Browsing by Author "Turner S-A"
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- ItemA Capra hircus chromosome 19 locus linked to milk production influences mammary conformation(BioMed Central Ltd, 2022-02-11) Jiang A; Ankersmit-Udy A; Turner S-A; Scholtens M; Littlejohn MD; Lopez-Villalobos N; Proser CG; Snell RG; Lehnert KBackground Economically important milk production traits including milk volume, milk fat and protein yield vary considerably across dairy goats in New Zealand. A significant portion of the variation is attributable to genetic variation. Discovery of genetic markers linked to milk production traits can be utilised to drive selection of high-performance animals. A previously reported genome wide association study across dairy goats in New Zealand identified a quantitative trait locus (QTL) located on chromosome 19. The most significantly associated single nucleotide polymorphism (SNP) marker for this locus is located at position 26,610,610 (SNP marker rs268292132). This locus is associated with multiple milk production traits including fat, protein and volume. The predicted effect of selection for the beneficial haplotype would result in an average production increase of 2.2 kg fat, 1.9 kg protein and 73.6 kg milk yield. An outstanding question was whether selection for the beneficial allele would co-select for any negative pleiotropic effects. An adverse relationship between milk production and udder health traits has been reported at this locus. Therefore, a genome wide association study was undertaken looking for loci associated with udder traits. Results The QTL and production associated marker rs268292132 was identified in this study to also be associated with several goat udder traits including udder depth (UD), fore udder attachment (FUA) and rear udder attachment (RUA). Our study replicates the negative relationship between production and udder traits with the high production allele at position 19:26,610,610 (SNP marker rs268292132) associated with an adverse change in UD, FUA and RUA. Conclusions Our study has confirmed the negative relationship between udder traits and production traits in the NZ goat population. We have found that the frequency of the high production allele is relatively high in the NZ goat population, indicating that its effect on udder conformation is not significantly detrimental on animal health. It will however be important to monitor udder conformation as the chromosome 19 locus is progressively implemented for marker assisted selection. It will also be of interest to determine if the gene underlying the production QTL has a direct effect on mammary gland morphology or whether the changes observed are a consequence of the increased milk volume.
- ItemAssociations between peripartum lying and activity behaviour and blood non-esterified fatty acids and β-hydroxybutyrate in grazing dairy cows(Elsevier B.V. on behalf of The Animal Consortium, 2022-03) Hendriks SJ; Phyn CVC; Turner S-A; Mueller KR; Kuhn-Sherlock B; Donaghy DJ; Huzzey JM; Roche JRDuring early lactation, most dairy cows experience negative energy balance (NEB). Failure to cope with this NEB, however, can place cows at greater risk of developing metabolic disease. Our objective was to characterise, retrospectively, lying behaviour and activity of grazing dairy cows grouped according to blood non-esterified fatty acids (NEFAs) and β-hydroxybutyrate (BHB) as indicators of postpartum metabolic state. Blood was sampled weekly for up to 4 weeks precalving, on the day of calving (day 0), daily between 1 and 4 days postcalving, and then at least weekly between week 1 and week 5 postcalving for analysis of plasma NEFAs and BHB concentrations. Two hundred and forty-four multiparous Holstein-Friesian and Holstein-Friesian × Jersey cows were classified into one of three metabolic status groups based on maximum blood NEFAs and BHB concentrations during week 1 and 2 postcalving. A cow was classified as having either: (1) low NEFAs and low BHB (Lo–Lo; n = 78), when all blood samples were <1.0 mmol/L for NEFAs and ≤1.0 mmol/L for BHB during the first 2 weeks postcalving; (2) high NEFAs and low BHB (Hi–Lo; n = 134), when blood NEFAs were ≥1.0 mmol/L and blood BHB was ≤1.0 mmol/L at the same sampling time point during the first 2 weeks postcalving; or (3) high NEFAs and high BHB (Hi–Hi; n = 32), when blood NEFAs were ≥1.0 mmol/L and blood BHB was ≥1.2 mmol/L at the same sampling time point during the first 2 weeks postcalving. Accelerometers (IceTag or IceQube devices; IceRobotics Ltd.) were used to monitor lying and activity behaviours peripartum (–21 to +35 days relative to calving). Changes in lying behaviour and activity occurred before the mean day that cows were classified Hi–Hi and Hi–Lo (2.2 and 3.5 d postcalving, respectively). Up to 3 weeks preceding calving, Hi–Hi cows were more active, had fewer daily lying bouts (LBs), and spent less time lying than Lo–Lo cows. In addition, Hi–Hi cows had fewer daily LBs and were less active up to 4 weeks postcalving than Lo–Lo cows, but these differences were biologically small. Groups of grazing cows classified as experiencing a more severe metabolic challenge behave differently up to 3 weeks precalving than their herdmates with lower blood NEFAs and BHB postcalving. These altered behaviours may allow identification of individual cows at risk of a metabolic challenge, but further research is required.
- ItemEstimates of Genetic Parameters for Milk, the Occurrence of and Susceptibility to Clinical Lameness and Claw Disorders in Dairy Goats(MDPI (Basel, Switzerland), 2023-04-17) Jaques N; Turner S-A; Vallée E; Heuer C; Lopez-Villalobos N; Davis ME; Bagnicka EThe New Zealand goat industry accesses niche markets for high-value products, mainly formula for infants and young children. This study aimed to estimate the genetic parameters of occurrence and susceptibility of clinical lameness and selected claw disorders and establish their genetic associations with milk production traits. Information on pedigree, lameness, claw disorders, and milk production was collected on three farms between June 2019 and July 2020. The dataset contained 1637 does from 174 sires and 1231 dams. Estimates of genetic and residual (co)variances, heritabilities, and genetic and phenotypic correlations were obtained with uni- and bi-variate animal models. The models included the fixed effects of farm and parity, deviation from the median kidding date as a covariate, and the random effects of animal and residual error. The heritability (h2) estimates for lameness occurrence and susceptibility were 0.07 and 0.13, respectively. The h2 estimates for claw disorder susceptibilities ranged from 0.02 to 0.23. The genotypic correlations ranged from weak to very strong between lameness and milk production traits (-0.94 to 0.84) and weak to moderate (0.23 to 0.84) between claw disorder and milk production traits.
- ItemModeling daily yields of milk, fat, protein, and lactose of New Zealand dairy goats undergoing standard and extended lactations(Elsevier Inc on behalf of the American Dairy Science Association, 2024-03) Boshoff M; Lopez-Villalobos N; Andrews C; Turner S-AThis study aimed to assess the milk production data for New Zealand dairy goats in either a standard lactation (SL; ≤305 d in milk [DIM]) or extended lactation (EL; >305 and ≤670 DIM) using a random regression (RR) with third- and fifth-order Legendre polynomials, respectively. Persistency of EL was defined as (B/A) × 100, where A was the accumulated yield from d 1 to 305, and B was the accumulated yield from d 366 to 670. On average, goats in SL produced 1,183 kg of milk, 37 kg of fat, 37 kg of protein, and 54 kg of lactose. The average production of milk, fat, protein, and lactose in EL were 2,473 kg, 78 kg, 79 kg, and 112 kg, respectively. The average persistences for milk, fat, protein, and lactose yields during EL were 98%, 98%, 102%, and 96%, respectively. The relative prediction errors were close to 10% and the concordance correlation coefficients >0.92, indicating that the RR model with Legendre polynomials is adequate for modeling lactation curves for both SL and EL. Total yields and persistency were analyzed with a mixed model that included the fixed effects (year, month of kidding, parity, and proportion of Saanen) as covariates and the random effects of animal and residual errors. Effects of year, month of kidding, and parity were significant on the total yields of milk, fat, protein, and lactose for both SL and EL. The total milk yield of first-parity goats with SL was 946 kg and the total milk yield of second-parity goats with SL was 1,284 kg, making a total of 2,230 kg over 2 years. The total milk yield of a first-parity goat with EL was 2,140 kg. Thus, on average, a goat with SL for the first and second parity produced 90 kg more milk than a first-parity goat subjected to EL. However, a second-parity goat subjected to EL produced 43 kg more milk (2,639 kg) than a goat with SL following the second and third parity (1,284 kg + 1,312 kg). These data, along with the various other benefits of EL (e.g., fewer offspring born and reduced risk of mastitis, lameness, and metabolic problems in early lactation), indicate that EL as a management strategy holds the potential to improve dairy goat longevity and lifetime efficiency without compromising milk production.
- ItemPrevalence and incidence rate of clinical lameness in three New Zealand dairy goat farms(Taylor and Francis Group, 2024-01-01) Jaques N; Turner S-A; Vallee E; Heuer C; Deeming L; Lopez-Villalobos NClinical lameness has an impact on animal welfare and profitability in different livestock industries. The objective of this study was to estimate the prevalence and incidence rate of clinical lameness within New Zealand dairy goat farms. Up to 3246 goats on three dairy goat farms were observed 4–5 times over one year. Data on locomotion scores and animal information were collected between June 2019 and June 2020. A 5-point (0–4) locomotion scoring scale was used, where scores 3 and 4 were classified as clinical lameness. The average herd-level prevalence of clinical lameness for farms A, B, and C were 23, 12, and 10%, respectively. The annual incidence rate of clinical lameness for farms A, B, and C were 104, 56, and 55 cases per 100 goat-years, respectively. Lameness appears to be a significant welfare issue, with incidence varying between farms and between goats. Investigating both farm-level and goat-level factors is required to understand the epidemiology of lameness and design evidence-based control and prevention measures. Further investigation should be undertaken to identify variables affecting the goat's odds of becoming clinically lame. This study sets the foundation for future study of lameness in commercial dairy goat farms nationally and internationally.
- ItemThe Effect of Lameness on Milk Production of Dairy Goats(MDPI (Basel, Switzerland), 2023-05-23) Jaques N; Turner S-A; Vallée E; Heuer C; Lopez-Villalobos N; Moraleda GR; Hall SJGLameness on dairy goat farms is a welfare concern and could negatively affect milk production. This study's objective was to evaluate the effects of clinical lameness on the daily milk production of dairy goats. Between July 2019 and June 2020, 11,847 test-day records were collected from 3145 goats on three farms in New Zealand. Locomotion scoring of goats used a five-point scoring system (0 to 4). The dataset was split into two groups by lactation type, where goats were classified as being in seasonal lactation (≤305 days in milk) or extended lactation (>305 days in milk). A linear mixed model was used to analyze datasets using milk characteristics as the dependent variables. Severely lame goats (score 4) in seasonal and extended lactation produced 7.05% and 8.67% less milk than goats not lame, respectively. When the prevalence of severe lameness is between 5 and 20% of the herd, the estimated average daily milk income lost was between NZD 19.5 and 104 per day. This study established the negative impact of lameness on milk production and annual income in dairy goats on three farms.
