and even more difficult to manipulate in order to achieve positive results.
Only one researcher, a graduate student in France, has examined the impact that the sow versus the piglets has on colostrum production. He discovered that piglets who were bottle-fed colostrum during the first 24 hours after birth and kept in a similar environment to sow-reared piglets, consumed 450 grams per kilogram of birth weight, which was twice the average consumption of sow-reared piglets (212 to 373 grams per kilogram of birth weight). These results suggest that the sow limits her piglets' intake of colostrum.
Obviously, the amount of colostrum available per piglet decreases – by 22 to 42 grams according to one study – for each additional piglet born, since the sow has more mouths to feed. Research has also shown that the piglets themselves can use their noses to their advantage as stimulation of the udder can encourage maximum colostrum production.
Colostrum composition differs among breeds of pigs. It has been previously reported that the colostrum of Duroc sows has higher protein levels than Landrace and Yorkshire sows, and Meishan sows have more lipid and less lactose than sows from the European white breeds.
In general, lactose levels tend to be higher in the more maternal Yorkshire breed compared to sire lines like the Belgian Landrace, Pietrain and Duroc. Concentrations of immunoglobulins in colostrum have also been shown to be breed-dependent. These differences suggest that selection strategies may be a useful tool in improving the composition of sow colostrum.
Nutrition plays a significant role in colostrum production as it has an impact on mammary gland development and the mechanisms controlling the secretion of colostrum in late-gestation. It is generally understood that overfeeding in gestation negatively affects mammogenesis as a result of excessive fat deposition in sows. In contrast, feed restriction in late gestation does not seem to represent a significant challenge to colostrum yield, because sows have already stored away large energy reserves.
Supplementing the diet of sows with fat during late gestation increases total lipids in colostrum and also appears to increase lactose content and IGF-I concentrations. The fatty acid composition of colostrum is ultimately determined by the fat level in the gestation ration and the source of fat.
Because long-chain polyunsaturated fatty acids have proven important in brain development and function, various studies have focused on including various types of fish oil in the gestation diet to increase the amount of polyunsaturated fats in sow milk. In general, the fatty acid composition of sow colostrum mirrors the amount and type of fat provided in the diet.
Historically speaking, the amino acid composition of colostrum and milk was thought to be fairly stable. If we follow this line of thinking, it would be unlikely that changes in dietary protein would alter amino acid composition of colostrum.
However, as so often happens in research, new data has challenged this theory. This year, research from Korea reported that increasing dietary lysine intake in late gestation above National Research Council recommended levels (eight grams per kilogram compared to the recommended level of six) increased total protein levels of colostrum in sows.
In response to the availability of specialized feed additives, researchers have been exploring the impact of various ingredients on immunoglobulin concentrations in sow colostrum (see Table 2). Mannan oligosaccharides are of particular interest because of their ability to alter microbial flora and stimulate immune function in swine. Adding mannan oligosaccharides in late gestation resulted in favourable changes in the immunoglobulin profile of colostrum.
Other studies examined the effects of adding conjugated linoleic acid, fermented liquid feed, oils and various other ingredients. Further research is needed to substantiate the effects and to identify the mechanisms involved; however, the preliminary results have been positive.
Newborn piglets depend on sow colostrum for their vitamin and mineral intake, so there have been some studies aimed at increasing the levels of these nutrients through sow nutrition. Vitamin E is stored in the sow's adipose tissue. This storehouse can be used to increase vitamin E concentrations in colostrum by increasing vitamin E in the gestation diet or by giving two injections of vitamin E on day 100 and 107 of pregnancy.
Similarly, vitamin A can be supplemented in the late gestation diet in order to increase the vitamin A level of the colostrum. In contrast, concentrations of many micronutrients (vitamin C, phosphorus, calcium, iron, copper and zinc) in milk, and also presumably in colostrum, appear to be independent of the dietary supply of these nutrients in the sow ration.
It is one thing to make sure that the colostrum is rich in all the essential nutrients and immunoglobulins, but it is quite another to ensure that each piglet in the litter gets its fair share of the colostrum within hours of birth. During this critical window of opportunity, the piglet's gut has the ability to rapidly absorb the immunoglobulins essential for good health and performance.
However, the gut begins to close off to large molecules within as little as six hours and after 24 hours the benefit of the immunoglobulins is no longer available to the piglet. Unless sufficient colostrum has been consumed within this tight timeframe, the piglet will be vulnerable to disease. Colostrum intake must be optimized as soon as possible after farrowing or piglet health and survival will be compromised.
While there is no doubt that colostrum plays a crucial role in the development and survival of newborn piglets, producers must do their part. It is up to producers to ensure that each piglet gets its fair share of colostrum.
This can be accomplished by supervising farrowing to ensure that the piglets start suckling, using batch farrowing or synchronized farrowing to allow for planning and supervision before and after farrowing to help piglets get that critical start, or cross-fostering piglets where necessary to take advantage of the opportunity to share the wealth that is colostrum. BP
Janice Murphy is a former swine nutritionist with the Ontario Ministry of Agriculture, Food and Rural Affairs who now lives and works in Prince Edward Island.
Sources:
Farmer, C. and Quesnel, H. 2008. Nutritional, hormonal and environmental effects on colostrum in sows. J. Anim. Sci. published online Sep 12, 2008.
Gill, P. 2002. Colostrum: Food for life. UK Meat and Livestock Commission.