Systemic prepartum treatment of end-term dairy heifers with penethamate hydriodide: Effect on udder health, milk yield, and culling until 120 days in milk

Abstract

Prepartum intramammary treatment with antimicrobials of end-term dairy heifers has frequently been proposed as a practice to reduce the prevalence of intramammary infections (IMI) at calving. From a safety standpoint for both animal and administrator, systemic treatment is preferred. A clinical trial was conducted on heifers from 10 well-managed, commercial dairy farms with a low prevalence of heifer mastitis. The aim was to assess both the short- and long-term effects of a systemic prepartum therapy with penethamate hydriodide on udder health and milk production. Because it was hypothesized that some herds would benefit more from this treatment than others, specific herd-level information was collected before the start of the actual trial to screen for and explain potential herd-specific treatment effects. Further, the effect of treatment on antimicrobial susceptibility of staphylococcal isolates was monitored. End-term heifers were either treated systemically (over 3 consecutive days) 2 wk before expected calving date with penethamate hydriodide (n=76) or remained untreated (n=73). Systemic prepartum treatment of end-term heifers with penethamate hydriodide resulted in fewer IMI in early lactation. However, all 6 cases of clinical mastitis in early lactation occurred in the treatment group [Streptococcus uberis (n=1), Corynebacterium bovis (n=1), Staphylococcus aureus (n=1); 1 sample was contaminated; 2 samples remained culture negative]. No long-term treatment effects (from 4 to 120 d in milk) on milk production, udder health, or culling hazard during later lactation were detected, although treated heifers belonging to herds classified as having low-yielding heifers out-produced the control heifers. Moreover, penicillin susceptibility of staphylococci isolated from milk samples of treated or control heifers did not differ. Herds with a low prevalence of heifer mastitis are not likely to benefit from prepartum systemic antimicrobial treatment of the end-term heifers.

Pathogen group-specific risk factors for intramammary infection in treated and untreated dairy heifers participating in a prepartum antimicrobial treatment trial

“…Although we considered 2 different data sets, making comparison difficult or even unwanted, we hypothesize that some heifers benefit more from treatment than others, especially heifers with an IMI with major pathogens. This hypothesis is supported by 2 other studies in which both the average cure rate (Borm et al, 2006) and the number of infected quarters (Sampimon et al, 2009;Passchyn et al, 2013) of prepartum treated heifers differed between both herds and heifers within herds. Still, the lack of data on cure rates in our study makes it difficult to further substantiate this hypothesis.…”

“…However, in the light of prudent drug use, and even though prepartum treatment of heifers with antimicrobials is probably the easiest way to reduce the prevalence of IMI at calving in the short term (Nickerson, 2009), preventing herd health problems, such as heifer mastitis, via nonantibiotic strategies is preferable over adopting blanket treatment protocols to reduce the risk of antibiotic residues in foodstuff (e.g., milk) and the development of antimicrobial resistance in pathogens and commensals. This needs to be stressed, as the long-term effects of prepartum antimicrobial treatment on farms suffering from heifer mastitis still remain undecided (Borm et al, 2006;Sampimon et al, 2009;Passchyn et al, 2013). Logic suggests that temporary use of antimicrobials in the control of a severe heifer mastitis problem can only be applied under strict conditions and when the etiology has been identified through culturing of milk samples, and should go along with the implementation of pathogen group-specific preventive measures at the same time to further reduce the risk for new IMI .…”

Nieuwe ontwikkelingen van een oude aandoening: mastitis onder de loep: Deel 1 - literatuuroverzicht

“…Het behandelen van vaarzen met antibiotica vóór het afkalven werd vroeger voorgesteld als een eenvoudige en effectieve methode om vaarzenmastitis onder controle te brengen. Positieve effecten op lange termijn wat betreft uiergezondheid en melkproductie werden echter soms wel (Sampimon et al, 2009a) en soms niet vastgesteld (Borm et al, 2009;Passchyn et al, 2013). Een algemeen advies om alle vaarzen te behandelen vóór de partus wordt derhalve alleen al omwille van economische redenen uitgesloten.…”

<b>Eficácia do tratamento com antibiótico injetável associado a selante de tetos sobre a saúde do úbere de novilhas com lactações induzidas</b>

“…Estudos prévios avaliaram o tratamento preventivo contra IIM antes da primeira lactação em novilhas utilizando diferentes modos de apresentação de antibióticos (injetável ou intramuscular) e se este era associado ou não com selante de tetos. Assim foi observada diminuição da prevalência de IIM após o tratamento em novilhas com antibióticos intramamários (OLIVER et al, 2003;MIDDLETON et al, 2005;OLIVER et al, 2004), antibióticos injetáveis (ATAEE et al, 2009;PASSCHYN et al, 2013;KREIGER et al, 2007;BRYAN e TAYLOR, 2009) Os patógenos mais frequentemente isolados durante as duas primeiras semanas de lactação no presente estudo foram: SCN e S. aureus. Estes resultados são semelhantes aos encontrados em outros estudos com novilhas com lactações não induzidas, nas quais o SCN foi o patógeno mais frequentemente isolado no pós parto (OLIVER et al,2003;COMPTON et al, 2007b;PARKER et al, 2007;PARKER et al, 2008;NICKERSON et al, 1995;DE VLIEGHER, et al, 2012;MACHADO;BICALHO, 2018;NAQVI et al, 2018).…”

“…Apesar de ser mais comum encontrar estudos na literatura com o uso de antibióticos intramusculares em relação antibióticos injetáveis, os antibióticos injetáveis apresentam vantagens contra, principalmente no requisito de praticidade e segurança dos funcionários no momento do manejo de aplicação dos medicamentos, além disso o manejo para realização do tratamento injetável é menor pois estes são de aplicação intramuscular e única, não havendo necessidade de aplicar antibiótico individualmente nos quatros quartos mamários PASSCHYN et al, 2013). Apesar de no presente estudo não ter sido avaliada cura bacteriológica após o tratamento com antibiótico injetável, nos estudos com vacas que compararam a cura bacteriológica dos antibióticos injetáveis vsintramamários, ambos tratamentos apresentaram curas bacteriológicas semelhantes (ST-ROSE et al, 2003;MCDOUGALL et al, 2007).…”