Determinants of permanent first incisor eruption in grazing Australian Angora goats

Objective: To investigate the effects of live weight, sex and other factors on deciduous (first incisor) loss and permanent first incisor development in Angora goats. Design: Goats were part of a pen study on the effects of energy intake in Angora does during pregnancy and lactation on kid growth and development. The design was three levels of nutrition in mid-pregnancy × two levels of postnatal nutrition in 17 randomised blocks. Methods: Conception times were calculated by using artificial insemination, with ultrasound examination 43 days after insemination. Does were fed different amounts of a formulated diet in their pens. After weaning, goats were grazed in sex groups. Deciduous first incisor loss and permanent first incisor development were recorded at 11 time points from 14 to 20 months of age. Results: For each sex, the time for visible eruption and full development of permanent first incisor declined linearly with increased live weight by 5.9 and 5.4 days/kg live weight, respectively. The time to reach similar development stages for first permanent incisors eruption was 3 months longer for the lightest animals compared with the heaviest animals. Date of birth, birth weight, doe age, growth rates, mid-pregnancy and postnatal nutrition, parity, day of weaning and weaning weight had no detectable effect. Conclusions: The results explain much of the substantial range in reported first permanent incisor eruption dates for small ruminants and have application in ageing of goats, marketing of kids for meat, in the selection of animals for breeding flocks and in educational material.

Micronutrient intakes affect early growth in extremely preterm infants : preliminary results from a Swedish cohort

Background: Extremely preterm infants generally experience postnatal growth failure. It is still unclear if this is related to micronutrient intakes.

Aim: To investigate the effect of micronutrient intakes (calcium, zinc, iron, phosphorus, sodium, potassium, chloride, magnesium, vitamin A, vitamin D, vitamin E, folate and vitamin B12) on growth during the first 28 days of life in extremely preterm infants.

Method: From the EXPRESS cohort (all infants born < 27 gestational weeks between 2004-2007 in Sweden), those who survived the first 28 days were included (n=524). Daily parenteral and enteral intakes and anthropometric measurements were retrieved from hospital records.

Results: Preliminary analyses of data from 333 infants (mean±SD gestational age 25.2±1.0 weeks, birth weight 753±168g) showed that macronutrient intakes were lower than recommended (energy 98±13kcal/kg/day, protein 2.9±0.4g/kg/day). Infants showed postnatal growth failure: mean standard deviation scores decreased by 2.2 for weight, 2.3 for length and 1.4 for head circumference. Intakes of micronutrients were generally low, e.g. adjusted enteral intakes of calcium were 66.6±21.4 mg/kg/day. The exception was iron, with a high parenteral intake of 2.7±1.6 mg/kg/day, mainly from blood transfusions. Adjusting for protein intake and other confounders, calcium intakes were positively correlated with head growth (r=+0.19, p=0.006) and iron intakes were negatively correlated with length gain (r=-0.18, p=0.009).

Conclusions: Low calcium intakes and high iron intakes were associated with poor growth with regard to head circumference and length, respectively. If these results are confirmed, optimized micronutrient intakes may improve early growth in extremely preterm infants.

Stage of perinatal development regulates skeletal muscle mitochondrial biogenesis and myogenic regulatory factor genes with little impact of growth restriction or cross-fostering

Foetal growth restriction impairs skeletal muscle development and adult muscle mitochondrial biogenesis. We hypothesized that key genes involved in muscle development and mitochondrial biogenesis would be altered following uteroplacental insufficiency in rat pups, and improving postnatal nutrition by cross-fostering would ameliorate these deficits. Bilateral uterine vessel ligation (Restricted) or sham (Control) surgery was performed on day 18 of gestation. Males and females were investigated at day 20 of gestation (E20), 1 (PN1), 7 (PN7) and 35 (PN35) days postnatally. A separate cohort of Control and Restricted pups were cross-fostered onto a different Control or Restricted mother and examined at PN7. In both sexes, peroxisome proliferator-activated receptor (PPAR)-γ coactivator-1α (PGC-1α), cytochrome c oxidase subunits 3 and 4 (COX III and IV) and myogenic regulatory factor 4 expression increased from late gestation to postnatal life, whereas mitochondrial transcription factor A, myogenic differentiation 1 (MyoD), myogenin and insulin-like growth factor I (IGF-I) decreased. Foetal growth restriction increased MyoD mRNA in females at PN7, whereas in males IGF-I mRNA was higher at E20 and PN1. Cross-fostering Restricted pups onto a Control mother significantly increased COX III mRNA in males and COX IV mRNA in both sexes above controls with little effect on other genes. Developmental age appears to be a major factor regulating skeletal muscle mitochondrial and developmental genes, with growth restriction and cross-fostering having only subtle effects. It therefore appears that reductions in adult mitochondrial biogenesis markers likely develop after weaning.

Effect of pregnancy for females born small on later life metabolic disease risk

There is a strong inverse relationship between a females own birth weight and her subsequent risk for gestational diabetes with increased risk of developing diabetes later in life. We have shown that growth restricted females develop loss of glucose tolerance during late pregnancy with normal pancreatic function. 

The relationship of the incidence of medullated fibres to the dimensional properties of mohair over the lifetime of Angora goats

In a range of animals, increasing mean fibre diameter (MFD) of fibre is associated with an increasing incidence of medullated fibres (Med). It would thus be expected that Med in mohair fleeces, from animals in a flock, would be related to the MFD of those fleeces. MFD of mohair is not the only dimensional attribute of fibres. Med in mohair is phenotypically and genetically related to the size of animals. This study examined how Med is related to dimensional properties of mohair over the lifetime of Angora goats and how the relationship varies with other lifetime factors. The relationship found is then examined to determine the extent that the relationship can be explained by variations in animal size of the goats. Measurements were made over 11 shearing periods on a population of Angora goats representing the current range and diversity of genetic origins in Australia, including South African, Texan and interbred admixtures of these and Australian sources. Records of breed, sire, dam, date of birth, dam age, birth weight, birth parity, weaning weight, live weight, fleece growth and fleece attributes were taken for castrated males (wethers). Animals’ fleece-free live weight (FFLwt, kg) were determined for each goat at shearing time by subtracting the greasy fleece weight from the live weight recorded immediately prior to shearing. The average of the FFLwt at the start of the period and the FFLwt at the end of the period was calculated. Two restricted maximum likelihood (REML) models were developed to relate Med to MFD, staple length (SL) and other lifetime factors. One model allowed FFLwt in the model and the other excluded FFLwt. With the exception of the 1.5 years shearing, Med strongly increased with increasing MFD whether or not adjustments were made for FFLwt measurements. In particular Med increased by 2.0% for each 1 μm increase in MFD, with no adjustment for FFLwt measurements, and increased by 1.5% for each 1 μm increase in MFD, with adjustment for FFLwt measurements. Within each shearing interval increasing average FFLwt was associated with increasing incidence of Med in a similar way to that which has been previously reported without including MFD in the model. There was no evidence that SL needed to be included in the models for Med. Mohair grown by the goats of Mixed genetic background grew mohair which had a higher incidence of Med at ages 2 and 2.5 years and the trend was apparent in other shearing periods. We can conclude that there is both a large response of Med to live weight and a large response to MFD, and that these responses are largely functionally separate. While the response to MFD is in accord with earlier work, there is an unrelated and unreported physiological mechanism that favours the production of Med in larger Angora goats. Clearly, larger Angora goats are biologically different compared with smaller animals from the same flock, in ways that are not purely related to the allometrics of size.

Exercise as an intervention to improve metabolic outcomes after intrauterine growth restriction

Individuals born after intrauterine growth restriction (IUGR) are at an increased risk of developing diabetes in their adult life. IUGR impairs β-cell function and reduces β-cell mass, thereby diminishing insulin secretion. IUGR also induces insulin resistance, with impaired insulin signaling in muscle in adult humans who were small for gestational age (SGA) and in rodent models of IUGR. There is epidemiological evidence in humans that exercise in adults can reduce the risk of metabolic disease following IUGR. However, it is not clear whether adult IUGR individuals benefit to the same extent from exercise as do normal-birth-weight individuals, as our rat studies suggest less of a benefit in those born IUGR. Importantly, however, there is some evidence from studies in rats that exercise in early life might be able to reverse or reprogram the long-term metabolic effects of IUGR. Studies are needed to address gaps in current knowledge, including determining the mechanisms involved in the reprogramming effects of early exercise in rats, whether exercise early in life or in adulthood has similar beneficial metabolic effects in larger animal models in which insulin resistance develops after IUGR. Human studies are also needed to determine whether exercise training improves insulin secretion and insulin sensitivity to the same extent in IUGR adults as in control populations. Such investigations will have implications for customizing the recommended level and timing of exercise to improve metabolic health after IUGR.

The value of visual fleece assessment in addition to objective measurements in identifying Angora goats of greater clean mohair production

Visual assessment of the fleece of Merino sheep is an accepted method to aid genetic improvement but there is little evidence to support the use of visual assessment for improving mohair production. This paper examines the extent that visual traits, including staple length, character (staple crimp), staple definition, tippiness, style and staple entanglement, are related to clean fleece weight in animals of similar live weight and mean fibre diameter (MFD) from the same flock. Measurements were made over 9 shearing periods on a population of castrated Angora males (wethers) goats representing the current range and diversity of genetic origins in Australia, including South African, Texan and interbred admixtures of these and Australian sources (these different genetic origins are defined as Breed in this work). Data on genetic origin, sire, dam, lifetime characteristics (date of birth, dam age, birth weight, birth parity (single or twin), weaning weight), live weight, fleece growth and visual fleece attributes were recorded. A restricted maximum likelihood (REML) model was developed to relate clean fleece weight with age, MFD, average fleece-free live weight, lifetime characteristics and visual fleece attributes. There were separate linear responses of clean fleece weight to MFD and staple length for each age group, a quadratic response to the square root of average fleece-free live weight, an effect of sire breed and linear responses to dam age, staple definition score and character. Depending on age at shearing, the increase in clean fleece weight was between about 50 and 80. g for each increase of 1. μm in MFD. At similar MFD, clean fleece weight was generally greater at summer shearings compared with winter shearings. There was a strong increase in clean fleece weight with average fleece-free live weight up to around 50. kg but little response in clean fleece weight for animals larger than 50. kg. There was some evidence of a smaller increase in clean fleece weight as the age of dam increased. There was an effect of Breed in the model but this effect disappeared when a random sire effect was included in the model. There was a positive response to staple length at some age groups but the response did not differ from zero in other age groups. This response varied from negligible to about 70. g per 1. cm increase in staple length. Clean fleece weight increased about 40. g per unit increase in staple definition score and increased about 30. g for every 4 units increase in the number of staple crimps. There was no evidence that clean fleece weight was affected by staple style, staple tip score or staple entanglement score or lifetime factors such as birth weight, date of birth, birth parity, or weaning weight. The results show that using a combination of measuring MFD and visually assessing the fleece for staple length, staple definition and crimps can help identify the most profitable Angora goats. In this process, the objective measurement of MFD appears essential. Visual assessment will provide some extra benefit in identifying these animals above that provided by measuring MFD alone. Animal size should be considered by mohair producers when identifying more productive mohair producing animals. © 2014 Elsevier B.V.

Lifetime and fleece quality traits associated with the occurrence of entangled mohair staples

Staple entanglement in mohair fleeces occurs when adhesions form between longer and faster growing fibres and shorter and slower growing fibres. This results in accentuated crimp of the longer fibres and an "apparently" reduced staple length. The appearance in the fleece of Angora goats of staple entanglements can lead to the downgrading of the mohair to poorer style and shorter length grades, resulting in up to 60% price reductions. This study examined how staple entanglement score (SES) is related to lifetime factors of Angora goats, and how this relationship can be explained by variations in animal size and fleece attributes. SES was scored using a five-point scale: 5, long free fibres easily separated as no adhesions; 4, some adhesions between fibres; 3, some effort to separate fibres as many adhesions; 2, many adhesions, staple fibres entangled, shortening of staple; 1, very entangled and shortened staple. Measurements were made over 9 shearing periods on a population of Angora castrated males (wethers) goats representing the current range and diversity of genetic origins in Australia, including South African, Texan and interbred admixtures of these and Australian sources. Data on genetic origin, sire, dam, date of birth, dam age, birth weight, birth parity, weaning weight, live weight, fleece growth and fleece attributes were recorded. Two restricted maximum likelihood (REML) models were developed to relate SES with age, animal lifetime factors, fleece quality attributes and live weight. One model allowed fleece quality and live weight traits in the model and the other excluded these traits. Staple entanglement was almost eliminated in mohair harvested from goats shorn every 3. months but was common in mohair from goats shorn twice or once per year. SES was less in goats of Texan genetic background, and was generally less in winter grown mohair. SES was higher for mohair with low fibre curvature (FC, 10°/mm) and a high clean washing yield (CWY, 90%) compared with mohair with low FC and lower CWY (80%), and compared with all mohair with high FC (18°/mm). The response of SES to shearing regime, genetic background, shearing season, age of goat and a response to dam age were almost identical whether or not an adjustment was made for CWY and FC. There was a moderate amount of variability due to sires and individuals. We can conclude that a large part of these effects observed, namely breed, dam age, sire, and a component of the FC and CWY effects, are genetic. Mohair producers can manage the genetic effects by careful selection of sires, especially avoiding those with low CWY or high FC, and avoiding sires with higher levels of staple entanglement or that have produced progeny with higher levels of staple entanglement. Also, unidentified environmental effects are affecting staple entanglement, although a lack of a live weight change effect on entanglement indicates that this effect might not be due to nutrition. © 2013 Elsevier B.V.

Study protocol: asking questions about alcohol in pregnancy (AQUA): a longitudinal cohort study of fetal effects of low to moderate alcohol exposure

Despite extensive research, a direct correlation between low to moderate prenatal alcohol exposure (PAE) and Fetal Alcohol Spectrum Disorders has been elusive. Conflicting results are attributed to a lack of accurate and detailed data on PAE and incomplete information on contributing factors. The public health effectiveness of policies recommending complete abstinence from alcohol during pregnancy is challenged by the high frequency of unplanned pregnancies, where many women consumed some alcohol prior to pregnancy recognition. There is a need for research evidence emphasizing timing and dosage of PAE and its effects on child development.

The marsupial: a unique model for understanding the regulation of lung development

 The project has exploited an Australian marsupial, tammar wallaby, as an experimental model to understand lung development. This research has focused on identifying the factors that regulate lung development and to develop new intervention therapies to improve health outcomes in human premature and low birth weight babies.

A review of the relationship between socioeconomic position and the early-life predictors of obesity

A range of important early-life predictors of later obesity have been identified. Children of lower socioeconomic position (SEP) have a steeper weight gain trajectory from birth with a strong socioeconomic gradient in child and adult obesity prevalence. An assessment of the association between SEP and the early-life predictors of obesity has been lacking. The review involved a two-stage process: Part 1, using previously published systematic reviews, we developed a list of the potentially modifiable determinants of obesity observable in the pre-natal, peri-natal or post-natal (pre-school) periods; and part 2, conducting a literature review of evidence for socioeconomic patterning in the determinants identified in part 1. Strong evidence was found for an inverse relationship between SEP and (1) pre-natal risk factors (pre-pregnancy maternal body mass index (BMI), diabetes and pre-pregnancy diet), (2) antenatal/peri natal risk factors (smoking during pregnancy and low birth weight) and (3) early-life nutrition (including breastfeeding initiation and duration, early introduction of solids, maternal and infant diet quality, and some aspects of the home food environment), and television viewing in young children. Less strong evidence (because of a lack of studies for some factors) was found for paternal BMI, maternal weight gain during pregnancy, child sleep duration, high birth weight and lack of physical activity in young children. A strong socioeconomic gradient exists for the majority of the early-life predictors of obesity suggesting that the die is cast very early in life (even pre-conception). Lifestyle interventions targeting disadvantaged women at or before child-bearing age may therefore be particularly important in reducing inequality. Given the likely challenges of reaching this target population, it may be that during pregnancy and their child's early years are more feasible windows for engagement.

Epigenetic regulation of neurodevelopmental genes in response to in utero exposure to phthalate plastic chemicals: how can we delineate causal effects?

Accumulating evidence, from animal models and human observational studies, implicates the in utero (and early postnatal) environment in the 'programming' of risk for a variety of adverse outcomes and health trajectories. The modern environment is replete with man-made compounds such as plastic product chemicals (PPC), including phenols and phthalates. Evidence from several human cohorts implicates exposure to these chemicals in adverse offspring neurodevelopment, though a direct causal relationship has not been firmly established. In this review we consider a potential causal pathway that encompasses epigenetic human variation, and how we might test this mechanistic hypothesis in human studies. In the first part of this report we outline how PPCs induce epigenetic change, focusing on the brain derived neurotrophic factor (BDNF) gene, a key regulator of neurodevelopment. Further, we discuss the role of the epigenetics of BDNF and other genes in neurodevelopment and the emerging human evidence of an association between phthalate exposure and adverse offspring neurodevelopment. We discuss aspects of epidemiological and molecular study design and analysis that could be employed to strengthen the level of human evidence to infer causality. We undertake this using an exemplar recent research example: maternal prenatal smoking, linked to methylation change at the aryl hydrocarbon receptor repressor (AHRR) gene at birth, now shown to mediate some of the effects of maternal smoking on birth weight. Characterizing the relationship between the modern environment and the human molecular pathways underpinning its impact on early development is paramount to understanding the public health significance of modern day chemical exposures.

Angiotensin converting enzyme inhibition from birth reduces body weight and body fat in Sprague-Dawley rats

In vitro studies have demonstrated that angiotensin II (ANG II) induces adipocyte hyperplasia and hypertrophy. The aim of the present study was to determine the effect of angiotensin-converting enzyme inhibition on body weight, adiposity and blood pressure in Sprague–Dawley rats. From birth half of the animals (n = 15) were given water to drink, while the remainder were administered perindopril in their drinking water (2 mg/kg/day). Food intake, water intake and body weight were measured weekly. Blood pressure was measured by tail cuff plethysmography at 11-weeks. Body fat content and distribution were assessed using dual energy X-ray absorptiometry and Magnetic Resonance Imaging at 12 weeks. Animals administered with perindopril had a body fat proportion that was half that of controls. This was consistent with, but disproportionately greater than the observed differences in food intake and body weight. Perindopril treatment completely removed hypertension. We conclude that the chronic inhibition of ANG II synthesis from birth specifically reduces the development of adiposity in the rat.

Evaluation of a brief pilot nutrition and exercise intervention for the prevention of weight gain in general practice patients

Objective To pilot-test a brief written prescription recommending lifestyle changes delivered by general practitioners (GPs) to their patients.

Design The Active Nutrition Script (ANS) included five nutrition messages and personalised exercise advice for a healthy lifestyle and/or the prevention of weight gain. GPs were asked to administer 10 scripts over 4 weeks to 10 adult patients with a body mass index (BMI) of between 23 and 30 kg m− 2. Information recorded on the script consisted of patients' weight, height, waist circumference, gender and date of birth, type and frequency of physical activity prescribed, and the selected nutrition messages. GPs also recorded reasons for administering the script. Interviews recorded GPs views on using the script.

Setting General practices located across greater Melbourne.

Subjects and results Nineteen GPs (63% female) provided a median of nine scripts over 4 weeks. Scripts were administered to 145 patients (mean age: 54 ± 13.2 years, mean BMI: 31.7 ± 6.3 kg m− 2; 57% female), 52% of whom were classified as obese (BMI >30 kg m− 2). GPs cited ‘weight reduction’ as a reason for writing the script for 78% of patients. All interviewed GPs (90%, n = 17) indicated that the messages were clear and simple to deliver.

Conclusions GPs found the ANS provided clear nutrition messages that were simple to deliver. However, GPs administered the script to obese patients for weight loss rather than to prevent weight gain among the target group. This has important implications for future health promotion interventions designed for general practice.

Body weight, body image, and eating behaviours : relationships with ethnicity and acculturation in a community sample of young Australian women

A study was conducted to investigate associations between ethnicity and acculturation status and risk factors for eating disorders among young adult women. A community sample of 14,779 women aged 18–23 completed a comprehensive mail-out survey, which incorporated questions on country of birth, length of time spent in Australia, body weight, weight dissatisfaction, dieting, binge eating, and compensatory disordered eating behaviours. Results showed that risk factors for eating disorders were present across a range of ethnic groups. Further, a strong acculturation effect was observed, such that the longer the time spent in Australia, the more women reported weight-related values and behaviours similar to those of Australian-born women. Results challenge claims that risk factors for disordered eating are restricted to Caucasian females in Western societies. Implications for understanding ethnic and sociocultural influences on body weight, dieting, and disordered eating are considered.