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• Greater pre-calving BCS was negatively associated with post-calving BCS maintenance/gain. • The optimum pre-calving BCS is 3.00 to 3.25 for dairy cows to prevent BCS loss. • Cows with extreme BCS loss had higher circulating NEFA and AST concentrations. • Cows with extreme BCS loss had higher peak and 305-d ME milk yields. • Cows with extreme BCS loss had lower fertility. Objectives were to (1) identify factors associated with postpartum body condition (BCS) maintenance/gain, (2) determine the optimum pre-calving BCS predictive of postpartum BCS maintenance/gain, and (3) evaluate the relationship between postpartum BCS change categories, serum analytes and performance in dairy cows. The BCS were determined in 271 primiparous and 640 multiparous cows from 11 dairy herds in Alberta, Canada at (mean ± SD) 9.0 ± 2.3 d pre-calving and at 34.6 ± 4.0 d post-calving, using a 5-point scale with 0.25 increments. Cows were grouped into BCS change categories according to BCS change between post- and pre-calving as follows: lost ≥ 0.75 units (extreme loss; EL; n = 343), lost either 0.25 or 0.50 units (moderate loss; ML; n = 390), no change in BCS (maintained; M; n = 104), or gained ≥ 0.25 units (gained; G; n = 74). In a subset of 178 cows, the concentrations of glucose, beta-hydroxybutyrate, non-esterified fatty acids, urea, cholesterol, haptoglobin and aspartate aminotransferase were measured in serum at 9.0 ± 2.3 d pre-calving and at 8.2 ± 3.7 d post-calving. The proportion of cows grouped into EL, ML, M and G categories were 38, 43, 11 and 8%, respectively. Pre-calving BCS, season of calving and sickness were identified as factors associated with BCS maintenance/gain. The optimum pre-calving BCS predictive of postpartum BCS maintenance/gain was 3.25 for primiparous cows and 3.00 for multiparous cows. Mean serum concentration of beta-hydroxybutyrate, urea, cholesterol and haptoglobin did not differ among BCS change categories. However, G cows tended to have greater mean serum concentration of glucose compared with ML cows, and mean serum concentration of aspartate aminotransferase tended to be greater for EL cows compared with other BCS change categories. Mean serum concentration of non-esterified fatty acids was greater post-calving for EL cows compared with other BCS change categories. Milk yield by 25 and 90 days in milk (DIM) did not differ among BCS change categories; however, peak and 305-d mature equivalent milk yields were greater for EL compared with G cows. Overall, EL cows had reduced fertility compared with other BCS change categories, including a smaller proportion of cows with a corpus luteum by 35 DIM, reduced pregnancy to first AI and pregnancy by 150 DIM, and reduced hazard ratio of pregnancy risk up to 250 DIM. In summary, EL cows had reduced fertility compared with other BCS change categories and increased milk yield compared with G cows. Ensuring cows calve at an appropriate BCS to promote BCS maintenance, or only moderate loss, will improve fertility without sacrificing milk yield. [ABSTRACT FROM AUTHOR]

• 34% of dairy cows had low serum Ca concentrations (≤ 2.10 mmol/L) 2 to 7 days in milk. • Cows with low Ca had lower serum concentrations of Mg, Na and K. • Cows with low Ca had evidence of negative energy balance and less dry matter intake. • Cows with low Ca had increased incidence of postpartum health disorders. • Cows with low Ca in general had reduced fertility and milk yield in early lactation. The objectives were to (1) investigate factors associated with serum Ca concentration, and (2) examine its relationship with serum analytes, incidence of health disorders, and productive and reproductive outcomes in dairy cows. Serum concentrations of macro minerals, metabolites, liver enzymes, β-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), and haptoglobin were determined between 2 and 7 days in milk (DIM) in 398 Holstein cows from 11 dairy herds in Alberta, Canada. Cows were categorized into either Low- (≤2.10 mmol/L; n = 136) or High- (>2.10 mmol/L; n = 262) Ca groups. Concentrations of Ca were affected by herd, calf sex and number, and DIM at sample collection. Low-Ca cows had lower concentrations of Mg, Na, K, albumin, globulin, total protein and cholesterol, and greater concentrations of urea, aspartate aminotransferase, BHB, NEFA and haptoglobin than High-Ca cows. Low-Ca cows had greater incidence of health disorders compared to High-Ca cows, with the exception of mastitis and displaced abomasum. Low-Ca cows had lower milk yield only by 25 DIM compared to High-Ca cows, with no difference in later milk yield measurements. The proportion of cows cyclic at 35 DIM and pregnant to first artificial insemination tended to be lesser for Low-Ca cows compared to High-Ca cows, with no difference in the proportion of cows pregnant by 150 DIM. In summary, cows categorized as Low-Ca had lower serum concentrations of macro minerals, greater concentrations of markers for fat mobilization and inflammation, greater incidence of postpartum health disorders and poorer reproductive outcomes compared to those categorized as High-Ca. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the prevalence and associations of early postpartum health disorders with production, reproduction, and survivability in dairy cows in Alberta. Holstein cattle (N = 1096) from 11 commercial dairy farms in Alberta, Canada were enrolled. Cows were evaluated daily for clinical postpartum health disorders and a blood sample was collected once within 2 wk after calving to diagnose subclinical disorders. Overall, 61% of cows were diagnosed with at least 1 postpartum health disorder, with 25% of cows having multiple disorders. Of the cows with only 1 health disorder, 71% were classified as inflammatory and 29% as metabolic disorders. Cows with multiple disorders were at the greatest risk of reduced milk production, impaired fertility, and leaving the herd. Cows with an inflammatory disorder had reduced productive and reproductive performance, whereas cows with a metabolic disorder were at the greatest risk of mortality., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

The objectives were to evaluate differences in serum concentration of metabolites, macro minerals and hepatic enzymes at pre and postpartum time-points in dairy cows diagnosed with clinical metritis, hypocalcaemia or ketosis postpartum. A total of 144 Holstein cows from 11 commercial dairy herds in Alberta, (Western Canada) were enrolled in this study. Cows with clinical metritis had lower serum concentrations of glutamate dehydrogenase (GLDH) at pre and postpartum and lower total Ca, albumin, urea, and cholesterol at postpartum when compared to control cows. Cows with hypocalcaemia had greater serum concentrations of Na, Cl, and calculated osmolarity (CalOsmo) at prepartum and lower concentration of total serum Ca, glucose, cholesterol, gamma-glutamyl transpeptidase (GGT), GLDH, total protein and albumin at postpartum. Prepartum serum concentrations of non-esterified fatty acids (NEFA), beta hydroxybutyrate (BHB), Cl, albumin/globulin ratio (A/G), Na, K and sum of Na and K were greater in ketotic cows when compared with control cows. Cows with ketosis had also greater postpartum serum concentrations of NEFA, BHB, GGT and aspartate transaminase (AST) when compared with control cows. Prepartum serum Na and Cl concentrations and CalOsmo were greater in cows diagnosed with hypocalcaemia or ketosis when compared with control cows. Furthermore, postpartum serum concentrations of total Ca, cholesterol, albumin and GLDH were significantly affected by hypocalcaemia or clinical metritis and concentrations of GGT by hypocalcaemia or ketosis. Finally, postpartum serum concentrations of haptoglobin increased in all disease groups when compared with control cows. These results suggest common metabolic features for clinical metritis, hypocalcaemia and ketosis in dairy cows in addition to the specific ones., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The objectives were to evaluate differences in circulating prepartum metabolites, minerals, cytokines and hormones based on postpartum disease category and determine critical circulating concentrations of prepartum analytes associated with postpartum disease in 229 cattle from 11 commercial dairies in Alberta, Canada. Blood was collected at 8.8 ± 2.1 d prepartum and analyzed for a wide array of analytes. Cattle were categorized as healthy (n = 76) or as having inflammatory (INF; n = 28), metabolic (MET; n = 34) or inflammatory and metabolic (INFMET; n = 91) postpartum diseases. The prepartum circulating concentrations of Cu were lesser (0.84 vs. 0.90 μg/mL; P = 0.02) and concentrations of Mo (19.1 vs. 16.5 ng/mL; P = 0.04) and NEFA (0.27 vs. 0.18 mmol/L; P = 0.01) were greater in INFMET cattle compared with healthy cattle. The critical threshold for Cu, Mo and NEFA prepartum concentration that predicted INFMET was ≤ 0.81 μg/mL (sensitivity 45.5% and specificity 74.3%), ≥ 9.91 ng/mL (sensitivity 70.0% and specificity 52.7%) and ≥ 0.19 mmol/L (sensitivity 62.2% and specificity 79.7%), respectively. Regardless of differences in the prepartum circulating concentrations of Cu, Mo and NEFA among healthy cattle and those with postpartum disease, the use of these analytes to predict the incidence of postpartum diseases was limited., (Crown Copyright © 2020. Published by Elsevier Ltd. All rights reserved.)