Agriculture Reference
In-Depth Information
overfed. Further, lactational feed intake capacity might be stimulated by feeding diets rich
in fibre during pregnancy (Chapter 5; Meunier-Salaün and Bolhuis, 2015).
Ambient temperature
Thermal requirements of lactating sows are considerably different from those of piglets.
Newborn piglets have a lower critical temperature, i.e. the temperature below which piglets
need extra energy to maintain homeostasis, of about 32-35 °C which gradually lowers
to 24-27 °C at 4 weeks of age. For sows, the upper critical temperature was not studied
in detail but is probably lower than 22 to 25 °C (Makkink and Schrama, 1998). Above
the upper critical temperature, sows will lower their feed intake to prevent overheating.
Based on 9 experiments, Black
et al.
(1993) calculated that for each degree Celsius above
16 °C, the daily voluntary feed intake of sows decreased by 2.4 MJ of digestible energy (a
normal lactating sow diet provides about 13.8 MJ digestible energy (DE)/kg). Quiniou
and Noblet (1999) showed that at temperatures ranging from 25 to 27 °C, voluntary
feed intake decreased by 214 g/ °C. In that similar temperature range, Silva
et al.
(2009a)
demonstrated that when humidity was high (relative humidity (RH) 94%), the decrease
in feed intake was dramatic (492 g/ °C/day). Therefore, high ambient temperatures can
significantly reduce feed intake during lactation. Skin wetting, drip cooling and snout
coolers may increase lactation feed intake of sows at high ambient temperatures (reviewed
by Makkink and Schrama, 1998). Wagenberg
et al.
(2006) and Silva
et al.
(2009b) showed
that floor cooling increased feed intake of sows by 12-18%, increased weaning weight
of piglets and reduced weight loss of sows. The effects of low ambient temperatures on
piglets are most severe during the first days after birth, whereas negative effects of high
ambient temperature on sows are predominant during mid and late lactation, when milk
production and feed intake are high. Therefore, higher ambient temperatures should be
provided during the first week of lactation and lower temperatures thereafter. According
to Makkink and Schrama (1998), room temperatures in late lactation may even be as low
as 16 °C when a good microclimate is available for piglets. Low ambient temperatures will
increase feed intake of sows during lactation and will therefore be helpful in preventing
reproductive problems.
Feed intake pattern
Some reports show that feeding lactating sows more than twice daily will improve feed
intake and better feed intakes are sometimes found when using
ad libitum
feeding systems.
Hoofs and Elst-Wahle (1993), for example, found a 10% greater feed intake when using
self-feeders instead of when feeding twice daily. Generally, it is advised to remove feed
from the trough once daily when using
ad libitum
feeding to prevent feed from moulding
and becoming sour. Koketsu
et al.
(1996a, 1996b) characterized feed intake patterns
during the course of lactation and studied their effects on reproductive output. Sows
showing an increase in feed intake, regardless of whether the increase was rapid or gradual,
with no drop during the course of lactation, had the best reproductive performance. To
prevent drops in feed intake during lactation, it is advised to use step-up schedules for
feed allowance in early lactation. Everts
et al.
(1995) recommend to give 2 kg of feed at
farrowing and to increase feed intake in a stepwise fashion of 0.5 kg per day until the
