Genetic and environmental factors associated with incidence of infectious bovine keratoconjunctivitis in preweaned beef calves1

Abstract

Infectious bovine keratoconjunctivitis (IBK) is one of the most economically important diseases in preweaned calves. This study examined the health records of 45,497 calves over a 20-yr period to determine environmental and genetic factors influencing the incidence of IBK. Three data sets were analyzed with an animal model. The first data set (n = 41,986) evaluated environmental factors and genetic differences among nine purebred (Angus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Pinzgauer, Red Poll, and Simmental) and three composite breeds (MARC I, MARC II, and MARC III). Weaning weights of calves diagnosed with IBK were 8.9 kg lighter (P < 0.05) than weights of healthy calves. Incidence of IBK was related to age of the calf and the seasonal life cycle of the face fly (Musca autumnalis). Incidence of IBK increased in the spring (June), peaked during the summer months (July to September), and then decreased in the fall. Herefords were the most susceptible breed (P < 0.05) compared with all other purebreds and composites. Estimates of direct heritability for the incidence of IBK were generally low and ranged from 0.00 to 0.28 by breed. The maternal permanent environmental and

Surto de ceratoconjuntivite infecciosa bovina e hemoncose causando mortalidade em bezerros

“…No entanto, a doença ocorre mais comumente em bovinos jovens, que usualmente apresentam as lesões mais graves (Webber & Selby 1981, Wilcock 2007). Há indícios de que exista uma predisposição racial para o desenvolvimento de CIB, já que bovinos Hereford e suas cruzas parecem ser mais susceptíveis (Webber & Selby 1981, Brown et al 1998, Snowder et al 2005) que as outras raças (Baptista 1979, Webber & Selby 1981, Punch & Slatter 1984, Snowder et al 2005. No surto aqui relatado, a doença se disseminou rapidamente entre os bovinos mais jovens do rebanho, confirmando seu caráter altamente contagioso e a alta suscetibilidade dos bovinos jovens.…”

Infectious Bovine Keratoconjunctivitis (Pinkeye)

“…The ocular pain associated with IBK along with reduced vision and subsequent reduced feed intake most likely account for reduced weight gains in cattle with IBK. 2,[30][31][32] In the most severe cases, corneal rupture can occur resulting in permanent blindness (see Fig. 10).…”

“…[1][2][3][4] The etiologic agent of IBK is considered to be the gram-negative rod-shaped organism named Moraxella bovis. The pathogenicity of Mor bovis requires the expression of pilin for attachment to the ocular surface 5,6 and a cytotoxin 7 that damages corneal epithelial cells both in vitro 8 and in vivo.…”

A putative quantitative trait locus on chromosome 20 associated with bovine pathogenic disease incidence1,2

“…Respiratory disease was treated by administering 1 or more medications (oxytetracycline, ceftiofur, flunixin meglumine, florfenicol, tylosin, enrofloxacin, and sulfadimethoxine) as described by Snowder et al (2006). Treatment of infectious keratoconjunctivitis included injections with antibiotics (oxytetracycline and ceftiofur sodium) and topical application of cloxacillin benzathine to the eye and covering with an eye patch (Snowder et al, 2005). Infectious pododermatitis was treated by administering oxytetracycline, ceftiofur, and sulfadimethoxine.…”

“…Additive genetic effects are known to influence resistance to specific diseases such as pinkeye (Snowder et al, 2005) and respiratory disease (Snowder et al, 2006) in beef cattle. In addition, a putative QTL associated with pinkeye has been reported (Casas and Stone, 2006).…”