Relationships Among Mineral Balance in the Diet, Early Growth Manipulation, and Incidence of Tibial Dyschondroplasia in Different Strains of Meat Type Chickens

Abstract

In two experiments, a high dietary level of available phosphorus (.65%) in the presence of high chloride concentrations (.36%) was associated with a significant increase in the incidence of tibial dyschondroplasia (TD) in male broiler chickens. The level of dietary calcium and the interaction between Ca and available P had no effect on TD. Heterozygous normal (DW/DW) male broilers had a significantly lower incidence of TD than homozygous normal (Dw/Dw) chicks (Experiments 1 and 2). In Experiments 3 and 4, there were no significant differences between BW at 14 days for roaster-broiler cross and broiler chicks. At 21 and 28 days, however, the roaster-broiler cross chicks weighed significantly less than the broilers and had a significantly lower incidence of TD. Decreasing growth rates in broiler chicks after 14 days of age resulted in a significant decrease in the incidence of TD (Experiments 4 and 5), but did not decrease the severity of TD lesions at 28 days (Experiment 5). Depressed growth from 0 to 14 days decreased, but did not eliminate, TD lesions (45%) at 28 days, but it did significantly decrease the severity of the lesions compared with that in the 14 to 28-day manipulation treatments (Experiment 5). In Experiment 5, chicks were growth restricted from 0 to 14 or 14 to 21 days and then ad libitum fed the control diet until 28 days of age. The serum growth hormone concentrations at 28 days were inversely related to the rate of BW gain from 21 to 28 days of age, independent of BW at 21 or 28 days or feed consumption from 21 to 28 days. There were no differences in serum concentration of thyroxine or triiodothyronine at 28 days.

Correlated Responses to Selection for High or Low Incidence of Tibial Dyschondroplasia in Broilers

“…Duff (1984) and Thorp and Duff (1988) reported that in broilers that naturally adopted a unilateral weightbearing stance, most TD occurred in the load-bearing leg. Reduction of the rate of growth by dietary manipulation resulted in a decrease in incidence of twisted legs (Haye and Simons, 1978), varus deformations (Riddell, 1983), and incidence of TD (Lilburn et al, 1989). In contrast to these results, Riddell and Pass (1987) obtained a greater incidence of TD at 4 and at 7 wk of age in the lighter group of broilers.…”

Skeletal Growth of Commercial Poultry Species

“…The physiological changes associated with this enhanced early relative growth are probably associated with the increased incidence and severity of TD in all three species. Lilburn et al (1989) had previ- ously reported that during the early stages of growth there are physiological windows during which TD incidence and severity might be manipulated independently.…”

“…There seems to be two general classes of leg problems reported in the literature. The first is tibial dyschondroplasia (TD), an easily identifiable cartilage anomaly in young broilers, turkeys, and ducks (Wise and Nott, 1975;Lilburn et al, 1989;Cherel et al, 1991;Kelly et al, 1993;Leach and Lilburn, 1993). The causes and pathophysiology associated with this lesion have been reviewed recently (Leach and Lilburn, 1993).…”

The Role of Environment and Management on Leg Abnormalities in Meat-Type Fowl

“…Male turkeys whose feed was restricted by 20% between 5 and 10 wk of age showed a reduction in body weight and in the incidence and severity of TD (Steinke, 1971). Reducing the growth rate of broilers between 0 and 14 d or after 14 d of age caused a decrease in the incidence of TD (Lilburn et al, 1989). Feed-restricted roasters showed a decreased incidence of cripples as compared with full-fed controls; however, the authors suggested that exercise may have been involved, as the feed-restricted roasters were more active (Riddell, 1983b).…”