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Daily milk losses associated with bunching, dairy cattle's protective behavior against stable flies (Stomoxys calcitrans), on a California dairy.

W. R. ElAshmawy

Events

06-24-2020

Abstract:

292
Daily milk losses associated with bunching, dairy cattle's protective behavior against stable flies (Stomoxys calcitrans), on a California dairy.
W. R. ElAshmawy*1,2, D. R. Williams1, A. C. Gerry3, S. S. Aly1,4. 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 Entomology, University of California Riverside Riverside, CA, 4Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis Davis, CA.

Bunching is the behavioral phenomenon of cattle aggregating in tight groups to protect them from biting by stable flies (Stomoxys calcitrans). The incidence of bunching varies between dairies and pens within the same dairy as it is associated with the intensity of stable flies on the dairy, management and environmental factors. In addition, bunching may be associated with heat stress experienced by cattle aggregation, as well as a decrease in feeding and laying times. Thus, bunching may affect dairy cows' milk production mediated through a reduction in dry matter intake and rumination times. However, there are no previous studies on the effect of bunching on milk production in lactating dairy cows. The objective of our study was to estimate the impact of cow bunching on milk production on a commercial dairy. A longitudinal study was conducted between April 26th, 2017 and July 31st, 2017 on a large Holstein herd housed in freestall pens in Tulare, California. The study dairy used the KattleGuard fly spray system (Dairy Solutions Inc., Tulare, CA) as a fly control program. Pen level cow bunching was recorded weekly on 4 lactating cow pens for 13 weeks. Bunching observations were matched to daily milk records from the study's 2 high production pens (558 cows) and 2 low production pens (591 cows) by day of observation. Two-piece spline linear mixed models were used to estimate the association between cow bunching and milk production. On average, bunching was associated with a decrease in daily milk production of 2.72 kg � 0.486 per cow (P < 0.01). In addition, cows in high producing pens had 2.68 kg � 0.302 more daily milk production compared with cows in low producing pens. Additionally, the model showed that, compared with first lactation cows, there was a significant increase in milk production in second lactation cows (8.92 kg � 0.564) and third or greater lactation cows (10.71 � 0.564 kg). Bunching due to stable flies can negatively affect dairy cattle welfare and productivity.

Keywords: bunching, daily milk, stable flies.

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.