An investigation of risk factors for two successive cases of clinical mastitis in the same lactation

Abstract

The objective of this study was to identify risk factors for the occurrence of two successive cases of clinical mastitis (CM). Two farms were visited monthly during 10 months. Milk samples were collected from all cases of CM that occurred during the study. Cows were observed prospectively from the beginning of the study and a case cow was defined when she experienced the second case of CM within the same lactation. For each case cow, 3 control cows matched by days in milk (DIM) were randomly selected from the cohort of cows who did not experience CM. On each visit day, a series of udder and teat characteristics were recorded during milking time: teat-end hyperkeratosis scoring, milking ease scoring, teat length and diameter, teat-to-ground distance, and udder position in relation to the hock. A total of 113 case cows and 324 control cows were used for analyses. The median time to occurrence of the first case of CM was 84 DIM and the median interval between the first and second cases of CM was 39 days. Of all second cases, 49.6% (N=55) occurred in the same mammary gland. Of these 55 cases, 29.1% had identical milk culture results from both first and second cases. Most cases of CM were caused by coliforms and environmental streptococci. Teat-to-ground distance, teat-end hyperkeratosis, udder position in relation to the hock, milking ease, parity, and milk production at the first test of lactation were individually associated with the occurrence of two successive cases of CM. Of all explanatory variables, 3 remained in the final multivariable model. The odds of two successive cases of CM were 3.7 times greater for cows who were "very easy to milk", as compared with cows who were "difficult to milk". Cows who had their udders below the hock, and those of parity > 2 were 3.6 and 2.5 times more likely to experience two successive cases of CM, as compared with cows whose udder was positioned above the hock, and cows of parity 1, respectively. Findings of this study highlight the importance of teat and udder characteristics as risk factors for two successive cases of CM. Further investigations are needed to elucidate the role of the teat canal in preventing mastitis for modern cows that have been selected for increased milk production, shorter teats, and greater milk flow rates.

Infection dynamics across the dry period using Dairy Herd Improvement somatic cell count data and its effect on cow performance in the subsequent lactation

“…Cows were considered healthy (test-day SCC <200,000 cells/mL before and after the dry period), newly infected (new IMI; test-day SCC <200,000 cells/mL before the dry-off and ≥200,000 cells/mL after calving), cured (from an existing IMI; test-day SCC ≥200,000 cells/mL before dry-off and <200,000 cells/mL after calving), or chronically infected (chronic IMI; test-day SCC ≥200,000 cells/mL before and after the dry period). cow-level factors that affect the risk of IMI in the subsequent lactation include teat apex hyperkeratosis and diameter (Breen et al, 2009;Guarín and Ruegg, 2016;Pantoja et al, 2016), udder and leg hygiene (Schreiner and Ruegg, 2003), negative energy balance (Suriyasathaporn et al, 2000), MY at drying off (Huxley et al, 2002;Dingwell et al, 2004), and genetic predisposition (Detilleux, 2009), yet these were not monitored in our study. A significant proportion of culling (Fetrow et al, 2006) and CM (Bradley and Green, 2004) occurs during early lactation; although these events were only monitored after the first DHI record (taking place between 12 and 42 DIM) in the present study, the infection dynamics were still significantly associated with culling and CM.…”

Association between teat-end hyperkeratosis and mastitis in dairy cows: A systematic review

“…Difference between proportions was used in 4 studies (Sieber and Farnsworth, 1981;Bhutto et al, 2010;Asadpour et al, 2015;Emre and Alaçam, 2015), difference between means or linear regression was used in 7 studies (Neijenhuis et al, 2001;Gleeson et al, 2004;Bhutto et al, 2010;Haghkhah et al, 2011;de Pinho Manzi et al, 2012;Mitev et al, 2012;Guarin et al, 2017), odds ratio in 7 studies (Dingwell et al, 2004;Breen et al, 2009a,b;de Pinho Manzi et al, 2012;Dufour et al, 2012;Cardozo et al, 2015;Pantoja et al, 2016), and risk ratio in 2 studies (Zadoks et al, 2001;Zoche-Golob et al, 2015).…”

“…Three studies investigated the association between THK and CM (Neijenhuis et al, 2001;Breen et al, 2009b;Pantoja et al, 2016). Neijenhuis et al (2001; prospective cohort with validity score = 5.6) compared THK scores between quarters that experienced CM and contralateral quarters of the same cow that did not experience CM (cross-sectional analysis) and reported positive associations that were not statistically significant.…”

“…Teat-end hyperkeratosis (THK) is one of the most prevalent pathologies of dairy cows, being characterized by hyperplasia of the teat orifice's keratin layer in response to chronic stimuli (Blowey and Weaver, 2011). In a scale ranging from 1 (no THK) to 4 (severe THK; Mein et al, 2001), the prevalence of Holstein cow teats scored as 3 ranged between 21.5% (415/1,931;de Pinho Manzi et al, 2012;Brazil) and 46.5% (939/2,019; Zoche-Golob et al, 2015;Germany) and scored as 4 ranged between 12.5% (51/408; Paduch et al, 2012;Germany) and 18.8% (39/207; Pantoja et al, 2016;Brazil).…”

“…Cows factors such as teat shape (Neijenhuis et al, 2001), teat position (front or rear; Neijenhuis et al, 2001;Mitev et al, 2012), stage of lactation (Neijenhuis et al, 2001), parity (Sandrucci et al, 2014;Pantoja et al, 2016), peak milk production (Neijenhuis et al, 2001), and machine-on time (Neijenhuis et al, 2000) have all been associated with THK. At the herd level, milking management factors and equipment settings, such as teat-end vacuum, pulsation system, duration of the pulsation cycle's D phase, liner characteristics (compression, tension, and material), and overmilking, have been associated with THK (Neijenhuis et al, 2000;Mein et al, 2001;Zucali et al, 2008;Sterrett et al, 2013).…”