Profitable and efficient milk produ

Profitable and efficient milk production depends upon cost-effective management of dairy herds. Diseases and reproductive efficiency affect yields of milk and culling decisions, which ultimately impact profitability of dairy farms. Mastitis is one of the most common diseases affecting dairy cows and it causes major economic losses to the dairy industry. DeGraves and Fetrow (1993) estimated that costs associated with mastitis for the US dairy industry are over 2 billion dollars a year. The economic impact of mastitis on dairy herds is related to reduced milk production, reduced milk quality with increases in SCC, increased costs with treatment and discarded milk, and increased risk for culling (DeGraves and Fetrow, 1993).

Beyond the negative impact on yields of milk and milk components, mastitis has recently been reported to have a detrimental effect on reproductive performance in lactating dairy cows. The first published report suggested that clinical mastitis caused by Gram negative (−) bacteria, Escherichia coli, could alter the interestrus interval ( Moore et al., 1991). Cows with clinical mastitis due to Gram − bacteria were 1.6 times more likely to have an altered interestrus interval than cows without mastitis. More recent reports have indicated that cows that develop clinical mastitis early in lactation are less likely to conceive (Barker et al., 1998). Furthermore, intramammary infections of subclinical nature were also associated with reduced reproductive efficiency (Schrick et al., 2001). Schrick et al. (2001) collected milk samples from 752 cows every 4–8 weeks during an entire lactation, at drying off, near calving, and when clinical mastitis was diagnosed. After grouping cows based on mastitis type as no mastitis, subclinical mastitis, and clinical mastitis, they observed that cows with clinical or subclinical mastitis before first service had increased days to first AI, days open, and increased services per conception compared to cows classified as not having mastitis. The most severe impact of mastitis on reproductive performance was observed when cows developed subclinical mastitis followed by clinical mastitis.

Acute mastitis caused by Gram − bacteria can result in bacteremia in over 30% of the affected cows (Wenz et al., 2001), and inflammation of tissues can trigger the release of inflammatory mediators, one of them being the two series of prostaglandins (Cullor, 1990). Moore et al. (1991) suggested that clinical mastitis caused by Gram − pathogens can alter the interestrus interval by the release of bacterial endotoxins with premature luteolysis due to PGF2α secretion.

Efficient reproductive performance is essential for the maintenance of consistently high levels of milk production. Herds with high prevalence of mastitis may experience lower reproductive efficiency. Reduced reproductive performance due to mastitis may be related to an extension in the interval from calving to first postpartum AI, reduced pregnancy to insemination, prolonged days open, and increased late embryonic mortality after pregnancy diagnosis.

The purpose of the present study was to determine the influence of timing of the first clinical mastitis case caused by environmental pathogens on reproductive parameters and lactational performance in high producing Holstein dairy cows.

ผลลัพธ์ (ไทย) 1:

ปริมาณน้ำนมที่มีประสิทธิภาพ และผลกำไรขึ้นอยู่กับประสิทธิภาพการจัดการฝูงโคนม โรคและประสิทธิภาพการสืบพันธุ์มีผลต่อผลผลิตนมและ culling ตัดสิน ซึ่งในท้ายที่สุด ส่งผลกระทบต่อผลกำไรของฟาร์มโคนม เต้านมอักเสบเป็นโรคพบมากที่สุดส่งผลกระทบต่อโคนมอย่างใดอย่างหนึ่ง และจะทำให้สูญเสียเศรษฐกิจหลักของอุตสาหกรรมนม DeGraves และ Fetrow (1993) โดยประมาณค่าใช้จ่ายที่เกี่ยวข้องกับเต้านมอักเสบสำหรับอุตสาหกรรมนมของสหรัฐอเมริกากว่า 2 พันล้านดอลลาร์ต่อปี ผลกระทบทางเศรษฐกิจของโรคเต้านมอักเสบในโคนมฝูงเกี่ยวข้องกับปริมาณน้ำนมลดลง ลดลงคุณภาพน้ำนมขึ้นใน SCC ต้นทุนเพิ่มขึ้น ด้วยการบำบัดและน้ำทิ้ง และเพิ่มความเสี่ยงสำหรับ culling (DeGraves และ Fetrow, 1993)Beyond the negative impact on yields of milk and milk components, mastitis has recently been reported to have a detrimental effect on reproductive performance in lactating dairy cows. The first published report suggested that clinical mastitis caused by Gram negative (−) bacteria, Escherichia coli, could alter the interestrus interval ( Moore et al., 1991). Cows with clinical mastitis due to Gram − bacteria were 1.6 times more likely to have an altered interestrus interval than cows without mastitis. More recent reports have indicated that cows that develop clinical mastitis early in lactation are less likely to conceive (Barker et al., 1998). Furthermore, intramammary infections of subclinical nature were also associated with reduced reproductive efficiency (Schrick et al., 2001). Schrick et al. (2001) collected milk samples from 752 cows every 4–8 weeks during an entire lactation, at drying off, near calving, and when clinical mastitis was diagnosed. After grouping cows based on mastitis type as no mastitis, subclinical mastitis, and clinical mastitis, they observed that cows with clinical or subclinical mastitis before first service had increased days to first AI, days open, and increased services per conception compared to cows classified as not having mastitis. The most severe impact of mastitis on reproductive performance was observed when cows developed subclinical mastitis followed by clinical mastitis.Acute mastitis caused by Gram − bacteria can result in bacteremia in over 30% of the affected cows (Wenz et al., 2001), and inflammation of tissues can trigger the release of inflammatory mediators, one of them being the two series of prostaglandins (Cullor, 1990). Moore et al. (1991) suggested that clinical mastitis caused by Gram − pathogens can alter the interestrus interval by the release of bacterial endotoxins with premature luteolysis due to PGF2α secretion.Efficient reproductive performance is essential for the maintenance of consistently high levels of milk production. Herds with high prevalence of mastitis may experience lower reproductive efficiency. Reduced reproductive performance due to mastitis may be related to an extension in the interval from calving to first postpartum AI, reduced pregnancy to insemination, prolonged days open, and increased late embryonic mortality after pregnancy diagnosis.The purpose of the present study was to determine the influence of timing of the first clinical mastitis case caused by environmental pathogens on reproductive parameters and lactational performance in high producing Holstein dairy cows.