Project description:Suboptimal reproductive performance of maiden (primiparous) ewes remains a source of inefficiency for the Australian sheep industry. However, the extent and causes of the poorer reproductive performance of maiden ewes on Australian sheep farms are not well understood. Here, we show the reproductive performance of maiden ewes relative to their multiparous counterparts on the same farms across Australia using a cohort survey. The difference in marking rate for non-Merino maiden ewe lambs compared to multiparous ewes was 58% (74 vs. 132%; p < 0.001), and this was attributable to a 50% difference in reproductive rate (109 vs. 159%; p < 0.001) and 16% difference in lamb survival to marking (67 vs. 83%; p < 0.001). The difference in marking rate for maiden Merino two-tooth ewes lambing at approximately 2 years-of-age compared to mature multiparous ewes was 22% (80 vs. 102%; p < 0.001) and this was attributable to a 24% difference in reproductive rate (108 vs. 132%; p < 0.001) and 3% difference for lamb survival (75 vs. 78%; p < 0.05). Positive correlations for reproduction traits (reproductive rate, lamb survival and marking rate) between maidens and multiparous ewes were observed for maiden Merino two-tooth ewes (p < 0.001), but these correlations were weak or non-existent for non-Merino ewe lambs. Strategies to improve both reproductive rate and lamb survival can address the poorer and more variable reproductive performance of maiden ewes.
Project description:Milk oligosaccharides (MOs) are complex carbohydrates with multifunctional health benefits for the neonate. Poor reproductive performance in primiparous gilts limits their productivity. Changes in the structure and abundance of porcine MO (PMOs) through lactation with parity remains unknown and may explain superior new-born growth in litters from multiparous sows relative to gilts. We report 55 PMOs structures, of which 25 are new (17 sialylated and 8 neutral). Their incidence in gilt and sow colostrum was almost identical (53 vs. 54), but not in transitional milk (48 vs. 53) nor mature milk (41 vs. 47). These PMOs including neutral-, sialyl- and fucosyl- MOs in colostrum were more abundant in the gilt than the sow, but always decreased during lactation. Structural diversity decreased, although fucosylated MO were conserved. In conclusion, high diversity and levels of MO in porcine milk is parity dependent. Given the similarity between porcine and human MO profiles, our findings may help define key roles for MOs as potential dietary additives to improve growth of neonates from first pregnancies in both human and sows.
Project description:BackgroundToxoplasma gondii causes reproductive losses in sheep worldwide, including Australia. The reproductive performance of primiparous ewes is typically lower than for mature, multiparous ewes, and younger ewes are more likely to be immunologically naïve and therefore more susceptible to reproductive disease if T. gondii infection occurs during pregnancy. The aim of this study was to assess the impact of infection with T. gondii on the reproductive performance of primiparous ewes in southern Australia using a prospective cohort study. This will inform the need for targeted control strategies for T. gondii in Australian sheep.ResultsToxoplasma gondii seropositivity using indirect ELISA was detected at 16/28 farms located across southern Australia. Apparent seropositivity to T. gondii was lower in primiparous ewes (1.1, 95% confidence interval (CI) 0.6, 1.8) compared to mature, multiparous ewes (8.1, 95% CI 6.0, 10.5; P < 0.001). Toxoplasma gondii seroconversion during the gestation and lambing period was confirmed for 11/1097 (1.0, 95% CI 0.5, 1.7) of pregnant primiparous ewes that failed to raise a lamb, and 1/161 (0.6, 95% CI 0.1, 2.9) primiparous ewes with confirmed mid-pregnancy abortion.ConclusionsLow frequency of detection of T. gondii seroconversion during gestation and low frequency of seropositivity to T. gondii suggests that toxoplasmosis was not an important contributor to reproductive losses in primiparous ewes on farms located over a wide geographical area in southern Australia.
Project description:Colostrum is rich in membranous vesicles of endocytic origin named exosomes, with proteins, lipids, RNA, and/or DNA cargos which can play different roles in physiological processes. Like other colostrum bioactive compounds, exosomes could be also influenced by individual characteristics. The objective of the study was to characterize miRNA cargo of colostrum exosomes from primiparous and multiparous cows in different farms. Twenty-seven colostrum samples of clinically healthy Holstein cows (11 primiparous and 16 multiparous) from 3 different farms were obtained and frozen. After thawing, exosomes were isolated following an ultracentrifugation protocol, and characterized morphologically. Particle size distribution and western immunoblotting were also analyzMaed. After RNA extraction, miRNAs were sequenced and analyzed to assess potential differences in profiles between primiparous and multiparous cows from different farms. Fourteen miRNA were upregulated and 11 miRNAs downregulated in primiparous compared with multiparous cows. Most of the miRNA differences between primiparous and multiparous cows regulate the gene expression of factors involved in mammary gland development and differentiation, and lipogenesis. In addition, miRNAs from one of the farms showed 8 miRNAs downregulated and 12 upregulated compared with the other 2 farms, independently of parity. Differences in miRNA between farms were mainly associated with immune and inflammatory-related genes. In conclusion, miRNA cargos of bovine colostrum exosomes differ in primiparous and multiparous cows, and some on-farm practices might also determine the content and activity of miRNA in colostrum exosomes.
Project description:Across the literature, there is large variation in lamb birth weight responses to changes in the ewe pregnancy nutrition. Much of this heterogeneity has been attributed to several factors inherent to each experiment; however, the relative contribution of these experimental factors has not yet been quantified. This meta-analysis aimed to systematically review the variation in lamb birth weight responses across nutritional studies involving adult multiparous ewes. Effect-sizes for individual studies were estimated using the unbiased estimator Hedges' g, whereby positive and negative values indicate heavier and lighter treatment lambs vs. controls, respectively. Heterogeneity varied between early-, mid- and late-pregnancy undernutrition studies (I2total [early pregnancy] = 19.90%, I2total [midpregnancy] = 52.10%, I2total [late pregnancy] = 68.70%). The small average effects for early- (0.04, highest posterior density [HPD] interval = -0.22, 0.28) and mid-pregnancy undernutrition (-0.15, HPD interval = -0.35, 0.05) suggest that if farmers anticipate a potential feed shortage, ewes can be allowed to lose weight providing nutrition is resumed to adequate levels later in pregnancy. On the contrary, late-pregnancy undernutrition was associated with a significant decrease in lamb birth weight (-0.72, HPD interval = -0.86, -0.55). Thus, management practices should focus on ensuring adequate nutrition in late pregnancy. Increasing lamb birth weight could be possible by feeding ewes above their pregnancy maintenance requirement (0.23, HPD interval = 0.002, 0.48), though the number of studies is limited and further research is needed.
Project description:BackgroundPrevious studies have identified many immune pathways which are consistently altered in humans and model organisms as they age. Dairy cows are often culled at quite young ages due to an inability to cope adequately with metabolic and infectious diseases, resulting in reduced milk production and infertility. Improved longevity is therefore a desirable trait which would benefit both farmers and their cows. This study analysed the transcriptome derived from RNA-seq data of leukocytes obtained from Holstein cows in early lactation with respect to lactation number.ResultsSamples were divided into three lactation groups for analysis: i) primiparous (PP, n = 53), ii) multiparous in lactations 2-3 (MP 2-3, n = 121), and iii) MP in lactations 4-7 (MP > 3, n = 55). Leukocyte expression was compared between PP vs MP > 3 cows with MP 2-3 as background using DESeq2 followed by weighted gene co-expression network analysis (WGCNA). Seven modules were significantly correlated (r ≥ 0.25) to the trait lactation number. Genes from the modules which were more highly expressed in either the PP or MP > 3 cows were pooled, and the gene lists subjected to David functional annotation cluster analysis. The top three clusters from modules more highly expressed in the PP cows all involved regulation of gene transcription, particularly zinc fingers. Another cluster included genes encoding enzymes in the mitochondrial beta-oxidation pathway. Top clusters up-regulated in MP > 3 cows included the terms Glycolysis/Gluconeogenesis, C-type lectin, and Immunity. Differentially expressed candidate genes for ageing previously identified in the human blood transcriptome up-regulated in PP cows were mainly associated with T-cell function (CCR7, CD27, IL7R, CAMK4, CD28), mitochondrial ribosomal proteins (MRPS27, MRPS9, MRPS31), and DNA replication and repair (WRN). Those up-regulated in MP > 3 cows encoded immune defence proteins (LYZ, CTSZ, SREBF1, GRN, ANXA5, ADARB1).ConclusionsGenes and pathways associated with lactation number in cows were identified for the first time to date, and we found that many were comparable to those known to be associated with ageing in humans and model organisms. We also detected changes in energy utilization and immune responses in leukocytes from older cows.
Project description:The present experiment was carried out to analyze the longitudinal changes in milk microorganisms. For this purpose, milk samples were collected from 12 healthy cows (n = 96; six primiparous cows and six multiparous cows) at eight different time points. The characteristics and variations in microbial composition were analyzed by 16S rRNA gene high-throughput sequencing. In the primiparous group, higher and more stable alpha diversity was observed in transitional and mature milk compared with the colostrum, with no significant difference in alpha diversity at each time point in the multiparous group. Proteobacteria, Firmicutes, Bacteroidota, and Actinobacteriota were the most dominant phyla, and Pseudomonas, UCG-005, Acinetobacter, Vibrio, Lactobacillus, Bacteroides, Serratia, Staphylococcus, and Glutamicibacter were the most dominant genera in both primiparous and multiparous cow milk. Some typically gut-associated microbes, such as Bacteroides, UCG-005, and Rikenellaceae_RC9_gut_group, etc., were enriched in the two groups. Biomarker taxa with the day in time (DIM) were identified by a random forest algorithm, with Staphylococcus showing the highest degree of interpretation, and the difference in milk microbiota between the two groups was mainly reflected in 0 d-15 d. Additionally, network analysis suggested that there were bacteria associated with the total protein content in milk. Collectively, our results disclosed the longitudinal changes in the milk microbiota of primiparous and multiparous cows, providing further evidence in dairy microbiology.
Project description:There is evidence that the Baby-Friendly Hospital Initiative (BFHI) results in improved breastfeeding outcomes in Western countries, but little is known of its impact in Middle-Eastern countries. This study investigated the impact of BFHI practices on duration of full breastfeeding in a cohort of 700 Iranian mothers recruited between June 2014 and March 2015 from maternity hospitals in Shiraz and followed-up prospectively for 6 months. At baseline, mothers self-reported exposure to 7 of the BFHI Ten Steps to Successful Breastfeeding (Steps 3 to 9). Data on breastfeeding outcomes were collected at baseline, 1, 3, 4, and 6 months postpartum. Cox regression analysis was conducted to determine the impact of individual and cumulative BFHI Steps on the duration of full breastfeeding, defined as the number of weeks since discharge that an infant received only breast milk and no complementary formula or food. Mothers reported experiencing on average 3.9 (SD 1.13, range 1 to 7) Steps, and only 28% of infants were fully breastfed at 6 months. There was a protective inverse relationship for primiparous (p for trend = .022) but not multiparous mothers (p for trend = .069), between the number of Steps a woman was exposed to and the likelihood of her discontinuing full breastfeeding within 6 months postpartum. Greater exposure to BFHI practices potentially could increase primiparous mothers' chances of fully breastfeeding to 6 months. Continual monitoring of the BFHI Steps and repeated education of healthcare staff are required to ensure that Iranian mothers receive adequate breastfeeding support.
Project description:Reducing dietary CP concentration can reduce feeding costs and N excretion in dairy production but may negatively impact productivity and efficiency. This study investigated the impact of reduced dietary CP concentration, across early, mid- and late-lactation stages in primiparous and multiparous lactating cows, on productivity, feed and energy use efficiency and CH4 emission parameters. Twenty-four Holstein-Friesian (12 primiparous, 12 multiparous) cows were allocated to three experimental total mixed rations containing 12.2, 15.1 or 18.1% CP (LCP, MCP and HCP, respectively; DM basis), in a continuous study across lactation (days 1-305). Digestibility and gas exchanges were measured in metabolism units and indirect open-circuit respiration calorimeter chambers during early, mid- and late-lactation. Data were analysed using a linear mixed model, with repeated measures, with CP concentration, stage of lactation, parity and their interactions as fixed effects, and a random effect of cow fitted as the subject and stage of lactation as the repeated measure. When compared with LCP treatment, MCP and HCP had higher DM intake (DMI) (+1.9 and +3.0 kg/d), milk yield (+5.5 and +7.7 kg/d), energy corrected milk yield (ECMY) (+5.0 and +7.1 kg/d), and feed efficiency (ECMY/DMI, +0.13 and +0.15 kg/kg; milk solids/DMI, +16 and +20 g/kg; milk energy output (EL)/DMI, +0.40 and 0.46 MJ/kg). Digestible energy intake (DEI)/gross energy intake (GEI), metabolisable energy intake (MEI)/GEI, MEI/DEI and milk energy output adjusted for zero energy balance (EL(0))/MEI were higher in HCP (+0.02, +0.03, +0.02, and +0.06 MJ/MJ) than LCP while there were no differences between LCP and MCP for DEI/GEI, or between MCP and HCP for MEI/DEI and EL(0)/MEI. Methane production per digestible DMI and ECMY were lower for MCP (-3.2 and -3.1 g/kg) and HCP (-3.8 and -3.4 g/kg), when compared with LCP. Methane energy per GEI, DEI and MEI were lower for the MCP (-0.007, -0.011 and -0.014 MJ/MJ) and HCP (-0.007, -0.014 and -0.017 MJ/MJ) than LCP. The significant interaction between CP concentration and stage of lactation on milk yield and ECMY showed that treatment differences (increased values in MCP or HCP vs LCP diets) reduced as lactation progressed. A diet containing 15.1% CP (DM basis) may be sufficient to maintain milk production and feed efficiency while reducing CH4 yield and intensity. However, regression analysis suggests that productivity may increase further between 15 and 18% CP (DM basis) but the response to dietary CP may depend on the stage of lactation.