Effect of Extending Voluntary Waiting Period on Health of Holstein Friesian Dairy Cows

The aim of this of this experimental study to investigate the effect of 3 voluntary waiting periods (VWP) on health of dairy cows. A total of 100 lactations of 100 Holstein Friesian cows with high milk production (average 9.442 ± 620 kg) were randomly (based on the ear tags digits of cows) distributed to 1 to 3 experimental groups with VWP of 50 (VWPG50;n = 32), 100 (VWPG100;n = 34) or 150 days (VWPG150;n = 34). Observations relating to diseases of the cows were made by the farm veterinarian and research personnel. Were defined eight disease: puerperal fever, retained fetal membranes, displaced abomasum, metritis, clinical ketosis, clinical mastitis, ovarian cysts, and claw diseases. The experimental days (ED) were from 4 days in milk (DIM) to 100 days after the next calving. The experiment was managed at Dairy Research Farm ?imnic-Craiova January 2018 to December 2022. A clear set of clinical signs were used to define a case at the diseases without the need for laboratory confirmation. Values of Lactational incidence risk (LIR) median postpartum days at diagnosis and pairwise comparison of proportion between VWPs were calculated. LIR for puerperal fiver, retained fetal membranes, displaced abomasum, clinical ketosis, clinical mastitis, ovarian cysts and claw disease were 4;5;2;8;8;and 4% respectively. Numerically, cows with VWP of 100 and150 days had more disease cases compared with VWP of 50 days. The differences between experimental groups of cows regarding proportions of cows with disease cases were not statistically significant. Any of the eight disorders reported in this study was analyzed independently to other health problems. For all enrolled cows (n = 100) VWP was extended until 100 or 150 days postpartum with no effect on the lactational incidence risk for the eight disorders analyzed.

Maternal supplementation with n-3 fatty acids affects placental lipid metabolism, inflammation, oxidative stress, the endocannabinoid system, and the neonate cytokine concentrations in dairy cows

Background The placenta plays a crucial role in supporting and influencing fetal development.We compared the effects of prepartum supplementation with omega-3(n-3)fatty acid(FA)sources,flaxseed oil(FLX)and fish oil(FO),on the expression of genes and proteins related to lipid metabolism,inflammation,oxidative stress,and the endocannabinoid system(ECS)in the expelled placenta,as well as on FA profile and inflammatory response of neonates.Late-pregnant Holstein dairy cows were supplemented with saturated fat(CTL),FLX,or FO.Placental cotyledons(n=5)were collected immediately after expulsion,and extracted RNA and proteins were analyzed by RTPCR and proteomic analysis.Neonatal blood was assessed for FA composition and concentrations of inflammatory markers.Results FO increased the gene expression of fatty acid binding protein 4(FABP4),interleukin 10(IL-10),catalase(CAT),cannabinoid receptor 1(CNR1),and cannabinoid receptor 2(CNR2)compared with CTL placenta.Gene expression of ECS-enzyme FA-amide hydrolase(FAAH)was lower in FLX and FO than in CTL.Proteomic analysis identified 3,974 proteins;of these,51–59 were differentially abundant between treatments(P≤0.05,|fold change|≥1.5).Top canonical pathways enriched in FLX vs.CTL and in FO vs.CTL were triglyceride metabolism and inflammatory processes.Both n-3 FA increased the placental abundance of FA binding proteins(FABPs)3 and 7.The abundance of CNR1 cannabinoid-receptor-interacting-protein-1(CNRIP1)was reduced in FO vs.FLX.In silico modeling affirmed that bovine FABPs bind to endocannabinoids.The FLX increased the abundance of inflammatory CD44-antigen and secreted-phosphoprotein-1,whereas prostaglandin-endoperoxide synthase 2 was decreased in FO vs.CTL placenta.Maternal FO enriched neonatal plasma with n-3 FAs,and both FLX and FO reduced interleukin-6 concentrations compared with CTL.Conclusion Maternal n-3 FA from FLX and FO differentially affected the bovine placenta;both enhanced lipid metabolism and modulated oxidative stress,however,FO increased some transcriptional ECS components,possibly related to the increased FABPs.Maternal FO induced a unique balance of pro-and anti-inflammatory components in the placenta.Taken together,different sources of n-3 FA during late pregnancy enhanced placental immune and metabolic processes,which may affect the neonatal immune system.

Repeated inoculation with rumen fluid accelerates the rumen bacterial transition with no benefit on production performance in postpartum Holstein dairy cows

Background The dairy cow’s postpartum period is characterized by dramatic physiological changes,therefore imposing severe challenges on the animal for maintaining health and milk output.The dynamics of the ruminal microbiota are also tremendous and may play a crucial role in lactation launch.We aim to investigate the potential benefits of early microbial intervention by fresh rumen microbiota transplantation(RMT)and sterile RMT in postpartum dairy cows.Twelve fistulated peak-lactation dairy cows were selected to be the donors for rumen fluid collection.Thirty postpartum cows were divided into 3 groups as the transplantation receptors respectively receiving 10 L fresh rumen fluid(FR),10 L sterile rumen fluid(SR),or 10 L saline(CON)during 3 d after calving.Results Production performance,plasma indices,plasma lipidome,ruminal microbiome,and liver transcriptome were recorded.After fresh and sterile RMT,we found that the molar proportion of propionic acid was increased on d 7 in the FR and SR groups and the bacterial composition was also significantly changed when compared with the CON group.A similarity analysis showed that the similarities between the CON group and FR or SR group on d 7 were 48.40%or 47.85%,whereas the similarities between microbiota on d 7 and 21 in the FR and SR groups were 68.34%or 66.85%.Dry matter intake and feed efficiency were not affected by treatments.Plasmaβ-hydroxybutyrate concentration in the FR group was decreased and significantly different lipids mainly included phosphatidylcholine and lysophosphatidylcholine containing polyunsaturated fatty acids.Hepatic transcriptomics analysis indicated acutephase response pathways were upregulated in the SR group.Conclusions Our study suggests that RMT can shorten the transition process of the ruminal microbiota of postpartum dairy cows with no benefit on dry matter intake or feed efficiency.Inoculation with rumen fluid may not be a useful approach to promote the recovery of postpartum dairy cows.

Spatially resolved transcriptomic profiling of placental development in dairy cow

The placenta plays a crucial role in successful mammalian reproduction.Ruminant animals possess a semi-invasive placenta characterized by a highly vascularized structure formed by maternal endometrial caruncles and fetal placental cotyledons,essential for full-term fetal development.The cow placenta harbors at least two trophoblast cell populations:uninucleate(UNC)and binucleate(BNC)cells.However,the limited capacity to elucidate the transcriptomic dynamics of the placental natural environment has resulted in a poor understanding of both the molecular and cellular interactions between trophoblast cells and niches,and the molecular mechanisms governing trophoblast differentiation and functionalization.To fill this knowledge gap,we employed Stereo-seq to map spatial gene expression patterns at near single-cell resolution in the cow placenta at 90 and 130 days of gestation,attaining high-resolution,spatially resolved gene expression profiles.Based on clustering and cell marker gene expression analyses,key transcription factors,including YBX1 and NPAS2,were shown to regulate the heterogeneity of trophoblast cell subpopulations.Cell communication and trajectory analysis provided a framework for understanding cell-cell interactions and the differentiation of trophoblasts into BNCs in the placental microenvironment.Differential analysis of cell trajectories identified a set of genes involved in regulation of trophoblast differentiation.Additionally,spatial modules and co-variant genes that help shape specific tissue structures were identified.Together,these findings provide foundational insights into important biological pathways critical to the placental development and function in cows.

Abomasal infusion of branched-chain amino acids or branched-chain keto-acids alter lactation performance and liver triglycerides in fresh cows

Background Dairy cows are at high risk of fatty liver disease in early lactation,but current preventative measures are not always effective.Cows with fatty liver have lower circulating branched-chain amino acid(BCAA)concentra-tions whereas cows with high circulating BCAA levels have low liver triglyceride(TG).Our objective was to determine the impact of BCAA and their corresponding ketoacids(branched-chain ketoacids,BCKA)on production performance and liver TG accumulation in Holstein cows in the first 3 weeks postpartum.Methods Thirty-six multiparous Holstein cows were used in a randomized block design experiment.Cows were abomasally infused for the first 21 d postpartum with solutions of 1)saline(CON,n=12);2)BCA(67 g valine,50 g leu-cine,and 34 g isoleucine,n=12);and 3)BCK(77 g 2-ketovaline calcium salt,57 g 2-ketoleucine calcium salt,and 39 g 2-ketoisoleucine calcium salt,n=12).All cows received the same diet.Treatment effects were determined using PROC GLIMMIX in SAS.Results No differences were detected for body weight,body condition score,or dry matter intake averaged over the first 21 d postpartum.Cows receiving BCK had significantly lower liver TG concentrations compared to CON(6.60%vs.4.77%,standard error of the mean(SEM)0.49)during the first 3 weeks of lactation.Infusion of BCA increased milk yield(39.5 vs.35.3 kg/d,SEM 1.8),milk fat yield(2.10 vs.1.69 kg/d,SEM 0.08),and lactose yield(2.11 vs.1.67 kg/d,SEM 0.07)compared with CON.Compared to CON,cows receiving BCA had lower plasma glucose(55.0 vs.59.2 mg/dL,SEM 0.86)but higherβ-hydroxybutyrate(9.17 vs.6.00 mg/dL,SEM 0.80).Conclusions Overall,BCAA supplementation in this study improved milk production,whereas BCKA supplementa-tion reduced TG accumulation in the liver of fresh cows.

Real-Time Monitoring Method for Cow Rumination Behavior Based on Edge Computing and Improved MobileNet v3

[Objective]Real-time monitoring of cow ruminant behavior is of paramount importance for promptly obtaining relevant information about cow health and predicting cow diseases.Currently,various strategies have been proposed for monitoring cow ruminant behavior,including video surveillance,sound recognition,and sensor monitoring methods.How‐ever,the application of edge device gives rise to the issue of inadequate real-time performance.To reduce the volume of data transmission and cloud computing workload while achieving real-time monitoring of dairy cow rumination behavior,a real-time monitoring method was proposed for cow ruminant behavior based on edge computing.[Methods]Autono‐mously designed edge devices were utilized to collect and process six-axis acceleration signals from cows in real-time.Based on these six-axis data,two distinct strategies,federated edge intelligence and split edge intelligence,were investigat‐ed for the real-time recognition of cow ruminant behavior.Focused on the real-time recognition method for cow ruminant behavior leveraging federated edge intelligence,the CA-MobileNet v3 network was proposed by enhancing the MobileNet v3 network with a collaborative attention mechanism.Additionally,a federated edge intelligence model was designed uti‐lizing the CA-MobileNet v3 network and the FedAvg federated aggregation algorithm.In the study on split edge intelli‐gence,a split edge intelligence model named MobileNet-LSTM was designed by integrating the MobileNet v3 network with a fusion collaborative attention mechanism and the Bi-LSTM network.[Results and Discussions]Through compara‐tive experiments with MobileNet v3 and MobileNet-LSTM,the federated edge intelligence model based on CA-Mo‐bileNet v3 achieved an average Precision rate,Recall rate,F1-Score,Specificity,and Accuracy of 97.1%,97.9%,97.5%,98.3%,and 98.2%,respectively,yielding the best recognition performance.[Conclusions]It is provided a real-time and effective method for monitoring cow ruminant behavior,and the proposed federated edge intelligence model can be ap‐plied in practical settings.

Feeding Calcium Salts of Linseed Oil on Metabolic Status and Reproductive Traits in Grazing Dairy Cows

This experiment aimed to evaluate the effect of calcium salts of linseed oil (rich in alpha-linolenic acid (ALA, C18:3n-3) on metabolic and reproductive traits in high-producing dairy cows under grazing. Thirty-six Holstein dairy cows were randomly assigned, in a complete block design, to receive ALA supplementation (0.85 kg∙day−1 of calcium salts of linseed oil) or to remain as untreated control (CON). The concentrate was formulated to offer the same amount of energy across treatments (CON cows received an extra kg of corn to compensate for the higher energy density of ALA treatment). A PMR + Alfalfa pasture was offered to all cows at the same time. A fixed time artificial insemination (FTAI) at 80 DIM, preceded by a Presynch plus Ovsynch protocol was implemented for the first service and later, on return to estrus, heat detection and artificial insemination (AI) were performed. Pregnancy diagnosis was checked at 30, 42, 60, and 90 d after AI. Blood and milk samples were taken biweekly. Treatment affected plasma cholesterol concentration (160.36 vs. 186.70 mg∙dl−1, p = 0.03, for ALA and CON, respectively) and on size of corpus luteum (CL, 17.6 vs. 13.7 mm, p = 0.02, for ALA and CON, respectively). Supplementation tended (p = 0.136) to increase conception rate by 200 DIM (81.69% vs. 55.43% in ALA and CON cows, respectively). However, treatment had no effect (p > 0.05) on body weight (BW), body condition score (BCS), and circulating levels of beta-hydroxybutyrate (BHBA), glucose, insulin, growth hormone (GH) and insulin-like growth factor (IGF-I). Our results suggest that supplementation with calcium salts of linseed oil could enhance ovarian function without affecting energy metabolism in early lactation dairy cows.

A Biogas Production Model from the Combination of Pig Manure and Cow Dung in N’Zérékoré City, Republic of Guine

This present research work focuses on the valorization of pig droppings for production of biogas in mono digestion and co-digestion with proportions of cow dung from the urban commune of N’Zérékoré. It was carried out in December 2020 in the Physics laboratory of the University of N’Zérékoré. The anaerobic digestion process took 25 days in an almost constant ambient temperature of 25˚C. Five digesters were loaded on 12/06/2020, two of which with 1 kg of pig dung and 1 kg of cow dung both in mono-digestion. The 3 other digesters in co-digestion with different proportions of pig manure and cow dung. The substrate in each digester is diluted in 2 liters of water, with a proportion of (1/2). The main results obtained are: 1) the evolution of the temperature and pH during digestion process, 2) the average biogas productions 0.61 liters for (D1);1.20 liter for (D2);1.65 liter for (D3);1.51 liter for (D4) and 1.31 liter for (D5). The cumulative amounts of biogas are respectively: D1 (7.95 liters), D2 (15.60 liters), D3 (21.50 liters), D4 (19.65 liters) and D5 (17.05 liters). The total cumulative production is 81.75 liters at the end of the process. The originality of this research work is that the proposed model examines the relation between the daily biogas production and the variation of temperature, pH and pressure. The combustibility test showed the biogas produced during the first week was no combustible (contains less than 50% methane). Combustion started from the biogas produced from the 15th day and it is from the 20th day that a significant amount of stable yellow/blue flame was observed. The results of this study show the combination of pig manure and cow dung presents advantages for optimal biogas production.

脉冲电沉积CoW/ZrO_(2)复合镀层的力学性能研究

研究了镀液中ZrO_(2)纳米颗粒添加量对COW/ZrO_(2)复合镀层质量和摩擦磨损性能的影响。采用单因素试验法,在一定条件下改变镀液中ZrO_(2)纳米颗粒的添加量从而获得不同的COW/ZrO_(2)复合镀层。用扫描电子显微镜SU5000观察镀层表面形貌,用X射线衍射和表面分析仪P7分别检测镀层的微观结构、厚度和表面粗糙度,研究镀层表面质量随镀液中ZrO_(2)纳米颗粒添加量的变化规律并测试镀层的摩擦学性能。试验结果表明:在一定条件下镀液中ZrO_(2)纳米颗粒的添加量对复合镀层质量的影响存在最优值,镀液中ZrO_(2)含量的变化对于镀层磨损率的减小存在最优值。采用脉冲电沉积法制备COW/ZrO_(2)复合镀层的过程中,ZrO_(2)纳米颗粒添加量为9g/L时复合镀层的表面质量和耐磨性最好。

Study of the Optimal Conditions for Anaerobic Digestion of Cow Dung in Households in Cote d’Ivoire

This paper investigates the optimal conditions for methanisation applied to cow dung. Four experimental 25 liters digesters were used in this work. The best biogas yield is obtained when the digester is installed in a metal box and exposed to sunlight. The temperature in this digester varied between 25˚C and 37˚C. The dry matter content of the collected cow dung was 15.5%. The digester was fed with 9 kg of cow dung mixed with 8.5 litres of water, one litre of cassava effluent and 200 ml of human urine. After a retention period of 22 days, the biogas obtained was 67% methane and 21% carbon dioxide. The use of human urine and cassava effluent improved the quality of the biogas.

Chemical Analysis of Activated Carbon from Bull and Cow Horns Pyrolysis to Be Used as Antidotes

The purpose of this study is to compare the results of chemical analysis of two types of activated from the pyrolysis of bull horn and that of cow. Six samples were used to measure pH, carbon, calcium and to determine adsorbent power. The pH was measured at a temperature of 20˚C using an “ANION 7010 ionomer” pH meter, the carbon (C) content was analyzed using a “EURO EA 3000” analyzer. and the electronic balance: “Sartorius CP-2P”, calcium (Ca) was analyzed using a DFS-8 spectrograph. For the adsorbency test, the 0.15% methylene blue R solution was used. At the end of this study, we found that the activated carbon from the bull horn demonstrated a carbon content that is higher than that of the cow horn (20.79% against 15.63%), activated carbon of cow horn is richer in calcium than that of bull horn (16.27% against 3.69%) and then the pH. The cow horn is higher than that of the bull horn (7.43 versus 6.5). For the adsorbent power, the sample (75% bull horn and 25% cow horn) was recorded with the greatest adsorbent power. Thus, from this study, it can be recommended as an activated carbon antidote to be used for poisonings treatment.

Dairy cows inoculated with highly pathogenic avian influenza virus H5N1

Highly pathogenic avian influenza(HPAI)H5N1 hemagglutinin clade 2.3.4.4b was detected in the United States in 2021.These HPAI viruses caused mortality events in poultry,wild birds,and wild mammals.On March 25,2024,HPAI H5N1 clade 2.3.4.4b was confirmed in a dairy cow in Texas in response to a multi-state investigation into milk production losses.1 Over 200 positive herds were identified in 14 U.S.states.The case description included reduced feed intake and rumen motility in lactating cows,decreased milk production,and thick yellow milk.2,3 The diagnostic investigation revealed viral RNA in milk and mammary tissue with alveolar epithelial degeneration and necrosis and positive immunoreactivity of glandular epithelium.A single transmission event,likely from birds,was followed by limited local transmission and onward horizontal transmission of H5N1 clade 2.3.4.4b genotype B3.13.4 We sought to experimentally reproduce infection with genotype B3.13 in Holstein yearling heifers and lactating cows.Heifers were inoculated by aerosol respiratory route and cows by intramammary route.Clinical disease was mild in heifers,but infection was confirmed by virus detection,lesions,and seroconversion.Clinical disease in lactating cows included decreased rumen motility,changes to milk appearance,and production losses.Infection was confirmed by high levels of viral RNA detected in milk,virus isolation,lesions in mammary tissue,and seroconversion.This study provides the foundation to investigate additional routes of infection,pathogenesis,transmission,and intervention strategies.

Dietary supplementation with xylooligosaccharides and exogenous enzyme improves milk production,energy utilization efficiency and reduces enteric methane emissions of Jersey cows

Background Sustainable strategies for enteric methane(CH_(4))mitigation of dairy cows have been extensively explored to improve production performance and alleviate environmental pressure.The present study aimed to investigate the effects of dietary xylooligosaccharides(XOS)and exogenous enzyme(EXE)supplementation on milk production,nutrient digestibility,enteric CH_(4) emissions,energy utilization efficiency of lactating Jersey dairy cows.Forty-eight lactating cows were randomly assigned to one of 4 treatments:(1)control diet(CON),(2)CON with 25 g/d XOS(XOS),(3)CON with 15 g/d EXE(EXE),and(4)CON with 25 g/d XOS and 15 g/d EXE(XOS+EXE).The 60-d experimental period consisted of a 14-d adaptation period and a 46-d sampling period.The enteric CO_(2)and CH_(4) emissions and O2 consumption were measured using two GreenFeed units,which were further used to determine the energy utilization efficiency of cows.Results Compared with CON,cows fed XOS,EXE or XOS+EXE significantly(P<0.05)increased milk yield,true protein and fat concentration,and energy-corrected milk yield(ECM)/DM intake,which could be reflected by the significant improvement(P<0.05)of dietary NDF and ADF digestibility.The results showed that dietary supplementation of XOS,EXE or XOS+EXE significantly(P<0.05)reduced CH_(4) emission,CH_(4)/milk yield,and CH_(4)/ECM.Furthermore,cows fed XOS demonstrated highest(P<0.05)metabolizable energy intake,milk energy output but lowest(P<0.05)of CH_(4) energy output and CH_(4) energy output as a proportion of gross energy intake compared with the remaining treatments.Conclusions Dietary supplementary of XOS,EXE or combination of XOS and EXE contributed to the improvement of lactation performance,nutrient digestibility,and energy utilization efficiency,as well as reduction of enteric CH_(4) emissions of lactating Jersey cows.This promising mitigation method may need further research to validate its long-term effect and mode of action for dairy cows.

Multi‑omics reveals that the host‑microbiome metabolism crosstalk of differential rumen bacterial enterotypes can regulate the milk protein synthesis of dairy cows

Background Dairy cows’lactation performance is the outcome of the crosstalk between ruminal microbial metabo-lism and host metabolism.However,it is still unclear to what extent the rumen microbiome and its metabolites,as well as the host metabolism,contribute to regulating the milk protein yield(MPY).Methods The rumen fluid,serum and milk of 12 Holstein cows with the same diet(45%coarseness ratio),parity(2–3 fetuses)and lactation days(120–150 d)were used for the microbiome and metabolome analysis.Rumen metabolism(rumen metabolome)and host metabolism(blood and milk metabolome)were connected using a weighted gene co-expression network(WGCNA)and the structural equation model(SEM)analyses.Results Two different ruminal enterotypes,with abundant Prevotella and Ruminococcus,were identified as type1 and type2.Of these,a higher MPY was found in cows with ruminal type2.Interestingly,[Ruminococcus]gauvreauii group and norank_f_Ruminococcaceae(the differential bacteria)were the hub genera of the network.In addition,differential ruminal,serum and milk metabolome between enterotypes were identified,where the cows with type2 had higher L-tyrosine of rumen,ornithine and L-tryptophan of serum,and tetrahydroneopterin,palmitoyl-L-carnitine,S-lactoylglutathione of milk,which could provide more energy and substrate for MPY.Further,based on the identi-fied modules of ruminal microbiome,as well as ruminal serum and milk metabolome using WGCNA,the SEM analysis indicated that the key ruminal microbial module1,which contains the hub genera of the network([Ruminococcus]gauvreauii group and norank_f_Ruminococcaceae)and high abundance of bacteria(Prevotella and Ruminococcus),could regulate the MPY by module7 of rumen,module2 of blood,and module7 of milk,which contained L-tyrosine and L-tryptophan.Therefore,in order to more clearly reveal the process of rumen bacterial regulation of MPY,we established the path of SEM based on the L-tyrosine,L-tryptophan and related components.The SEM based on the metabolites suggested that[Ruminococcus]gauvreauii group could inhibit the energy supply of serum tryptophan to MPY by milk S-lactoylglutathione,which could enhance pyruvate metabolism.Norank_f_Ruminococcaceae could increase the ruminal L-tyrosine,which could provide the substrate for MPY.Conclusion Our results indicated that the represented enterotype genera of Prevotella and Ruminococcus,and the hub genera of[Ruminococcus]gauvreauii group and norank_f_Ruminococcaceae could regulate milk protein synthesis by affecting the ruminal L-tyrosine and L-tryptophan.Moreover,the combined analysis of enterotype,WGCNA and SEM could be used to connect rumen microbial metabolism with host metabolism,which provides a fundamental understanding of the crosstalk between host and microorganisms in regulating the synthesis of milk composition.

基于Cow-DETR与深度图像的非接触式奶牛体质量评估

针对当前牧场奶牛体质量(体重)称量效率低,人工参与容易引发奶牛应激等问题,提出了一种基于改进DETR(Detection transformer)网络的端到端式奶牛体质量评估方法(Cow-DETR),实现利用奶牛背部深度图像进行非接触式奶牛体质量评估。首先设计并搭建实验数据采集装置,利用Intel RealSense D435深度相机和体重秤采集奶牛背部深度图像和体质量数据;然后,通过边缘平滑滤波器和孔洞填充滤波器对深度图像进行补全处理,减少深度数据缺失对体质量评估的影响;最后,以DETR网络为基础建立奶牛体质量评估模型,通过在预测模块中添加含有交替全连接层的体质量预测单元,提升奶牛体质量相关的特征信息提取能力,实现端到端式奶牛背部定位的同时进行奶牛体质量非接触式评估。结果表明,本文方法可以实现较高精度的奶牛体质量评估,通过5倍交叉验证,在含有139头奶牛数据的数据集中,平均绝对误差不超过17.21 kg,平均相对误差不超过3.71%,单幅图像平均识别时间为0.026 s。通过与现有体质量评估方法相对比,本文方法比其他6种方法在更多的奶牛头数的数据集中取得了更低的平均绝对误差和平均相对误差,同时本文方法对奶牛站立姿势要求较低,更符合牧场实际生产需要,为奶牛体质量评估提供了新的解决思路。

Effects of omega-3 supplementation on components of the endocannabinoid system and metabolic and inflammatory responses in adipose and liver of peripartum dairy cows

Background:Dietary supplementation of omega-3 fatty acids can reduce the activation of the endocannabinoid system(ECS)by decreasing the availability of arachidonic acid,thus lowering endocannabinoids(e CBs)levels.The ECS is a modulator of energy metabolism,stress response and inflammation in mammals,yet there is little information on the roles of the ECS in transition dairy cows.During the periparturient period,the adipose tissue and liver are the main metabolic organs that participate in the adaptations of dairy cows to onset of lactation;however,exceeded adipose tissue lipolysis and accumulation of lipids in the liver have adverse effects on cows'physiology.Here we aimed to examine whether omega-3 supplementation during the transition period will modulate ECS activation and affect metabolic and inflammatory indices in postpartum dairy cows,by supplementing twenty-eight transition Holstein dairy cows with either saturated fat(CTL)or encapsulated flaxseed oil(FLX).Components of the ECS,metabolic and inflammatory markers were measured in blood,liver,and subcutaneous adipose tissue.Results:FLX supplementation reduced feed intake by 8.1%(P<0.01)and reduced plasma levels of arachidonic acid(by 44.2%;P=0.02)and anandamide(by 49.7%;P=0.03)postpartum compared to CTL.The m RNA transcription levels of the cannabinoid receptor 1(CNR1/CB1)tended to be lower(2.5 folds)in white blood cells of FLX than in CTL(P=0.10),and protein abundance of ECS enzyme monoacylglycerol lipase was higher in peripheral blood mononuclear cells of FLX than in CTL(P=0.04).In adipose tissue,palmitoylethanolamide levels were lower in FLX than in CTL(by 61.5%;P=0.02),relative m RNA transcription of lipogenic genes were higher,and the protein abundance of cannabinoid receptor 2(P=0.08)and monoacylglycerol lipase(P=0.10)tended to be higher in FLX compared to CTL.Hepatic 2-arachidonoylglycerol tended to be higher(by 73.1%;P=0.07),and interlukin-6 m RNA transcription level was 1.5 folds lower in liver of FLX than in CTL(P=0.03).Conclusions:Nutritional supplementation of omega-3 fatty acids seems to partly modulate ECS activation,which could be related to lower feed intake.The altered ECS components in blood,adipose tissue and liver are associated with moderate modulations in lipid metabolism in the adipose and inflammation in liver of peripartum dairy cows.

Heat stress affects dairy cow health status through blood oxygen availability

Background Rises in global warming and extreme weather occurrence make the risk of heat stress(HS)induced by high ambient temperatures more likely in high-yielding dairy cows,resulting in low milk quality and yield.In ani-mals,oxygen is involved in many physiological and metabolic processes,but the effects of HS on oxygen metabolism remain unclear.Thus,the current study aimed to investigate how oxygen metabolism plays a role in health status of dairy cows by measuring the milk yield,milk composition,and blood biochemical variables of cows under different levels of HS:none(No-HS),mild(Mild-HS),and moderate HS(Mod-HS).Results The HS significantly increased rectal temperature(Ptreat<0.01)and respiration rate(Ptreat<0.01).Under Mod-HS,greater Na+(P<0.05)and lower total CO_(2),and pH(P<0.05)were observed relative to those under No-HS and Mild-HS.Oxygen concentrations in both coccygeal artery and mammary vein(Ptreat<0.01)were lower under Mod-HS than under No-HS.Coccygeal vein concentrations of heat shock protein 90(HSP90)(P<0.05)increased during Mod-HS compared with those in cows under No-HS.Malondialdehyde increased during Mod-HS,and glu-tathione peroxidase(P<0.01)increased during Mild-HS.Coccygeal vein concentrations of vascular endothelial growth factor(P<0.01),heme oxygenase-1(P<0.01),and hypoxia-inducible factor 1α(P<0.01)were greater in cows under Mod-HS than those under No-HS.Red blood cell count(P<0.01)and hemoglobin concentration(P<0.01)were lower in the coccygeal vein of dairy cows under Mild-and Mod-HS than those of cows under No-HS.Conclusions Exposure to HS negatively impacts the health status and lactation performance of dairy cows by limit-ing oxygen metabolism and transportation.However,the specific mechanism by which HS affects mammary function in cows remains unclear and requires further exploration.

The effect of ensiled paulownia leaves in a high-forage diet on ruminal fermentation,methane production,fatty acid composition,and milk production performance of dairy cows

Background:The use of industrial by-products rich in bioactive compounds as animal feeds can reduce greenhouse gas production.Paulownia leaves silage(PLS)was supplemented to dairy cows'diet and evaluated in vitro(Exp.1;Rusitec)and in vivo(Exp.2,cannulated lactating dairy cows and Exp.3,non-cannulated lactating dairy cows).The study investigated the PLS effect on ruminal fermentation,microbial populations,methane production and concentration,dry matter intake(DMI),and fatty acid(FA)proportions in ruminal fluid and milk.Results:Several variables of the ruminal fluid were changed in response to the inclusion of PLS.In Exp.1,the p H increased linearly and quadratically,whereas ammonia and total volatile fatty acid(VFA)concentrations increased linearly and cubically.A linear,quadratic,and cubical decrease in methane concentration was observed with increasing dose of the PLS.Exp.2 revealed an increase in ruminal p H and ammonia concentrations,but no changes in total VFA concentration.Inclusion of PLS increased ruminal propionate(at 3 h and 6 h after feeding),isovalerate,and valerate concentrations.Addition of PLS also affected several populations of the analyzed microorganisms.The abundances of protozoa and bacteria were increased,whereas the abundance of archaea were decreased by PLS.Methane production decreased by 11%and 14%in PLS-fed cows compared to the control in Exp.2 and 3,respectively.Exp.3 revealed a reduction in the milk protein and lactose yield in the PLS-fed cows,but no effect on DMI and energy corrected milk yield.Also,the PLS diet affected the ruminal biohydrogenation process with an increased proportions of C18:3 cis-9 cis-12 cis-15,conjugated linoleic acid,C18:1 trans-11 FA,polyunsaturated fatty acids(PUFA),and reduced n6/n3 ratio and saturated fatty acids(SFA)proportion in milk.The relative transcript abundances of the 5 of 6 analyzed genes regulating FA metabolism increased.Conclusions:The dietary PLS replacing the alfalfa silage at 60 g/kg diet can reduce the methane emission and improve milk quality with greater proportions of PUFA,including conjugated linoleic acid,and C18:1 trans-11 along with reduction of SFA.

Predicting nitrogen use efficiency,nitrogen loss and dry matter intake of individual dairy cows in late lactation by including mid‑infrared spectra of milk samples

Background Nitrate leaching to groundwater and surface water and ammonia volatilization from dairy farms have negative impacts on the environment.Meanwhile,the increasing demand for dairy products will result in more pollution if N losses are not controlled.Therefore,a more efficient,and environmentally friendly production system is needed,in which nitrogen use efficiency(NUE)of dairy cows plays a key role.To genetically improve NUE,extensively recorded and cost-effective proxies are essential,which can be obtained by including mid-infrared(MIR)spectra of milk in prediction models for NUE.This study aimed to develop and validate the best prediction model of NUE,nitrogen loss(NL)and dry matter intake(DMI)for individual dairy cows in China.Results A total of 86 lactating Chinese Holstein cows were used in this study.After data editing,704 records were obtained for calibration and validation.Six prediction models with three different machine learning algorithms and three kinds of pre-processed MIR spectra were developed for each trait.Results showed that the coefficient of determination(R2)of the best model in within-herd validation was 0.66 for NUE,0.58 for NL and 0.63 for DMI.For external validation,reasonable prediction results were only observed for NUE,with R2 ranging from 0.58 to 0.63,while the R2 of the other two traits was below 0.50.The infrared waves from 973.54 to 988.46 cm−1 and daily milk yield were the most important variables for prediction.Conclusion The results showed that individual NUE can be predicted with a moderate accuracy in both within-herd and external validations.The model of NUE could be used for the datasets that are similar to the calibration dataset.The prediction models for NL and 3-day moving average of DMI(DMI_a)generated lower accuracies in within-herd validation.Results also indicated that information of MIR spectra variables increased the predictive ability of models.Additionally,pre-processed MIR spectra do not result in higher accuracy than original MIR spectra in the external validation.These models will be applied to large-scale data to further investigate the genetic architecture of N efficiency and further reduce the adverse impacts on the environment after more data is collected.

Evaluation of Holstein cows with different tongue‑rolling frequencies:stress immunity,rumen environment and general behavioural activity

Background The tongue-rolling behaviour of cows is regarded as an outward sign of stressed animals in a low welfare status.The primary aim of this observational study was to evaluate the association between the frequency of tongue-rolling behaviour and its physiological function.The secondary aim was to explore the relationship between general activities and the frequency of tongue-rolling behaviour of cows.A total of 126 scan sampling behavioural observations were collected over 7 d on 348 Holstein cows with the same lactation stage in the same barn.The tongue-rolling frequency was defined as the number of tongue-rolling observations as a percentage to the total observations per individual cow.According to their tongue-rolling frequency,the cows were grouped into the CON(no tongue-rolling),LT(frequency 1%),MT(frequency 5%),and HT(frequency 10%)groups.Six cows from each group were randomly selected for sampling.Serum samples,rumen fluid,milk yield,and background infor-mation were collected.The general behaviour data during 72 continuous hours of dairy cows,including eating time,rumination time,food time(eating time+rumination time),and lying time,were recorded by the collar sensor.Results Cortisol(P=0.012),γ-hydroxybutyric acid(P=0.008),epinephrine(P=0.030),and dopamine(P=0.047)levels were significantly higher in tongue-rolling groups than in the CON group.Cortisol levels and tongue-rolling frequency had a moderate positive correlation(linearly r=0.363).With the increase in tongue-rolling frequency,the rumen pH decreased first and then increased(P=0.013),comparing to the CON group.HT cows had significantly less food time than CON cows(P=0.035).The frequency of tongue-rolling had a moderate negative relationship with rumination time(r=-0.384)and food time(r=-0.492).Conclusions The tongue-rolling behaviour is considered as a passive coping mechanism,as the stress response in cows with high tongue-rolling frequency increased.Food intake and rumination activities were all closely related to the occurrence of tongue-rolling behaviour.