EFFECT OF FARROWING IN A PEN OR CRATE ON SOW BEHAVIOR, ENDOCRINOLOGY, INNATE
IMMUNITY, AND PRODUCTIVITY.
Lay, Jr., D.C., J.E. Cunnick, S.P. Ford, and L.M. Hohenshell Iowa State
University, Ames, IA.
The confinement method used during farrowing has the potential to affect
both sow and piglet welfare. Allowing the sow freedom to move and turn
permits her to express some maternal behaviors which she is motivated to
perform prior to farrowing. Restricting the movement of the sow decreases
the number of piglets crushed after farrowing. It would appear that the
sow's welfare must be compromised for that of the piglet at this critical
time. However, a need exists to firmly establish the degree to which the
sow's welfare is compromised and how (if) this compromise affects production
and health. Eighteen Yorkshire x Landrace sows were assigned to farrow
either in a pen (n = 10) or a crate (n = 8). The outward dimensions of
both the pen and crate were 1.5 x 2.3 m; however, the pen allowed the sow
virtually the entire area, whereas, the crate allowed the sow a 2.3 x .58
m area in which to live. At approximately 12 days prior to their expected
farrowing date, the sows were moved from gestation stalls into their respective
treatments. At approximately 10 days prior to expected farrowing, sows
were fitted with indwelling vena cava catheters. Blood samples were collected
throughout the week prior to expected farrowing and for 2 weeks post-farrowing.
Blood samples were analyzed to determine cortisol and progesterone concentrations.
Additionally, peripheral monocytes and granulocytes were isolated from
the blood samples to determine their ability to phagocytose bacteria. Behavior
was recorded using time-lapse photography starting at the initiation of
farrowing (emergence of the first pig) until 48 hours after farrowing.
The time spent lying, standing and sitting, as well as the number of position
changes and nursing bouts were recorded from these videotapes. Production
data recorded included: farrowing duration, number of piglets born alive,
number stillborn, number crushed, birth weights, 7-day weights, etc. The
farrowing environment did not effect peripheral hormone concentrations
(P > .10). Both plasma cortisol and progesterone declined from 4 days pre-farrowing
to 4 days post-farrowing (P < .002).
Behavior did not differ between treatments with sows from both groups exhibiting
an equal incidence of position changes and amount of time spent lying,
standing, and sitting (P > .10). The only production parameter that tended
to be effected by treatment was in net pigs weaned per sow (net pig = number
born/number weaned), with sows in crates weaning more pigs than sows in
pens (P < .07) even though crushing was not affected by treatment (P
> .20). Phagocytic ability of monocytes and granulocytes did not change
during the 4 days post-farrowing in sows housed either in gestation crates
or pens (P > .10). Sows in this experiment gestated in crates. Therefore,
sows housed in farrowing pens had a change in their environment that entailed
a greater degree of movement when compared to the sows housed in farrowing
crates. Whether the housing environment should be changed during the critical
period around parturition is a valid concern. This study indicates that
sows readily adapt to this change in environment and that no adverse effects
on behavior, plasma cortisol, plasma progesterone, or innate immunity result.