Composition of sow colostrum and milk - The Gestating and Lactating Sow - page 192

Numerous studies have demonstrated that dietary sources of fat affect the proportion of
fatty acids in colostrum and milk (see for examples Azain, 1993; DeMan and Bowland,
1963; Fritsche et al. , 1993; Lauridsen and Danielsen, 2004; Peng et al. , 2010; Rooke et al. ,
1998; Schmid et al. , 2008; Taugbøl et al. , 1993; Yao et al. , 2012). Fatty acid composition
of sow milk phospholipids was reported by Keenan et al. (1970). Chapter 16 (Bontempo
and Jiang, 2015) of this topic addresses the impact of various dietary fat sources on the
neonatal piglet.

9.6.3 Other factors

In a comparison of European-derived breeds, Fahmy (1972) found that fat percentage in
milk, but not in colostrum, is affected by breed. Yet, a later study comparing the Duroc
and Landrace breeds, and selected and non-selected lines within each breed, showed no
significant differences in milk fat content (Shurson and Irvin, 1992). Milk fat percentage
is affected by genetic selection for sow cholesterol level, with low cholesterol sows
having lower milk fat percentage than sows selected for high cholesterol (Kandeh et al. ,
1993). Chinese Meishan sows have colostrum and milk that has higher fat content than
Yorkshire (Zou et al. , 1992) or crossbred sows representing several breeds of European
origin (Alston-Mills et al. , 2000). Meishan-derived sows also have more milk fat than
Yorkshires on day 23 of lactation (Farmer et al., 2001).

Colostrum fat percentage is significantly affected by colostrum yield, with higher
percentages of fat being found in colostrum of low yield sows (Foisnet et al. , 2010a).
Similarly, sow milk fat content appears to be negatively correlated with milk yield (White
et al. , 1984), although other studies have not found an effect of milk yield on fat percentage
(Garst et al. , 1999). Parity does not appear to affect fat percentage in sow colostrum, at
least through parity 4 (Mahan and Peters, 2004). Results of the latter study also indicate
that fat percentage in milk declines from parity 1 to parity 4. Peters and Mahan (2008)
observed a quadratic effect of parity on milk fat between parity 1 and parity 6, with
parities 3 and 4 having the lowest milk fat content. Goransson (1990) observed that fat
percentage in colostrum of sixth parity sows was lower than that from first parity. Still,
others have not observed a significant difference in milk fat content among parities (Baas
et al. , 1992; Klobasa et al. , 1987). Increasing the number of piglets nursed is associated
with a decrease in milk fat content at day 20 of lactation (Baas et al. , 1992), however,
others have not observed an effect of litter size on fat percentage (Klobasa et al. , 1987).
Milk fat content is not affected by body protein loss (Clowes et al. , 2003).

Studies that have evaluated the effect of environmental temperature on sow milk fat
content have had variable results, with some showing a tendency for reduced fat percent
when comparing 32 vs. 20 ° (Schoenherr et al. , 1989), but no effect when comparing 29
vs. 20 °C (Renaudeau and Noblet, 2001) or 30 vs. 20 °C (Prunier et al. , 1997). In that
latter study, fat content of colostrum was also unaffected by ambient temperature. The fat
content of sow milk is not affected by season (Shurson et al. , 1986).