Marcela Marrero

• Zoetis

Many aspects of the bovine immune system remain poorly characterized, which poses an obstacle to improving dairy cow health. Herein, we describe two flow cytometry panels that included antibodies against CD8α, CD4, TCR-δ, CD172α, CD14, MHCII, CD21, CD62L, and CD11b. These panels were used to characterize the phenotype of leukocyte subpopulations fr...

In cattle, mechanistic studies of endometrial function rely on cell lines or primary culture of cells harvested postmortem. Understanding the endometrial physiology in dairy cows is essential, because approximately 50% of pregnancies are lost in the first 3 wk of gestation for unknown reasons. The objective was to validate an in vivo, minimally inv...

Dairy calves exposed to late-gestation heat stress weigh less, have impaired immunity, produce less milk across multiple lactations, and have reduced productive life. However, less is known about the relationship between in utero heat stress and organ morphology and development. Herein, we characterized the consequences of late-gestation in utero h...

Heat stress has well-known influences on dairy calf physiology, but less is understood about calf behavioral responses to heat stress. Herein, we evaluated milk replacer intake, standing activity, and lying behaviors of calves exposed to prenatal or postnatal heat stress or both. Holstein calves were born to dams experiencing heat stress (HT; shade...

Cultured primary endometrial cells are used extensively to study uterine function in cattle. However, most protocols harvest endometrial cells from slaughtered animals at estimated stages of the estrous cycle. The goal of this study was to establish and validate an in vivo, minimally invasive, and estrous cycle stage-specific method to obtain endom...

Exposure to heat stress can alter the development and immune system function in dairy calves. Serotonin is an immunomodulatory biogenic amine that functions as a neurotransmitter and as a stress-response mediator. Our objectives were to characterize the patterns of serum serotonin concentrations and the pattern of serotonin-related genes expressed...

In mammals, peripheral serotonin is involved in regulating energy balance. Herein, we characterized the transcriptomic profile and microstructure of adipose and muscle in pre-weaned calves with increased circulating serotonin. Holstein bull calves (21 ± 2 days old) were fed milk replacer supplemented with saline (CON, 8 mL/day n = 4) or 5-hydroxytr...

Simple Summary Late-gestation heat stress increases blood prolactin and decreases oestrogen concentrations in dry cows. These hormonal alterations may disturb mammary gland remodelling during the dry period, thereby being potentially responsible for the observed production impairments during the subsequent lactation. This project aimed to better un...

Dairy calves are born with a naïve immune system, making the pre-weaning phase a critical window for immune development. In the U.S., 40–60% of dairy farms feed milk replacer to pre-weaned calves, which are devoid of bioactive factors with immunological roles. Serotonin is a bioactive factor with immunoregulatory properties naturally produced by th...

Objective: Our objective was to determine whether the infrared temperature of short-milking-tubes, as an esti-mator of milk temperature, differs between subclinically mastitic quarters with or without the presence of mastitis pathogens. Results and Discussion: The milk temperature, mea-sured through the short-milking-tubes with an infrared camera...

Prenatal heat stress during late gestation exerts long-term effects on growth and productivity of the dairy calf. Further, direct exposure to heat stress during the preweaning period impairs calf thermoregulation and performance. We examined the effects of heat stress abatement during the prenatal period, postnatal period, or both on calf performan...