Inflamatory status and leukocyte function during the peripartum period and subsequent effects on reproduction and lactational performance in dairy cattle

The physiologic and metabolic demands of the commercial dairy cow are greatest during the transition period, or going from lactating to non-lactating back to lactating in roughly a 60-day time period at dry-off to calving. During this time there are profound stressors from several pen moves, therefore cohort re-socializations, the physiologic and hormonal demands of calving itself, and the initiation of lactogenesis, which drives most cows into some degree of negative energy balance. Consequently, this is the time of the gestation/lactation cycle that results in the highest incidence of metabolic disorders such as ketosis, hypocalcemia, displaced abomasum, and retained placenta, as well as, infectious diseases like metritis and mastitis. Early detection could be beneficial in reducing the severity of disease outcomes and monitoring blood metabolites can be useful in the identification of at-risk animals prior to the exhibition of clinical symptoms, possibly leading to a favorable outcome and reduction of animals involuntarily exiting the herd. In the first study, the association of plasma haptoglobin concentrations and leukocyte responses following parturition and subsequent reproductive efficiency in multiparous Holstein cows was investigated. Cows from eight commercial dairy herds in Western Texas and Eastern New Mexico were included in the study. Peripheral blood was taken from 30 cows per herd at 2-8 days in milk. Plasma haptoglobin concentrations were measured and classified into quartiles as low (below the limit of detection to 0.0084 g/L), moderate (0.0084 to 0.458 g/L), or high (0.459 to 1.757 g/L) responders. Plasma glucose, urea nitrogen, non-esterified fatty acids and β-hydroxybutyrate concentrations vi Texas Tech University, Cameron R. Nightingale, December 2016 were included in the metabolic measurements. Leukocyte responses measured were total leukocyte counts and differentials, neutrophil surface expression of L-selectin, neutrophil oxidative burst capacity when co-cultured with an environmental Escherichia coli, as well as the secretion of tumor necrosis factor-α and interferon-γ when diluted whole blood were co-cultured with lipopolysaccharide and phytohemagglutinin-P, respectively. This study demonstrated a stronger acute phase response in the first week after calving is associated with suppressed adaptive immune system and activated innate leukocyte profiles and may be causative to lesser reproductive efficiency. In the second study, the association of the development of postpartum health events and altered neutrophil function was explored. Seventy-five cows in their 1st to 8th lactation from one large commercial dairy in Eastern New Mexico were included in the study. Whole blood was collected via jugular venipuncture from each animal at -7 ± 3 and -3 ± 3 days prior to their expected calving date based on the herd’s average gestation of 275 days carried calf. The same cows sampled prepartum were subsequently sampled at 7 ± 3 and 28 ± 3 DIM. Neutrophil function measures included the surface expression of L-selectin and oxidative burst capacity when stimulated with an environmental Escherichia coli. Plasma metabolites included β-hydroxybutyrate and haptoglobin concentrations. Cows were classified as either a low, moderate, or high BHBA based on their plasma BHBA concentration at 7 days postpartum. Cows were classified as low, moderate, or high haptoglobin responders at both the 7 and 28-day postpartum sampling. Plasma haptoglobin concentrations ranged from 0.88 to 1.56 g/L, 1.57 to 2.03 g/L, and 2.04 to 4.69 g/L at 7 DIM and 0.72 to 1.48 g/L, 1.49 to 1.72 g/L, and 1.73 to 2.14 g/L at 28 DIM. The degree of subclinical endometritis was evaluated in all cows at the 28 ± 3 vii Texas Tech University, Cameron R. Nightingale, December 2016 DIM sampling using a commercially available Metricheck device. To determine the effects of parity on neutrophil function, cows were classified as primiparous (lactation = 1) or multiparous (lactation = 2 and greater). Cows were also classified based on presence or absence of clinical mastitis during the first 150 DIM. The association between neutrophil function and pregnancy status was determined by classifying cows as either pregnant or not pregnant by 150 DIM. High BHBA postcalving was associated with lower neutrophil oxidative burst capacity at -7 days prepartum. Cows that did not become pregnant by 150 DIM had greater neutrophil L-selectin expression at 28 DIM than cows that did become pregnant by 150 DIM. Cows that were culled after 28 DIM had greater neutrophil L-selectin expression at 7 DIM than cows that were culled prior to 28 DIM, while cows that were culled after 28 DIM had greater neutrophil L-selectin expression at 28 DIM than cows that were not culled. Study 2 suggests there may be some associations between peripartum energy balance, immune status, and subsequent negative health and reproductive outcomes. The third study evaluated leukocyte responses and measures of inflammation in clinically healthy multiparous dairy cows after supplementation of OmniGen-AF®. Forty- seven multiparous Holstein cows were randomly assigned to two treatments (Control; n=24, OmniGen-AF®; n=23). The OmniGen-AF® cows were supplemented with 56 grams/cow/day of OmniGen-AF® from dry-off through approximately 28 days in milk of the subsequent lactation. Peripheral blood was collected from cows at dry-off (approximately -60 days relative to calving), move to close-up pen (approximately -30 days relative to calving), immediately post calving, and 14 and 28 days postpartum. Neutrophil surface expression of L-selectin, neutrophil oxidative burst capacity when co- viii Texas Tech University, Cameron R. Nightingale, December 2016 cultured with an environmental Escherichia coli, and the secretion of tumor necrosis factor-α and interferon-γ when diluted whole blood was co-cultured with lipopolysaccharide and phytohemagglutinin-P, respectively were the leukocyte responses evaluated. Metabolites measured were the plasma concentrations of glucose, urea nitrogen, non-esterified fatty acids, β- hydroxybutyrate, and haptoglobin. Total leukocyte count and differential were also measured. Hemoglobin concentrations and hematocrit percentages decreased on day 14 and were lower among Control cows from day -30 to 28. Neutrophil L-selectin surface protein concentrations decreased at parturition in Control cows, but were maintained in OmniGen-AF® cows on day 0. Plasma haptoglobin concentrations were also elevated among Control cows on day 14. These data indicate supplementing OmniGen-AF® attenuates the peripartum suppression of neutrophil surface L-selectin, hemoglobin concentrations, and hematocrit percentage. Moreover, treatment cows did not have elevated haptoglobin concentrations on day 14, suggesting OmniGen-AF® improved the health status during this period. Taken as a whole, these data suggest negative energy balance postpartum appears to have a suppressive effect on neutrophil function, and a quick and efficient neutrophil response with rapid resolution is key to limiting the scope of further disease and tissue damage. Cows that do not follow this optimal neutrophil functional response pattern may be at a greater risk of exiting the herd and not achieving reproductive success. Commercially available nutritional additives such as OmniGen-AF® may be able to alleviate peripartum immunosuppression and possibly improve health and reproductive outcomes.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Animal Science

Grantor

Texas Tech University

Year dc:date.issued

2016

Author dc:creator

• Nightingale, Cameron

Chair dc:contributor.committeechair

• Ballou, Michael A.

Committee members dc:contributor.committeemember

• Loneragan, Guy H.
• Sarturi, Jhones O.
• Trojan, Sara J.
• Brashears, Michael Todd

• Dairy cow, transition, immune

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/2346/72332

OAI identifier oai:identifier

oai:ttu-ir.tdl.org:2346/72332