Research article · 2025 · Full text
International Journal of Biology SciencesImpact of subclinical mastitis on milk yield in dairy crossbred cows: A case study of 217 cows
Volume 7(2) · Pages 33–36 · DOI: 10.33545/26649926.2025.v7.i2a.296 ↗
Research areasGenetic and phenotypic traits in livestock
Abstract
Author-writtenSubclinical mastitis is a pervasive and economically significant disease in dairy cows, often characterized by an increase in somatic cell counts (SCC) without visible changes in milk or the udder. This study investigates the effect of subclinical mastitis on milk yield in a sample of 217 dairy crossbred cows, where 97 cows were found to have subclinical infection as detected by the SCC method. Our findings reveal a notable average decline in milk yield by 15% in affected cows compared to the healthy quarters of the same cows, emphasizing the economic implications of subclinical mastitis in dairy farming.
Summary
Source-checkedPlain-language reading of the full paper, prepared with AI and checked against the text. Each point links to the authors' own words.
Why it matters
- Mastitis is an inflammation of the mammary gland and is considered one of the most economically damaging diseases for dairy cows globally. View evidence ↗
- Unlike clinical mastitis, which has visible symptoms like swelling and redness, subclinical mastitis has no overt signs, making it harder to detect. View evidence ↗
- Subclinical mastitis can lead to significant reductions in milk yield, changes in milk composition, and a higher risk of secondary infections. View evidence ↗
The question
- The study aims to quantify how subclinical mastitis affects milk yield in dairy crossbred cows using somatic cell count (SCC) for diagnosis. View evidence ↗
What they did
- The study enrolled a total of 217 dairy crossbred cows from various farms. View evidence ↗
- Somatic cell counts (SCC) were analyzed using a DeLaval cell counter from milk samples collected aseptically from all quarters of each cow. View evidence ↗
- Cows were classified as healthy if SCC was below 200,000 cells/ml and subclinically infected if SCC was 200,000 cells/ml or higher. View evidence ↗
- Milk yield was recorded over six months, comparing production from affected quarters to healthy quarters within the same cows. View evidence ↗
What they found
- Of the 217 cows examined, 97 (44.7%) were found to have subclinical mastitis. View evidence ↗
- Affected quarters showed an average decline in milk yield of 15% compared to the healthy quarters of the same cows. View evidence ↗
- The estimated daily loss in milk yield was approximately 0.71 kg per cow. View evidence ↗
- Greater milk yield losses correlated with higher SCC levels, which averaged 4 lakh cells per ml in subclinical cases. View evidence ↗
- In clinical cases, milk yield losses are greater than 20% and can be even higher in severe cases. View evidence ↗
What it means
- The authors conclude that subclinical mastitis, detected by SCC, causes a marked average decline of 15% in milk yield in dairy crossbred cows. View evidence ↗
- The authors recommend implementing mastitis control strategies, specifically regular SCC monitoring, to reduce economic losses and improve cow health. View evidence ↗
- The authors note that economic losses may vary by breed, management, and market, and suggest further research across different farming contexts. View evidence ↗
Visual summary
1 visualsIllustrations explain the paper; they do not show study data.
Correlation of SCC and Milk Yield
AI-generated conceptual illustration (dairy crossbred cows). It explains the idea and does not show study data.
View source evidence ↗Figures & tables
From the original paper
Figure 1
Figure 1
Figure 2
Figure 3Introduction
Mastitis, an inflammation of the mammary gland, is one of the most economically impactful diseases affecting dairy cows worldwide. While clinical mastitis presents with visible symptoms such as swelling, redness, and abnormal milk, subclinical mastitis lacks overt signs, making it more insidious and challenging to detect. Despite the absence of visible symptoms, subclinical mastitis can significantly reduce milk yield, alter milk composition, and increase the risk of secondary infections (Tandoğan & Güleş, 2024) [1] . Subclinical mastitis is primarily identified through the measurement of somatic cell counts (SCC) in milk, which serve as an indicator of inflammation within the mammary gland. Elevated SCC levels are associated with reduced milk production and compromised milk quality. This condition often goes unnoticed until substantial economic losses occur, underscoring the importance of routine monitoring and early detection (Tesfaye et al., 2010) [2] . The economic impact of subclinical mastitis extends beyond decreased milk yield to include increased veterinary costs, discarded milk, and potential culling of chronically infected cows. This research focuses on quantifying the impact of subclinical mastitis on milk yield in dairy crossbred cows, using somatic cell count (SCC) as a diagnostic tool to provide insights into effective management strategies (Mungube et al., 2005) [3] .
Materials and Methods
A total of 217 dairy crossbred cows were enrolled in this study from various dairy farms. Milk samples were collected aseptically from all quarters of each cow and analyzed for SCC using a DeLaval cell counter. Cows were categorized into two groups: healthy (with SCC <200,000 cells/ml) and subclinically infected (with SCC ≥200,000 cells/ml). Milk yield data were recorded for individual cows over a six-month period, comparing the production from affected quarters to that from healthy quarters within the same animals.
Results
Out of the 217 cows examined, 97 (44.7%) were identified as having subclinical mastitis based on elevated SCC levels (Fig. 1). Analysis of milk production data revealed an average decline of 15% in milk yield from the affected quarters compared to the healthy quarters of the same cows. Specifically, the daily milk yield loss was estimated to be approximately 0.71 kg per cow (Tandogan & Gules, 2024) [1] .
The severity of milk yield reduction varied among cows, with higher SCC levels correlating with greater losses with average 4 lakh cells per ml in subclinical cases (Fig. 2). This reduction in milk production highlights the significant economic loss associated with subclinical mastitis, even in the absence of clinical symptoms (Tesfaye et al., 2010) [2] . The losses in clinical cases are greater than 20% and can reach upto a substantial percentage in severe cases (Fig. 3).
Discussion
The findings of this study underscore the hidden costs of subclinical mastitis in dairy herds. A 15% decrease in milk yield from affected cows not only represents a substantial loss in potential revenue for dairy farmers but also indicates the broader implications for dairy product quality and animal welfare. The economic impact extends to increased veterinary expenses, reduced reproductive performance, and the potential need for premature culling of affected animals (Mungube et al., 2005) [3] . The use of SCC as a diagnostic tool proved effective in identifying subclinical cases, suggesting that routine monitoring of SCC levels could play a crucial role in early detection and management of mastitis. Implementing regular SCC screening can help farmers identify infected cows early, allowing for timely intervention and treatment to mitigate milk yield losses (Shende et al., 2020) [4] .
This study's results align with previous research indicating that subclinical mastitis can lead to significant reductions in milk production. However, the precise economic loss may vary depending on factors such as cow breed, management practices, and market conditions. Therefore, further research is warranted to explore the broader economic implications of subclinical mastitis across different dairy farming contexts (Gonçalves et al., 2020) [5] .
Conclusion
This study demonstrates a marked average decline of 15% in milk yield in dairy crossbred cows affected by subclinical mastitis, as detected by SCC. These findings highlight the importance of implementing effective mastitis control strategies, including regular SCC monitoring, to mitigate economic losses and improve dairy cow health. Future research should focus on developing cost-effective interventions and management practices tailored to the specific challenges faced by dairy farmers in managing subclinical mastitis.
References
4 in the original paper- Tandoğan M, Güleş Ö. Estimation of milk yield losses from subclinical mastitis in dairy cows. Kocatepe Vet J. 2024. Available from: http://dx.doi.org/10.30607/kvj.1506469.
- Tesfaye GY, Regassa F, Kelay B. Milk yield and associated economic losses in quarters with subclinical mastitis due to Staphylococcus aureus in Ethiopian crossbred dairy cows. Trop Anim Health Prod. 2010;42:925-931.
- Mungube E, Tenhagen B, Regassa F, Kyule M, Shiferaw Y, Kassa T, et al. Reduced milk production in udder quarters with subclinical mastitis and associated economic losses in crossbred dairy cows in Ethiopia. Trop Anim Health Prod. 2005;37:503-512.
- Gonçalves JL, Kamphuis C, Vernooij H, Araújo JP, Grenfell R, Juliano L, et al. Pathogen effects on milk yield and composition in chronic subclinical mastitis in dairy cows. Vet J. 2020;262:105473.