חיפוש מתקדם
Theriogenology
Furman, O., Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, Israel
Leitner, G., Mastitis Reference Center, The Veterinary Institute, Bet Dagan, Israel
Roth, Z., Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, Israel
Lavon, Y., Cattle Breeders Association, Caesarea, Israel
Jacoby, S., Institute of Animal Science, Agricultural Research Organization, Bet-Dagan, Israel
Wolfenson, D., Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, Israel
This study establishes an experimental model for subclinical mastitis induced by Gram-positive (G+) exosecretions of Staphylococcus aureus origin or Gram-negative (G-) endotoxin of Escherichia coli origin to examine its effects on follicular growth and steroid concentrations in Holstein dairy cows. Cows were synchronized with the Ovsynch protocol followed by a series of follicular cycles that included GnRH and PGF2α doses administered every 8days. Cows received small intramammary doses of either G+ (10μg, n=10) or G- (0.5μg, n=6) toxin, or saline (n=6; uninfected control) every 48hours for 20days. Follicular fluids were aspirated from preovulatory follicles before (aspiration one: control), at the end of (aspiration two: immediate effect), and 16days after the end of (aspiration three: carryover effect) toxin exposure. During the 3weeks of subclinical mastitis induced by G+ or G-, no local inflammatory signs were detected in the mammary gland and no systemic symptoms were noted: body temperatures of the treated cows did not differ from controls; plasma cortisol and haptoglobin concentrations were not elevated and did not differ among groups. Somatic cell count was higher in the treated groups than in controls, and higher in the G- versus G+ group. For analysis of reproductive responses, cows were further classified as nonaffected or affected based on an more than 20% decline in follicular androstenedione concentration in aspiration two or three relative to the first, control aspiration. Most G- (5/6) and 40% of G+ (4/10) cows were defined as affected by induced mastitis. An immediate decrease in the number of medium-size follicles was recorded on Day 4 of the induced cycle, toward the end of the 20-day mastitis induction, in the affected G+ compared with uninfected control group (1.0±0.5 vs. 3.0±0.4 follicles; P<0.05); the affected G- and nonaffected G+ subgroups exhibited a similar numerical decline in the number of follicles. A carryover (but not immediate) decrease to 51% and 62% in follicular estradiol concentrations in G- affected group and G+ affected group was detected relative to controls (P<0.05). The nonaffected G+ subgroup did not differ from its control counterparts. Based on the current experimental model, subclinical IMI induced by G+ or G- toxin disrupts follicular functions, and it seems that the ovarian pool of early antral follicles is susceptible to subclinical mastitis. © 2014 Elsevier Inc.
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הספר "אוצר וולקני"
אודות
תנאי שימוש
Experimental model of toxin-induced subclinical mastitis and its effect on disruption of follicular function in cows
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Furman, O., Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, Israel
Leitner, G., Mastitis Reference Center, The Veterinary Institute, Bet Dagan, Israel
Roth, Z., Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, Israel
Lavon, Y., Cattle Breeders Association, Caesarea, Israel
Jacoby, S., Institute of Animal Science, Agricultural Research Organization, Bet-Dagan, Israel
Wolfenson, D., Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, Israel
Experimental model of toxin-induced subclinical mastitis and its effect on disruption of follicular function in cows
This study establishes an experimental model for subclinical mastitis induced by Gram-positive (G+) exosecretions of Staphylococcus aureus origin or Gram-negative (G-) endotoxin of Escherichia coli origin to examine its effects on follicular growth and steroid concentrations in Holstein dairy cows. Cows were synchronized with the Ovsynch protocol followed by a series of follicular cycles that included GnRH and PGF2α doses administered every 8days. Cows received small intramammary doses of either G+ (10μg, n=10) or G- (0.5μg, n=6) toxin, or saline (n=6; uninfected control) every 48hours for 20days. Follicular fluids were aspirated from preovulatory follicles before (aspiration one: control), at the end of (aspiration two: immediate effect), and 16days after the end of (aspiration three: carryover effect) toxin exposure. During the 3weeks of subclinical mastitis induced by G+ or G-, no local inflammatory signs were detected in the mammary gland and no systemic symptoms were noted: body temperatures of the treated cows did not differ from controls; plasma cortisol and haptoglobin concentrations were not elevated and did not differ among groups. Somatic cell count was higher in the treated groups than in controls, and higher in the G- versus G+ group. For analysis of reproductive responses, cows were further classified as nonaffected or affected based on an more than 20% decline in follicular androstenedione concentration in aspiration two or three relative to the first, control aspiration. Most G- (5/6) and 40% of G+ (4/10) cows were defined as affected by induced mastitis. An immediate decrease in the number of medium-size follicles was recorded on Day 4 of the induced cycle, toward the end of the 20-day mastitis induction, in the affected G+ compared with uninfected control group (1.0±0.5 vs. 3.0±0.4 follicles; P<0.05); the affected G- and nonaffected G+ subgroups exhibited a similar numerical decline in the number of follicles. A carryover (but not immediate) decrease to 51% and 62% in follicular estradiol concentrations in G- affected group and G+ affected group was detected relative to controls (P<0.05). The nonaffected G+ subgroup did not differ from its control counterparts. Based on the current experimental model, subclinical IMI induced by G+ or G- toxin disrupts follicular functions, and it seems that the ovarian pool of early antral follicles is susceptible to subclinical mastitis. © 2014 Elsevier Inc.
Scientific Publication