Thermotolerance capabilities, blood metabolomics, and mammary gland hemodynamics and transcriptomic profiles of slick-haired Holstein cattle during mid lactation in Puerto Rico.

Holstein cattle carrying a prolactin receptor gene mutation (SLICK) exhibit short and sleek hair coats (short-haired Holstein [SLK]) enhancing thermotolerance and productivity compared with wild type-haired Holstein (WT) under tropical conditions. The objectives were to unravel the physiological and molecular mechanisms that confer an advantage to this slick genotype in Puerto Rico and determine potential correlations between metabolites and physiological variables. At 160 ± 3 DIM we compared vaginal temperatures (VT) and voluntary solar radiation exposure (VSRE) during 48 h between 9 SLK and 9 WT Holsteins, whereas a subsample of 7 SLK and 7 WT were used to assess udder skin temperature, mammary gland hemodynamics and transcriptomics, and blood plasma untargeted metabolomics at a single time point.

Melatonin in Health and Disease: A Perspective for Livestock Production.

Mounting evidence in the literature indicates an important role of endogenous and exogenous melatonin in driving physiological and molecular adaptations in livestock. Melatonin has been extensively studied in seasonally polyestrous animals whereby supplementation studies have been used to adjust circannual rhythms in herds of animals under abnormal photoperiodic conditions. Livestock undergo multiple metabolic and physiological adaptation processes throughout their production cycle which can result in decreased immune response leading to chronic illness, weight loss, or decreased production efficiency; however, melatonin's antioxidant capacity and immunostimulatory properties could alleviate these effects.

Melatonin Supplementation Alters Maternal and Fetal Amino Acid Concentrations and Placental Nutrient Transporters in a Nutrient Restriction Bovine Model.

Melatonin rescues uterine blood flow and fetal body weight in a seasonal dependent manner within a nutrient restriction bovine model. We sought to identify the effects of nutrient restriction, melatonin, and sampling time on maternal and fetal amino acids, and placental nutrient transporters. Pregnant heifers received adequate or restricted nutrition, and 20 mg of melatonin or placebo from gestational days 160-240 over two seasons.

Maternal nutrient restriction and dietary melatonin alter neurotransmitter pathways in placental and fetal tissues.

Introduction: Recent research indicates an important role in the placental fetal brain axis, with a paucity of information reported in large animals. Melatonin supplementation has been investigated as a potential therapeutic to negate fetal growth restriction. We hypothesized that maternal nutrient restriction and melatonin supplementation would alter neurotransmitter pathways in fetal blood, cotyledonary and hypothalamus tissue.

Seasonal and temporal variation in the placenta during melatonin supplementation in a bovine compromised pregnancy model.

Compromised pregnancies result in a poorly functioning placenta restricting the amount of oxygen and nutrient supply to the fetus resulting in intrauterine growth restriction (IUGR). Supplementing dietary melatonin during a compromised pregnancy increased uteroplacental blood flow and prevented IUGR in a seasonal-dependent manner. The objectives were to evaluate seasonal melatonin-mediated changes in temporal alterations of the bovine placental vascularity and transcript abundance of clock genes, angiogenic factors, and nutrient sensing genes in 54 underfed pregnant Brangus heifers (Fall, n = 29; Summer, n = 25).

Effects of Maternal Nutrient Restriction and Melatonin Supplementation on Cardiomyocyte Cell Development Parameters Using Machine Learning Techniques.

The objective of the current study was to examine the effects of maternal feed restriction and melatonin supplementation on fetal cardiomyocyte cell development parameters and predict binucleation and hypertrophy using machine learning techniques using pregnant beef heifers. Brangus heifers (n = 29) were assigned to one of four treatment groups in a 2 × 2 factorial design at day 160 of gestation: (1) 100% of nutrient requirements (adequately fed; ADQ) with no dietary melatonin (CON); (2) 100% of nutrient requirements (ADQ) with 20 mg/d of dietary melatonin (MEL); (3) 60% of nutrient requirements (nutrient-restricted; RES) with no dietary melatonin (CON); (4) 60% of nutrient requirements (RES) with 20 mg/d of dietary melatonin (MEL). On day 240 of gestation, fetuses were removed, and fetal heart weight and thickness were determined.

Harnessing the value of reproductive hormones in cattle production with considerations to animal welfare and human health.

The human population is ever increasing while the quality and quantity of natural resources used for livestock production decline. This calls for improved product efficiency and the development of improved and sustainable cattle production methods to produce higher quality products to satisfy the demands of both the modern and transient world. The goal of this review was to summarize the interactions, challenges, and opportunities in cattle production relating to their endocrine system, and how reproductive hormones and others impact economically important traits, animal welfare, and human health.

Differences in bovine placentome blood vessel density and transcriptomics in a mid to late-gestating maternal nutrient restriction model.

Introduction: Prenatal development is reliant on a functioning placenta, which can be influenced by maternal nutrition. Moreover, the variation in cotyledonary capacity within an animal has not been fully examined to date. Therefore, the purpose of this study was to determine the effect of (1) placentome size and (2) maternal nutrient restriction on molecular, microscopic, and macroscopic features of bovine placentomes during late gestation.

Melatonin alters bovine uterine artery hemodynamics, vaginal temperatures, and fetal morphometrics during late gestational nutrient restriction in a season-dependent manner.

The objectives were to examine melatonin-mediated changes in temporal uterine blood flow (UBF), vaginal temperatures (VTs), and fetal morphometrics in 54 commercial Brangus heifers (Fall, n = 29; Summer, n = 25) during compromised pregnancy. At day 160 of gestation, heifers were assigned to one of the four treatments consisting of adequately fed (ADQ-CON; 100% National Research Council [NRC]; n = 13), global nutrient restricted (RES-CON; 60% NRC; n =13), and ADQ or RES supplemented with 20 mg/d of melatonin (ADQ-MEL, n = 13; RES-MEL, n = 15). In the morning (0500 hours; AM) and afternoon (1300 hours; PM) of day 220 of gestation, UBF was determined via Doppler ultrasonography, while temperature data loggers attached to progesterone-free controlled internal drug releases were used to record VTs.

Melatonin-induced changes in the bovine vaginal microbiota during maternal nutrient restriction.

Altering the composition of the bovine vaginal microbiota has proved challenging, with recent studies deeming the microbiota dynamic due to few overall changes being found. Therefore, the objectives of this study were to determine whether gestational age, endogenous progesterone, maternal nutrient restriction, or dietary melatonin altered the composition of the bovine vaginal microbiota. Brangus heifers (n = 29) from timed artificial insemination to day 240 of gestation were used; at day 160 of gestation, heifers were assigned to either an adequate (ADQ; n = 14; 100% NRC requirements) or restricted (RES; n = 15; 60% NRC requirements) nutritional plane and were either supplemented with dietary melatonin (MEL; n = 15) or not supplemented (CON; n = 14).

Vaginal bacterial community composition and concentrations of estradiol at the time of artificial insemination in Brangus heifers.

The knowledge surrounding the bovine vaginal microbiota and its implications on fertility and reproductive traits remains incomplete. The objective of the current study was to characterize the bovine vaginal bacterial community and estradiol concentrations at the time of artificial insemination (AI). Brangus heifers (n = 78) underwent a 7-d Co-Synch + controlled internal drug release estrus synchronization protocol.

Temporal transcript abundance of clock genes, angiogenic factors and nutrient sensing genes in bovine placental explants.

Recent research has shown expression of clock genes in peripheral tissue explants, targeting multiple pathways leading to the entrainment of circadian rhythms. Temporal variations are not solely regulated by photoperiod, but factors such as maternal feed availability can entrain fetal circadian clock. Currently, a paucity of information exists for clock gene expression and short-term temporal transcript abundance in the bovine placenta, which is essential for proper offspring development.