Siobhan Walsh

Siobhan Walsh
Waterford Institute of Technology | WIT · Department of Chemical & Life Sciences

BAgrSc, MAgrSc, PhD

About

53
Publications
9,020
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1,717
Citations
Additional affiliations
October 2013 - present
Waterford Institute of Technology
Position
  • Lecturer
Education
December 2007 - January 2012
University College Dublin
Field of study
  • Factors affecting ovarian follicle development in cattle
September 2005 - October 2007
September 2001 - June 2005
University College Dublin
Field of study
  • Animal Science

Publications

Publications (53)
Article
Implementation of guidelines to reduce the amount of biodegradable municipal waste (BMW) sent to landfill has created a need in the waste-management industry to investigate possible methods of accelerating biostabilisation of residual BMW. The effect of commercially feasible manipulations (lime and green waste (GW)) on the rate of biostabilisation...
Article
Sexual dimorphism, the phenomenon whereby males and females of the same species are distinctive in some aspect of appearance or size, has previously been documented in cattle for traits such as growth rate and carcass merit using a quantitative genetics approach. No previous study in cattle has attempted to document sexual dimorphism at a genome le...
Article
Full-text available
Background: Linear type traits, which reflect the muscular characteristics of an animal, could provide insight into how, in some cases, morphologically very different animals can yield the same carcass weight. Such variability may contribute to differences in the overall value of the carcass since primal cuts vary greatly in price; such variabilit...
Article
Full-text available
While breeding indexes exist globally to identify candidate parents of the next generation, fewer tools exist that provide guidance on the expected monetary value of young animals. The objective of the present study was therefore to develop the framework for a cattle decision-support tool which incorporates both the genetic and non-genetic informat...
Article
Meticulous culling decisions, coupled with careful breeding decisions, are fundamental to shifting a population distribution in the favorable direction and improving the profit per cow. Nevertheless, there is a paucity of easy-to-use dynamic tools to aid in culling decisions in beef cattle. The motivation for the present study was to develop a mone...
Article
Full-text available
Linear type traits describing the skeletal characteristics of an animal are moderately to strongly genetically correlated with a range of other performance traits in cattle including feed intake, reproduction traits and carcass merit; thus, type traits could also provide useful insights into the morphological differences among animals underpinning...
Article
Sustainable dairy cow performance relies on coevolution in the development of breeding and management strategies. Tailoring breeding programs to herd performance metrics facilitates improved responses to breeding decisions. Although herd-level raw metrics on performance are useful, implicitly included within such statistics is the mean herd genetic...
Article
Genetic evaluations decompose an observed phenotype into its genetic and nongenetic components; the former are termed BLUP with the solutions for the systematic environmental effects in the statistical model termed best linear unbiased estimates (BLUE). Geneticists predominantly focus on the BLUP and rarely consider the BLUE. The objective of this...
Article
Linear type traits describing the skeletal, muscular, and functional characteristics of an animal are routinely scored on live animals in both the dairy and beef cattle industries. Previous studies have demonstrated that genetic parameters for certain performance traits may differ between breeds; no study, however, has attempted to determine if dif...
Chapter
The environment encountered during fetal life exerts a profound influence on development, physiological function, and risk of disease in adult life in mammals. Poor maternal nutrition, including micronutrient deficiencies, contributes to at least 20% of maternal deaths and it increases the probability of poor pregnancy outcomes such as intrauterine...
Article
Full-text available
To compare gene expression among bovine tissues, large bovine RNA-seq datasets were used, comprising 280 samples from 10 different bovine tissues (uterine endometrium, granulosa cells, theca cells, cervix, embryos, leucocytes, liver, hypothalamus, pituitary, muscle) and generating 260 Gbases of data. Twin approaches were used: an information-theore...
Article
Full-text available
Implications • Maternal nutrition during gestation influences the development and function of many biological systems in offspring. • There is evidence to show that both maternal undernutrition and overnutrition during gestation are detrimental to the reproductive development of offspring and that the effects are permanent after birth and visible i...
Article
The objective was to characterise the hormonal composition of follicular fluid from mares with distinct anovulatory-cystic follicles. Follicular fluid was aspirated from six mares that presented with cystic follicles and from pre-ovulatory follicles of five normal mares (controls). Differences in progesterone, oestradiol, testosterone, IGF-I and IG...
Article
Follicular fluid, an important microenvironment for the development of oocytes, contains many proteins that are glycosylated with N-linked glycans. This study aimed 1) to present an initial analysis of the N-linked glycan profile of bovine follicular fluid using hydrophilic interaction liquid chromatography, anion exchange chromatography, HPLC (hig...
Article
Previous studies have documented that ovarian antral follicle count (AFC) is positively correlated with number of healthy follicles and oocytes in ovaries (ovarian reserve), as well as ovarian function and fertility in cattle. However, environmental factors (e.g., nutrition, steroids) during pregnancy in cattle and sheep can reduce AFC in offspring...
Article
Full-text available
Severe prenatal under nutrition is usually associated with low birth weights in offspring and disorders including hypertension, obesity and diabetes. Whether alterations in maternal nutrition insufficient to impair birth weight or prenatal growth impact the cardiovascular, stress or metabolic systems is unknown. In addition, little is known about t...
Article
Lactation in dairy cattle is associated with a multitude of endocrine, metabolic and immunological changes that not only influence animal health, but also affect fertility, and in particular ovarian function. We have previously generated a global transcriptomic profile of bovine follicular tissue using RNA sequencing. This study aimed to: identify...
Article
Contents Mammals such as cattle, swine, sheep and humans are born with a highly variable number of ovarian follicles and oocytes in the ovaries that dwindle during ageing and are never replenished. This variation in the ovarian reserve is reflected in the numbers of antral follicles in the ovaries at all ages after birth. As numbers of follicles in...
Article
Dietary restriction in growing cattle and severe negative energy balance in lactating cows have been associated with altered gonadotropin secretion, reduced follicle diameter, reduced circulating oestradiol concentrations and anovulation. Therefore, we hypothesised that acute dietary restriction would influence the fate and function of the dominant...
Article
Full-text available
The total number of ovarian follicles ≥ 3mm in diameter (antral follicle count, AFC) during follicular waves varies among cattle of similar age, but AFC is highly repeatable within individuals. We hypothesized that lower AFC could be associated with reduced fertility in cattle. The AFC was assessed by ultrasonography for 2 d consecutively during th...
Article
Cellular mechanisms that contribute to low estradiol concentrations produced by the preovulatory ovarian follicle in cattle with a compromised metabolic status are largely unknown. To gain insight into the main metabolic mechanisms affecting preovulatory follicle function, two different animal models were used. Experiment 1 compared Holstein-Friesi...
Article
Full-text available
The failure of cows to successfully establish pregnancy after insemination is an important limiting factor for the efficiency of dairy production systems. The physiological reasons for this are many and pertain to the post partum and early pregnancy periods. Cows that suffer severe negative energy balance after parturition are prone to diseases (in...
Article
The oviduct provides the environment to support gamete maturation, fertilisation and early embryo development. As there is a high incidence of early embryonic death in lactating dairy cows, this study compared expression of IGF family members in the oviduct between lactating Holstein-Friesian dairy cows (n=16, 81±2.4 days in milk) and nulliparous h...
Article
The preovulatory surge of LH induces oocyte maturation and ovulation, but also initiates luteinisation of theca and granulosa cells even before ovulation, leading to a functional switch from estradiol (E2) to progesterone (P4) production. Lactating dairy cows display low circulating P4 concentrations and this contributes to their poor fertility com...
Article
Environmental perturbations during gestation negatively impact offspring development including size of the ovarian reserve, metabolism and cardiovascular health, but little is known about the relationships between suboptimal maternal environment and long-term health of offspring in cattle. We tested the effects of restricting maternal nutrient supp...
Article
Fertility in dairy cows has declined over the past five decades as milk production per cow has increased. Many hypotheses have been proposed to explain this including issues of genetics, physiology, nutrition and management, and these factors have been investigated at the animal, organ and cellular level at critical time points of the productive li...
Article
Full-text available
There has been a marked decline in the fertility of dairy cows over the past decades, and metabolomic analysis offers a potential to investigate the underlying causes. Metabolite composition of the follicular fluid, which presents the intrafollicular environment, may be an important factor affecting oocyte maturation and subsequent early embryo dev...
Article
Full-text available
We hypothesised that higher serum FSH concentrations in cattle with low v. high follicle numbers during follicular waves are caused by a different capacity of the pituitary gland to produce gonadotropins. Dairy cows with high (> or = 30; n = 5) and low (< or = 15; n = 5) follicle numbers were selected and serum concentrations of oestradiol and FSH...
Article
The primary functions of the preovulatory follicle in cattle are to nurture development of the oocyte, to produce estradiol to stimulate estrous behaviour and after ovulation to form the corpus luteum. Poor expression of estrus (low intensity and duration) in lactating cows contributes to their poor fertility compared with heifers. The objective of...
Article
Full-text available
The mechanisms whereby the high variation in numbers of morphologically healthy oocytes and follicles in ovaries (ovarian reserve) may have an impact onovarian function, oocyte quality, and fertility are poorly understood. The objective was to determine whether previously validated biomarkers for follicular differentiation and function, as well as...
Article
The objective of this study was to investigate the potential differences among Holstein-Friesian (HF), Montbéliarde (MB), Normande (NM), Norwegian Red (NRF), Montbéliarde x Holstein-Friesian (MBX), and Normande x Holstein-Friesian (NMX) across 2 seasonal grass-based systems of milk production. The effects of breed and feeding system on milk product...
Article
The objective of this study was to quantify differences in udder health and milking characteristics among the Holstein-Friesian (HF), Montbéliarde (MB), Normande (NM), Norwegian Red (NRF), Montbéliarde x Holstein-Friesian (MBX), and Normande x Holstein-Friesian (NMX) genotypes, while considering the effect of feeding system and parity. A total of 7...
Article
The total number of ovarian follicles ≥ 3mm in diameter (antral follicle count, AFC) during follicular waves varies among cattle of similar age, but AFC is highly repeatable within individuals. We hypothesized that lower AFC could be associated with reduced fertility in cattle. The AFC was assessed by ultrasonography for 2 d consecutively during th...

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