The objectives were:: 1) establish cow-level thresholds for prepartum nonesterified fatty acids (NEFA) and postpartum NEFA, β-hydroxybutyrate (BHB), and haptoglobin (Hp) concentrations associated with negative health events; 2) evaluate cow-level associations between biomarkers and 305-d mature equivalent milk at the 4th test day (ME305) and reproductive performance; and 3) identify herd-alarm levels (proportion of cows sampled above the critical threshold) for biomarkers that are associated with herd-level changes in disorder incidence [displaced abomasum (DA) and clinical ketosis (CK)], reproductive performance, and ME305. In a prospective cohort study, 1,473 cows from 72 farms were enrolled from Northeastern United States. At the cow-level and herd-level, elevated biomarker concentrations were associated with an increased disorder risk and varied performance responses.

Our objective was to describe management and herd characteristics of the transition period on freestall dairy herds in the Northeastern United States using an on-farm survey and prospective cohort design. Enrolled herds (n = 72) had a median of 900 milking cows (range: 345 to 2,900), a rolling herd average of 12,674 kg (standard deviation ± 1,220 kg), and 87.2% (n= 82/94) of fresh pens were milked at least 3×/d. The prevalence of herds with ≥ 15% of sampled cows with elevated concentrations of non-esterified fatty acids (NEFA) prepartum (≥ 0.27 mmol/L, 2 to 14 d prior to parturition) and postpartum [primiparous: ≥ 0.60 mmol/L, multiparous: ≥ 0.70 mmol/L, 3 to 14 d in milk (DIM)], postpartum β-hydroxybutyrate (≥ 1.2 mmol/L, 3 to 14 DIM), and postpartum haptoglobin (≥ 1 g/L, 0 to 12 DIM) was 51%, 51%, 51%, and 57%, respectively. In most herds, cows were moved to a calving pen when showing signs of labor (73.6%; n = 53/72) instead of 0 to 3 d prior to expected calving (26.4%, n = 19/72). Cows remained in the calving or maternity pen for a median (range) time of 2 (0 – 24) h after parturition before moving to the next pen. Primiparous cows remained in the first pen moved to after parturition for a longer period than multiparous cows [median (range) d: 12 (1.5 – 25) vs. 6 (1.5 - 22). Nearly 20% of herds administered routine vaccinations in the maternity or calving pen, first pen after parturition, or both. Almost all herds (n = 69/72) performed fresh cow health checks; however, only 53% (n = 38/72) locked up all fresh cows daily. More herds housed primiparous and multiparous cows in separate pens during the far-off dry (65.3%; n = 47/72) and high lactation (81.9%; n = 59/72) periods compared to the close-up dry (31.9%; n = 23/72) and fresh periods (27.8%; n = 20/72). At least half of the pens observed during the far-off dry, close-up dry, and fresh periods had a stocking density <100%. Approximately 1/3 of pens observed during the far-off dry period had feed pushed up ≤4×/d compared to approximately 15 to 20% of pens observed during the close-up dry, fresh, and high lactating periods. More than half of the total mixed ration samples acquired from the far-off and close-up dry period visits had greater than the recommended proportion of particles in the 19-mm screen of the Penn State Particle Separator. The results of this observational study illustrate the range of management practices used in freestall herds in this region and lay the groundwork for future hypothesis-driven studies using this sampled population.

Our objective was to describe management and herd characteristics of the transition period on freestall dairy herds in the Northeastern United States using an on-farm survey and prospective cohort design. Enrolled herds (n = 72) had a median of 900 milking cows (range: 345 to 2,900), a rolling herd average of 12,674 kg (standard deviation ± 1,220 kg), and 87.2% (n= 82/94) of fresh pens were milked at least 3×/d. The prevalence of herds with ≥ 15% of sampled cows with elevated concentrations of non-esterified fatty acids (NEFA) prepartum (≥ 0.27 mmol/L, 2 to 14 d prior to parturition) and postpartum [primiparous: ≥ 0.60 mmol/L, multiparous: ≥ 0.70 mmol/L, 3 to 14 d in milk (DIM)], postpartum β-hydroxybutyrate (≥ 1.2 mmol/L, 3 to 14 DIM), and postpartum haptoglobin (≥ 1 g/L, 0 to 12 DIM) was 51%, 51%, 51%, and 57%, respectively. In most herds, cows were moved to a calving pen when showing signs of labor (73.6%; n = 53/72) instead of 0 to 3 d prior to expected calving (26.4%, n = 19/72). Cows remained in the calving or maternity pen for a median (range) time of 2 (0 – 24) h after parturition before moving to the next pen. Primiparous cows remained in the first pen moved to after parturition for a longer period than multiparous cows [median (range) d: 12 (1.5 – 25) vs. 6 (1.5 - 22). Nearly 20% of herds administered routine vaccinations in the maternity or calving pen, first pen after parturition, or both. Almost all herds (n = 69/72) performed fresh cow health checks; however, only 53% (n = 38/72) locked up all fresh cows daily. More herds housed primiparous and multiparous cows in separate pens during the far-off dry (65.3%; n = 47/72) and high lactation (81.9%; n = 59/72) periods compared to the close-up dry (31.9%; n = 23/72) and fresh periods (27.8%; n = 20/72). At least half of the pens observed during the far-off dry, close-up dry, and fresh periods had a stocking density <100%. Approximately 1/3 of pens observed during the far-off dry period had feed pushed up ≤4×/d compared to approximately 15 to 20% of pens observed during the close-up dry, fresh, and high lactating periods. More than half of the total mixed ration samples acquired from the far-off and close-up dry period visits had greater than the recommended proportion of particles in the 19-mm screen of the Penn State Particle Separator. The results of this observational study illustrate the range of management practices used in freestall herds in this region and lay the groundwork for future hypothesis-driven studies using this sampled population.