by A change in formulation practices is to include a higher fraction of coarse particles in the diet. In order to make it easier for females to access nutrients, fine particles have traditionally been included in weaning diets. But as scientists learn more about the gastrointestinal systems of young pigs, they realize that the rapid rate of passage of fine particles is not entirely beneficial.
A pig’s stomach and intestines do more than digest food and absorb nutrients. The gastrointestinal tract (GIT) also plays a central role in the management of pathogens, for example Escherichia coli, may lead to diarrheal challenges. As producers aim to reduce antimicrobial use in their herds, nutrition provides a strategy to help guide piglet gut development and manage gut health issues.
The case for including rough components
Although finely ground ingredients are linked to an increase in nutrient digestibility, feed efficiency and daily gain, it has been noted in the literature that diets containing only fine particles may be at risk for increased stomach keratinization, mucosal erosions and ulceration. New trials show that a wider distribution of particle sizes – including coarser components – could improve animal health and strengthen intestinal maturation.
Shifting the diet to include rougher ingredients may allow life to remain in the GIT longer to support physiological functions, address pathogens and make piglets more resilient to challenges. In studies, animals fed diets with different particle sizes tended to have higher stomach weight and increased empty colon weight – indicators that GIT development was stimulated. Additionally, diets designed with coarse particles have been found to improve the barrier between the large intestine and the small intestine and help establish stomach pH levels where selected pathogens cannot survive.
Viewing trial data
Piglets were challenged in a feeding trial which looked at the size of the particles with the E. coli inoculum on day 7 after weaning for 3 consecutive days. 3 diets based on Milkiwean Vital Start recommendations were offered during phase one – days 0–21 – and piglets were monitored until day 42 after weaning. The diets included a feed containing only fine particles, a feed with some coarse particles and an optimal blend with multiple particle sizes.
Different grinds resulted in similar pellet hardness and durability. The average particle size of the fine diet was 138 µm, 291 µm of the coarse diet and 270 µm of the best diet. After the E. coli challenge, there was more variation in response, with the smooth diet showing the lowest performance (P<0.05). By day 36, body weight was highest (P<0.05) for piglets on the coarse and optimal ground diets (22.6 kg) and lowest for animals on the fine feed (22.0 kg).
Faecal scores were given on a 5-point scale (scores 2 and 3 representing 2 levels of diarrhoea). The number of days in a period in which pens scored 2 or 3 (diarrhoea) were calculated and reported as diarrhea frequencies, which were consistently lower for the best diet and mostly for the bland diet.
Performance under disease pressure
The results of the feeding trial were validated with a series of three field trials that investigated the effect of particle size on piglet performance and faecal consistency. One trial was conducted at a facility with a known on-farm diarrheal strain. In each trial, animals received a diet containing only finely ground particles or a diet with the optimal particle size distribution.
The tests showed no reduction in performance when coarser particles were included and when health pressure was low. Differences were noted in animal mortality, treatment and diarrhoea. In two trials, animal deaths were higher in piglets receiving the fine diet (10.0% vs 2.5% and 8.9 vs 6.5%). In the trial at the disease-stressed farm, animal deaths were slightly higher for piglets that received the diet including coarse particles (1.6% vs 2.2%). However, animals receiving the coarsely ground diet had fewer treatment days for gut health issues (2.4% vs 1.9%) and tended to see fewer treatment days for other problems. In addition, animals on the close diet had fewer cases of diarrhoea, with the incidence in the first two weeks after weaning being 6% for the maximum particle size diet compared to 21% for the fine (P<0.05).
Implications
The results of the trial indicate that the formulation of diets with an optimal distribution of particle sizes could promote gut development, help piglets to combat gut health disorders and reduce the incidence of diarrhea. Since rougher elements in the feed slow down the rate of feed transfer, this may allow sufficient time for regulatory mechanisms in the GIT to function. If coarser particles are taken into account, the piglet’s resilience in health-challenging environments can be supported without reducing performance. Results from feeding trials informed Milkiwean Vital Start’s improved feeding program. It is specially adapted for use in facilities with potential heather challenges, and the increased diet includes more ground feed particles to support better piglet performance. Feeding a diet with an optimal particle size distribution can help support piglet performance and gut health in challenging conditions.
References available on request.
