A method for estimating the outer exposure of dairy cows to deoxynivalenol (DON) and zearalenone (ZEN) as a precondition for risk assessment based on inner exposure with toxin residue levels in blood and urine as indicators.

DON and ZEN residues in the blood and urine of dairy cows can be used to predict the outer exposure to DON and ZEN expressed per kilogram diet for a risk evaluation based on comparisons to critical dietary concentrations. This method was used to evaluate the exposure of dairy cows from 12 farms located in Brandenburg, Germany, fed rations with unknown DON and ZEN concentrations (N = 244). The corresponding diet concentrations predicted by different methods from analyzed blood and urine samples varied significantly amongst farms from 0 to 1.6 mg/kg for DON and 0 to 3.0 mg/kg for ZEN at a reference dry matter content of 88% but independently of lactational state (post-partum vs. early lactation). This significant variation was noticed below the critical dietary DON concentration of 5 mg/kg, while the ZEN concentration in one farm exceeded the critical ZEN level of 0.5 mg/kg markedly. Predicted DON concentrations of rations increased with the proportion of maize silage, while the high ZEN concentration found in one farm was most likely related to a higher proportion of sugar beet pulp supposedly highly contaminated by ZEN. Exceeding the critical dietary ZEN concentration and significant variations in DON contents below the critical level was not related to performance, reproductive performance, and health-related traits of cows. For a more consistent evaluation of possible associations between the inner exposure of cows to DON and ZEN, more frequent longitudinal observations of both mycotoxin residue levels and performance and health traits are required.

Case report: Teat stenosis in a suckler cow.

Bovine veterinarians are regularly confronted with teat lesions in cows. The number of studies on the diagnosis and treatment of teat lesions as well as the exchange of practical experience among clinicians are extensive in dairy cows compared with suckler cows. The aim of this case report was to describe the successful treatment of teat stenosis in a suckler cow and discuss possible challenges. A four-year-old Simmental cow, in her third lactation and 4 days in milk, was referred to our clinic along with her calf because of teat stenosis in the front left quarter. The owner had repeatedly used a rigid teat cannula in an attempt to relieve the stenosis during the previous lactation. However, the cow had refused to allow the current calf to suckle the affected teat and resisted attempts by the owner to cannulate the teat. The results of clinical examination, ultrasonography, and milk sampling showed stenosis of the proximal, middle, and distal parts of the front left teat cistern, accompanied by thelitis and cisternitis and mild chronic clinical mastitis. Based on published recommendations, treatment of the thelitis, cisternitis, and mastitis was initiated before resolution of the stenosis surgically. The first week of treatment included the administration of an intramammary product containing cefapirin and prednisolone, a systemic non-steroidal anti-inflammatory drug, a wax teat-boogie, and bandaging of the teat. Thereafter, the treatment was reduced to insertion of a wax-teat boogie and bandaging. Conservative treatment resulted in resolution of the mastitis, cisternitis, and stenosis in the proximal and middle parts of the teat, which had most likely been caused by repeated cannulation of the teat by the owner. Lateral theloscopy was then used to remove the distal stenosis, which was the primary lesion. Healing of the surgical wound and resolution of the swelling occurred several days postoperatively, and the calf's first attempt to suckle the teat was successful. The cow and calf were discharged from the clinic 2 weeks after surgery. A follow-up visit 4.5 months after surgery revealed that the calf was still nursing the teat and the operated quarter was producing a normal amount of milk.

Evaluation of multifactorial digestive disorders in a dairy herd at different stages of lactation.

The manager of a large dairy herd (total confinement, total mixed ration feeding, 10130 kg milk sold per cow and year) requested a workup of a digestive disorder problem that had been ongoing for several years. The cows were at all stages of lactation, and the incidence proportion (events/100 cows at risk) of digestive disorders was approximately 5 to 10%. The clinical picture included an abnormal demeanor of varying severity and signs that differed among the cows. The latter included decreased milk production and physical activity, low body condition score, abnormal rumen motility and stratification, small intestinal dilatation, diarrhea, undigested fiber particles in the feces, fever and abdominal pain.The following approach was used to investigate the digestive disorder problem:1. The herd was assessed for production levels, housing requirements, feeding protocols and animal health management. The latter comprised evaluation of different animal scores, metabolic profile analysis, diagnosis of disease, culling records and slaughter data. The results revealed risk factors concerning the feeding and animal health monitoring, (e. g. in dry matter intake and silage quality management, disease detection and diagnosis in fresh cows). The assessment also identified a high occurrence of digestive disorders of unknown origin.2. Fifteen cows that represented the ongoing digestive disorder problem were selected to undergo clinical examination, hematological analysis, urinalysis, and ultrasonography of the ventral abdomen. The clinical examinations revealed different digestive disorders, which were mainly inflammatory in nature, in all the cows. Eight cows had localized reticuloperitonitis and 13 had left displaced abomasum with different degrees of displacement and adhesions between the abomasum and reticulum attributable to reticuloperitonitis.Our results revealed a multifactorial problem caused by several risk factors relating to animal health and feeding management protocols that resulted in different types of digestive disorders. The wires from damaged tires used to hold the pit silo tarps in place were identified as a possible traumatic cause of the reticuloperitonitis. Treatment, prevention and follow-up of the different conditions were discussed.

Effects of an intensive experimental protocol on health, fertility, and production in transition dairy cows.

Animal experimentation is required to investigate complex physiological relationships and facilitates development of evidence-based knowledge. However, experimental protocols can interfere with the daily routine of the animals, result in stress and pain, and have adverse effects on health and production. The goal of this study was to investigate the effects of an intensive experimental protocol on health traits and production in transition dairy cows. Eighty experimental dairy Holstein cows (EXP group) underwent serial protocol-based clinical and ultrasonographic examinations, puncture of the jugular vein for blood collection or drug application, and liver biopsy samples, 14 d before until 42 d after parturition. Controls (CTR group) included 206 cows from the same herd, which fulfilled the same inclusion criteria and were kept under the same production management but were not handled for the purpose of this study. Procedure-related effects with a potentially negative effect on health and production were recorded. Furthermore, production, fertility and culling traits of the 2 groups (CTR, EXP) were compared. Most procedure-related adverse effects were associated with transcutaneous liver biopsies and included diffuse inflammation of the skin incision in 11.9% (42 of 320), abscessation of the skin or subcutis in 4.6% (11 of 240), and increased liver echogenicity of the biopsy site in 10.4% (27 of 240). The experimental procedures had a negative effect on milk yield at the start [days in milk (DIM) 5-50, difference: 2.3 kg, standard error (SE): 0.8 kg] and end of lactation (DIM 251-300, difference: 2.0 kg, SE: 1.0 kg; DIM 301-350, difference: 2.3 kg, SE: 1.2 kg) resulting in a lower 305-d milk yield in the EXP group than in the CTR group (difference: 472 kg, SE 214 kg). The milk fat % was higher in the EXP group than in the CTR group from 251 DIM onward (DIM 251-300, difference: 0.20%, SE: 0.09%; DIM 301-350, difference: 0.41%, SE: 0.17%). Also, the somatic cell score was higher in the EXP group than in the CTR group, during early (5-50 DIM, difference: 0.43, SE: 0.22) and from mid-lactation onward (DIM 151-200, difference: 0.43, SE: 0.2; DIM 201-250, difference: 0.49, SE: 0.22; DIM 251-300, difference: 0.55, SE: 0.25; DIM 301-350, difference: 0.61, SE: 0.28). Experimental procedures had no effect on first service conception rate and time to pregnancy, but had a positive effect on stillbirth rate with fewer stillbirths in the CTR group (0%) than in the EXP group (3.9%). Furthermore, experimental handling had no effect on time to culling or type of culling, whereby poor production was a more frequent reason noted for culling in the EXP group. Procedure-associated impairment of production in dairy cows is rarely reported and allows the estimation of the effects of such a study protocol on animal health and production. As a limitation for the interpretation of the results, the number of animals included and conduction in one single herd have to be considered.

Qualitative and Quantitative Changes in Total Lipid Concentration and Lipid Fractions in Liver Tissue of Periparturient German Holstein Dairy Cows of Two Age Groups.

Fatty liver syndrome (FLS) is a common disease in high-producing dairy cows. Studies in humans suggest that the different hepatic lipid fractions play a role in this context. In dairy cows, little is known about the composition of fat stored in the liver, its periparturient dynamics, and the effect of cows' age. Therefore, our goal was to generate primary data in healthy cows to serve as reference values for future studies. Eight healthy German Holstein cows (2nd lactation, n = 3; ≥3rd lactation, n = 5) were examined 14 d antepartum and 7, 28, and 42 d postpartum. The examinations included clinical assessment, liver biopsy, blood sampling, and recording of milk yield. Total lipids (TL) in liver tissue were measured gravimetrically. The TL were separated into lipid fractions (triacylglycerol, TAG; phospholipids, PL; non-esterified fatty acids, NEFA; and cholesterol esters) using thin-layer chromatography, followed by gas chromatography for fatty acid determination. Concentrations of NEFA, ß-hydroxybutyrate, and cholesterol were analyzed in blood. Concentrations of TL, TAG, NEFA, and cholesterol esters in liver tissue and NEFA in blood increased in the periparturient period. The older cows had higher hepatic TL, TAG, and PL concentrations, higher relative hepatic concentrations of TAG in TL, higher NEFA concentrations in blood, a greater decrease in body condition, and higher milk yields between d 9 and 40 than the younger cows. We proposed that due to higher milk yield, older cows mobilized and deposited more fat in the liver, and the increase in hepatic TAG concentration was longer-lasting than in younger cows. Higher levels of structural lipids (PL) in older cows could be explained by higher demand for storage of TAG and cholesterol esters in lipid droplets or for the export of TAG via very-low-density lipoproteins. Results show that hepatic fat storage is a reversible process and does not necessarily cause clinical disease. Nevertheless, older cows have a more sustained and greater increase in hepatic TAG concentration, which may explain their increased risk of FLS. The results are limited in their extrapolation due to the small sample size and thereby possible selection bias but present a valuable basis for future studies.