A time series analysis of bulk tank somatic cell counts of dairy herds located in Brazil and the United States

Abstract

Bulk tank somatic cell counts (BTSCC) is widely used to monitore the mammary gland health at the herd and regional level. The BTSCC time series from specific regions or countries can be used to compare the mammary gland health and estimate the trend of subclinical mastitis at the regional level. Three time series of BTSCC from dairy herds located in the USA and the Southeastern Brazil were evaluated from 1995 to 2014. Descriptive statistics and a linear regression model were used to evaluate the data of the BTSCC time series. The mean of annual geometric mean of BTSCC (AGM) and the percentage of dairy herds with a BTSCC greater than 400,000 cells mL-1 (%>400) were significantly different (P<0.05) according to the countries and the times series. Linear regression model used for the USA time series was statistically significant for AGM and the %>400 (P<0.05). The first and second USA time series presented an increasing and decreasing trend for AGM and the %>400, respectively. The linear regression model for the Brazil time series was not significant (P>0.05) for both dependent variables (AGM and %>400). The Brazil time series showed no increasing or decreasing trend for the AGM and %>400. Consequently, approximately 40 to 50% of the dairy herds from southeastern Brazil will not achieve the regulatory limits for BTSCC over the next years.

Staphylococcus aureus and Streptococcus agalactiae: prevalence, resistance to antimicrobials, and their relationship with the milk quality of dairy cattle herds in Minas Gerais state, Brazil

“…Findings of the present study showed that 50% of the herds presented BMSCC ≥400,000 cell/mL, with mean of 483,000 cell/mL. These results are in agreement with those reported by Rodrigues et al (2017), who verified a geometric annual BMSCC mean in herds in southeastern Brazil of 518,000 cell/mL, with a confidence interval from 491,000 to 546,000 cell/mL; these results are similar to those found in the present study -483,000 cell/mL. High levels of BMSCC can cause numerous losses to the dairy industry, because they directly affect the composition of milk and, consequently, reduce its shelf life and that of its derivatives (Silva & Nogueira 2010).…”

“…The high prevalence rates observed in the present survey for pathogens S. aureus and S. agalactiae (Table 1) suggest that the control measures for infectious mastitis are not being correctly applied, a finding that corroborates the results reported by Rodrigues et al (2017). This fact emphasizes the need to adopt specific measures for the control of these contagious pathogens that affect the daily production of herds and the milk quality, especially the BMSCC index.…”

Effect of heat stress on udder health of dairy cows

“…Bulk tank SCC worldwide SCC measured at bulk tank level is a widely used indicator when troubleshooting herds with multiple milk quality and allows an estimate of the trends of clinical and subclinical mastitis at the herd and regional level (Olde Riekerink et al, 2007;Rodrigues et al, 2017). Moreover, bulk tank SCC is significantly correlated with polymorphonuclear neutrophilic leukocytes (PMN) content of milk, which is influenced by environmental temperature and act as a vital indicator of dairy herd health (O'Sullivan et al, 1992;Kelly et al, 2000).…”

Prevalence and antibiotic resistance of Staphylococcus aureus and Streptococcus agalactiae in family-owned dairy herds in the state of Minas Gerais, Brazil

“…agalactiae (see Table 1) indicates that control measures for contagious mastitis have not been applied correctly. This points to a need for specific measures to control these contagious pathogens that impact the productivity of herds and the quality of milk, especially when it comes to the BMSCC (RODRIGUES et al, 2017).…”