- Agronomic: corn, soybeans
- Animals: swine
- Animal Production: feed additives, feed formulation, feed rations, housing
- Education and Training: on-farm/ranch research
The objective of this study was to determine the most efficacious dietary cation-anion level that will allow mature gilts to self-regulate feed intake when fed ad libitum in group housing.
The treatment diets consisted of one of the following levels of DCAD: 50 (control), -225, or -450 mEq/kg diet.
Dietary cation-anion difference had a direct linear relationship with average daily feed intake (as DCAD became more negative feed intake decreased). The results suggest that decreased DCAD may be useful in regulating feed intake of group-housed gilts, suppressing feed intake with no apparent negative effects on body condition or general well-being.
The swine industry is currently facing an enormous amount of public pressure to eliminate the use of individual gestation stalls in favor of group housing for gestating sows. Since over consumption of feed is a common problem in gestating sows, there is a need for development of an inexpensive, low-maintenance feeding system that can limit feed intake of the loose housed sow while still providing all essential nutrients. Most aggressive behavior of group-housed sows occurs during feeding (Levis, D.G. 2007). Several methods of limit feeding loose housed sows are available to swine producers. These methods include: electronic feeders, floor feeding, half stall feeding and full stall feeding. Electronic stalls allow for individual sow access and individual regulation of feed intake. Electronic feeding stalls are expensive and require more intense maintance. Floor feeding is economical but requires at least a portion of the floor to be solid and can result in excessive sow aggression during feeding. Full feeding stalls can result in individual sow feeding and less fighting during feeding but can require more labor during feeding and are more expensive than floor feeding. One-half stalls require less labor but may not prevent aggression during feeding and limit the potential to individually feed sows. Allowing sows ad libitum access to feed may decrease aggression and improve sow welfare. The use of self-feeders could be an ideal option for producers utilizing group-housed gestation systems; however, over-consumption of feed may be a problem. Decreasing dietary cation-anion difference (DCAD) by the addition of ammonium chloride or calcium chloride has been shown to decrease feed intake in pigs (Yen et al., 1981) and may be useful in the development of a simple feeding strategy that reduces excessive feed intake of gestating sows-- particularly when they are housed in groups.
The mechanism by which low DCAD decreases feed intake is not fully understood, but metabolic acidosis may play a part in depressing appetite (Yen et al., 1981). Several other physiological changes, including decreased urine and blood pH, mobilization of calcium, and decreased water intake have been observed to accompany the decrease in feed intake induced by decreased DCAD (Rude and Rankins, 1997; Dersjant-Li et al., 2001a). The extent to which these factors negatively affect full-grown pigs has not been extensively studied. Observing the effects of a diet with low DCAD on gilts before applying the ideas to gestating sows decreases the risk of severe negative effects on sow well-being. If successful, lowering DCAD could be an extremely simple and effective way of regulating feed intake of gestating sows.
Our hypothesis was that lowering the DCAD would decrease feed intake and weight gain without negatively affecting gilt physical well-being while maintaining optimum body condition.
Therefore, the objectives of this study were to formulate a diet that will allow group-housed gilts to regulate their feed intake to approximately 2.5 kg/gilt/day by varying DCAD, as well as to determine dietary apparent DM, nitrogen, and energy digestibility.