Seed, Feed and Weed

Dr Steve Collett of the University of Georgia’s Poultry Diagnostic Research Centre introduced the audience to the ‘Seed, Feed and Weed’ approach to gut health. This approach ensures that broiler chicks have the correct gut microflora to promote early development of the intestine, leading to more efficient use of feed, reduced risk of gut disease and shorter finishing times.

Dr Collett told delegates that while much attention is given to the health of the upper intestinal tract as that determines efficient use of feed, the caecal or lower part of the tract deserves just as much attention.

“Not only does the caecal microflora help breakdown feed in the upper tract but it also handles all the waste products from digestion.”

The aim, he said, was to ensure good gut health from day one.

“We know a 16-day-old embryo has gut microflora from its parent so we need to manage parent stock to help get chicks off to a good start by passing on healthy gut flora via the eggs,” he explained. “We also need to be mindful of hygiene in the breeder farm and in the hatchery as unwanted microflora can be picked up from contamination on the shell.”

“Unlike chicks in the wild which continue to pick up beneficial microflora after hatching from exposure to adult faeces in the nest environment, we need to replicate this seeding down of the benefi cial gut fl ora for the farmed bird. This can be achieved by spraying newly hatched chicks with an appropriate competitive exclusion or probiotic product,” he added.

In the UK, a popular and effective competitive exclusion product is Aviguard. “The sooner you can apply competitive exclusion the better,” he said.

Having seeded down the gut with beneficial flora the task is to feed this microflora to perform the task of breaking down feed higher up the intestinal tract for absorption.

“We can feed the microflora using organic acids applied to drinking water. If we get this right, villi in a healthy intestine can be seen easily with the naked eye in regular parallel lines.”

The UK’s reliance on strict disinfection and removal of all bedding material between batches of broilers would help keep harmful microflora from developing for up to three weeks compared to a week in US houses where bedding is recycled.

“While you have the advantage the harmful microflora still need to be weeded out. We can do this in a number of ways but a healthy gut will help competitively exclude unwanted micro-flora, and the use of a competitive exclusion product maximizes this. Other methods include use of essential oils or type 1 (yeast-based) fimbriae blockers that make colonisation by unwanted microfl ora more difficult.”

Introduction to Coccidiosis Vaccination

Dr Linnea Newman, global technical consultant on gut health with MSD, discussed the changes in broiler production seen over the last 30 years, and the ways in which they had affected the coccidiosis challenge faced by broilers. She described how, in the United States, coccidiosis vaccination of broilers is now more commonplace because of these changes. There is no hard and fast rule over coccidial vaccine use, suggested Dr Newman. While some producers used vaccine on each crop, some operations ran three vaccinated and two on in feed anticoccidials in succession.

“It’s whatever works best for a particular unit as the coccidial challenge will be different for each site,” she explained.

Given the increase in stocking density since the mid 1980s (12.5 birds per square metre versus 26 birds today in some systems), risks of a coccidia challenge had also escalated in part by extra heat and moisture in the bird environment.

Improvements in genetics would continue to develop birds that grow faster and use feed more effi ciently reducing faecal output and coccidia hosting. However, with pressure on margins from high feed costs the temptation for manufacturers to turn to lower cost ingredients will continue to challenge our nutritionists to balance cost and the desired faecal consistency, she warned. Other management strategies could also help reduce coccidia challenge. Hatch brooding and raised floors for broilers both had merit but did not provide a complete solution to the disease, she added. “With vaccination you achieve less carry-over and more uniformity, in birds presented for slaughter.”

Vaccination and Nutrition

In the following presentation, Oklahoma State University research leader, Professor Bob Teeter, reinforced that birds vaccinated with a live coccidiosis vaccine should be fed starter and grower diets that support flocks during peak vaccination response. For this to be successful, the starter and grower diet must be a high-energy diet. He explained that early coccidiosis stress has a minor effect whilst late coccidiosis challenge has a major effect on feed consumption, average daily gain, liveweight yield and feed conversion ratio.

He explained that good field management is needed to achieve an earlier faecal oocyst peak after vaccination, which allows a compensatory gain period to occur earlier than with field challenge. This means that birds between 35 and 42 days can take advantage of the lower energy finisher ration, when more feed is consumed. Reduced energy finisher rations may also offer savings in feed cost and offer additional benefit in vaccination.

“Where birds are challenged earlier in their lives (under 29 days old) there is a potential to save 211kcals,” he suggested. Given that feed costs account for between 60 to 75 per cent of production costs the need to protect feed use efficiency was paramount, he added.

French Experiences of Coccidiosis Vaccination

In France, birds reared for Label Rouge have been vaccinated against coccidiosis to good effect over a period of 15 years, explained Alain Riggi of MSD Animal Health.

Data from Label Rouge broiler suppliers showed that feed conversion efficiency improved from 3.07 in untreated birds to 3.01 for vaccinated birds, daily live-weight gain rose from 26.72g to 27.68g and mortality fell from 1.68 per cent to 0.92 per cent, when Paracox 5 was used for three consecutive crops, he explained.

He added that based on the Label Rouge and certified broiler experiences with Paracox 5, a major integrator company has introduced Paracox 5 for their standard broiler production as well.

Canadian Experiences of Coccidiosis Vaccination

Canadian poultry farmer and consultant Derek Detzler has been using a coccidiosis vaccine (Coccivac B) in standard broiler production for the last nine years. He found that results achieved by just rotating anticoccidials and a coccidiosis vaccine were not proving completely satisfactory. In an attempt to increase effectiveness he tried various methods to make the vaccine cycle as early as possible and found that by operating the misting system in their sheds for 10 minutes at days 5 to 7, he has achieved the desired effects.

The small volume of added moisture in the litter helped the sporulation of oocysts and this in turn helped to bring the oocyst shedding peaks earlier by three to four days. The earlier peaks resulted in less damage in the gut and birds have more time for producing compensatory growth.

Manipulating the cycle in this way has resulted in excellent results and since 2012 they have been successfully using the vaccine on a continuous basis.

This article was first published in 'Poultry World' in May 2013.

November 2013