Agriculture Reference
In-Depth Information
body protein, which will negatively impact on litter performance and subsequent
reproductive performance, especially in parity 1 sows. To accommodate the relatively
high amino acid requirements of parity 1 lactating sows or higher parity sows with better
than average litter growth rates, a top dress containing high-protein and very palatable
ingredients may be used. At a constant litter growth rate, an increase in sow voluntary
feed intake results in increased daily amino acid requirements (Table 6.3). This response
can be attributed to reduced body protein mobilization at the higher feed intake level,
and to the associated reduction in transfer of amino acids from mobilized body protein
into milk protein.
6.5
Feeding management
6.5.1
Feed processing considerations
The influence of feed processing methods on sow performance has received little attention
in terms of research. Reducing particle size of corn from 1,200 to 400 microns in diets for
lactating sows linearly improved voluntary feed intake and apparent digestibility of dry
matter, nitrogen, and gross energy with little improvements in sow performance, except
for an 11% increase in litter weight gain (Wondra
et al.
, 1995). The reduced particle size
increased the incidence of gastric ulcers and keratinization of the stomach with no visible
signs of compromised sow health during the single lactation studied. Multi-parity studies
have not been conducted to determine the long-term effects of small diet particle size
on gastric health of sows. Pettigrew
et al.
(1985) reported no effects on voluntary feed
intake of lactating sows, sow performance or litter performance when comparing corn
particle sizes of 619 to 444 microns in corn-soybean meal based diets. Improved nutrient
digestibility of diets caused by reduced particle size benefits the environment because of
reduced nutrient excretion. But, reducing particle size of diets can create problems with
flowability of feed in commercial feed delivery systems (Ganesan
et al.
, 2005). Reduced
flowability could be counter-productive if feed does not flow readily through feed delivery
systems and into sow feeders such that the sow's voluntary feed intake is restricted.
Problems with reduced flowability of finely-ground diets can be mitigated by pelleting
of the diet. Pelleting diets improves apparent digestibility of dietary dry matter, energy,
and nitrogen with no effect on voluntary feed intake or sow performance (Johnston
et
al.
, 1998). Selection of the proper particle size for sow diets entails a balance between the
benefits of improved sow feed intake and nutrient digestibility on the one hand, and the
challenges of maintaining gut health of sows and managing efficient, reliable feed delivery
on the other hand.
6.5.2
Gestation feeding systems
Feed intake of gestating sows is usually restricted to prevent excessive pregnancy weight
gains. Limited feed intake in gestating sows can elicit behavioral vices called stereotypies
(Lawrence and Terlouw, 1993), which may be considered signs of compromised sow
welfare. Feeding systems need to provide the required nutrients on a daily basis but
must also minimize the possibility of reducing sow welfare. Frequency of feeding can
