Effects of pathogen-specific clinical mastitis on probability of conception in Holstein dairy cows

Abstract

The objective of this study was to estimate the effects of pathogen-specific clinical mastitis (CM), occurring in different weekly intervals before or after artificial insemination (AI), on the probability of conception in Holstein cows. Clinical mastitis occurring in weekly intervals from 6 wk before until 6 wk after AI was modeled. The first 4 AI in a cow's lactation were included. The following categories of pathogens were studied: Streptococcus spp. (comprising Streptococcus dysgalactiae, Streptococcus uberis, and other Streptococcus spp.); Staphylococcus aureus; coagulase-negative staphylococci (CNS); Escherichia coli; Klebsiella spp.; cases with CM signs but no bacterial growth (above the level that can be detected from our microbiological procedures) observed in the culture sample and cases with contamination (≥ 3 pathogens in the sample); and other pathogens [including Citrobacter, yeasts, Trueperella pyogenes, gram-negative bacilli (i.e., gram-negative organisms other than E. coli, Klebsiella spp., Enterobacter, and Citrobacter), Corynebacterium bovis, Corynebacterium spp., Pasteurella, Enterococcus, Pseudomonas, Mycoplasma, Prototheca, and others]. Other factors included in the model were parity (1, 2, 3, 4 and higher), season of AI (winter, spring, summer, autumn), day in lactation of first AI, farm, and other non-CM diseases (retained placenta, metritis, ketosis, displaced abomasum). Data from 90,271 AI in 39,361 lactations in 20,328 cows collected from 2003/2004 to 2011 from 5 New York State dairy farms were analyzed in a generalized linear mixed model with a Poisson distribution. The largest reductions in probability of conception were associated with CM occurring in the week before AI or in the 2 wk following AI. Escherichia coli and Klebsiella spp. had the greatest adverse effects on probability of conception. The probability of conception for a cow with any combination of characteristics may be calculated based on the parameter estimates. These findings may be helpful to farmers in assessing reproduction in their dairy cows for more effective cow management.

Associations of the first occurrence of pathogen-specific clinical mastitis with milk yield and milk composition in dairy cows

“…A first-order autoregressive correlation structure among the repeated measurements of milk yield and composition within a cow's lactation was incorporated. These models were adopted from earlier research on the effects of pathogen-unidentified or -specific CM on milk yield (Gröhn et al 2004;Wilson et al 2004;Bar et al 2007;Hertl et al 2014). Wilson et al (2004) showed a first-order autoregressive correlation structure among the repeated measurements of milk yield was the best structure in their analyses.…”

An update on environmental mastitis: Challenging perceptions

“…Direct and indirect economic losses due to mastitis have been estimated (Halasa et al., ) and vary greatly between animals and pathogens. For example, yield losses in heifers are greatest after E. coli CM and in multiparous animals after Klebsiella CM, and both coliforms have greater impact on fertility than other pathogen species (Hertl et al., , ). Yield losses may persist for months after coliform or GPCN mastitis, whilst CM with non‐aureus staphylococci does not cause reduced production (Hertl et al., ).…”

“…For example, yield losses in heifers are greatest after E. coli CM and in multiparous animals after Klebsiella CM, and both coliforms have greater impact on fertility than other pathogen F I G U R E 4 Faecal contamination is a major source of exposure to environmental pathogens regardless of the use of sawdust (left), straw (right) or other bedding material. Photographs: RN Zadoks species (Hertl et al, 2014a(Hertl et al, , 2014b. Yield losses may persist for months after coliform or GPCN mastitis, whilst CM with non-aureus staphylococci does not cause reduced production (Hertl et al, 2014a).…”

Longitudinal metagenomic profiling of bovine milk to assess the impact of intramammary treatment using a third-generation cephalosporin

“…Thus, in-depth understanding of disease mechanisms is critical to promote animal health and at the same time encourage judicious use of antibiotics in livestock. Mastitis is one of the most common diseases in dairy herds, and approximately 20% to 30% of dairy cows develop clinical mastitis at least once during lactation12. Not surprisingly, prophylaxis and treatment of mastitic cows are the major reasons for antibiotic usage in dairy farms34.…”