Transition feeding of sows - The Gestating and Lactating Sow - page 135

7. Transition feeding of sows

P.K. Theil
Department of Animal Science, Aarhus University, Research Centre Foulum, Blichers Álle
20, P.O. Box 50, 8830 Tjele, Denmark; [e-mail]

Abstract

The transition period from late gestation to early lactation is rather short, but it is
nonetheless of major importance for the productivity of high-prolific sows. The
transition period, here defined as the last 10 d of gestation and the first 10 d of lactation,
encompasses substantial changes for the sow. More specifically, fetal growth, mammary
growth, colostrum production and sow maintenance require substantial amounts of
nutrients during late gestation. After parturition, nutrients are mainly required for milk
synthesis and sow maintenance, but the regressing uterus supplies considerable amounts
of amino acids to the blood. The physiology of the sow ensures that nutrient transfer to the
offspring is not being compromised and that nutrients are preferentially being allocated
to uterine tissues before parturition and to the udder after parturition. During the
transition period, the sow becomes catabolic due to the high priority of milk production
and to current feeding practices. Indeed, feed is changed from a gestation to a lactation
diet for most sows and the feed supply typically goes from a restricted supply to an ad
libitum allowance. In addition, transition sows are often exposed to shifts in housing,
and in Europe, this shift is now associated with a change from loose group housing to
individual housing. Around parturition, colostrum is being secreted and milk synthesis is
initiated in the mammary glands. After the onset of lactation, milk composition changes,
especially during the first few days of lactation, and milk yield increases throughout the
transition period and becomes the most important determinant of nutrient requirements.
Thus, nutrient requirements of transition sows are affected by many intrinsic factors and
these requirements change rapidly, yet, sow feeding practices do not acknowledge these
changes. Development of new feeding strategies specifically adapted for the transition
sow is likely of importance to match the rapid changes in nutrient requirements.

Keywords: colostrum synthesis, mammary secreta, nutrient requirement, periparturient
sow, protein

7.1 Introduction

In the past, it was common to feed sows with one diet throughout gestation and lactation,
and this may still be the prevalent feeding practice in some countries where protein
sources are rather cheap and livestock density low. However, most sows nowadays are
fed a diet low in energy and protein throughout most of (or during the entire) gestation,
and are shifted to a lactation diet high in energy and protein at some point during the