Effect of Horn Fly (<I>Haematobia irritans</I>) Control on Growth and Reproduction of Beef Heifers

Abstract

The influence of horn fly control with commercially available ear tags was studied on beef replacement heifers (n = 670) for growth and reproductive performance. The study was conducted at five sites in Louisiana over 3 yr. Heifers used were yearling replacement females that were exposed to fertile bulls during a limited spring breeding season that coincided with the horn fly season. In mid to late May of each year, heifers were randomly assigned to one of two horn fly treatments: untreated and treated for horn fly control. The trial continued each year until September or October at the end of fly season. Pregnancy status was determined by rectal palpation. Horn fly populations were controlled on the treated heifers at moderate levels (84%). Total weight gain of treated heifers was 14% greater than for untreated heifers. Horn fly treatment had no effect on pregnancy rate (78% and 75% for untreated and treated heifers, respectively). Treatment differences for weight gain were of greater magnitude for heifers failing to conceive than for heifers that became pregnant. Weight gains of nonpregnant treated heifers were 33% greater than for nonpregnant untreated heifers, whereas weight gains of pregnant treated heifers were 8% greater than for pregnant untreated heifers. In conclusion, horn fly control on yearling beef replacement heifers improved weight gain but had no effect on first exposure reproduction.

Antifeedant Effects and Repellent Activity of Loline Alkaloids from Endophyte-Infected Tall Fescue against Horn Flies, Haematobia irritans (Diptera: Muscidae)

“…Currently in Chile, H. irritans is found between the regions of Arica y Parinacota and Aysén and it emerges from November until May, showing a large population from December until March [12]. Both H. irritans sexes use their piercing proboscis to feed on cattle 24-38 times per day [5], causing annoyance and alteration of grazing behavior, especially when the animals suffer a massive infestation (>200 horn flies per animal) [13][14][15]. This provokes a reduction in feed conversion efficiency and reduced milk production and weight gain [5,[15][16][17][18].…”

Insecticidal, Repellent and Antifeedant Activity of Essential Oils from Blepharocalyx cruckshanksii (Hook. & Arn.) Nied. Leaves and Pilgerodendron uviferum (D. Don) Florin Heartwood against Horn Flies, Haematobia irritans (Diptera: Muscidae)

“…Both, male and female H. irritans use their piercing proboscis to feed on cattle, typically 24-38 times per day [1,13,14]. The fly feeding activity causes extreme annoyance to cattle, which spend energy in defensive behaviors, principally, head and tail toss, bunching and seeking refuge to keep the flies off their bodies resulting in elevated heart and respiratory rates, and reduced grazing time, especially when the animals suffer a massive infestation (>200 horn flies per animal) [15][16][17]. This provokes a reduction in sleeping time and worsening of feed conversion efficiency, reduced milk production and weight gain [13,[17][18][19][20].…”

Differences in the fly-load of Haematobia irritans (Diptera: Muscidae) on cattle is modified by endophyte infection of pastures

“…The economic impact of horn fly biting on weight gain in beef cattle and milk production has been reviewed by Oyarzún et al (2008). An infestation between 200 and 400 flies per animal can cause a 4-20% decrease in weight gain and 4-12% decrease in milk production (Guglielmone et al 1998;DeRouen et al 2003). In the US, horn flies cause annual losses of over US$ 730 million (Byford et al 1992).…”