High Cost of Coccidiosis in Broilers
US - Coccidiosis is the most prevalent disease affecting the US broiler industry. An estimated $90 million is spent in the US, and over $3 billion spent worldwide, for coccidiosis prevention annually.
8 February 2013
6 minute read
The global impact of coccidiosis due to decreased performance, morbidity, and mortality is an estimated $300 million US dollars.
Coccidia infect every poultry house worldwide. Eradication is nearly impossible. The parasites are very prolific, and capable of developing resistance to antibiotics, chemicals and ionophores. To further complicate the situation, limited industry resources are dedicated to new product development for coccidia control. Therefore, it is beneficial to understand the disease, recognize its impact on bird health and performance, and have an effective anti-coccidial rotation program implemented.
Life cycle of coccidia
High reproductive rate is a primary factor contributing to coccidiosis being problematic for commercial poultry. The life stages of coccidia in chickens are present both internally and externally. The developmental stages within the chicken produce a microscopic egg (oocyst), which is passed via the feces. See figure 1 below.
Under proper temperature/moisture, the oocyst develops within 1-2 days to form a sporulated oocyst, which is capable of infecting other chickens. At this stage, the oocyst contains eight bodies (sporozoites), each of which is capable of entering a cell in the chicken's intestine after the oocyst is eaten.
When sporozoites enter the cells, they divide many times, producing offspring (merozoites). Each merozoite may then enter another intestinal cell, and the cycle may be repeated several times. Due to the cyclic multiplication, large numbers of intestinal cells are destroyed.
Eventually, the cycle stops, sex cells are produced and fertilization occurs to produce an oocyst. The oocyst ruptures from the intestinal cell and passes in the droppings. An infected chicken may pass thousands of oocysts in the droppings; therefore, poultry raised in crowded and/or unsanitary conditions are at great risk of becoming infected.
Coccidia species in U.S. broilers
A 2011 sampling from US commercial broiler farms indicated 80% of field isolates had two or more species of coccidia present (reported by Dr Greg Mathis, 2012). The following species infect broilers:
E. acervulina
Infects upper 1/3 of small intestine
Identified by white/gray striations on intestinal lining
Negatively impacts feed conversion
Weight loss in bird
E. maxima
Infects middle 1/3 of small intestine
Causes inflammation of intestinal tract
Weight loss in bird
Typically leads to secondary bacterial infections: Necrotic Enteritis and Clostridium
E. tenella
Infects ceca (two blind pouches where small & large intestines join)
Oocysts found in fecal droppings
Causes bloody droppings
May cause morbidity and mortality
Transmission
Oocysts are passed in the feces, and infective oocysts gradually build up in the environment. Young chicks become infected from contaminated litter, housing, equipment, etc. These may have been contaminated previously by other young infected birds, or by adult birds that recovered from the condition. Areas around waterers are a prime source of infection.
Oocysts remain viable in litter for many months, thereby contaminating a farm from year to year. Oocysts are only killed by freezing, extreme dryness and high temperatures.
Management
Good management practices will help control coccidiosis.
- Dry litter
- Maintain drinkers at correct pressure and height
- Avoid overcrowding
- Brooding: Full vs. partial House - affects rate of exposure to oocysts
- Brooding: Turn out times - follow closely to avoid stress and wet litter
- Temperature - avoid large swings in house temperature to provide uniform conditions for growth
- Lighting - affects activity; more active will ingest oocysts sooner for immunity
- If coccidiosis does break out, start treatment immediately
Cocci control methods
- Vaccination
- Advantage: exposes chicks early, early immunity, early oocyst cycling.
- Disadvantage: stress on intestinal track from earlier cycling makes birds susceptible to necrotic enteritis infection.
- Chemical
- Advantage: results in early feed conversion advantage.
- Disadvantage: Becomes resistant quickly to chemical; must rest between uses.
- Ionophore
- Advantage: slow resistance.
- Disadvantage: allows oocyst population to build up, create late cycling of cocci, poor feed conversion, poor growth rate, gangrenous dermatitis.
Recent research findings suggest synergistic effect of XPC + ionophore
A recent study conducted by Dr. Greg Mathis at Southern Poultry Research (SPR) evaluated the effects of Diamond V Original XPC with a mixed coccidiosis challenge.
Broiler chicks were placed on treatment diets day 1 and challenged with E. acervulina (75,000), E. maxima (25,000), and E. tenella (75,000) on day 21.
On day 27, broilers were necropsied and lesions were scored.
Challenge Results
- Reduced severity of coccidian lesions;
- Improved body weight gain;
- Improved feed efficiency;
- Provided additive effect on weight gain and feed efficiency when used with Salinomycin.
Additional poultry research with XPC and coccidiosis
XPC broiler study (Gao, 2009)
E. tenella challenge at 21 d
42 d broiler study
Broilers: E. tenella challenge
- Improved daily body weight gain;
- Improved feed conversion;
- Improved intestinal immunity.
In addition to the broiler work cited above, XPC has been shown to mitigate coccidiosis in laying hens and turkeys.
Lensing, et. al., (2008) challenged laying hens at 21 weeks of age with E. maxima. Hens fed XPC from day of age had reduced incidence and severity of coccidian lesions compared to hens consuming feed without XPC.
A live coccidia vaccine challenge was evaluated in turkeys +/- XPC (McElroy, 2010). Turkeys receiving vaccine at hatch + 1.25 lbs XPC/ton had improved daily body weight gain and improved livability compared to vaccinated turkeys without XPC.
Summary
Coccidiosis has a very serious economic impact on the broiler industry. Coccidiosis presents itself in many strains and reproduces rapidly in all poultry houses, making eradication difficult. Ionophores, chemicals and vaccinations all have pros and cons. XPC has been shown in several poultry studies to mitigate the effects of coccidiosis on bird performance. Therefore, XPC may be used synergistically with any current cocci control program.
Implication: XPC would be complimentary to any Cocci-control program
Diamond V Original XPC balances the immune system, thereby allowing the animal to mitigate stress more effectively.
XPC has been shown to increase intestinal villi height, thereby increasing surface area for nutrient digestibility (improve feed conversion).
