Year of Publication

2020

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Agriculture, Food and Environment

Department

Animal and Food Sciences

First Advisor

Dr. Roberta Dwyer

Second Advisor

Dr. Tyler Mark

Abstract

Mastitis is considered one of the most common and costly diseases in the dairy industry. Intramammary infection status at a herd level is measured using somatic cell count (SCC). Understanding the total cost of an elevated somatic cell count can help influence dairy farmers to lower SCC and select management practices to produce higher quality milk. The first objective of our research was to determine if the cost of an elevated somatic cell count to farms can be decreased through the adoption of management practices with varying expenses. Using stochastic simulation modeling, the adoption of three differently priced management practices were modeled in herds with varying somatic cell counts. Results were highly dependent on whether a premium scheme for lower SCC milk was in place and how close a herd’s initial SCC was to a premium level. When herd SCC reduced enough to receive a premium, the total cost of SCC to the farm was dramatically reduced.

One management practice that has historically been used in the industry is treating every quarter of every cow with an intramammary antibiotic at the end of her lactation. However, future restrictions of antibiotic use in animal agriculture may pressure dairy farmers to treat only cows with an intramammary infection at the end of the lactation. The second objective of our research was to complete an economic analysis comparing the total cost of dry cow therapy in simulated dairy farms when every quarter of every cow was treated with intramammary antibiotics compared treating only cows with an intramammary infection at end of the lactation. Results from the model indicate the treating every quarter of every cow at the end of lactation was most economically feasible in simulated farms. However, as the cost of a case of mastitis and mastitis incidence decrease, treating only cows with an intramammary infection may become economically feasible.

Within recent years, the dairy industry in the Southeastern United States has shown interest in changing the way milk is priced. Currently, dairy farmers in the Southeast are paid for total fluid volume and butterfat, while other areas are paid for milk fat, protein, and other solids yields. The third objective of our research was to determine the differences in milk value using the conventional milk pricing system compared to a multiple component pricing system using cow production records. After examining average milk values, multiple component pricing may result in Southeastern dairy farmers being paid more for their milk.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2020.052

Included in

Dairy Science Commons

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