Agriculture Reference
In-Depth Information
6.1
Introduction
Optimizing nutrition of the gestating and lactating sow is critical to ensure her health,
wellbeing and long-term productivity. In this chapter, best feeding management practices
to provide the energy and amino acid needs for gestation and lactation are discussed.
The chapter includes presentation of the latest recommendations on dietary energy and
amino acid requirements of sows, and description of the key components and concepts
behind the NRC (2012) prediction of these requirements.
6.2
Overarching principles
An important concept to grasp in the applied feeding of sows is the fact that phases of the
reproductive cycle are interrelated. The first objective of any practical feeding program
is for the practitioner to satisfy the sow's current nutrient requirements. But, just as
importantly, the practitioner must consider performance of sows in future phases of the
reproductive cycle and plan the current nutritional program accordingly. The current diet
and feeding management system must lay the foundation for optimal future performance.
Gestation feeding practices can influence performance during the next lactation,
as well as the subsequent reproductive performances. The level of feed intake during
gestation seems to be related inversely to voluntary feed intake of sows during lactation.
Weldon
et al.
(1994) demonstrated that sows allowed
ad libitum
access to feed in the
last 40 d of pregnancy consumed twice as much feed as sows fed to their nutrient
requirements. However, in the subsequent lactation, voluntary feed intake of these
sows was approximately 50% of the intake for sows fed restrictively during the previous
gestation. Similar depressions in voluntary feed intake during lactation due to liberal
gestation feeding levels have been reported by other researchers (Dourmad, 1991; Sinclair
et al.
, 2001). The depression in lactation feed intake is problematic if one considers the
relationship between lactation feed intake and post-weaning performance of sows.
Lactation feed intake and the resulting nutrient balance in the sow's body can influence
subsequent reproductive performance. Several researchers have clearly demonstrated
that excessive lactation weight loss resulting from low voluntary nutrient intake relative
to milk output lengthens the post-weaning interval to estrus and increases the incidence
of anestrous sows (Johnston
et al.
, 1989; Koketsu
et al.
, 1996a; Yoder
et al.
, 2013). Sows
are susceptible to this negative nutrient balance at any stage (early, middle or late) of
lactation (Koketsu
et al.
, 1996b; Zak
et al.
, 1997a). These nutritional insults also can affect
the quality of oocytes (Yang
et al.
, 2000; Zak
et al.
, 1997b), embryo survival (Zak
et al.
,
1997b) and thus litter size in the next pregnancy.
Nutrition can have important influences on longevity of sows in the breeding herd. Sow
longevity has important economic and animal welfare ramifications. A replacement
gilt entering the breeding herd often does not begin to generate a profit until about the
third parity because of the costs associated with raising the female (Stalder
et al.
, 2003).
So, females culled for poor performance or loss of functionality before the third parity
