Agriculture Reference
In-Depth Information
weaning mortality of live-born piglets varies between countries, from approximately 9%
in Brazil up to 14% in France, Canada or Denmark (Baxter and Edwards, 2013). Piglet
mortality is highest in the first 3 d after birth and it has been established that early death is
mainly due to a low consumption of colostrum (Edwards, 2002; Le Dividich
et al.
, 2005).
Crushing by the sow has also been identified as a main cause for piglet mortality during
lactation. It is likely that the risk of being crushed increases when piglets are weak due to
low or no colostrum intake. The present chapter deals with the impact of factors related
to the sow, the litter, the environment or maternal feeding on colostrum and milk yields.
8.2
Definitions of colostrum, transient milk and mature milk
Colostrum and milk differ in timing of secretion and in composition. Colostrum is the
first secretion of the mammary glands which is largely synthesized before parturition.
It is characterised by high concentrations of immunoglobulins (Ig) compared with milk
(Table 8.1) and contains lower concentrations of lactose and lipids than milk (Table 8.2).
However, mammary secretions gradually change over time and may therefore be more
finely differentiated. We define colostrum as the mammary secretions ingested by piglets
until 24 h after the onset of parturition, as suggested by Devillers
et al.
(2004), transient
milk as the mammary secretions being produced after colostrum until day 4 of lactation,
and mature milk from day 10 of lactation. Transient milk may be rich in lipid (Table
8.1) whereas chemical composition of mature milk is essentially constant from day 10 of
lactation onward (Csapó
et al.
, 1996; Klobasa
et al.
, 1987).
8.3
Colostrum production
8.3.1
Roles of colostrum for the newborn piglet
As is the case for many mammals, piglets at birth are suddenly exposed to a cold
environment. Thus, maintenance of homeothermia by activation of thermoregulatory
mechanisms is vital. Unlike other mammals, however, the newborn piglet is devoid of
thermogenic brown adipose tissue. Moreover, compared to most other mammals, its
overall lipid content is low (less than 2%; Seerley and Poole, 1974). Hepatic and muscle
glycogen thus represent the main stores provisioning heat-producing nutrients for
oxidation. These energy stores are completely depleted within 12 to 17 h after birth in the
Table 8.1. Contents of immunoglobulins in sow colostrum and milk (Loisel
et al.,
2013).
Colostrum
Milk
Time after the onset of parturition
0 h
24 h
7 d
21 d
IgG (mg/ml)
51.9
10.4
-
-
IgA (mg/ml)
11.9
4.8
2.2
4.1
