Agriculture Reference
In-Depth Information
postpartum and to 9,500 l/d at d 17 of lactation (Krogh
et al.
, unpublished). The various
factors affecting sow milk yield are covered in Chapter 8 (Quesnel
et al.
, 2015).
Macrochemically, sow milk is composed of lactose, fat, protein, minerals, vitamins and
water (Theil
et al.
, 2012). For a more detailed description of milk constituents, see Chapter
9 (Hurley, 2015). Right after the onset of lactation, milk composition changes quite
fast, although not as fast as during the colostrum period (Jackson
et al.
, 1995). Studies
from Klobasa
et al.
(1987) and Csapo
et al.
(1996) demonstrated that changes in milk
composition occur during the transition period, whereas the composition of sow milk is
constant after d 10 of lactation. This is in line with the mathematical model developed by
Hansen
et al.
(2012b). The increased content of milk fat in the transition period, either in
response to stage of lactation or to dietary fat supplementation (Lauridsen and Danielsen,
2004), is coupled with a similar increase in the dry matter fraction. In contrast, the lactose
concentration is rather constant at 5 to 6% because lactose draws water into milk. The
protein concentration is slightly higher (6.0 to 6.5%) at d 2 to 4 of lactation whereas it is
rather constant at 5.5% thereafter (Klobasa
et al.
, 1987). Concomitantly with the drop in
milk protein at d 5, the relative concentrations of amino acids change (gram of amino acid
per 100 g protein; Csapo
et al.
, 1996). Some amino acids become more abundant after d
5 (glutamic acid, proline, isoleucine, and lysine), some become less abundant (threonine,
serine, glycine, alanine, cysteine, valine, methionine, leucine, and phenylalanine) and
yet others are constant when expressed relative to milk protein (aspartic acid, tyrosine,
histidine, tryptophan, and arginine).
7.2.10
Production-related diseases in the transition period
A healthy sow around the time of parturition is important for the overall sow productivity
and piglet performance after birth, but the incidence of diseases seems to increase around
parturition (Blaney
et al.
, 2000; Oliviero
et al.
, 2010). The causes for this are unknown,
but it may be speculated that the general immunity of the sow is affected, for example,
by the loss of immunoglobulins to the colostrum production which makes the sow extra
vulnerable to risk factors associated with diseases close to parturition. Diseases related to
the farrowing process cover a wide range of disorders and mastitis and the postpartum
dysgalactia syndrome [PPDS; defined as inadequate and insufficient colostrum and milk
production in sows up to 72 h after birth of the first piglet (Klopfenstein, 2006)] receive
most attention because of their major impact on milk production. An overview of sow
health and diseases is provided in Chapter 18 (Friendship and O'Sullivan, 2015). Even
though the causes for the production- related diseases are diverse and often not well
characterized, many factors are involved and sow nutrition is an important aspect. For
instance, feeds produced from wheat (and rye) infected with ergot can dramatically
reduce the yields of colostrum (Blaney
et al.
, 2000) and sow milk (Kopinski
et al.
, 2008).
Providing a daily intake of fiber during the transition period also seems to be important
to reduce the risk of constipation at parturition. Indeed, if the fiber intake is reduced, the
hindgut fermentation drops, and the amounts of digesta in the hindgut and of feces drop
accordingly. The fiber intake is determined by feed intake and fiber content of the sow
diet. Typically, fiber intake is reduced in late gestation either because the feed supply is
lowered in late gestation or because the fiber content is lowered in lactation diets (which
