Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
Browse
23 results
Search Results
Item Characterizing the dynamics of the rumen microbiota, its metabolites, and blood metabolites across reproductive stages in Small-tailed Han sheep.(American Society for Microbiology, 2023-11-10) Sha Y; Liu X; Pu X; He Y; Wang J; Zhao S; Shao P; Wang F; Xie Z; Chen X; Yang WDifferent reproductive stages of mammals involve complex biological processes, and the intestinal microbiota, as an endocrine organ or an “invisible organ,” is involved in the regulation of hormone levels, immune function, and metabolism. However, the effects of the rumen microbiota, its metabolites, and blood metabolites on the reproductive performance of ruminants remain unclear. This study revealed that the Prevotella abundance increased significantly during pregnancy (P < 0.01); the Fibrobacter abundance increased significantly during lactation (P < 0.05); and rumen microbial carbohydrate metabolism, glucose biosynthesis, and metabolic functions were significantly enriched during pregnancy (P < 0.05). Microbial metabolic profile analysis showed that the differentially abundant microbial metabolites during pregnancy and lactation were mainly enriched in the biosynthesis of ubiquinone and other terpenoid quinones, and there was a certain correlation with the microbiota. Among them, sapindoside A was increased during pregnancy, nicotinamide riboside and β-cryptoxanthin were reduced during pregnancy, and L-tryptophan was significantly increased during lactation. In addition, the volatile fatty acid levels in lactation were significantly higher than those in non-pregnancy and pregnancy (P < 0.05), and the NH3-N content during pregnancy was significantly higher than that during lactation and non-pregnancy (P < 0.05). Moreover, there were differences in the serum metabolite levels at different reproductive stages, and similar metabolites existed when comparing the rumen metabolites, which were mainly enriched in arachidonic acid metabolism, vitamin B6 metabolism, and ABC transporter protein, resulting in significantly higher serum IgA and IgM levels during lactation than during non-pregnancy and pregnancy (P < 0.05).Item Whole-genome resequencing of the native sheep provides insights into the microevolution and identifies genes associated with reproduction traits(BioMed Central Ltd, 2023-07-11) Zhu M; Yang Y; Yang H; Zhao Z; Zhang H; Blair HT; Zheng W; Wang M; Fang C; Yu Q; Zhou H; Qi HBACKGROUND: Sheep genomes undergo numerous genes losses, gains and mutation that generates genome variability among breeds of the same species after long time natural and artificial selection. However, the microevolution of native sheep in northwest China remains elusive. Our aim was to compare the genomes and relevant reproductive traits of four sheep breeds from different climatic environments, to unveil the selection challenges that this species cope with, and the microevolutionary differences in sheep genomes. Here, we resequenced the genomes of 4 representative sheep breeds in northwest China, including Kazakh sheep and Duolang sheep of native breeds, and Hu sheep and Suffolk sheep of exotic breeds with different reproductive characteristics. RESULTS: We found that these four breeds had a similar expansion experience from ~ 10,000 to 1,000,000 years ago. In the past 10,000 years, the selection intensity of the four breeds was inconsistent, resulting in differences in reproductive traits. We explored the sheep variome and selection signatures by FST and θπ. The genomic regions containing genes associated with different reproductive traits that may be potential targets for breeding and selection were detected. Furthermore, non-synonymous mutations in a set of plausible candidate genes and significant differences in their allele frequency distributions across breeds with different reproductive characteristics were found. We identified PAK1, CYP19A1 and PER1 as a likely causal gene for seasonal reproduction in native sheep through qPCR, Western blot and ELISA analyses. Also, the haplotype frequencies of 3 tested gene regions related to reproduction were significantly different among four sheep breeds. CONCLUSIONS: Our results provide insights into the microevolution of native sheep and valuable genomic information for identifying genes associated with important reproductive traits in sheep.Item Late-gestation heat stress impairs daughter and granddaughter lifetime performance(Elsevier Inc on behalf of the American Dairy Science Association, 2020-08) Laporta J; Ferreira FC; Ouellet V; Dado-Senn B; Almeida AK; De Vries A; Dahl GERecords of late-gestation heat stress studies conducted over 10 consecutive years in Florida were pooled and analyzed to test the hypothesis that maternal hyperthermia during late gestation impairs performance of the offspring across multiple generations and lactations, ultimately impeding the profitability of the US dairy sector. Dry-pregnant multiparous dams were actively cooled (CL; shade of a freestall barn, fans and water soakers, n = 196) or not (HT; shade only, n = 198) during the last 46 d of gestation, concurrent with the entire dry period. After data mining, records of 156 daughters (F1) that were born either to CL (CLF1, n = 77) or HT dams (HTF1, n = 79) and 45 granddaughters (F2) that were born either to CLF1 (CLF2, n = 24) or HTF1 (HTF2, n = 21) were used in the analysis. Life events and daily milk yield for 3 lactations of daughters and granddaughters were obtained. Milk yield, reproductive performance, and productive life data were analyzed using MIXED and GLIMMIX procedures, and lifespan was analyzed using PHREG and LIFETEST procedures of SAS (SAS Institute Inc., Cary, NC). Milk production of HTF1 was reduced in their first (2.2 kg/d), second (2.3 kg/d), and third lactations (6.5 kg/d) compared with CLF1. More HTF1 were culled before first calving, and the productive life and lifespan of HTF1 were reduced relative to CLF1 (4.9 and 11.7 mo, respectively). The granddaughters (HTF2) born to HTF1 produced less milk in their first lactation (1.3 kg/d) relative to granddaughters (CLF2) born to CLF1. More HTF2 were culled before first breeding relative to CLF2; however, productive life and lifespan were not different between HTF2 and CLF2 animals. An economic analysis was then performed based on the number of heat stress days, dry cows per state, and the aforementioned impairments on daughters' lifespans and milk production. Collectively in the United States, the economic losses for additional heifer rearing cost, reduced productive life, and reduced milk yield of the F1 offspring were estimated at $134, $90, and $371 million per year, respectively. In summary, late-gestation heat stress exerts carryover effects on at least 2 generations. Providing heat abatement to dry-pregnant dams is important to rescue milk loss of the dam and to prevent losses in their progeny.Item Reproductive plasticity in response to the changing cluster size during the breeding period: a case study in a spider mite(Springer Nature, 2023-10) Weerawansha N; Wang Q; He XZAnimals living in clusters should adjust their reproductive strategies to adapt to the social environment. Theories predict that the benefits of cluster living would outweigh the costs of competition. Yet, it is largely unknown how animals optimize their reproductive fitness in response to the changing social environment during their breeding period. We used Tetranychus ludeni Zacher, a haplodiploid spider mite, to investigate how the ovipositing females modified their life-history traits in response to the change of cluster size (i.e., aggregation and dispersal) with a consistent population density (1 ♀/cm2). We demonstrate that (1) after females were shifted from a large cluster (16 ♀♀) to small ones (1 ♀, 5 and 10 ♀♀), they laid fewer and larger eggs with a higher female-biased sex ratio; (2) after females were shifted from small clusters to a large one, they laid fewer and smaller eggs, also with a higher female-biased sex ratio, and (3) increasing egg size significantly increased offspring sex ratio (% daughters), but did not increase immature survival. The results suggest that (1) females fertilize more larger eggs laid in a small population but lower the fertilization threshold and fertilize smaller eggs in a larger population, and (2) the reproductive adjustments in terms of egg number and size may contribute more to minimize the mate competition among sons but not to increase the number of inhabitants in the next generation. The current study provides evidence that spider mites can manipulate their reproductive output and adjust offspring sex ratio in response to dynamic social environments.Item Genetic and phenotypic relationships between ewe reproductive performance and wool and growth traits in Uruguayan Ultrafine Merino sheep.(Oxford University Press on behalf of the American Society of Animal Science, 2023-03-07) Ramos Z; Garrick DJ; Blair HT; De Barbieri I; Ciappesoni G; Montossi F; Kenyon PRThis study reports genetic parameters for yearling and adult wool and growth traits, and ewe reproductive performance. Data were sourced from an Uruguayan Merino flock involved in a long-term selection program focused on reduced fiber diameter (FD), and increased clean fleece weight (CFW) and live weight (LW). Pedigree and performance data from approximately 5,700 mixed-sex yearling lambs and 2,000 mixed-age ewes born between 1999 and 2019 were analyzed. The number of records ranged from 1,267 to 5,738 for yearling traits, and from 1,931 to 7,079 for ewe productive and reproductive performance. Data on yearling and adult wool traits, LW and body condition score (BCS), yearling eye muscle area (Y_EMA), and fat thickness (Y_FAT), and several reproduction traits were analyzed. The genetic relationships between FD and reproduction traits were not different from zero. Moderate unfavorable genetic correlations were found between adult CFW and ewe lifetime reproduction traits (-0.34 ± 0.08 and -0.33 ± 0.09 for the total number of lambs weaned and total lamb LW at weaning, respectively). There were moderate to strong positive genetic correlations between yearling LW and all reproduction traits other than ewe-rearing ability (-0.08 ± 0.11) and pregnancy rate (0.18 ± 0.08). The genetic correlations between Y_EMA and reproduction traits were positive and ranged from 0.15 to 0.49. Moderate unfavorable genetic correlations were observed between yearling FD and Y_FAT and between adult FD and BCS at mating (0.31 ± 0.12 and 0.23 ± 0.07, respectively). The genetic correlations between adult fleece weight and ewe BCS at different stages of the cycle were negative, but generally not different from zero. This study shows that selection for reduced FD is unlikely to have any effect on reproduction traits. Selection for increased yearling LW and Y_EMA will improve ewe reproductive performance. On the other hand, selection for increased adult CFW will reduce ewe reproductive performance, whereas selection for reduced FD will negatively impact body fat levels. Although unfavorable genetic relationships between wool traits and both FAT and ewe reproductive performance existed, simultaneous improvements in the traits would occur using appropriately designed indexes.Item Diets for Tamarixia triozae adults before releasing in augmentative biological control(Springer Nature, Switzerland AG for International Organization for Biological Control, 2022-06) Chen C; He XZ; Zhou P; Wang Q; Riddick EThe effectiveness of augmentative biological control using parasitoids often depends on their physiological state and the pest population density at the time of release. Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) is a primary host-feeding parasitoid of a serious invasive pest Bactericera cockerelli (Šulc) (Hemiptera: Triozidae). Here we investigated the effects of adult diets (honey, water, yeast, and hosts) and timing of their provision on T. triozae fitness and oviposition patterns, providing knowledge for enhancement of its biological control potential. Adults fed with honey for four days with no access to hosts or with water or yeast for one day followed by host feeding for three days had similar longevity and lifetime pest killing ability. Adults fed with only water for one day before release had significantly greater intrinsic rate of increase, shorter doubling time, and higher daily fecundity peak. Adults fed with honey or yeast for one day followed by host feeding for three days significantly flattened their daily oviposition curves. These findings have several implications for augmentative biological control using T. triozae. First, honey diet may allow at least four days for successful shipment of host-deprived adults without compromising biological control effectiveness. Second, the release of host-deprived adults with one-day water feeding may achieve rapid pest suppression when the pest population density is high. Finally, releasing host-deprived adults with one-day honey or yeast feeding followed by three-day host feeding can increase their establishment success and reduce the risk of massive removal of hosts when the pest population density is low.Item Development of LIME-NZ: a generic tool for prompt estimation of economic impacts of disease for New Zealand livestock.(Taylor and Francis Group, 2024-02-04) Wada M; Compton C; Hickson R; Bingham PAIMS: To develop a simple and robust generic tool to measure the impacts of livestock diseases on New Zealand dairy, beef and sheep farms using enterprise gross margin models. METHODS: The most recent (2018-2020) livestock production benchmarking data was extracted from industry-led economic surveys. Gross margin models were built for each enterprise type, accounting for 11 dairy farm types and 16 farm types for beef and sheep. Disease parameters, including changes in mortality, reproduction performance, milk yield, price of animals and culling rate, as well as additional expenses for veterinary intervention, were applied to the infected compartment of the herd/flock using the assumed annual within-herd disease incidence. Farm-level disease impacts were estimated as the difference in annual profit between the baseline and infected farm. The baseline gross margin models were validated against the industry data. The disease impact models were validated using a recently published study on bovine viral diarrhoea (BVD). The impact assessment tool, LIME-NZ, was developed using the statistical software R and implemented in the web-based R package Shiny. The input parameters can be varied interactively to obtain a range of disease impacts for uncertain disease parameters. RESULTS: The baseline gross margin models demonstrated reasonable accuracy with a mean percentage error of <14% when compared with the industry reports. The estimated annual impacts of BVD were comparable to those reported in the BVD study, NZ$38.5-140.4 thousand and $0.9-32.6 thousand per farm per year for dairy and beef enterprises, respectively. CONCLUSIONS: LIME-NZ can be used to rapidly obtain the likely economic impacts of diseases that are endemic, recently introduced or at increased risk of introduction in the New Zealand context. This will aid communication and decision-making among government agencies and the livestock industry, including veterinarians and livestock producers, about the management of diseases, until refined information becomes available to improve decision-making.Item Identification of risk factors for ewe mortality during the pregnancy and lambing period in extensively managed flocks(BioMed Central Ltd, 2023-12-06) Flay KJ; Chen AS; Yang DA; Kenyon PR; Ridler ALBACKGROUND: Ewe mortality during pregnancy and lambing is an issue for sheep producers globally, resulting in reduced productivity and profitability, compromised ewe welfare, and poor consumer perception. Despite these negative consequences, there was little investigation into factors associated with ewe death during this time. Therefore, this study aimed to assess associations between ewe body condition score (BCS), weight, reproductive parameters, and risk of mortality during pregnancy and lambing. METHODS: Four cohorts from three commercial New Zealand farms participated, with 13,142 ewe lambs enrolled and followed over time. Data were collected for five consecutive lambings. Visits aligned with key on-farm management times, specifically: prior to breeding, at pregnancy diagnosis (PD), prior to lambing (set-stocking), and, at weaning of their lambs. At each visit, ewes were weighed, BCS assessed and reproductive status was recorded when relevant (litter size at PD and lactation status after lambing). Ewes that died or were culled were recorded, and any ewes that were absent from consecutive visits were presumed dead. Logistic regressions were developed to assess the relationship between weight and BCS at each visit, PD result (single or multiple-bearing) and lactation status (wet or dry) in each year, and, risk of mortality during the pregnancy and lambing period in each year. RESULTS: In the PD to weaning period, mortality incidence ranged from 6.3 to 6.9% for two-tooth (18-months-old at breeding) to mixed-age (54-months-old at breeding) ewes. For ewe lambs (7 to 8-months-old at breeding), mortality was 7.3% from set-stocking to weaning. Heavier ewe lambs at PD were less likely to die during lambing (OR: 0.978, p = 0.013), as were those with greater set-stocking BCS. In subsequent years, BCS was a predictor of ewe death, with odds of mortality greatest for ewes < BCS 2.5. Additionally, for poorer BCS ewes, increasing weight reduced risk of mortality, but there was no impact of increasing weight in greater BCS ewes. CONCLUSIONS: This study identified risk factors associated with ewe mortality during the pregnancy and lambing period. Flock owners can use these to either cull at-risk ewes or proactively intervene to reduce likelihood of mortality, thereby improving flock productivity, profitability and welfare.Item Reproductive biology of male common dolphins (Delphinus delphis) in New Zealand waters.(Springer Nature, 2023-10-06) Palmer EI; Betty EL; Murphy S; Perrott MR; Smith ANH; Stockin KA; Siebert UReproductive parameters were assessed in 64 male common dolphins (Delphinus delphis) examined post-mortem from strandings and bycatch in New Zealand between 1999 and 2020. The stages of male sexual maturation were assessed using morphological measurements and histological examination of testicular tissue. Age was determined via growth layer groups (GLGs) in teeth. The average age (ASM) and length (LSM) at attainment of sexual maturity were estimated to be 8.8 years and 198.3 cm, respectively. Individual variation in ASM (7.5–10 years) and LSM (190–220 cm) was observed in New Zealand common dolphins. However, on average, sexual maturity was attained at a similar length but at a marginally younger age (< 1 year) in New Zealand compared to populations in the Northern Hemisphere. All testicular variables proved better predictors of sexual maturity compared to demographic variables (age and total body length), with combined testes weight the best outright predictor of sexual maturity. Reproductive seasonality was observed in male common dolphins, with a significant increase in combined testes weight in austral summer. This aligns with most other studied populations, where seasonality in reproduction is typically observed. Given the known anthropogenic impacts on New Zealand common dolphins, we recommend that these findings be used as a baseline from which to monitor population-level changes as part of conservation management efforts.Item ‘Is it okay to have a child?’: figuring subjectivities and reproductive decisions in response to climate change(Springer Nature, 2023-10-27) Meynell L; Morgan M; Van Ommen CIn this article, we engage feminist theorisations of figurations as “performative images that can be inhabited” (Haraway 1997/2018) to trace some of the figures which are animating stories about climate change and reproduction in Global North contexts. We focus our reading on a handful of texts which circulate around the question of ‘Is it okay to have a child, given our climate conditions and futures?’ Throughout, we consider the relationship between figurations and our subjective becomings in response to environmental devastations. We critique and resist the hegemonic figuring of ‘the human subject’ as rational and unitary (Braidotti 2014), as this figure naturalises the Western social power relations of advanced capitalism, population control and human exceptionalism. Seeking multiplicity, we look for figures and subjective openings which enable us to become response-able to the pain of ecological worlds dying around us (Haraway 2016), including from our disciplinary location of psychology.
- «
- 1 (current)
- 2
- 3
- »