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Effect of treatment at dry-off with intramammary antibiotics, internal teat sealants, or both on milk production in dairy cows.

W. R. ElAshmawy




Effect of treatment at dry-off with intramammary antibiotics, internal teat sealants, or both on milk production in dairy cows.
W. R. ElAshmawy*1,2, E. Okello1,3, D. R. Williams1, R. J. Anderson4, B. Karle5, T. W. Lehenbauer1,3, S. S. Aly1,3. 1Veterinary Medicine Teaching and Research Center, School of Veterinary Medicine, University of California-Davis Tulare, CA, 2Department of Internal Medicine and Infectious Diseases, Faculty of Veterinary Medicine, Cairo University Giza, Egypt, 3Department of Population Health & Reproduction, School of Veterinary Medicine, University of California-Davis Davis, CA, 4Animal Health Branch, California Department of Food Agriculture Sacramento, CA, 5Cooperative Extension, Division of Agriculture and Natural Resources, University of California Orland, CA.

Milk production is the main source of income to the dairy industry and mastitis remains the greatest challenge for dairy producers. Among the approaches implemented to control and prevent mastitis on dairies are vaccination, pre and post milking teat dip and treatments at dry off including intramammary antibiotics and teat sealants. The objectives of our study were to evaluate the effect of different treatments at dry off on milk production and somatic cell count (SCC) in the subsequent lactation. A block randomized trial was conducted between December 2016 and February 2018 on 8 herds from 4 of the top 10 milk producing counties in California: Tulare, Kings, Stanislaus, and San Joaquin. Cows were enrolled during winter and summer seasons to account for the seasonal variability and eligible cows were treated at dry off with either intramammary antibiotics (AB), internal teat sealant (ITS), both or none and followed through 150 d in milk (DIM) post calving. Milk production and SCC data were extracted from monthly milk test day records (Dairy Comp305, Valley Ag Software, Tulare, CA). Two-piece spline linear mixed models were used to model the milk production (kg) and log10 of SCC (cells/mL). After accounting for parity, breed, season and dry period duration, the milk model showed a significant increase in milk production (1.88 kg/d) in cows treated with both AB and ITS at dry off in comparison to the controls; while there was a numerical increase in milk produced by cows that received either AB or ITS. Different dry cow treatments were associated with a significant reduction in the log10 SCC during the first 150 d following calving. The greatest reduction was associated with administration of both AB and ITS (−0.41; P < 0.01), followed by AB (−0.30; P < 0.01), and finally ITS (−0.19; P = 0.03) in comparison to controls. Dry cow treatments can be used selectively to address specific herd production and milk quality goals. Dairies with high SCC may benefit from treating cows at dry off with both AB and ITS .

Keywords: dry cow treatment, somatic cell count, clinical trial.

Biography: Wagdy ElAshmawy is specialized in veterinary epidemiology and infectious diseases. ElAshmawy graduated from Cairo University with a Bachelor of Veterinary Sciences (BVSc) in 2004. Between 2005 and 2016 he joined the faculty as a graduate student, instructor and with completion of his graduate degrees (MVSc and PhD) ascended to the rank of assistant professor of Infectious Diseases at the Department of Internal Medicine and Infectious Diseases, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt. ElAshmawy in 2019 finished the Dairy Production Medicine residency from UC Davis at the Veterinary Medicine Teaching and Research Center in the heart of the dairy's industry, Tulare, CA. ElAshmawy's strong interests in epidemiology and infectious diseases were enriched with his Master in Preventive Veterinary Medicine degree (MPVM) in epidemiology with special interest on the diagnosis and prevention of diseases in 2018. In addition, ElAshmawy pursuing his research interests at Dairy Epi Lab at VMTRC, UC Davis working with a large trial on building the algorithm for the selective dry cow therapy on dairy herds. In addition, he is researching the risk factors associated with different health and production parameters of dairy cows in different treatment scenarios. He is working on mathematical modelling of the effect of cow bunching and stable flies on the milk production and estimating the economic losses to provide a guideline for the dairy industry on their budget to spend on control of stable flies.