Initial lameness inflammation leads to chronic lameness and development of chronic pain due to the release of pro-inflammatory mediators such as reactive oxygen species (ROS), which are implicated in the transition from acute to chronic pain, and free radical scavengers countering thiol, substance P (SP), and β-endorphin (BE). The present study aimed to evaluate the dynamic thiol–disulfide homeostasis, α-tocopherol concentrations and SP and BE concentrations in the spinal cord of chronically lame dairy cows. Ten lame and 10 non-lame cows with a parity range of 2–6 were selected for the study. Lame cows had a history of up to 3 months of lameness. Spinal cord samples were obtained from the L2 to L4 lumbar vertebrae aspect of each animal. A thiol–disulfide homeostasis assay was performed using absorbance, and the α-tocopherol concentration was determined by HPLC. SP and BE concentrations were measured using ELISA kits. The results indicated that SP and BE were significantly higher in the spinal cord of lame cows. In contrast, disulfide levels and α-tocopherol concentrations were significantly lower in the spinal cord of lame cows. In conclusion, disulfide levels and α-tocopherol concentrations indicated a defective antioxidant response in cows with chronic lameness. The results of SP and BE concentrations suggested chronic pain and a defective endogenous analgesic response.

Bovine Abortion Syndrome (bas) has a significant impact on commercial dairies. Abortion rates vary between 2 and 20 % and there is little information regarding non-infectious factors affecting fetal stages. We analyzed the joint relationship of infectious and non-infectious factors with the probability of abortion in dairy cows. We used dairy cows from the Ñuble province of Chile (n = 148) at 42 days of pregnancy. We then took monthly blood samples until abortion or calving. We determined plasma concentrations for the following: amino transferase, albumin, cholesterol, globulin, fibrinogen, â-hydroxybutyrate, retinol, á-tocopherol, calcium, phosphorus, glutathione peroxidase, total proteins and urea. Serology was performed for infectious diseases and body conditions were recorded. Our study used a multivariable logistic regression model and proportional hazard regression. There was an (p < 0.05) association with abortion, (or = 4.27) for Neospora caninum and (hr = 94.35) for Leptospira interrogans, with a low cholesterol concentration (p < 0.05) in the fourth month of pregnancy (or = 0.61), and a decrease in body condition from month three to four (or = 0.32). bas is associated with negative energy balances, protective effects of high cholesterol plasma concentrations in the first trimester of gestation and incidences of Neospora caninum, Leptospira interrogans, and a conjunction of the two. It is important to provide epidemiological surveillance tools that help anticipate herd reproductive losses through management measures, infectious disease control and proper nutritional management.

The objective of this study was to investigate the effect of a fine needle liver biopsy (FNB) on the behavior and milk production of postpartum dairy cows during and after the procedure. In Experiment 1, cows at 10 ± 1.1 days in milk were assigned to receive either a FNB (n = 26), involving collection of a liver sample using an 18G spinal needle under local anesthesia, or a sham procedure (n = 26). Behavioral responses during the procedure, such as vocalizations, kicking, and abrupt movements, were recorded and analyzed by a trained observer. In Experiment 2, a separate group of cows (n = 48), also at 10 ± 1.1 days in milk, underwent a FNB, and their daily lying behavior, rumination, and milk yield were monitored using automated sensors over three consecutive days: the day before (day -1, baseline), the day of (day 0), and the day after the procedure (day +1). No significant differences were observed in the behavioral responses between cows that received FNB and those that underwent the sham procedure. Post-procedure, daily lying time, rumination time, and milk yield remained stable compared to baseline values. On day +1, an increase in the number of lying bouts and a decrease in bout duration were noted. The results of this study indicate that liver FNB has little immediate or short-term effect on behavior or milk production, suggesting that it is a minimally painful procedure, supporting its suitability for clinical and research applications.

The aim of this study was to evaluate the relationship between cows’ hepatic lipid content (HLC) at 10 days in milk (DIM) and their metabolic status, health, and production during transition and early lactation periods. HLC was determined in 103 cows from a grazing Chilean dairy herd via cytologic examination of the liver through fine needle biopsies, categorized as mild, moderate, or severe. Blood metabolites were evaluated in the transition period, together with diseases in the postpartum period and milk production during the first 90 DIM. In pre-partum and postpartum periods, primiparous cows with severe HLC showed higher plasma cholesterol than multiparous cows with mild HLC. Postpartum, cows with severe HLC had higher serum non-esterified fatty acids (NEFAs) and NEFA/cholesterol ratios than those with mild HLC. Similarly, cows with moderate and severe HLC presented higher plasma β-hydroxybutyrate and greater risk of subclinical ketosis than cows with mild HLC. Additionally, cows with severe HLC had higher milk production and lower milk protein content than those with mild HLC. These results indicate that moderate to severe HLC at 10 DIM was associated with negative energy balance and subclinical ketosis, whereas severe HLC was associated with increased milk production and decreased milk protein content.