5 Evaluating the reproductive performance of beef cattle based on horn fly infestation

• Published in: Journal of animal science Vol. 103; no. Supplement_2; p. 110
• Main Authors: Agostino, Ashley Di, Giles, Kris, Talley, Justin, Crosswhite, Mellissa
• Format: Journal Article
• Language: English
• Published: Champaign Oxford University Press 17.06.2025
• Subjects: Beef; Beef cattle; Birth weight; Calves; Cattle; Cattle production; Economic impact; Estrus cycle; Fertility; Haematobia irritans; Immune response; Infestation; Reproduction; Weaning
• ISSN: 0021-8812; 1525-3163
• DOI: 10.1093/jas/skaf170.126

The horn fly, Haematobia irritans irritans (L.) (Diptera: Muscidae) is an important pest to cattle. The horn fly is known to cause extensive economic loss and negatively affect cattle production. This is due to both male and female flies taking blood meals from cattle. Reproductive loss associated with horn fly infestation is relatively unknown. Beef heifer fertility and reproductive management is crutial for producers to have a profitable production system. We examined the hypothesis that high horn fly infestations negatively affect bovine reproduction by increasing the calving interval due to an increase in an immune response against the fly. Fly counts were taken on 50 cattle at the Oklahoma State University Purebred Center in Stillwater, OK between June and August 2024, with a sampling unit being one entire side of a cow. Fly infestations were categorized as low, moderate, and high with < 200 flies/side, 200-499 flies/side, and >500 flies/side, respectively. To mimic the normal estrous cycle of a beef cow, calving dates were categorized into four blocks, each representing a 21-day interval. There was no significant difference of fly infestation with calving blocks 1, 2, and 4 (p=0.1856). However, there was a significant effect of infestation level on block 3 calving group (p< 0.01), but was likely due to low number of cattle represented in each block. There was also no significant effect of infestation level on calf weaning weight, calf birth day, and calf birth weight (p=0.2102). The inconsistency in results indicates the need for more research on this subject, as a major limitation of this study is the lack of a large sample size. Further research with larger sample sizes is necessary to conclusively determine the impact of horn fly infestations on bovine reproduction.