Composition of sow colostrum and milk - The Gestating and Lactating Sow - page 205

Chandan et al. (1968) found lipase and ribonuclease activity in sow milk, but not lysozyme
activity. Krakowski et al. (2002) reported lysozyme activity of 15 to 20 ng/ml in sow
colostrum immediately after parturition. Trypsin inhibitor activity has been identified
in sow colostrum (Jensen, 1978). Ceruloplasmin concentrations in sow milk are higher
at day 3 compared with day 33 of lactation (Cerveza et al. , 2000).

9.13 Effects of physiological state

The initiation of lactation, known as lactogenesis, has been described as occurring in
two phases (Hartmann, 1973). The initial phase involves structural and enzymatic
differentiation of the mammary cells preparing them for secretion of milk. This phase
coincides with colostrum formation. In the sow, this phase of lactogenesis is occurring
during the late stages of gestation (Kensinger et al. , 1982). The second phase of lactogenesis,
referred to as copious milk secretion, coincides with a rapid increase in secretion volume,
which may not fully begin until 33 to 34 h postpartum in the sow (Krogh et al. , 2012; Theil
et al. , 2014). Natural variability is observed in the physiological coordination between
parturition and progression through the stages of lactogenesis. For example, sows with
low volume production of mammary secretions during the initial 24 h after the onset of
farrowing, as determined by piglet body weight variation, had greater total solids, fat and
gross energy contents, but lower lactose content of colostrum at parturition than sows
with high colostrum production (Foisnet et al. , 2010a). This suggests that sows with low
colostrum production were not as far advanced in the process of lactogenesis at the time
of parturition as the high colostrum-producing sows. Total solids content of mammary
secretions at 24 h postpartum is not different between low and high colostrum producing
sows (Foisnet et al. , 2010a).

A misalignment of the timing of parturition and lactogenesis is also seen in studies
where parturition is hormonally manipulated to occur earlier or later than normal.
Induction of parturition to occur prior to day 114 of gestation can decrease fat content of
colostrum secretions, while lactose concentration in colostrum is not affected by induced
early parturition (Jackson et al. , 1995). Sows treated on day 113 of gestation to induce
parturition at day 114 have higher lactose content, lower protein and ash content and
tend to have lower total solids content of colostrum at parturition than sows not induced
(Foisnet et al. , 2011). On the other hand, delaying parturition of sows to day 116 with a
progestogen does not affect total solids, lactose, fat, protein or ash content of colostrum
at parturition or at 24 h (Jackson et al. , 1995; Foisnet et al. , 2010b), however total solids
and gross energy percentages are decreased at 48 h postpartum (Foisnet et al. , 2010b).

Altering the lactogenic process through transgenic modification of mammary cell function
can also alter colostrum composition. In transgenic first lactation sows expressing the
bovine α-lactalbumin gene, total solids in colostrum within 6 h of farrowing are lower
than in non-transgenic sows (Noble et al. , 2002). Lactose content of colostrum from
transgenic sows is higher than in non-transgenic sows, suggesting that the process
of lactogenesis, indicated here through lactose synthesis, was more advanced in the