Seasonal and post-freezing variation of crude protein content and digestibility of willow and cottonwood leaves in regard to giraffe nutrition

The nutrient content of giraffe diets has not been well established. Many diets are lacking or have excessive amounts of protein, and protein is a good indicator of overall nutrient content. Hay and alfalfa are not ideal food items, and browse or leaves are the natural food choice for wild giraffe. In climates that experience seasons, browse is not always readily available, and must be frozen to be fed over the winter months. It was not known if freezing had detrimental effect on the protein content of leaves, and also if there is a difference in the protein content of leaves during the growing months. Willow and cottonwood trees were studied as they were a favorite of the giraffe. Crude protein was measured using the Kjeldahl process, and in vitro dry matter digestibility was measured to determine how much of that crude protein was usable. ANOVA tests were run on the data. The results showed that there was no difference between fresh and frozen leaves, as there is a p value of 0.06. Results also showed there is a difference between willow and cottonwood leaves, with a p value of 8.49E-05. It was determined that there is more crude protein in the earlier months, and crude protein declines with the season. The p value for the month of collection was 8.84E-07. Willow leaves have slightly more crude protein than do cottonwood leaves. The mean crude protein for fresh willow was 15.85% and the mean crude protein for frozen willow was 14.87%. The mean crude protein for fresh cottonwood was 12.70% and for frozen cottonwood it was 11.07%.

Last Updated
January 27, 2021
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