Rachel Forrest

Polymorphisms in the ovine myostatin gene (MSTN) and their association with growth and carcass traits in New Zealand Romney sheep

Myostatin is a regulator of myogenesis and has been implicated in the regulation of adiposity and in controlling the structure and function of tendons. Polymerase Chain Reaction Single-Stranded Conformational Polymorphism (PCR-SSCP) analysis of intron-1 was used to identify five variants (designated A-E) of the myostatin gene (MSTN). The effect of this genetic variation on growth and carcass traits was investigated in 517 Romney male lambs from 17 sire-lines, born on a South Island New Zealand farm. General linear mixed effect models revealed that the presence of allele A in a lambs genotype was associated with decreased leg, loin and total yield of lean meat, whereas the presence of allele B was associated with increased loin yield and proportion loin yield (loin yield divided by total yield expressed as percentage). The effect of the number of allele copies present was investigated, and it was found that the absence of A, or the presence of two copies of B, was associated with increased mean leg yield, loin yield and total yield. Two copies of B were also associated with a decrease in proportion of shoulder yield, whereas two copies of A were associated with a decrease in proportion of loin yield. Associations with allele C were not detected. No associations of MSTN variation with birth weight, weaning weight, pre-weaning growth rate, draft age and hot carcass weight (H-W) were detected. These results suggest that variation in ovine MSTN is associated with meat production, but not birth weight or growth rate in New Zealand Romney sheep.

Wool Keratin-Associated Protein Genes in Sheep—A Review

The importance of sheep’s wool in making textiles has inspired extensive research into its structure and the underlying genetics since the 1960s. Wool keratin-associated proteins (KAPs) are a key structural component of the wool fibre. The characterisation of the genes encoding these proteins has progressed rapidly with advances in the nucleotide and protein sequencing. This review describes our knowledge of ovine KAPs, their categorisation into families, polymorphism in the proteins and genes, the clustering and chromosomal location of the genes, some characteristics of gene expression and some potential effects of the KAPs on wool traits. The extent and nature of genetic variation in wool KAP genes and its association with fibre characteristics, provides an opportunity for the development of gene-markers for selective breeding of sheep to produce better wool with properties highly matched to specific end-uses.

Association between variation in faecal egg count for a mixed field-challenge of nematode parasites and IGHA gene polymorphism.

Research has shown that variation in ovine immunoglobulin A (IgA) levels are associated with reduced faecal egg counts (FECs) in sheep hosting gastro-intestinal (GI) parasites. Variation in the constant region of the ovine IgA heavy alpha chain gene (IGHA) may result in structurally and functionally different IgA molecules and may consequently lead to variation in the IgA response to parasitisation. This study involved three sheep breeds (Merino, Polwarth and Corriedale) and a total of 2098 lambs from eight New Zealand farms that underwent a mixed field-challenge of nematode parasites. Faecal samples were taken at approximately 4 and 9 months of age and FECs for Nematodirus and Strongyle species determined along with total eggs per gram (EPG). Analysis of all eight farms collectively revealed no significant differences in FECs associated with the presence or absence of a particular IGHA allele. However, when the data was split into predominant challenge type groups, associations were detected. In 4-month-old lambs predominantly challenged by Nematodirus sp., the presence of the IGHA allele *01 was associated (P<0.05) with higher Strongyle FECs. In 9-month-old lambs predominantly challenged by Trichostrogylus sp., the presence of IGHA allele *02 was associated (P<0.006) with a higher mean total EPG at 9 months of age. These results suggest that IGHA gene variation will not be an effective gene-marker for reducing overall FEC but may be useful in defined or specific species challenges.

Genetic variations in the myostatin gene ( MSTN ) in New Zealand sheep breeds

Myostatin, which is also known as growth and differentiation factor 8 (GDF8), acts as a negative regulator of skeletal muscle growth. Variation in the myostatin gene (MSTN) has been associated with variation in muscularity in many animals including sheep. Polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis was used to investigate MSTN in a diverse range of sheep breeds including the New Zealand (NZ) Romney, Coopworth, Corriedale, Dorper, Perendale, Suffolk, Merino, Dorset Down, Poll Dorset, Texel and other NZ cross-bred sheep. A total of 28 nucleotide substitutions were identified from nucleotide c.-1199 in the promoter region to c.*1813 (based on NCBI GenBank accession number DQ530260) and including the well-described substitution c.*1232G>A (MSTN g+6223G>A). Of these 28 substitutions, 3 were located in the promoter region, 3 in the 5′UTR, 11 in intron 1, 5 in intron 2 and 5 in the 3′UTR. One substitution in exon 1 (c.101G>A) potentially results in an amino acid substitution of glutamic acid (Glu) with glycine (Gly) at codon 34. Ten of these substitutions have not been reported previously. The genetic variation revealed in this study suggests this gene is more variable than hitherto reported and provides a foundation for future research into how this variation affects muscle and growth traits.

Polymorphism of the ovine β3-adrenergic receptor gene (ADRB3) and its association with wool mean staple strength and yield.

We investigated the possibility that variation in ovine ADRB3 is associated with various wool traits, in particular mean staple strength (MSS). Polymerase chain reaction-single strand conformational polymorphism analysis of part of the ADRB3 intron was used to genotype 695 Merino lambs born on three farms in the South Island of New Zealand and which were shorn as 2-tooths. For each fleece, MSS, mean fibre diameter, mean staple length and yield were measured. The results from mixed-effects models and half-sib analyses suggest that ADRB3 alleles A and D have a negative impact on some wool traits, whereas ADRB3 alleles C and E appear to have a positive impact, with allele C potentially having a greater impact than allele E on MSS. This variation in the ADRB3 may assist in the genetic selection for increased MSS and yield in Merino sheep.

Genetic diversity of selected genes that are potentially economically important in feral sheep of New Zealand.

BackgroundFeral sheep are considered to be a source of genetic variation that has been lost from their domestic counterparts through selection.MethodsThis study investigates variation in the genes KRTAP1-1, KRT33, ADRB3 and DQA2 in Merino-like feral sheep populations from New Zealand and its offshore islands. These genes have previously been shown to influence wool, lamb survival and animal health.ResultsAll the genes were polymorphic, but no new allele was identified in the feral populations. In some of these populations, allele frequencies differed from those observed in commercial Merino sheep and other breeds found in New Zealand. Heterozygosity levels were comparable to those observed in other studies on feral sheep. Our results suggest that some of the feral populations may have been either inbred or outbred over the duration of their apparent isolation.ConclusionThe variation described here allows us to draw some conclusions about the likely genetic origin of the populations and selective pressures that may have acted upon them, but they do not appear to be a source of new genetic material, at least for these four genes.

Aberrant Work Environments, Rationed Care as System Failure or Missed Care as Skills Failure?

Missed’ care has emotional, professional and legal connotations because, as one participant from our study noted, the environment can change so quickly and staffing is not allocated to accommodate this. This study used the MISSCARE survey distributed to nurses in New Zealand to find out what care was routinely missed, and why they missed it. The analysis of data returned from 199 nurses revealed that nurses routinely miss care and become frustrated because they are unable to use the knowledge and skill to provide the care; rather they are forced to prioritise care, some of which is either delayed or consciously missed. Whilst this study supported findings of previous research, the emergence of presenteeism as a factor that affects nurses missing care, was highlighted. This has wider implications to the nursing workforce related to their ability to provide safe and effective care, as well as to the organisations in terms of both budget and safety in care provision.

Discharge Planning: Screening Older Patients for Multidisciplinary Team Referral

The objective was to determine whether the Elders Risk Assessment Index can predict multi-disciplinary team referral of older patients (≥ 65 years) in Emergency Department same-day discharges. The study identified 1,376 qualifying individuals from a regional New Zealand hospital database. Of these, 12.7 % were referred to the multi-disciplinary team. Univariate and multivariate analyses were used to explore associations between the Index, its components, and other demographic factors with referral. With every unit increase in the Index there was a 9% increase in the odds of being referred. When the components of the Index were analysed separately, an increased likelihood of being referred was associated with not being married, having had a previous hospital admission of more than five days, having chronic obstructive pulmonary disease, and being older. Conversely, a decreased likelihood was associated with having diabetes. When non-Index items were analysed it was found that females were more likely to be referred than males and that Māori were less likely to be referred than New Zealand Europeans. With adaptation, the Elders Risk Assessment Index may provide a simple, cost-effective, and timely tool to assist in determining the need for multi-disciplinary team referral for older people who present to the Emergency Department.

Variation in exon 10 of the ovine calpain 3 gene (CAPN3) and its association with meat yield in New Zealand Romney sheep

Variation in the ovine CAPN3 gene was analysed using PCR-single strand conformational polymorphism, and its effect on growth and carcass traits was assessed in 513 New Zealand Romney lambs produced by 17 unrelated rams. Among the four allelic variants detected, the presence of variant *02 was found to be associated with an increased proportion of shoulder yield (absent: 32.6±0.01%; present: 33.4±0.03%; P=0.016), and tended to be associated with increased shoulder yield (lean meat yield of the shoulder expressed as a percentage of the hot carcass weight) (absent: 16.6±0.06%; present: 17.02±0.20%; P=0.067). No association was detected with growth traits or other carcass traits.

No evidence for a universal association between variation in faecal egg count for a mixed field-challenge of gastrointestinal parasites and the presence of the Ovar-DQA1 null haplotype in sheep.

We tested the association of the Ovar-DQA1 null haplotype with faecal egg count (FEC) in 4676 male lambs sourced from 185 different sire-lines and four breeds. For each lamb a faecal sample was collected at weaning (approx. 4 months of age) and mid-autumn (approx. 9 months of age) and each was typed for the presence of Ovar-DQA1 null. General Linear Mixed Models (GLMMs) were used to analyse the relationship between FEC and Ovar-DQA1 null, both across and within breeds. Two models were used, the first testing the effect of the presence/absence of Ovar-DQA1 null and the second testing the effect of the number of copies of Ovar-DQA1 null present in an animals genotype (i.e. dominant/recessive or additive effects). Across the breeds, no significant effect of the presence of Ovar-DQA1 null on FEC for Nematodirus sp., Strongyle genera, or total FEC was detected at either 4 or 9 months of age using either of the models. Within breeds, significant associations were detected at 4 months in South African Meat Merinos, with the presence of Ovar-DQA1 null in an animals genotype being associated with a lower strongyle (absent: n=23, geometric mean=135epg; present: n=10, geometric mean=67epg; P=0.025) and total FEC (absent: n=23, geometric mean=220epg; present: n=10, geometric mean=121epg; P=0.017). These associations were not detected at 9 months of age.