Amy L. Skibiel

Amy L. Skibiel
University of Idaho | UID · Department of Animal and Veterinary Science

PhD

About

48
Publications
11,693
Reads
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924
Citations
Citations since 2017
34 Research Items
706 Citations
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2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
Introduction
My research interests pertain to environmental effects on mammary gland biology and lactation physiology as well as fetal and lactocrine programming of offspring phenotype.

Publications

Publications (48)
Article
Full-text available
Exposure to heat stress during late gestation exerts negative carryover effects on the postnatal performance of the calf. In this study, we evaluated the health, growth, and activity patterns of calves born to cows exposed to heat stress (HT, provided only shade, n = 31) or cooling (CL, fans, soakers, and shade, n = 29) during late gestation (∼46 d...
Article
Full-text available
The maternal environment exerts important influences on offspring mass/growth, metabolism, reproduction, neurobiology, immune function, and behavior among birds, insects, reptiles, fish, and mammals. For mammals, mother's milk is an important physiological pathway for nutrient transfer and glucocorticoid signaling that potentially influences offspr...
Article
Full-text available
In mammals, nutrient allocation during lactation is a critical component of maternal care as milk intake promotes juvenile growth and survival, and hence maternal and offspring fitness. Milk composition varies widely across mammals and is hypothesized to have arisen via selection pressures associated with environment, diet and life history. These h...
Article
Wildfires are particularly prevalent in the Western United States, home to more than 2 million dairy cows that produce more than 25% of the nation's milk. Wildfires emit fine particulate matter (PM2.5) in smoke, which is a known air toxin and is thought to contribute to morbidity in humans by inducing inflammation. The physiological responses of da...
Article
Full-text available
Phenological shifts associated with directional changes in climate, resulting in earlier spring activities, have been documented in several animal species. However, the extent to which species respond to overall climate change versus local climate variation is rarely studied. In addition, climate data are usually averaged over large spatial scales,...
Article
Full-text available
Exposure to heat stress during a cow’s dry period disrupts mammary gland remodeling, impairing mammary function and milk production during the subsequent lactation. Yet, proteomic changes in the mammary gland underlying these effects are not yet known. We investigated alterations in the mammary proteome and phosphoproteome during lactation as a res...
Article
Full-text available
Dry period heat stress impairs subsequent milk production, but its impact on milk protein content and yield is inconsistent. We hypothesize that dairy cow exposure to dry period heat stress will reduce milk protein synthesis in the next lactation, potentially through modified amino acid (AA) transport and compromised mTOR signaling in the mammary g...
Article
Full-text available
Lactation is physiologically demanding, requiring increased nutrient and energy use. Mammary and extramammary tissues undergo metabolic changes for lactation. Although it has long been recognized that mitochondria play a critical role in lactation, the mitochondrial adaptations for milk synthesis in supporting tissues, such as liver and skeletal mu...
Article
Exposure to stressors during early developmental windows, such as prenatally (i.e., in utero), can have life-long implications for an animal's health and productivity. The mammary gland starts developing in utero and, like other developing tissues and organs, may undergo fetal programming. Previous research has implicated factors, such as prenatal...
Article
Maternal exposure to stressors during lactation has previously been demonstrated to impact various aspects of milk synthesis and to have long-term physiological effects on offspring. Much of the current literature investigating the effects of stress during lactation has used acute stressors, and the studies investigating the effects of chronic stre...
Article
As milk production in dairy cattle continues to increase, so do the energetic and nutrient demands on the dairy cow. Difficulties making the necessary metabolic adjustments for lactation can impair lactation performance and increase the risk of metabolic disorders. The physiological adaptations to lactation involve the mammary gland and extramammar...
Article
Full-text available
Hormonal alterations occurring under late gestation heat stress may disturb mammary gland remodelling, resulting in a reduced milk yield during the subsequent lactation. We investigated the effects of an altered endocrine environment on mammary gene expression at different stages of the dry period. Mammary gland biopsies from in vivo-cooled (CL) or...
Article
Dry period heat stress impairs subsequent milk yield. Our objective was to evaluate the effect of heat stress or cooling during the early and late dry period on mammary gland gene expression and microstructure. Cows were dried off ~45 d before expected parturition and randomly assigned to 1 of 2 treatments: heat stress (HT, n = 39) or cooling (CL,...
Article
Full-text available
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...
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The bovine dry period is a non-lactating period between consecutive lactations characterized by mammary gland involution and redevelopment phases to replace senescent mammary epithelial cells with active cells primed for the next lactation. Dairy cows exposed to heat stress during the dry period experience milk yield reductions between 3–7.5 kg/d i...
Article
Heat stress during late gestation adversely impacts the developing calf. Calves that experience heat stress are born at a lower bodyweight and those deficits persist at least until puberty. In utero heat stress reduces passive transfer and calf survival. Late gestation heat stress programs a phenotype with lower milk yield, relative to herd mates b...
Article
Cooling during the entire dry period abates the negative effects of heat stress postpartum, yet the temporal relationship of cooling (i.e., early or late dry period) to performance is unknown. We evaluated the effect of heat stress early, late, and for the entire dry period on subsequent performance. Cows were selected based on mature-equivalent mi...
Article
Full-text available
Earth’s rising temperature has substantial repercussions for food-producing animals by increasing morbidity and mortality, diminishing reproductive potential, and reducing productivity. In the dairy industry this equates to massive losses in milk yield, which occur when cows are exposed to heat stress during lactation or during the non-lactating pe...
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Full-text available
Exposure to intrauterine heat stress during late gestation affects offspring performance into adulthood. However, underlying mechanistic links between thermal insult in fetal life and postnatal outcomes are not completely understood. We examined morphology, DNA methylation, and gene expression of liver and mammary gland for bull calves and heifers...
Article
Full-text available
The bovine dry period is a dynamic non-lactating phase where the mammary gland undergoes extensive cellular turnover. Utilizing RNA sequencing, we characterized novel genes and pathways involved in this process and determined the impact of dry period heat stress. Mammary tissue was collected before and during the dry period (−3, 3, 7, 14, and 25 da...
Article
Full-text available
Heat stress negatively affects cow performance, compromises immune function, and increases susceptibility to metabolic disorders, particularly during the dry period and as cows transition from gestation to lactation. Metabolic adaptations of the liver are critical for successful transition, yet it is unclear how heat stress affects metabolic pathwa...
Article
Full-text available
Heat stress during late gestation negatively affects the physiology, health, and productivity of dairy cows as well as the calves developing in utero. Providing cows with active cooling devices, such as fans and soakers, and supplementing cows with an immunomodulating feed additive, OmniGen-AF (OG; Phibro Animal Health Corporation), improves immune...
Article
Full-text available
Through maternal effects, information about environmental conditions experienced in the maternal generation can be transmitted to subsequent generations. Although maternal effects have been described and quantified in many mammalian species, the underlying causal links are often under-studied. The close association between mother and neonate during...
Article
Allocating a greater amount of limited resources, such as energy, to current reproduction can reduce the amount of energy available for somatic maintenance and can ultimately impair future breeding success or maternal survival (i.e. cost of reproduction hypothesis). Although there is some support for the cost of reproduction hypothesis in birds, fe...
Article
Full-text available
Milk is essential to a mammalian mother's reproductive strategy and is necessary for offspring growth and development. In hibernators with a short duration between weaning and winter immergence, milk synthesis is likely constrained by time and trade-offs between maternal and offspring condition, thus influencing milk composition. We characterized t...
Article
In their recent comment in this journal, T. M. Blackburn and colleagues called into question the use of standardized partial regression modelling (also called path analysis and structural equation modelling) when null expectations for regression coefficients are not zero. Here, we answer their critique by showing how randomization can be used to il...
Article
In this study, we examined influences of maternal traits on offspring birth mass, growth rate, and weaning mass for two populations of Columbian ground squirrels (Spermophilus columbianus). We tested relationships between maternal body condition, structural size, change in mass (during gestation, during lactation, and during the entire reproductive...
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Aim To test the influences of island area, island isolation, and human-introduced mammalian predators on avian extinctions that have occurred on oceanic islands worldwide. Location The oceanic islands of the world. Methods We augmented and re-examined an existing data set for 218 oceanic islands by means of causal modelling using path analysis (a f...
Article
at about 0.74 and the regression weight at 0.60 (given random data), which is higher than the empirical correlation of 0.47 and regression weight 0.43. They insightfully point out that our path of 0.61 from number of extant avifauna to number of threatened avifauna is positive, as is the null hypothesis. Nevertheless, our path of 0.61 was a standar...
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Enrichment can increase the complexity of the captive environment and possibly enhance captive animals' well-being by stimulating active behaviors and reducing stereotypical behaviors commonly seen in zoo felids. In this study, three different enrichment items were added to outdoor enclosures of felids at the Montgomery Zoo to test their effects on...
Article
Results of the study by Blackburn et al. (2004a) of avifauna on oceanic islands suggest that distance from the mainland and time since European colonization have major influences on species extinctions and that island area is a significant but secondary contributing factor. After augmenting the data of the study on geographical properties for some...
Article
Summary This article describes a simple classroom activity that helps students immediately visualize and understand the meaning and mathematical properties of the Poisson distribution.

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