Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/24/2005
Publication Date: 7/29/2005
Citation: Buhr, R.J., Northcutt, J.K., Richardson, L.J., Cox Jr, N.A., Fairchild, B.D. 2005. Incidence and size distribution of unabsorbed yolk sacs in commercial broilers processed at six weeks of age [abstract]. Poultry Science Association Meeting Abstract. 84(Suppl.1):24.
Technical Abstract: Unabsorbed yolk sacs are being investigated as a possible vehicle for vertical transmission of Campylobacter and salmonellae from broiler breeder hens to broilers. However, it is unknown at what frequency unabsorbed yolk sacs exist in present day commercial broilers at the time of processing. Two hundred broiler carcasses (100 on each of two separate days) were obtained from a commercial processing plant following defeathering and transported to the pilot processing plant. Each carcass was aseptically opened and inspected for the presence of an unabsorbed yolk sac. For each carcass, the antimesenteric side of the mid-ileum segment of the small intestine was examined for the presence or absence of a yolk stalk (Meckel's diverticulum). Carcasses with obliterated yolk stalks or stalks with no detectable yolk material were categorized as normal. Those with unabsorbed yolk sacs were further separated into two groups: 1) attached to the yolk stalk; or 2) free-floating within the abdominal cavity. Yolk sacs were further classified by size: 1) small (less than 2 mm in diameter); 2) medium (2mm to 10 mm); and 3) large (greater than 10 mm). From the 200 broiler carcasses, 51% were categorized as normal, 34% had an unabsorbed yolk sac attached to the yolk stalk, and 15% were free-floating. Of the 68 unabsorbed yolk sacs attached to yolk stalks, 26.5% were sacs, 6.5% were classifed as small, 8% as medium, and 0.5% as large. While most of the unabsorbed yolk sacs were dark yellow in color and were pliable, others were black and hard. The incidence of unabsorbed yolk sac in 6-wk-old commercial broilers appears high (49%). Future evluation of broiler stocks maintained from the 1950's will determine if the frequency of unabsorbed yolk sacs has changed in the past 50 years of selection of modern broilers.