Trenton Jones Master Thesis
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Two experiments studied the harvest pathology and grading characteristics of cull dairy cows by breed, reason for leaving the herd, days in milk, and lactation number. The first experiment compared the harvest pathology and grading characteristics of cull Holstein and Jersey cows. Cull Jersey cows were younger at harvest compared to Holsteins. Holsteins had a lower edibility frequency due to a greater liver abscess frequency when compared to Jerseys. Jersey cows had a greater frequency of livers with carotenitis cows. Holstein cows had a greater lung abnormalities. Holstein cows had larger longissimus muscle areas, heavier hot carcass weights, and lower cutability yield grades. The younger Jersey cows had a greater frequency of USDA Standard or better compared to the older Holstein cows. The sirloin had the highest frequency of bruising of the primals. Holstein cows had a greater frequency of bruises and larger bruises compared to Jersey cows. The most frequent reason for a carcass to be railed out was contamination. Septicemia was the most frequent reason for an animal to be condemned by the USDA veterinarian. In experiment two, cull Jersey cows harvest pathology and grading characteristics were matched with their on dairy record for the last year. The most frequent reason for a cow leaving the herd for culling was low production and mastitis respectively. Cows culled for digestive disorders had the greatest frequency of non-abscess abnormalities. Cows culled for respiratory disease had the greatest frequency of inflated lungs. Subcutaneous fat depth, intramuscular fat, longissimus muscle area, and hot carcass weight worked inversely to a milk lactation curve. Inflated lung frequency increased as age increased. Hot carcass weight increased from cows on their first lactation to cows on their third lactation.