The aim of this study was to evaluate the effects of repeated oronasal administration of lipopolysaccharide (LPS) on milk composition and the overall productive performance of dairy cows. One hundred pregnant Holstein...The aim of this study was to evaluate the effects of repeated oronasal administration of lipopolysaccharide (LPS) on milk composition and the overall productive performance of dairy cows. One hundred pregnant Holstein dairy cows were randomly assigned to two treatment groups (n = 50). 30 cows out of 100 were selected for intensive sampling (n = 15) starting at 28 d before parturition. Cows were administered orally and nasally with 2 and 1 mL of saline solution, respectively (control), or saline solution containing 3 doses of LPS from Escherichia coli 0111:B4 as follows: 1) 0.01 μg/kg body weight (BW) on d ﹣28, 2) 0.05 μg/kg BW on d ﹣25 and ﹣21, and 3) 0.1 μg/kg BW on d ﹣18 and ﹣14. Daily feed intake and milk production were recorded for each cow during the first 28 d postpartum. Milk samples were obtained once per week and analyzed for various milk components. Overall, results indicated that treatment did not affect feed intake, milk yield, milk efficiency, fat content, fat yield, protein content, protein yield, lactose content, lactose yield, milk urea nitrogen (MUN), total solid contents, fat-corrected milk (FCM), and energy-corrected milk (ECM;P > 0.05). However, milk somatic cell count (SCC) tended to be lower in the treated cows (P eek interaction for milk energy (P = 0.03), and tendencies for FCM, ECM, lactose content, and milk efficiency展开更多
Profiles of energy metabolites and haptoglobin (Hp) in dairy cows that are transitioned from conventional to organic management in various Alberta farms were compared with those of dairy cows managed conventionally at...Profiles of energy metabolites and haptoglobin (Hp) in dairy cows that are transitioned from conventional to organic management in various Alberta farms were compared with those of dairy cows managed conventionally at the University of Alberta dairy farm. Blood samples were collected during the following periods: Dry, 0 - 30, 30 - 60, and 60 - 90 days in milk (DIM, n = 7 cows). Concentrations of metabolites were evaluated by enzymatic colorimetric methods. Concentrations of Hp were determined by bovine ELISA kits. Data were analyzed by the mixed procedures of SAS. Concentrations of NEFA and BHBA in blood were elevated (P < 0.001) 0 to 30 d, intermediate 30 to 60, and 60 to 90 d, and lower in the dry period. In addition, BHBA was higher (P < 0.0001) at all stages of lactation in conventional than organic cows (e.g. 1289.4 ± 88.6 vs. 883.6 ± 47.5 μmol/L in conventional and organic cows at 0 - 30 d, respectively). Serum concentrations of cholesterol increased with increasing DIM and returned to nadir levels during dry period and was higher (P < 0.0001) in conventional than organic cows. Low glucose concentrations were observed 0 to 30 d, levels were intermediate 30 to 60 and 60 to 90 d, and peaked during the dry period (P < 0.54) between conventional and organic cows. Lactate did not (P < 0.24) vary with DIM or day × farm type but was higher (P < 0.0001) in organic cows than in conventional cows. Serum concentrations of Hp were elevated during dry period;reached peak levels 0 to 30 d and decreased gradually with increasing days postpartum and were much higher at all periods in conventional than organic cows. Overall, concentrations of Hp were 528.1 ± 45.2 μg/mL in conventional cows vs. 261.1 ± 16.9 μg/mL in organic cows (P < 0.0001). Taken together, these data indicate that metabolic changes associated with initiation of lactation are preceded by an acute phase response in dairy cows, and that cows in organic systems seem to be healthier than cows under conventional systems. These differences might be due to differences in nutritional management in the two systems.展开更多
The objective of this study was to evaluate whether repeated oronasal administration of LPS before parturition showed effects on metabolic and clinical responses in periparturient dairy cows. Hundred Holstein dairy co...The objective of this study was to evaluate whether repeated oronasal administration of LPS before parturition showed effects on metabolic and clinical responses in periparturient dairy cows. Hundred Holstein dairy cows were randomly allocated to two treatment groups (n = 50). Thirty cows out of 100 were randomly assigned for intensive sampling (n = 15) started at 28 d before the expected day of parturition. Cows received an oral and a nasal treatment of 2 mL and 1 mL of sterile saline solution (0.15 M of NaCl), respectively, alone (control), or containing 3 increasing doses of LPS from Escherichia coli 0111:B4 as follows: 1) 0.01 μg/kg body weight (BW) on d ﹣28, 2) 0.05 μg/kg BW on d ﹣25, and ﹣21, and 3) 0.1 μg/kg BW on d ﹣18 and ﹣14. Blood samples were collected from coccygeal vein at different time points around parturition and analyzed for glucose, lactate, non-esterified fatty acids (NEFA), cholesterol, and betahydro-xybutyrate (BHBA). Clinical monitoring of animals was done throughout the experiment at different time points for overall health status, udder edema (UE), manure score, and body condition score (BCS). Results showed that oronasal administration of LPS increased concentrations of glucose and cholesterol in the serum compared to the control group (P 0.05). Oronasal LPS did not influence BCS, manure score or the incidence of UE (P > 0.05). Overall, repeated oronasal administration of LPS modulated some serum metabolites related to energy metabolism around parturition in the treated cows. Further research is warranted to elucidate the mechanisms behind greater glucose and cholesterol status in the serum and their potential effects on long-term metabolic health status of dairy cows.展开更多
文摘The aim of this study was to evaluate the effects of repeated oronasal administration of lipopolysaccharide (LPS) on milk composition and the overall productive performance of dairy cows. One hundred pregnant Holstein dairy cows were randomly assigned to two treatment groups (n = 50). 30 cows out of 100 were selected for intensive sampling (n = 15) starting at 28 d before parturition. Cows were administered orally and nasally with 2 and 1 mL of saline solution, respectively (control), or saline solution containing 3 doses of LPS from Escherichia coli 0111:B4 as follows: 1) 0.01 μg/kg body weight (BW) on d ﹣28, 2) 0.05 μg/kg BW on d ﹣25 and ﹣21, and 3) 0.1 μg/kg BW on d ﹣18 and ﹣14. Daily feed intake and milk production were recorded for each cow during the first 28 d postpartum. Milk samples were obtained once per week and analyzed for various milk components. Overall, results indicated that treatment did not affect feed intake, milk yield, milk efficiency, fat content, fat yield, protein content, protein yield, lactose content, lactose yield, milk urea nitrogen (MUN), total solid contents, fat-corrected milk (FCM), and energy-corrected milk (ECM;P > 0.05). However, milk somatic cell count (SCC) tended to be lower in the treated cows (P eek interaction for milk energy (P = 0.03), and tendencies for FCM, ECM, lactose content, and milk efficiency
文摘Profiles of energy metabolites and haptoglobin (Hp) in dairy cows that are transitioned from conventional to organic management in various Alberta farms were compared with those of dairy cows managed conventionally at the University of Alberta dairy farm. Blood samples were collected during the following periods: Dry, 0 - 30, 30 - 60, and 60 - 90 days in milk (DIM, n = 7 cows). Concentrations of metabolites were evaluated by enzymatic colorimetric methods. Concentrations of Hp were determined by bovine ELISA kits. Data were analyzed by the mixed procedures of SAS. Concentrations of NEFA and BHBA in blood were elevated (P < 0.001) 0 to 30 d, intermediate 30 to 60, and 60 to 90 d, and lower in the dry period. In addition, BHBA was higher (P < 0.0001) at all stages of lactation in conventional than organic cows (e.g. 1289.4 ± 88.6 vs. 883.6 ± 47.5 μmol/L in conventional and organic cows at 0 - 30 d, respectively). Serum concentrations of cholesterol increased with increasing DIM and returned to nadir levels during dry period and was higher (P < 0.0001) in conventional than organic cows. Low glucose concentrations were observed 0 to 30 d, levels were intermediate 30 to 60 and 60 to 90 d, and peaked during the dry period (P < 0.54) between conventional and organic cows. Lactate did not (P < 0.24) vary with DIM or day × farm type but was higher (P < 0.0001) in organic cows than in conventional cows. Serum concentrations of Hp were elevated during dry period;reached peak levels 0 to 30 d and decreased gradually with increasing days postpartum and were much higher at all periods in conventional than organic cows. Overall, concentrations of Hp were 528.1 ± 45.2 μg/mL in conventional cows vs. 261.1 ± 16.9 μg/mL in organic cows (P < 0.0001). Taken together, these data indicate that metabolic changes associated with initiation of lactation are preceded by an acute phase response in dairy cows, and that cows in organic systems seem to be healthier than cows under conventional systems. These differences might be due to differences in nutritional management in the two systems.
文摘The objective of this study was to evaluate whether repeated oronasal administration of LPS before parturition showed effects on metabolic and clinical responses in periparturient dairy cows. Hundred Holstein dairy cows were randomly allocated to two treatment groups (n = 50). Thirty cows out of 100 were randomly assigned for intensive sampling (n = 15) started at 28 d before the expected day of parturition. Cows received an oral and a nasal treatment of 2 mL and 1 mL of sterile saline solution (0.15 M of NaCl), respectively, alone (control), or containing 3 increasing doses of LPS from Escherichia coli 0111:B4 as follows: 1) 0.01 μg/kg body weight (BW) on d ﹣28, 2) 0.05 μg/kg BW on d ﹣25, and ﹣21, and 3) 0.1 μg/kg BW on d ﹣18 and ﹣14. Blood samples were collected from coccygeal vein at different time points around parturition and analyzed for glucose, lactate, non-esterified fatty acids (NEFA), cholesterol, and betahydro-xybutyrate (BHBA). Clinical monitoring of animals was done throughout the experiment at different time points for overall health status, udder edema (UE), manure score, and body condition score (BCS). Results showed that oronasal administration of LPS increased concentrations of glucose and cholesterol in the serum compared to the control group (P 0.05). Oronasal LPS did not influence BCS, manure score or the incidence of UE (P > 0.05). Overall, repeated oronasal administration of LPS modulated some serum metabolites related to energy metabolism around parturition in the treated cows. Further research is warranted to elucidate the mechanisms behind greater glucose and cholesterol status in the serum and their potential effects on long-term metabolic health status of dairy cows.
