Reproductive Performance Research Articles

Effects of dietary digestible lysine levels in breeding Japanese quails on productive and reproductive performance, egg quality, blood metabolites and immune responses.

The vegetable-based diet alone does not provide the lysine (Lys) needed to maximize poultry productive performance. This experiment aimed to evaluate the effects of dietary digestible Lys (dLys) level on productive and reproductive performance, egg quality, blood metabolites and immune responses in breeding Japanese quails (Coturnix japonica). The experiment was conducted in a completely randomized design with 6 treatments, 5 replicates and 15 (12 females and 3 meals) 10-week-old breeding Japanese quails each. A basal diet was formulated to meet nutritional requirements of breeding quails except dLys. The basal diet was supplemented with graded (+0.82g/kg) levels of l-Lys-HCl, corresponding to dietary dLys levels of 0.690%, 0.755%, 0.820%, 0.885%, 0.950% and 1.015%. The experiment lasted for 12 weeks, which was divided into 3-4-week periods. Significant differences were observed for egg production (EP), egg mass (EM) and feed efficiency (FE) in response to increasing dietary dLys concentration with quadratic trends. The highest traits were observed in the birds fed with a diet containing 0.885% dLys. However, feed intake, egg quality, reproductive performance, blood metabolites and immune responses against sheep red blood cell inoculation were not significantly affected by increasing dietary dLys concentrations. The dLys requirements during 11-14, 15-18, 19-22 and 11-22 (overall) weeks of age for optimal EP, EM and FE, based on the quadratic broken-line regression analysis, were estimated 272, 265, 250 and 266; 293, 285, 264 and 279; and 303, 294, 281 and 293mg/bird/day, respectively. The dLys requirements vary depending on the EP phase and the trait being optimized. The estimated dLys requirement for FE was higher than those for EP and EM. During the peak stage of the first laying cycle, the dietary dLys level of 0.932% and a daily intake of 303mg dLys/bird are sufficient for optimal performance.

Predictive Models for the Implementation of Targeted Reproductive Management in Multiparous Cows on Automatic Milking Systems

Targeted reproductive management (TRM) aims to improve the fertility efficiency of the dairy herd by applying group-level management strategies based on expected reproductive performance. Key to the utility of TRM is the accuracy with which an animal's reproductive performance can be predicted. Automatic milking systems (AMS) allow for the collection of data relating to milk quantity, quality, and robot visit behavior throughout the transition period. In addition to this, auxiliary data sources such as rumination and activity monitors, as well as historical cow-level data are often readily available. The utility of this data for the prediction of fertility has not been previously explored. The objective of this study was first, to assess the accuracy with which the likelihood of expression of oestrus between 22 and 65 d in milk (DIM) and conception to first insemination between 22 and 80 DIM could be predicted using data collected by AMS from 1 to 21 DIM. Our second objective was to assess the change in model performance following the addition of 2 auxiliary data sources. Using data derived solely from the AMS (RBT data set) a binary random forest classification model was constructed for both outcomes of interest. The performance of these models was compared with models constructed using AMS data in conjunction with 2 auxiliary sources (RBT+ data set). Expression of oestrus was classified with an area under the receiver operator curve (AUC-ROC) of 0.6 and 0.65, conception to first insemination with an AUC-ROC of 0.56 and 0.62 for the RBT and RBT+ data sets respectively. No statistically significant improvement in classification accuracy was achieved by the addition of auxiliary data sources. This is the first study to report the utility of data collected by AMS for the prediction of reproductive performance. Though the performance described is comparable with previously reported models, their utility for the implementation of TRM is limited by poor classification accuracy within key sub-groups. Of note within this study is the failure of the addition of auxiliary data sources to increase the accuracy of prediction over models built using AMS data alone. We discuss the advantages and limitations the integration of additional data sources imposes on model training and deployment and suggest alternative methods to improve performance while preserving model parsimony.

Investigating the Significance of the Transgenerational Impact of High and Repeated Doses of Ivermectin: Effects on Paternal Testis Histopathology, Pups' Development, and Sexual Behavior

Paternal exposure to environmental challenges is critical for the offspring's future health, and the transmission of acquired traits through generations increases the risk of offspring developing diseases. Ivermectin (IVM) is widely used in veterinary and human medicine to treat parasitosis. Our previous studies showed that IVM acute administration induced disorganization of the germinal epithelium and could cause damage to sperm production. Thus, this study investigated the effects of paternal exposure to repeated high ivermectin doses on paternal testis histology. After mating, their pups' development and sexual behavior in adult rats were examined. Method: Two groups of male rats were treated with IVM or its vehicle once a week for three weeks. We observed these males' body weight, organs and testis histology, and testosterone levels. These rats were mated with females without any treatment: the reproductive performance, the offspring development, and the male and female sexual behavior observed in adulthood. Relative to controls, the IVM paternal testis histology showed hypertrophy and hyperplasia of Leydig cells and increased diameter of the seminiferous tubules—no impairment in reproductive performance. In males and females, the physical and reflexes were modified. In adult age, female rats of the IVM group showed reduced sexual behavior and sexual preferences for the same sex, while male sexual behavior was not altered. Thus, it is possible that paternal exposure to IVM interfered with pups' hormonal and growth factors during development and in adult age. Further studies are needed to explore IVM transgenerational effects identifying possible mechanisms underpinning behavioral effects.

Impact of comb type on production performance, egg production quality, reproductive performance, and blood biochemical indexes in Tianfu chickens

Impact of comb type on production performance, egg production quality, reproductive performance, and blood biochemical indexes in Tianfu chickens

The Beneficial Application of Turmeric (Curcuma longa L.) on Health and Egg Production, in Layers: A Review.

Turmeric (Curcuma longa L.) is a widely recognized spice and medicinal plant that has gained significant attention for its potential health benefits. This review aims to provide a comprehensive overview of the beneficial applications of turmeric in improving health and egg production in layers. The objective of this review is to assess the current scientific literature on the effects of turmeric supplementation in layer diets and evaluate its impact on layer health and egg production. A systematic search was conducted in Google Scholar database to identify relevant studies published in peer-reviewed journals. Studies investigating the effects of turmeric or its bioactive compound curcumin on layer health and egg production were included. Data on various parameters, including immune function, reproductive performance, egg quality and production parameters, were extracted and analysed. Turmeric contains a bioactive compound called curcumin, which possesses antioxidant, anti-inflammatory, antimicrobial and immunomodulatory effects. These properties have been extensively studied and have shown promising results in enhancing layer health and performance. Turmeric supplementation has been reported to improve the overall immune response in layers, reducing the incidence and severity of infectious diseases. It has also been shown to have positive effects on gut health by modulating the gut microbiota composition, improving nutrient absorption and reducing digestive disorders. Furthermore, studies have demonstrated that turmeric supplementation in layer diets can improve egg weight, shell quality, yolk colour and egg production rates. The mechanisms underlying these effects involve the antioxidant properties of turmeric, which protect the reproductive organs, enhance ovarian function and improve reproductive performance. The findings underscore the potential of turmeric as a natural, cost-effective and sustainable intervention for improving layer well-being, egg quality and productivity. However, further research is needed to fully understand the mechanisms of action, optimize dosage regimens and evaluate the long-term effects of turmeric supplementation in layer diets.

Seroprevalence and Associated Risk Factors of Infectious Bovine Rhinotracheitis (IBR) and Animal Owners' Knowledge, Attitude and Practice (KAP) Towards the Disease in Selected Districts of East Wollega Zone, Oromia Regional State, Ethiopia.

Infectious bovine rhinotracheitis (IBR) is one of the most important diseases affecting production and productivity. Cross-sectional study was aimed at to determine the seroprevalence of IBR and associated risk factors, and animal owners' knowledge, attitude and practice towards the disease from April 2021 to June 2022. Accordingly, a total of 384 serum samples were collected from both crossbreed (70) and local breed (314) cattle from purposively selected districts of East Wollega zone of Western Ethiopia. Competitive enzyme-linked immunosorbent assay (ELISA) was used for testing glycoprotein antibodies (anti-gB) for bovine herpes virus-1 (BoHV-1) virus in collected serum, and the obtained data were analysed by multiple logistic regressions by using R software 3.62 version. However, questionnaire data were analysed for descriptive statistics by SPSS version 20.0 (IBM. Corp, 2011). The total prevalence of IBR in the study area was found to be 70.54% at herd and 80.47% at individual cattle level. The significant association (p ) was found for breed, age, body condition and herd size but not for district and sex as risk factors. The BoHV-1 virus seropositivity in adult animals increased significantly, with an odds ratio of 1.65 (95% CI 0.705-3.85) compared to young. Local breed cattle were 2.055 times more likely to test positive for IBR with an odds ratio of 0.77 (95% CI 0.23-2.22) compared to crossbreed cattle. The chances of cattle in medium herds testing positive for the BoHV-1 virus with an odds ratio of (1.78 95% CI 1.303-7.50) are greater than the chances of cattle in smaller herds testing positive. The survey results showed that 70% of animal owners identified IBR as a major challenge in animal production, whereas 35% mentioned long calving intervals. However, 92% of the participants were not informed about the level of knowledge and attitude regarding particular diseases such as IBR. This study showed that there is a high prevalence of IBR in cattle in the study area, and that owners have low awareness of the disease. Therefore, it is necessary to develop an immediate control system and conduct additional research on molecular detection to evaluate its effects on reproductive performance.

The bta-miR-22-3p can alleviate LPS-induced inflammatory response in yak endometrial epithelial cells by targeting KSR2

Bovine endometritis is a common reproductive system disease in dairy cows that leads to decreased milk production and reproductive performance, causing significant economic losses for farmers. Research has shown that microRNAs (miRNAs) play a significant role in regulating the expression of biological genes and are closely related to the occurrence of inflammation, including bta-miR-22-3p. However, the specific molecular mechanisms by which miRNAs regulate bovine endometritis remain unclear. To investigate the regulatory mechanism of bta-miR-22-3p in yak endometritis, uterine tissues were collected from three healthy bos grunniens and three bos grunniens with endometritis, approximately 21 days postpartum. Various methods were employed, including real-time quantitative polymerase chain reaction (RT-qPCR), Western blot (WB), enzyme-linked immunosorbent assay (ELISA), and immunofluorescence (IF). The results demonstrated that overexpression of bta-miR-22-3p led to a significant decrease (P<0.05) in factors related to the mitogen-activated protein kinase (MAPK) signaling pathway and associated inflammatory factors, such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (P38), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β). Furthermore, dual-luciferase assays confirmed that the kinase suppressor of the Ras 2 (KSR2) gene is a downstream target of bta-miR-22-3p. Overexpression of bta-miR-22-3p inhibited the expression of KSR2. When KSR2 was inhibited, the levels of MAPK signaling pathway-related factors and inflammation also significantly decreased(P<0.05). Thus, bta-miR-22-3p suppresses the activation of the MAPK signaling pathway through the inhibition of KSR2, resulting in a reduction of inflammatory factors. In conclusion, this study demonstrated that bta-miR-22-3p targets the KSR2 gene to alleviate LPS (Lipopolysaccharide)-induced inflammatory damage.

Evaluation of safety and biomedical potential of water-soluble oat lignin Avena sativa L.

The study of the value of lignin for biomedical use is generating growing interest. For the first time, the safety and biological efficacy of lignin from the stems of the oat Avena sativa L. were studied, necessary for a preliminary assessment of its biomedical potential, have been studied. In vitro experiments, a sample of oat lignin exhibited cytotoxicity to the HeLa, A549, and HT-29 cancer cell lines, depending on the concentration. At maximum concentrations 125 and 150 μg/ml, it reduced their survival and increased the level of reactive oxygen species. In vivo experiments, a sample of oat lignin, with acute (from 5 to 250 mg/kg body weight) and chronic (300, 1200 and 2000 mg/kg body weight) administration, did not have a toxic or genotoxic effect on the organs of mice. The biological efficacy of the oat lignin was manifested in activation of repair processes in bone marrow and thyroid gland, a decrease in the level of abnormal spermatozoa in males, stimulation of reproductive performance of females and in increase in research activity and a decrease in the level of anxiety in animals. The results indicate the prospects for further study of the medical and biological potential lignin of the oat.

Supplementing the Beltsville Extender With Mitoquinol Improves the Quality and Fertility Potential of the Rooster's Cooled Sperm.

Supplementing freeze diluents with certain antioxidants can maintain the quality of chilled sperm. The present study was an attempt to investigate the effect of Beltsville extender supplementation with the mitochondrial-targeted antioxidant 'Mitoquinol' on the quality parameters and fertility potential of rooster sperm during the cooling process. Semen samples were diluted in Beltsville extender, divided into five groups, and supplemented with 0, 1, 10, 100 and 1000 nM Mitoquinol. Samples were stored at 5°C for up to 50 h and then assayed for sperm motility, viability, mitochondrial function, membrane integrity and malondialdehyde concentration after 0, 25 and 50 h of cooling. To assess reproductive performance, artificial insemination was performed using sperm cooled for 25 h. The results showed no differences between groups at the beginning time. Extender supplementation with 10 and 100 nM Mitoquinol resulted in an improvement in total motility, progressive motility, membrane integrity, mitochondrial function and viability (p ≤ 0.05), as well as a lower malondialdehyde concentration (p ≤ 0.05) in comparison to the other groups during 25 and 50 h storage. Fertility rates were higher when roosters were inseminated with semen samples supplemented with 10 and 100 nM Mitoquinol, compared to the control group. Therefore, supplementing Beltsville extender with Mitoquinol (10 and 100 nM) effective in improving the quality and fertility potential of cooled rooster sperm.

Maternal Supplementation Spermidine During Gestation Improves Placental Angiogenesis and Reproductive Performance of High Prolific Sows.

Spermidine (SPD) is a widely recognized polyamine compound found in mammalian cells and plays a key role in various cellular processes. We propose that SPD may enhance placental vascular development in pregnant sows, leading to increased birth weight of piglets. Six hundred and nine sows at 60 days of gestation were randomly assigned into a basal diet (CON group), basal diet supplemented 10 mg/kg of SPD (SPD1 group), and basal diet supplemented 20 mg/kg of SPD (SPD2 group), respectively. Compared with the CON, SPD1 significantly increased the average number of healthy piglets per litter and the placental efficiency (P < 0.05), while the average number of mummified fetus per litter and the percentage of weak piglets significantly decreased (P < 0.05). In the plasma metabolomics, SPD content in plasma of sows (P = 0.075) and umbilical cord plasma of piglets (P = 0.078) had an increasing trend in response to SPD1. Furthermore, SPD1 increased the expression of the vascular endothelial cell marker protein, platelet endothelial cell adhesionmolecule-1 (PECAM-1/CD31) and the density of placental stromal vessels (P < 0.05). Moreover, as compared to CON, SPD2 significantly decreased the average number of mummified fetus per litter (P < 0.05), while the placental efficiency and the expression of amino acid transporter solute carrier (SLC) family 7, member7 (SLC7A7) and glucose transporters SLC2A2) and SLC5A4 in placental tissue significantly increased (P < 0.05). These results suggest that maternal supplementation of SPD during pregnancy increased healthy litter number, and promoted placental tissue development. Our findings provide evidence that maternal SPD has the potential to improve the production performance of sows.

Predictive Indicators of Cryotolerance and Fertility in Bovine Sperm: Evaluating Fresh Semen Quality to Improve AI Outcomes With Frozen-Thawed Sperm.

The success of artificial insemination (AI) with frozen-thawed semen in cattle is influenced by both female factors and sperm quality. In terms of sperm quality, prior studies indicate that the ability of frozen-thawed bovine sperm to fertilise an oocyte is dependent on their quality and resilience to cryopreservation. Cryopreservation induces oxidative stress, leading to ultrastructural damage in the sperm. This study aimed to determine whether the quality of fresh semen can identify bulls with good and poor sperm freezability. This difference between fresh and frozen semen from the same bull allows us to predict fertility. Motility and kinetic parameters were assessed using computer-assisted sperm analysis (CASA), while six functional variables were evaluated through flow cytometry, both before and after the freeze-thaw process on the sperm from 13 bulls. Invivo fertility was measured using 90-day non-return rates. The principal component analysis (PCA) of eight sperm variables post-thaw identified one principal component explaining 81.19% of the total variance and classified the bulls into two groups: Poor freezability bulls (progressive motility: 48.12% ± 8.41%; viability: 77.51% ± 7.61%) and good freezability bulls (progressive motility: 58.64% ± 6.64%; viability: 88.12% ± 2.52%). Bulls with higher freezability showed better sperm viability and motility, as well as lower levels of ROS, superoxides and intracellular calcium before cryopreservation that were significantly correlated with higher non-return rates (NRR). The results underscore the importance of assessing the quality and functionality of fresh semen to predict the fertility potential of cryopreserved sperm. This approach can aid in selecting ejaculates with the best potential for successful artificial insemination, ultimately improving reproductive performance in dairy cattle.

Targeted reproductive management for lactating Holstein cows: Economic return.

Targeted reproductive management (TRM), employing automated monitoring devices (AMD), is as an alternative to the blanket adoption of ovulation synchronization protocols (OvSP) for first postpartum artificial insemination (AI) and a means of reducing the use of OvSP for re-AI of non-pregnant cows. We hypothesized that a TRM that relies heavily on AI of cows on AMD-detected estrus increases improves reproductive performance and economic return. Early-postpartum estrus characteristics of multiparous (n = 941) cows were evaluated at 40 and 41 DIM (Herds 1and 2, respectively) and early-postpartum estrus characteristics of primiparous (n = 539) cows were evaluated at 54 and 55 DIM (Herds 1 and 2, respectively). Cows in the control treatment were enrolled in the Double-Ovsynch protocol and AI at fixed time (TAI) at 82 and 83 DIM (primiparous cows in Herds 1 and 2, respectively) and 68 and 69 DIM (multiparous in Herds 1 and 2, respectively). Cows enrolled in the TRM treatment were managed according to early-postpartum estrus characteristics as follows: 1. Cows with ≥1 intense estrus (heat index ≥70; 0 = minimum, 100 = maximum) were AI upon AMD detected estrus for 42 d and, if not AI, were enrolled in the Double-Ovsynch, 2. Cows without an intense estrus were enrolled in the Double-Ovsynch at the same time as cows in the control treatment. Control cows were re-AI based on visual or patch aided detection of estrus, whereas TRM cows were re-AI as described for control cows with the aid of the AMD. All cows received a GnRH injection 27 ± 3 d after AI and, if diagnosed as non-pregnant, completed the 5-d Cosynch protocol and received TAI 35 ± 3 d after insemination. The hazard of pregnancy was greater for cows in the TRM treatment [adjusted hazard ratio = 1.17, 95% confidence interval = 1.05, 1.32], resulting in more cows from the TRM treatment starting a new lactation (82.6 vs. 77.2%) and fewer of them sold (15.5 vs. 20.8%). Treatments did not differ regarding total milk yield (control = 12,782.1 ± 130.6 kg, TRM = 13,054.7 ± 136.1 kg). The gross profit ((milk income + sale value + subsequent lactation calf value) - (feed cost + replacement cost + fixed cost + reproductive management cost)) of cows in the TRM treatment was $108 greater than the control treatment ($3,061.6 ± 45.9 vs. $2,953.8 ± 45.2). According to a Monte Carlo stochastic simulation, the mean (±SD) difference in gross profit was $87.8 ± 12.6/cow in favor of the TRM treatment and 95% of the scenarios ranged from $67.2/cow to $108.5/cow (minimum = $30.2/cow, maximum = $141.1/cow). In the conditions of the current experiment, the TRM treatment improved the gross profit of Holstein cows because the increased hazard of pregnancy changed culling dynamics, reducing replacement cost and cow sales and increasing calf value. The findings of the current experiment emphasize the importance of efficient reproductive management and its substantial economic implications, particularly in the context of high-producing Holstein cows.

Integrated transcriptomic hypothalamic-pituitary-ovarian axis network analysis reveals the role of energy availability on egg production in layers

Energy is a crucial component for maintaining egg production in layers. The hypothalamic-pituitary-ovarian (HPO) axis is an energy-sensitive functional axis for follicle development, synthesis, and secretion of reproductive hormones, and plays a key role in modulating sustained ovulation in layers. To investigate the mechanism of integrated network regulation of the HPO axis under energy fluctuation, ninety Hy-line brown layers (265-day-old, 1.92 ± 0.02 kg) were randomly divided into three groups for an 17-day experiment: a control group (Con group) fed ad libitum from days 1 to 17, an energy deprived group (ED group) that was fed ad libitum from days 1 to 12 and then underwent a fasting period from days 13 to 17 to induce a pause in laying, and a re-fed group (Rf group) that fasted for seven days (specifically, days 1 to 5, day 7, and day 9), had ad libitum access to feed on days 6 and 8, and were continuously fed from days 10 to 17. Each treatment consisted of 10 replicates with 3 birds per replicate. The study found that energy deprivation significantly decreased reproductive performance such as egg laying rate, ovarian index, number of small yellow follicles (SYF), and normal hierarchical follicles (NHIE) (P < 0.05), which recovered after refeeding, indicating the importance of energy availability for sustained ovulation in layers. In addition, estradiol (E2), estradiol/progesterone ratio (E2/P4), and luteinizing hormone (LH) displayed changes similar to follicle number, whereas follicle-stimulating hormone (FSH) exhibited a contrasting pattern. Transcriptome analysis revealed that energy deprivation downregulated genes related to energy and appetite-regulated neurotransmitter receptors and neuropeptides in the hypothalamus. These signals combined to inhibit gonadotropin-releasing hormone (GnRH) secretion and subsequently downregulated the crucial genes responsible for synthesizing gonadotropins, gonadotropin releasing hormone receptor (GnRHR), and glycoprotein hormones alpha chain (CGA). Consequently, this suppression of the hypothalamus and pituitary affected ovarian function through ovarian steroidogenesis and the extracellular matrix (ECM)-receptor interaction. These findings suggest that energy deprivation inhibits the function of the HPO axis, leading to impaired follicle development and reduced egg production and that refeeding can partially restore these indicators.

Incidence of puerperal metritis and associated risk factors in dairy cows in Hawassa, Southern Ethiopia

Metritis has considerable economic impact on dairy herd profitability due largely to reduced reproductive performance. Studies in Ethiopia only report prevalence, with no available data on the incidence of metritis. The present prospective cohort study aimed to estimate the incidence of puerperal metritis, identify risk factors, and isolate the causative bacteria in dairy cows in Hawassa. Daily follow-up of 120 dairy cows from parturition to 21 days postpartum was carried out from November 2019 to February 2021. Of these, 21 developed puerperal metritis with an incidence rate of 0.94 cases per 100 cow days at risk (95 % CI: 0.6–1.4). The cumulative incidence was found to be 17.5 % (95 % CI: 11.8–25.6). Over 90 % of the puerperal metritis occurred within the first 10 days of parturition. The mean day of occurrence of puerperal metritis was 7.7 days postpartum and the mean rectal temperature in metritic cows was 40.5 °C. Retained fetal membranes (RFM) (p < 0.001) emerged as the only predisposing factor for metritis in the final Cox regression model. Cows with RFM faced a 14.9 times higher risk of metritis compared to cows without RFM. A total of 52 bacterial isolates, belonging to 4 genera, were recovered from the aerobic culture of 21 uterine swab samples. E. coli and Staphylococcus spp. were the most frequently isolated bacteria, with recovery from 21 (100 %) and 20 (95.2 %) of the metritic uteri, respectively. Results of this study suggested the importance of reducing incidence of RFM to reduce incidence of metritis in dairy cows.

Genome-Wide Association Studies and Runs of Homozygosity Reveals Genetic Markers Associated with Reproductive Performance in Korean Duroc, Landrace, and Yorkshire Breeds

Genome-Wide Association Studies and Runs of Homozygosity Reveals Genetic Markers Associated with Reproductive Performance in Korean Duroc, Landrace, and Yorkshire Breeds

A review of extended lactation in dairy cows managed in high-input and pasture-based farming systems

Traditionally the lactation cycle of a dairy cow is based around a 12-month calving interval, allowing for 10 months of lactation, followed by a 2-month dry period. This means that the cow has to conceive within 2–3 months after calving, when she is also at peak lactation and metabolically is in a negative energy balance. Such challenging physiological conditions make it challenging for the cow to conceive at this time and many modern high-producing cows fail to get pregnant within the constraints of a 12-month calving interval. In addition, many cows still produce at a high level at drying-off time, increasing the risk of intramammary infections. Therefore, delaying conception past peak production and, as a result, extending the lactation beyond 10 months may increasingly be necessary. Additionally, extended lactation (EL) may offer other advantages such as fewer calves being born and thus fewer ‘surplus’ calves needing to be culled at a young age, fewer health and welfare issues and improved environmental outcomes (i.e. less greenhouse-gas emission; less antibiotic usage) during the lifetime of the animal. Extending lactation is a straight forward management practice in high-input dairy systems where a consistent supply of feed supplements is readily available, but may be more challenging to implement in low(er)-input pasture-based systems. The latter are much more seasonal, with a 12-month calving interval allowing pasture growth and quality to match the cow’s nutritional demands; cows calve in spring when high-quality pasture is abundant and are dried-off during winter when pasture growth is more limited. In this review, we explored the impact of EL in both high-input systems and pasture-based systems. It covers the effects of EL on milk production, composition and processing, as well as on reproductive performance, health and welfare, and environmental and economic outcomes.

Impacts of winter crop choice and ewe body condition score change on whole farm profitability and production

Variations in body condition score (BCS) in ewes influences lamb survival, ewe survival and ewe lactation performance. Feeding a low protein diet such as fodder beet to ewes in mid-to-late pregnancy increases lamb losses and reduces lamb weaning weight even further. However, using high yielding forages such as fodder beet can reduce the area of winter crop required, introducing potential whole-farm benefits which may alter profitability. We analysed the effects of winter crop choice (brassica or fodder beet) and BCS (maintaining or reducing) on whole-farm production and profitability, using a targeted supplement to offset the impacts of fodder beet feeding. Eight farms were selected to represent low or high rainfall (590 and 1090 mm/annum respectively) regions of the South Island. Impacts of changing BCS on ewe and lamb survival at lambing, and lamb liveweight gain to weaning were calculated when fed either adequate (brassica) or low protein (fodder beet) diets in mid-to-late pregnancy. Production statistics and profitability were calculated using Farmax. Whole farm profitability was analysed using BCS change and winter forage crop as main treatments, blocked by low or high rainfall. Applying the effects of BCS and low protein diets on reproductive performance from prior published studies resulted in variation of 102 to 141 lambs weaned per 100 ewes mated, with the lowest value when the low protein, fodder beet only diet was used. Greatest number of lambs weaned was achieved when BCS was maintained through winter through provision of a balanced supplement, regardless of winter forage diet (P&lt;0.05). Lamb sale dates were later when fodder beet was used, due to lower lamb weaning weights, resulting in marginally higher prices due to changes in pricing schedule. Farm profitability was increased by 25% when BCS was maintained though winter (P&lt;0.05) irrespective of the diet used. Use of fodder beet must be accompanied by targeted supplementation to avoid ewe BCS loss increased lamb losses and the negative effects on wastage and animal welfare. Extra profitability could only be generated by opportunities to sell surplus feed during the summer. These responses were similar in both high and low rainfall environments. This study is unique in testing measured responses of BCS and targeted nutritional supplementation under specific physiological conditions on whole-farm profitability. Farmer decisions on feed utilisation and sale also have a significant influence on the potential to mitigate the effects of variations in winter forage choice.

Seasonal Factors and The Potential of Artificial Insemination (AI) in Dairy Cattle

Dairy cattle are dominant milk producer in Indonesia. Several programs have been carried out to increase the population of dairy cattle and milk production, one of which is Artificial Insemination (AI). Indonesia is a tropical country that has two seasons, namely the rainy season and the dry season. This study was conducted in the KPSBU Lembang working area, West Java, from November 2019 to January 2020. Rainfall data from the BMKG Dramaga Climatology Station and artificial insemination (AI) records of Frisian Holstein dairy cattle from 2017 to 2019 were collected. AI success was assessed using the Service per Conception (S/C) and Conception Rate (CR) parameters, obtained through pregnancy checks two months after insemination. Pregnancy checks were conducted using rectal palpation to confirm conception. Statistical analysis focused on seasonal differences in reproductive performance based on these metrics. Highest S/C value was 2.02 with CR Value 53.27% on rainy season with rainfall 253.67 mm month-1. The analysis showed a strong correlation (α = 0.005) between S/C and CR value (0.89*), very weak correlation between rainfall with S/C (r = -0.05) and CR (r = -0.08). The results of the research show that the rainy season and the dry season are not the main factors affecting the AI in dairy cattle, however they didn’t directly affect the season to increase the productivity of saplings.

Reproductive Performances of SIMGOUD Crossbreed Cows and The Effect of Concentrate Feed Supplementation on The Production and Chemical Composition of Milk

Reproductive Performances of SIMGOUD Crossbreed Cows and The Effect of Concentrate Feed Supplementation on The Production and Chemical Composition of Milk

Biological traits and biome features mediate responses of terrestrial bird demography to droughts.

Changing drought regimes are a rising threat to biodiversity, yet their impacts on wildlife vary greatly. Acknowledging the factors associated with these consequences brings novel insights into species vulnerability resulting from extreme climatic events and facilitates effective mitigation of climate change risks. Based on 319 observations from 29 peer-reviewed studies on birds-a well-monitored taxonomic group-we extract the responses of demographic metrics to droughts for 204 species across eight terrestrial biomes to examine the consequences of droughts. According to relevant studies, we chose the factors potentially moderating bird demography under droughts and compiled the data for these factors from published datasets. A meta-analysis is performed to determine the drought effect on bird demography at individual and population levels, accounting for the influence of species traits, timescale and severity of droughts, as well as biome features. The results show that droughts have an overall negative effect on bird demography, and the effect is mediated by different factors at each level. For individuals exposed to droughts, declines in demographic rates are found to be related to narrower extents of occurrence of species, and a significant overall reduction in demographic rates is identified for individuals residing in deserts and xeric shrublands. At the population level, declines in abundance or reproductive performance are generally identified for invertivores, frugivores, nectarivores and omnivores; short-lived species with small clutch sizes also show greater susceptibilities under the impacts of droughts. Our findings additionally suggest that the demographic vulnerability of bird individuals and populations could be affected by the duration and magnitude of drought episodes. Although our results are subject to publication bias, these conclusions advance the assessment of vulnerability to extreme climatic events that used to be based on equally weighted species traits and support bird conservation by prioritizing the declining populations of species with drought-susceptible traits.