This study investigated (1) protective effects of a commercially available mycotoxin adsorbent (MA) and (2) endocrine effects of in vivo exposure to zearalenone (ZEA) in cattle. The sample included a Japanese Black female cattle herd (MYT herd) that displayed persistently high urinary ZEA concentrations. A second herd (NM herd) was used as a control. Three groups from each herd were assessed: MX (n=6; MA mixed with concentrate), TD (n=6; MA applied as topdressing with the concentrate), and a positive control (n=6; no MA application). Urine and blood samples were collected at the start of MA supplementation (day 0), on the final day of supplementation (day 16), and on the final day of the sampling period (day 58 for MYT herd and day 50 for NM herd). Urinary ZEA concentrations (pg/mg of creatinine) were measured by ELISA and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Haematological and serum biochemical analyses were performed to monitor hepatic, renal, nutritional, and mineral intake statuses. Ovulation status was assessed by progesterone (P4) and antral follicle population by anti-Müllerian hormone (AMH) levels. The urinary concentrations of ZEA and its metabolites in the MX and TD groups were significantly lower (P<0.05) at day 16 compared with the control group, as measured by LC-MS/MS. The valid ratio of AMH-positive (≯0.08 ng/ml) cattle was significantly higher in the NM herd than in the MYT herd without affecting the P4-positive (≯3 ng/ml) ratio, suggesting different populations of antral follicles. Significant differences were also observed between the MX and the control in aspartate aminotransferase and γ-glutamyltransferase at day 58, suggesting preventive effects of MA supplementation. Our field trial indicated that MA supplementation of a ZEA-contaminated diet has beneficial effects in reducing ZEA absorption from the intestine of cattle, maintaining endocrine homeostasis and reversing hepatic effects.

Ten reared cows of a Japanese Black cattle herd in Kagoshima prefecture, Japan, exhibited extremely low blood urea nitrogen (BUN) concentration (2.6 ± 0.6 mg/dL). Examination of dietary feed nutrition and relevant pastureland soil content suggested a correlation with crude protein (CP) deficiency or unbalanced nutritional dietary feeds. Thirteen months after the introduction of a dietary remedial measure (bean cake supplementation), BUN, total cholesterol and albumin concentration from five of the original 10 cows increased significantly compared with their values of before the dietary remedy. The postpartum day open period was significantly lower after the dietary remedial measure than that before it. The abnormally low BUN levels of the cattle herd may be due to inadequate dietary nutritional content, primarily from the imbalance of total digestible nutrient and CP of the feed and far lower han average CP value. In conclusion, routine examination of serum biochemical parameters in Japanese Black breeding cattle may be a useful strategy for determining subclinical metabolic failure of cattle herds, and consequently, its effect on reproductive performance of the herd.

ABSTRACT. The study aims were (1) to confirm the effects of nutritional improvement in prepartal and postpartal periods, monitored using the serum metabolic profile test (MPT) and reproductive performance, and (2) to clarify regional characteristics of the MPT results within our jurisdiction by using our MPT database. Experiment 1: Among 42 breeding cattle herds in our jurisdiction mainly fed home-pasture roughage, 3 experimental herds showing subnormal blood urea nitrogen (BUN) levels were selected and compared with 1 representative excellent herd. Dietary remedial measures were implemented from feed analysis in each herd. BUN concentration in all 3 herds increased significantly, and open days postpartum in 2 of the herds were significantly reduced, compared with values before dietary supplementation. Experiment 2: Thirty-seven herds within our jurisdiction were grouped into 3 categories (Area 1, 2 and 3) by location and soil condition of the herd pastureland. The MPT and reproductive performance in cows whose blood samples were collected at both prepartum (60-20 days before calving) and postpartum (30-90 days after calving) were compared among the 3 areas. Significant regional differences were found in prepartal albumin, total cholesterol, BUN, and glucose and postpartal BUN, glucose and open days (P<0.05). Overall, the MPT (especially BUN) might be useful for determining the metabolic nutritional status of breeding cattle herds, particularly those fed home-pasture roughage. Additionally, poor/unsatisfactory reproductive performance of beef breeding cattle herds probably reflects inadequate nutritional content of the diet, possibly arising from regional pastureland differences.

This retrospective study was conducted to confirm the relationship between pre- and postpartum metabolic parameters and postpartum reproductive performance and to clarify seasonal characteristics of the metabolic parameters by using our metabolic profile test (MPT) database of Japanese Black breeding herds. In evaluation 1, MPT databases of blood samples from multiparous cows collected prepartum and postpartum were divided into two groups according to calving interval, and each MPT parameter was compared. In evaluation 2, the same MPT databases used in evaluation 1 were divided into two groups according to the sampling period. Significant differences were found in the prepartal total protein and postpartal γ-glutamyltransferase in evaluation 1. In evaluation 2, significant differences were found in the prepartal and postpartal total protein, albumin/globulin ratio, and glucose. Clear seasonal differences in MPT results emphasized the usefulness of the MPT in breeding cattle herds fed home-pasture roughage and suggest that unsatisfactory reproductive performance during hot periods reflects inadequate nutritional content of the diet and possible reduced feed intake due to heat stress.

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