M.A. Crookenden

Grazing dairy cows had decreased interferon-γ, tumor necrosis factor, and interleukin-17, and increased expression of interleukin-10 during the first week after calving

Peripartum, and especially during the transition period, dairy cows undergo dramatic physiological changes. These coincide with an increased risk of disease during the first 2 wk after calving and have been linked to dairy cows failing to achieve production as well as reproductive targets. Previous evidence suggests that these physiological changes affect the immune system and that transition dairy cows experience some form of reduced immunocompetence. However, almost all of these studies were undertaken in high-production, housed dairy cows. Grazing cows have much lower levels of production and this study aimed to provide clarity whether or not the dysfunctional attributes of the peripartum immune system reported in high production housed cows are evident in these animals. Therefore, cell culture techniques, flow cytometry, and quantitative PCR were applied to analyze the cellular composition of peripheral blood mononuclear cells from transition dairy cows as well as the performance of these cells in an in vitro assay. First, a combination of in vitro stimulation and quantitative PCR for cytokines was validated as a quantifiable immunocompetence assay in 29 cattle and a correlation of quantitative PCR and ELISA demonstrated. Second, the relative number of T helper cells, cytotoxic T cells, B cells, γδ T cells, natural killer cells, and monocytes in peripheral blood was measured, of which B cells and natural killer cells increased in number postcalving (n=29) compared with precalving. Third, following in vitro stimulation cytokine profiles indicated decreased expression of IFNγ, tumor necrosis factor, and IL-17 and increased expression of IL-10 wk 1 after calving, which later all returned to precalving values (n=39). Additionally, treatment of transition cows with a nonsteroidal anti-inflammatory drug (i.e., carprofen) administered on d 1, 3, and 5 postcalving (n=19; untreated control n=20) did not affect the cytokine expression at any time point. In conclusion, an immunocompetence assay has been developed that highlights a characteristic expression pattern for IFNγ, tumor necrosis factor, IL-17, and IL-10 that reflects a state of reduced immunocompetence in moderate-yielding pasture-based transition cows after calving, which is similar to that described for higher-yielding housed cows.

Effects of precalving body condition score and prepartum feeding level on production, reproduction, and health parameters in pasture-based transition dairy cows

Precalving feeding level alters postcalving energy balance, dry matter intake, the liver and adipose tissue transcriptome, hepatic lipidosis, and the risk of metabolic diseases in both high-production cows consuming total mixed rations and moderate-production cows grazing pasture. We hypothesized that the reported benefits of a controlled restriction before calving are dependent on precalving body condition score (BCS): low BCS animals would not benefit from reduced feeding levels precalving, but high BCS cows would have metabolic and immunomodulatory profiles indicative of an improved health status. One hundred sixty-one days before calving, 150 cows were allocated randomly to 1 of 6 treatment groups (n = 25) in a 2 × 3 factorial arrangement: 2 precalving BCS categories (4.0 and 5.0; based on a 10-point scale: BCS4 and BCS5, respectively) and 3 levels of energy intake during the 3 wk preceding calving (75, 100, and 125% of estimated requirements). Cows in the BCS4 and BCS5 groups were managed through late lactation to ensure that target calving BCS was achieved at dry off. Cows were then fed to maintain this BCS target until 3 wk before expected calving date, at which point they were managed within their allotted precalving energy intake treatments by offering different allowances of fresh pasture/cow per day. Milk production, body weight, and BCS were measured weekly; blood was sampled weekly before and after calving and on d 0, 1, 2, 3, and 4 relative to calving. Aspirated plasma was assayed for nonesterified fatty acids, β-hydroxybutyrate, total protein, albumin, cholesterol, haptoglobin, IL-1β, IL-6, total antioxidant capacity, and reactive oxygen species. Liver was sampled wk 1, 2, and 4 postcalving for triacylglycerol analysis. Results confirm that precalving BCS and precalving feeding level have both independent and interdependent effects on production and health characteristics of transition dairy cows. Irrespective of precalving BCS, a controlled restriction precalving reduced the net release of nonesterified fatty acids from adipose tissue postpartum and increased plasma calcium concentrations, reducing the risk of milk fever. Fatter cows produced more milk but lost more BCS postcalving and had greater blood β-hydroxybutyrate concentrations and increased hepatic lipidosis. In comparison, after calving, indicators of reduced immune competence were accentuated in BCS4 cows subjected to a feed restriction before calving, probably increasing the risk of infectious diseases. It would appear from these results that optimally conditioned cows will benefit from a short-term (2-3 wk) controlled feed restriction (75-90% of requirements), whereas cows in less than optimal condition should be fed to requirements before calving.

Body condition score and plane of nutrition prepartum affect adipose tissue transcriptome regulators of metabolism and inflammation in grazing dairy cows during the transition period

Recent studies demonstrating a higher incidence of metabolic disorders after calving have challenged the management practice of increasing dietary energy density during the last ~3 wk prepartum. Despite our knowledge at the whole-animal level, the tissue-level mechanisms that are altered in response to feeding management prepartum remain unclear. Our hypothesis was that prepartum body condition score (BCS), in combination with feeding management, plays a central role in the peripartum changes associated with energy balance and inflammatory state. Twenty-eight mid-lactation grazing dairy cows of mixed age and breed were randomly allocated to 1 of 4 treatment groups in a 2 × 2 factorial arrangement: 2 prepartum BCS categories (4.0 and 5.0, based on a 10-point scale; BCS4, BCS5) obtained via differential feeding management during late-lactation, and 2 levels of energy intake during the 3 wk preceding calving (75 and 125% of estimated requirements). Subcutaneous adipose tissue was harvested via biopsy at -1, 1, and 4 wk relative to parturition. Quantitative polymerase chain reaction was used to measure mRNA and microRNA (miRNA) expression of targets related to fatty acid metabolism (lipogenesis, lipolysis), adipokine synthesis, and inflammation. Both prepartum BCS and feeding management had a significant effect on mRNA and miRNA expression throughout the peripartum period. Overfed BCS5 cows had the greatest prepartum expression of fatty acid synthase (FASN) and an overall greater expression of leptin (LEP); BCS5 was also associated with greater overall adiponectin (ADIPOQ) and peroxisome proliferator-activated receptor gamma (PPARG), whereas overfeeding upregulated expression of proadipogenic miRNA. Higher postpartum expression of chemokine ligand 5 (CCL5) and the cytokines interleukin 6 (IL6) and tumor necrosis factor (TNF) was detected in overfed BCS5 cows. Feed-restricted BCS4 cows had the highest overall interleukin 1 (IL1B) expression. Prepartum feed restriction resulted in greater chemokine ligand 2 (CCL2) expression. Overall, changes in mRNA expression were consistent with the expression pattern of inflammation-related miRNA. These data shed light on molecular mechanisms underlying the effect of prepartum BCS and feeding management on metabolic and inflammatory status of adipose tissue during the peripartum period. Data support the use of a controlled feed restriction prepartum in optimally conditioned cows, as well as the use of a higher level of dietary energy in under-conditioned cows.

Adipose and liver gene expression profiles in response to treatment with a nonsteroidal antiinflammatory drug after calving in grazing dairy cows

The peripartal or transition period in dairy cattle is often characterized by an inflammatory state that, if not controlled, could be detrimental to production, health, and fertility. Approaches to control the postpartal degree of inflammation include treatments with nonsteroidal antiinflammatory drugs (NSAID) postcalving, which have improved cow production and health. To date, most of the research on NSAID has been conducted in confinement cows that reach milk production levels substantially greater than those on pasture. Furthermore, little data are available on the effect of NSAID on the mRNA expression of inflammation and metabolism-related genes. Transcription regulation is an important mechanism of inflammation and metabolic control. The present study was conducted to examine hepatic and adipose tissue gene expression in response to injections of an NSAID, carprofen, on 1, 3, and 5 d after calving. Grazing Holstein-Friesian cows from a control group and 1 treated with carprofen during the first 5 d postcalving were used. Liver and subcutaneous adipose tissue biopsies were harvested at -1, 1, and 2 wk relative to parturition. More than 30 genes associated with fatty acid oxidation, growth hormone/insulin-like growth factor-1 axis, hepatokines, lipoprotein metabolism, gluconeogenesis, and inflammation were analyzed. After calving, data suggest that both tissues respond to inflammation signals at the onset of lactation. Administration of NSAID led to greater hepatic expression of pyruvate dehydrogenase kinase, isozyme 4 (PDK4), which helps regulate gluconeogenesis, and microsomal triglyceride transfer protein (MTTP), important for the assembly and secretion of very low-density lipoproteins. In adipose tissue, NSAID administration resulted in greater expression of the inflammation-related genes interleukin-1, β (IL1B), interleukin-6 receptor (IL6R), toll-like receptor 4 (TLR4), and chemokine (C-C motif) ligand 5 (CCL5). The data support the role of inflammation as a normal component of the homeorhetic adaptations to lactation and reveal a possible mechanism of action of carprofen in transition dairy cows, but do not reflect an effect of this NSAID on the extent of the peripartum inflammation.

Prepartum feeding level and body condition score affect immunological performance in grazing dairy cows during the transition period

Precalving feeding level affects dry matter intake, postcalving energy balance, the risk of hepatic lipidosis and metabolic disease, and gene expression in liver and adipose tissue. These coincide with a higher risk of disease postpartum and, very likely, a failure to reach optimum production as well as reproductive targets. Current interpretation of the available evidence suggest that metabolic stressors affect the immune system of transition dairy cows and lead to reduced immunocompetence. The objective of the current study was to investigate the effect of precalving body condition score (BCS) and level of feeding on immunocompetence during the peripartum period. Twenty-three weeks before calving, 78 cows were allocated randomly to 1 of 6 treatment groups (n=13) in a 2 × 3 factorial arrangement: 2 precalving BCS categories (4.0 and 5.0, based on a 10-point scale) and 3 levels of energy intake during the 3 wk preceding calving (75, 100, and 125% of estimated requirements). Blood was sampled precalving and at 1, 2 and 4 wk after calving. Cells were analyzed by flow cytometry and quantitative real-time PCR. The numbers of T helper lymphocytes (CD4+), cytotoxic T lymphocytes (CD8+), natural killer cells (CD335+), and γδ T lymphocytes (WC1+) as well as their activation status [IL-2 receptor (CD25)+ cells] were highly variable between animals, but there was no evident effect of BCS, feeding level, or time. All groups presented with an increase in expression of cytokines in unstimulated blood cells in the week after calving, although this was significant only for IFNG in the BCS 4.0 group. Analysis of in vitro-stimulated cells allowed 2 general observations: (1) cows with high energy intake precalving (125%) had increased cytokine expression precalving, and (2) all cows had increased cytokine expression in the week after calving. The present study provides evidence that prepartum feed management can affect immunocompetence during the transition period. Considering the current results, optimally conditioned animals might benefit from a restricted precalving diet, whereas underconditioned cows can be fed to requirements.

Corrigendum to “Parturition in dairy cows temporarily alters the expression of genes in circulating neutrophils” (J. Dairy Sci. 99:6470–6483)

In Table 3 (page 6478), the means and standard errors of the difference (SED) for 9 of the parameters were tabulated as log values, rather than in the original units. All P-values and Tukey comparisons are correct. The corrected table is shown below, with corrected parameters and values in bold. The authors regret the errors.