Abstract
Inflammation may be a major contributing factor to peripartum metabolic disorders in dairy cattle. We tested whether administering an inflammatory cytokine, recombinant bovine tumor necrosis factor-α (rbTNFα), affects milk production, metabolism, and health during this period. Thirty-three Holstein cows (9 primiparous and 24 multiparous) were randomly assigned to 1 of 3 treatments at parturition. Treatments were 0 (Control), 1.5, or 3.0 µg/kg body weight rbTNFα, which were administered once daily by subcutaneous injection for the first 7 days of lactation. Statistical contrasts were used to evaluate the treatment and dose effects of rbTNFα administration. Plasma TNFα concentrations at 16 h post-administration tended to be increased (P<0.10) by rbTNFα administration, but no dose effect (P>0.10) was detected; rbTNFα treatments increased (P<0.01) concentrations of plasma haptoglobin. Most plasma eicosanoids were not affected (P>0.10) by rbTNFα administration, but 6 out of 16 measured eicosanoids changed (P<0.05) over the first week of lactation, reflecting elevated inflammatory mediators in the days immediately following parturition. Dry matter and water intake, milk yield, and milk fat and protein yields were all decreased (P<0.05) by rbTNFα treatments by 15 to 18%. Concentrations of plasma glucose, insulin, β-hydroxybutyrate, non-esterified fatty acids, triglyceride, 3-methylhistidine, and liver triglyceride were unaffected (P>0.10) by rbTNFα treatment. Glucose turnover rate was unaffected (P = 0.18) by rbTNFα administration. The higher dose of rbTNFα tended to increase the risk of cows developing one or more health disorders (P = 0.08). Taken together, these results indicate that administration of rbTNFα daily for the first 7 days of lactation altered inflammatory responses, impaired milk production and health, but did not significantly affect liver triglyceride accumulation or nutrient metabolism in dairy cows.
Highlights
The periparturient period in dairy cows is characterized by substantial metabolic stress, endocrine changes, depressed feed intake, and negative energy balance [1]
Inflammatory Signals Compared with Control, plasma tumor necrosis factor-a (TNFa) concentrations tended to be increased (P = 0.09) by recombinant bovine tumor necrosis factor-a (rbTNFa) treatments, but 1.5 mg/kg did not differ (P = 0.19) from 3 mg/kg rbTNF (Figure 1A)
The pro-inflammatory class as a composite was unaffected by treatments; the antiinflammatory class tended (P = 0.08) to be decreased by the 3 mg/ kg compared with 1.5 mg/kg rbTNFa dose (Figure 2), though rbTNFa treatment did not differ from Control (P = 0.22)
Summary
The periparturient period in dairy cows is characterized by substantial metabolic stress, endocrine changes, depressed feed intake, and negative energy balance [1]. In response to these changes, dairy cows mobilize adipose tissue triglyceride (TG), leading to elevated non-esterified fatty acid (NEFA) concentrations in the blood. Excessive production of ketones often leads to ketosis, which is characterized by elevated blood concentrations of b-hydroxybutyrate (BHBA), depressed appetite, and decreased milk production [3]. Because ruminants are inefficient at exporting TG from the liver, excessive TG accumulation or fatty liver occurs. Meeting glucose needs can be a tremendous metabolic challenge for early-lactation dairy cows, which often experience inadequate feed intake. Lipid and glucose metabolism in periparturient cows has been extensively studied, the mechanisms underlying the development of these metabolic disorders are not fully understood
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