Locomotor disorders are one of the main pathologies encountered in broiler chickens. They may be of infectious origin, i.e. caused by bacteria (E. coli, Enterococcus cecorum…) or viruses (reovirus…), or of metabolic origin.
A study was carried out to determine the most important periods for ossification.
JA987 broilers slaughtered at 45 days of age, twenty animals were sampled at each age. The two parameters measured to assess ossification were :
Fracture strength (expressed in Newton/mm): a force is applied to the bone until it breaks. The greater the force required, the stronger the bone.
Alkaline phosphatase (PAL, expressed in Units/L): this is an enzyme produced when bone is growing. The more this enzyme is present, the greater the bone growth.
The first 4 weeks of life are crucial
The evolution of these parameters with age can be seen in the graphs below.
These two graphs show that ossification is mainly determined during the first four weeks of rearing: it is therefore worth concentrating supplementation with vitamin D3, phosphorus, calcium and trace elements (copper, zinc, manganese) on this period.
Impact of strong growth on ossification disorders
Moreover, strong growth favors the appearance of ossification disorders: the greater the growth potential of a chicken strain, the greater the need for supplementation.
This can be seen in the graph below, which shows greater bone growth in Ross 308 than in JA987 at a young age.
Fast-growing strains such as Ross 308 are therefore more likely to develop poor ossification than slower-growing strains such as JA987. To ensure good bone strength, supplementation should therefore be more important for Ross 308 than for strains like JA987. Hence the development of 2 nutritional plans to meet the specific needs of fast-growing strains on the one hand, and slower-growing strains on the other.
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Males more at risk than females
Moreover, males are more at risk than females, as their bone growth is greater at all ages, whatever the strain, as shown in the graphs below.
To conclude, the faster the batch grows, the greater the requirements (for vitamin D3, phosphorus, calcium and trace elements). Male Ross 308 chickens are the animals most at risk of locomotor disorders.
In the absence of lame animals, we recommend complete and effective supplementation to improve ossification during the first three weeks of life. Supplementation can be repeated according to the animal’s growth rate.