Stage Of Lactation Research Articles

Biochemical, Molecular, Postmortem and Histopathological Characterization of Bovine Theilerioses at Different Stages of Production and Reproduction

Theilerosis is the most important common vector (Tick) born and hemoprotozoan diseases (TBDS) which pose a serious threat to the livestock population in terms of mortality, reduced milk yield and lowered draft power. The disease is having impact on biochemistry and systemic functions affecting at different stages of production and reproduction of dairy cattle as well as there is lack of accurate diagnosis of this disease. A total 1900 cases were suspected for theileriosis on the basis of clinical signs and total 950 cases were found positive for theileriosis on the basis of blood smear examination. As per the stages of pregnancy and lactation, the cases were classified as cows in early pregnancy, cows in late pregnancy, cows in post parturient stage, cows in early and late lactation period. Biochemical alterations like increased AST, ALT and BUN level indicating liver and kidney dysfunctions in all the groups and significantly higher in post parturient group. The serum phosphorus, calcium and magnesium level decreased in all the affected groups and mostly in late pregnancy period and post parturient stage indicating metabolic disturbances during the disease which were aggravated during theileriosis. Through molecular diagnosis 114 cows (65.51%) were found positive for T. annulata and 41 cows (22.9%) were found positive for T. orientalis and 19 cows (10.9%) were found positive for both Theileria annulata and Theileria orientalis. Phylogenetic analysis revealed the accession number for Theileria annulata was OQ230445 which is having 100% similarity with puri isolate and 98% similarity with Khorda isolate and the accession number for T. orientalis was OQ 230446 having 85% similarity with Khorda isolate. On necropsy, the animals were weak, debilitated with atrophy of the muscles. In some cases, the liver was enlarged, markedly congested and in some cases yellowish tinged surface and cut edges with distension of gall bladder was evident. Abomasal ulcers were distinct and considered as pathognomonic. On histopathological examination, the liver revealed necrosis of hepatocytes with sinusoidal congestion and infiltration of mononuclear cells. In lymphnode, there was depletion of lymphocytes in lymphoid follicles with congestion and haemorrhage. Pulmonary edema was also evident in few cases. The combined approach involving biochemical, molecular, Post-mortem and histopathological characters were found to be fruitful in diagnosis of the bovine theileriosis at different stages of production and reproduction with optimum specificity.

The Assessment of Iodine Concentrations in Colostrum and Breast Milk Using ICP-MS: The Impact of Delivery Type, Thyroid Function and Gestational Diabetes-A Pilot Study.

Considering the spectrum of benefits of breast milk feeding, determining the essential components of an infant's only food-mother's milk-seems justified, especially in the case of those whose deficiency (e.g., iodine) may result in developmental disorders. The main aim of this study was the determination of the total iodine content of breast milk (including colostrum and mature milk). A secondary objective was to assess the influence of factors such as the type of delivery, hypothyroidism, gestational diabetes or the stage of lactation on this parameter. The study materials were colostrum and milk after 1 (n = 14), 2 and 3 months (n = 8) of lactation with a range of iodine concentrations (µg/L): 195-1648 and 170-842, 174-650 and 273-751, respectively. Iodine was determined using the inductively coupled plasma mass spectrometry (ICP-MS). Multivariate statistical analysis revealed, e.g., that delivery by caesarean section or dose of L-thyroxine taken by women to normalise thyroid hormones, had a significant effect on iodine concentrations in breast milk. Further research aimed at assessing the quality of breast milk should also include determining the factors influencing it.

Complete characterization of the fatty acid profile of mare milk from commercial semi-extensive farms during lactation

The present study aimed to thoroughly describe the profile of fatty acids in mare milk from farms with different management systems and changes during lactation. Eighteen mares belonging to three commercial farms (6 mares per farm) were milked during the complete lactation period (six months). Fat content was determined by infrared spectroscopy, while fatty acid methyl esters were analyzed using a GC-FID. Mare milk, in general, contained 47.5 % saturated, 25.3 % monounsaturated, and 26.5 % polyunsaturated fatty acids. A high proportion of 18:2n-6 and 18:3n-3 but a low concentration of their long-chain metabolites was observed, and seven branched-chain fatty acids were identified. Stage of lactation significantly influenced the content of most individual fatty acids, and in general, milk from mares managed under pasture-based feeding systems showed a higher content of n-3 polyunsaturated fatty acids. This study provides new insights into mare milk FA composition and into dynamics of mare milk nutritional quality as affected by lactation stage and grazing intensity.

Evaluation of Rumen Microbes For Milk Fat Yield in Cattle Based on 16S rRNA Amplicon Metagenomic Sequencing

Background: Ruminal microbes support growth, lactation and maintenance of animals by providing energy and protein yielding nutrients. Metagenomics is the study of microbial communities directly in their natural environments such as soil, water, gut samples etc. The 16S rRNA gene sequencing is one of the basic genetic markers for the characterisation of prokaryote microorganism community. Current study exploited complex gut microbial communities present in cattle rumen based on variation in milk fat yield. Methods: The study was conducted in cattle reared at University Livestock Farm, Kerala Veterinary and Animal Sciences University. Twelve healthy cattle in the initial stages of lactation (less than three months) were selected and divided into two groups of six each based on high and low milk fat composition. Rumen samples were collected and DNA was isolated. Amplicons of 16S rRNA has been generated from metagenomic DNA targeting V3 and V4 hyper variable regions. Qiime2 was used for analysis for 16S rRNA amplicon sequencing. Result: Results revealed that a total of 38,28,241 sequences were obtained after demultiplexing. Majority of sequence length ranged around 295 to 301 nucleotides for forward reads and 216 to 300 nucleotides for reverse reads. After denoising, a total of 6,62,498 sequences were obtained. Clustering (de-replication) produced 711 unique sequence features. In kingdom level of taxonomy, for bacterial kingdom, there was no significant difference in abundance of organisms for high milk fat yield and low milk fat yield cows. For archaea, significant difference observed between abundance of high milk fat and low milk fat groups at five per cent level in the current study.

Mammary fat globules as a source of mRNA to model alterations in the expression of some milk component genes during lactation in bovines

BackgroundThe milk's nutritional value is determined by its constituents, including fat, protein, carbohydrates, and minerals. The mammary gland's ability to produce milk is controlled by a complex network of genes.Thereby, the fat, protein, and lactose synthesis must be boost in milk to increase milk production efficiency. This can be accomplished by fusing genetic advancements with proper management practices. Therefore, this study aimed to investigate the association between the Lipoprotein lipase (LPL), kappa casein CSN3, and Glucose transporter 1 (GLUT1) genes expression levels and such milk components as fat, protein, and lactose in different dairy breeds during different stages of lactation.MethodsTo achieve such a purpose, 94 milk samples were collected (72 samples from 36 multiparous black-white and red-white Holstein–Friesian (HF) cows and 22 milk samples from 11 Egyptian buffaloes) during the early and peak lactation stages. The milk samples were utilized for milk analysis and genes expressions analyses using non- invasive approach in obtaining milk fat globules (MFGs) as a source of Ribonucleic acid (RNA).ResultsLPL and CSN3 genes expressions levels were found to be significantly higher in Egyptian buffalo than Holstein–Friesian (HF) cows as well as fat and protein percentages. On the other hand, GLUT1 gene expression level was shown to be significantly higher during peak lactation than early lactation. Moreover, lactose % showed a significant difference in peak lactation phase compared to early lactation phase. Also, fat and protein percentages were significantly higher in early lactation period than peak lactation period but lactose% showed the opposite pattern of Egyptian buffalo.ConclusionTotal RNA can be successfully obtained from MFGs. The results suggest that these genes play a role in glucose absorption and lactose synthesis in bovine mammary epithelial cells during lactation. Also, these results provide light on the differential expression of these genes among distinct Holstein–Friesian cow breeds and Egyptian buffalo subspecies throughout various lactation phases.

Comparative analysis of lipid composition in colostrum and mature milk from women of seven Chinese ethnic groups

This study compared the lipid content, total and sn-2 fatty acids, and the levels of 1, 3-dioleoy-2-palmitoyl glycerol (OPO), 1-oleoyl-2-palmitoyl-3-linoleoyl glycerol (OPL), and 1, 3-linoleoyl-2-palmitoyl glycerol (LPL) in colostrum and mature milk (n = 122) from seven ethnic groups in China. Compared with the Han breast milk, the content of saturated fatty acid (SFA) and trans fatty acid (TFA) in the breast milk of ethnic groups (especially in Uygur) was higher, while monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) were lower. This disparity may be attributed to the higher consumption of meat and diary products. In terms of the distribution of fatty acids and the content of triacylglycerol (TAG), ethnic groups and Han showed consistency. The OPO, OPL, and LPL in colostrum (0.16 ± 0.06, 0.17 ± 0.08, 0.09 ± 0.04 g 100 mL−1) were significantly lower than those in mature milk (0.28 ± 0.11, 0.26 ± 0.09, 0.16 ± 0.07 g 100 mL−1). The results have shown that the composition and content of total and sn-2 FAs in breast milk were affected by lactation stage, ethnic minority background, and maternal diets. This study contributed to the enhancement of the Chinese breast milk lipid database and offered a scientific foundation for formulating lipid compositions in infant formulas tailored to specific ethnic groups.

The prevalence and factors associated with mastitis in dairy cows kept by small-scale farmers in Dodoma, Tanzania

Bovine mastitis is among the major diseases of economic importance in the dairy industry worldwide. Hygienic conditions during milking and housing are important determinants of mastitis infections. However, arid and semi-arid areas have a scarcity of water, which is an essential component of cleanliness. Thus, the study determined the prevalence of mastitis and associated factors in Dodoma, a semi-arid region in Tanzania. Three hundred and sixty-eight lactating cows were selected randomly from 114 farms in the Dodoma urban district for mastitis determination based on clinical signs and the California Mastitis Test. About 59.8 % of the cows had mastitis, and the subclinical type dominated. Factors associated with mastitis prevalence were cleanliness (hand and udder washing before milking), farmers' awareness of mastitis, the cow's parity and lactation stage, and herd size. Milk yield was not associated with the mastitis status of the cow but was related to the breed of the cow, whether warm or cold water was used to wash the cow's udder, parity, and lactation stage. Improvement in education on the importance of hygiene is necessary, as 38.6 % of the farmers were unaware of mastitis. Further detailed studies on microbiology, such as bacteriologic culture and polymerase chain reaction, are recommended to formulate interventions.

Multispecies pasture diet and cow breed impacts on milk composition and quality in a seasonal spring-calving dairy production system

In recent years, there has been significant emphasis on the composition of pasture-based cow feed and the potential benefits of incorporating multispecies swards to improve sustainability and biodiversity. This study compared the effects of a conventional perennial ryegrass (PRG) monoculture supported by high chemical nitrogen (N) usage with a low chemical N application multispecies sward system (MSS) on the composition and quality of milk across lactation using spring-calving Holstein-Friesian (HF) and Jersey Holstein-Friesian (JFX) cows. Bulk milk samples (n = 144) were collected from each group at morning and evening milking on a weekly basis (n = 36) throughout lactation and analyzed for gross composition and physico-chemical properties. Cow breed had a significant impact on milk profile, with milk from HF cows having significantly smaller milk fat globule (MFG) size, higher instability index values, higher yield, and lower total solids levels, compared with JFX cows. Notably, HF cows had increased milk total solids and fat levels when fed on MSS, as opposed to the PRG-fed HF cows. Feeding MSS pasture increased creaming velocity values in mid and late lactation, and resulted in similar milk gross composition to PRG. In comparison to PRG, MSS-fed groups showed significantly increased total solids yield, including higher levels of protein and fat yield. In late lactation, MSS feeding was associated with reduced MFG size. All physicochemical properties studied (MFG size, creaming velocity, instability index) showed decreasing values from early to late lactation stage. Overall, these findings demonstrate the significant effects of cow diet, breed and stage of lactation on compositional and physico-chemical characteristics of milk, with important implications for milk processing and dairy product quality.

Effect of Birth Season and Lactation Stages on the Level of Some Hormones and Milk Yield of Holstein x Janoubi Cows

Effect of Birth Season and Lactation Stages on the Level of Some Hormones and Milk Yield of Holstein x Janoubi Cows

Unmasking seasonal cycles in a high-input dairy herd in a hot environment: How climate shapes dynamics of milk yield, reproduction, and productive status

This study aimed to predict the annual herd milk yield, lactation, and reproductive cycle stages in a high-input dairy herd in a zone with prolonged thermal stress. Also, the impact of climatic conditions on milk yield and productive and reproductive status was assessed. An autoregressive integrated moving average (ARIMA) model was used in data fitting to predict future monthly herd milk yield and reproductive status using data from 2014 to 2020. Based on the annual total milk output, the highest predicted percentage of milk yield based on the yearly milk production was in February (9.1%; 95% CI = 8.3–9.9) and the lowest in August (6.9%; 95% CI = 6.0–7.9). The predicted highest percentage of pregnant cows for 2021 was in May (61.8; 95% CI = 53.0–70.5) and the lowest for November (33.2%; 95% CI = 19.9–46.5). The monthly percentage of dry cows in this study showed a steady trend across years; the predicted highest percentage was in September (20.1%; CI = 16.4–23.7) and the lowest in March (7.5%; 4.0–11.0). The predicted days in milk (DIM) were lower in September (158; CI = 103–213) and highest in May (220; 95% CI = 181–259). Percentage of calvings was seasonal, with the predicted maximum percentage of calvings occurring in September (10.3%; CI = 8.0–12.5) and the minimum in April (3.2%; CI = 1.0–5.5). The highest predicted culling rate for the year ensuing the present data occurred in November (4.3%; 95% CI = 3.2–5.4) and the lowest in April (2.5%; 95% CI = 1.4–3.5). It was concluded that meteorological factors strongly influenced rhythms of monthly milk yield and reproductive status. Also, ARIMA models robustly estimated and forecasted productive and reproductive events in a dairy herd in a hot environment.

Understanding the dynamics of mastitis in milk yield: decoding onset and recovery patterns in response to mastitis occurrence

No recent study attempted to model daily milk losses before and after mastitis onset and the moment when it begins. Thus, we aimed to describe the impact of mastitis on milk production based on mastitis level and moment of occurrence. We used data from 11 dairy farms, and the data set consisted of 885,759 daily individual milk test records from 3,508 cows in different lactations, with an average milk yield from January 2017 to December 2022. We modeled the impact of mastitis severity [i.e., 1 (mild) and 2 (severe)] based on the drop and recovery of milk yield following 3 steps. First, we removed milk recorded on the day of diagnosis of mastitis from the data set and fitted a Wood's Curve for each cow and parity. Second, we returned the mastitis data to the data set and estimated the residual milk loss due to mastitis from 15 d before to 30 d after the mastitis event. Third, we used generalized additive mixed effect models to estimate the residual milk loss, including farm as a random effect. In addition to the random effect of the farm, we also included the predicted value of mastitis, the day effect before and after mastitis incidence, and the interaction between the predicted value of mastitis and days. On average, mastitis level 2 resulted in a more severe milk yield drop in all represented stages of lactation (80, 170, and 260 d in milk), suggesting a higher loss close to the lactation peak, approximately 130 kg more than mastitis level 1. Moreover, the occurrence of mastitis case level 1 during early phase of lactation (DIM 80) can cause an average milk loss of 158 L and a ML 2, an average loss of 288 L. The estimations suggest that milk drop occurs 14 to 4 d before mastitis onset and can last until 15 to 25 d from the diagnosis, which would be the necessary time for a cow to reestablish their predicted milk yield. Therefore, our study brings new perspectives to investigate milk yield drop and recovery due to mastitis infections and how much mastitis can deplete and impair milk production.

Advancing Dairy Herd Health: Predictive Models for Hoof Trimming in Lameness Management

Hoof lesions and lameness in cattle is currently a serious problem in the dairy industry which significantly affects the health and welfare of animals. Predictive modelling offers a promising solution by leveraging data analytics to anticipate when an animal may require hoof trimming, thereby enhancing proactive lameness management strategies. The aim of this study was to develop models on hoof trimming intervention on lameness in dairy cattle before and after hoof trimming. In this study twenty lame cows were selected and lameness index score was given to them (0-5 score). Lameness index scores were recorded before week of hoof trimming (HT) and after hoof trimming intervention it was recorded on 0thday, 3rdday, 6thday, 8thday,11thday and 14thday. To predict the lameness, best fit models were constructed using different independent variables which were significantly influencing lameness. The reliable model was applied to draw the significant interference based on the coefficient of determination (R²). Only those independent variables which were significantly influencing lameness were used to construct prediction models. Among all the variables used for multiple regression analysis, age, parity, milk yield, milk pH, stage of lactation and dung pH was attributing significantly to the prediction of lameness in all studied lame dairy cows..

The study of the embryotoxic effect of the drug "Endoseptam"

Most diseases affecting cows in the early stages of lactation are of an inflammatory nature and are associated with a decrease in reproductive function. Unfavorable environmental factors cause metabolic disorders, hormonal disorders and a decrease in the body's resistance. Favorable conditions are created for the development of opportunistic microflora in the reproductive organs of cows, causing inflammatory processes that can lead to infertility, decreased milk productivity and large economic losses. All this justifies the great interest shown in the study of obstetric and gynecological pathology by veterinary specialists, who consider the development and implementation of preventive and therapeutic measures to combat infertility as an urgent and serious task. Postpartum endometritis is a common disease in dairy herds. Antibiotics in treatment regimens become ineffective because pathogens infecting the uterine cavity develop resistance to them. Complex remedies are needed that have antiseptic, myotropic, wound healing and anti-inflammatory effects. A therapeutic veterinary drug «Endoseptam» has been developed, its high effectiveness in the prevention and treatment of endometritis has been proven. Studies are being conducted to establish the safety profile of the product. This article presents the results of studying the embryotoxic effect of the newly developed drug. White rats were used in the experiment. The drug was administered to laboratory animals per os at doses of 2000 mg/ kg and 20,000 mg / kg during 19 days of pregnancy. On the 20th day of pregnancy, some of the animals were euthanized and autopsied to assess the effects of «Endoseptam» on developing embryos/fetuses. The remaining part of the animals in the experiment was monitored to record the growth and development of offspring. The data obtained confirm the absence of toxic effects on developing embryos/fetuses of a complex remedy for the prevention and treatment of endometritis. When observing the physical development of offspring, there were no violations of embryonic development manifested in the postnatal period of life. The drug «Endoseptam» does not have an embryotoxic effect.

Profiling several key milk miRNAs and analysing their signalling pathways in dairy sheep breeds during peak and late lactation.

The comprehensive understanding of microRNAs (miRNAs) in sheep milk during various lactation periods and their impact on milk yield and composition remains limited. This study aimed to investigate the expression patterns of four highly expressed miRNAs in sheep milk and their association with milk composition and yield parameters during peak and late lactation stages. A total of 40 healthy 4-year-old Akkaraman (n = 20) and Awassi (n = 20) ewes registered with the Ministry of Agriculture and Forestry of the Republic of Türkiye were used in the present study. For miRNA isolation from milk, the Qiagen miRNeasy Serum/Plasma Advanced Kit was utilised following the manufacturer's instructions. The expression levels of miRNAs were assessed using Qiagen miRNA PCR Assays. The significant fold changes in the expression levels of oar-miR-30a-5p, oar-miR-148a and oar-miR-181a were observed between peak and late lactation periods in the Awassi sheep breed. Conversely, only oar-miR-30a-5p and oar-miR-148a exhibited statistically significant changes in the Akkaraman sheep breed during the same lactation periods. Furthermore, oar-miR-21-5p demonstrated a significant fold change exclusively in peak lactation compared to Akkaraman and Awassi ewes. The findings suggest that the expression of the analysed miRNAs is influenced by both the lactation stage and different sheep breeds. This study offers valuable insights into the relationship between key miRNA expressions in sheep milk and milk composition and yield parameters during peak and late lactation, contributing to the existing knowledge in this field.

Makroelementi u mlijeku lakon ovaca u ovisnosti o stadiju laktacije

This research aspires to demonstrate how the stage of lactation influences the content of macroelements in the Lacaune sheep milk. The research was conducted with 30 Lacaune sheep in their fourth lactation during the early (60 days), middle (120 days), and late lactation stages (180 days). The macroelement concentration (Ca, K, Na, and Mg) of the Lacaune sheep milk was determined by the ICP. As lactation progressed, a significant increase in the concentrations of Mg and Na and a significant decrease in K were observed in the Lacaune sheep milk. A stability of Ca and P concentrations during lactation was demonstrated by the lack of significant variation in the Lacaune sheep milk, based on the stage of lactation. A significant positive correlation was detected between Ca:Mg, Ca:P, and K:P, as well as a significant negative correlation between Mg:K and K:Na. The obtained results prove a significant effect of lactation stage on the content of most macroelements in the Lacaune sheep milk, except Ca and P, which should be included in the research scheme.

Kidney function, but not nitrogen excretion, differs between Brown Swiss and Holstein dairy cows

Brown Swiss (BS) cows have greater urea concentrations in milk and blood compared with Holstein (HO) cows. We tested the hypothesis that BS and HO cows differ in kidney function and nitrogen excretion. Blood, saliva, urine, and feces were sampled in 31 multiparous BS and 46 HO cows kept under identical feeding and management conditions. Samples were collected at different lactational stages after the monthly DHIA control test-day. To test the glomerular filtration rate (GFR) and urea excretion, concentrations of creatinine and urea were measured in serum, urine, and saliva. As an additional marker to estimate GFR, we determined symmetric dimethylarginine (SDMA) in serum. Feces were analyzed for dry matter content and nitrogen concentration. Data on milk urea and protein concentrations, and daily milk yield were obtained from the monthly DHIA test-day records. The effects of breed, time, and parity number on blood, saliva, urine, feces, and milk parameters were evaluated with the GLM procedure with breed, time, and parity number as fixed effects. Differences between BS and HO were assessed by the Tukey-corrected t-test at P < 0.05. Concentrations of urea, creatinine, and SDMA in serum, were greater in BS than in HO cows (P < 0.01): 5.46 ± 0.19 vs 4.72 ± 0.13 mmol/L (urea), 105.96 ± 2.23 vs 93.07 ± 1.50 mmol/l (creatinine), and 16.78 ± 0.69 vs 13.39 ± 0.44 µg/dL (SDMA). We observed a greater urea concentration in BS cows (25.8 ± 0.7 vs 21.8 ± 0.7 mg/dL) and protein content in milk (3.70 ± 0.08 vs 3.45 ± 0.07%) than in HO cows (P < 0.01). Urea and creatinine concentrations in urine and saliva did not differ among breeds. No differences between BS and HO were observed for milk yield, fecal DM, and fecal nitrogen content. Dry matter intake and body weight were similar in BS and HO cows (P > 0.05). Despite greater urea, creatinine, and SDMA concentrations in blood as well as a higher milk urea content in BS compared with HO, respective concentrations in urine did not differ between breeds. In conclusion, our results demonstrate a lower renal GFR in BS compared with HO cows, thereby contributing to the greater plasma urea concentration in BS cows. However, estimation of nitrogen excretion via milk, urine, and feces does not entirely reflect nitrogen turnover within the animal.

Effect of drinking water frequency on nutrient digestibility in lactating Deoni cows

A trial was conducted to study the effect of drinking water frequency on production performance of lactating Deoni cows with the objectives to assess the effect of different drinking water frequency on water intake, dry matter intake and nutrient digestibility. Nine lactating Deoni cows were selected on the basis of age, body weight, parity, stage of lactation and milk yield and divided into three groups comprising of 3 animals in each group. The experiment was conducted in three periods in Switch over design in order to expose each group to all the three treatments. The control treatment (T1) received ad libitum drinking water whereas, treatment T2 and T3 received drinking water twice and thrice daily, respectively. Significantly higher water intake was noticed in thrice daily watering than rest of the treatments, while intake of water was decreased in twice daily watering compared to other treatments. Dry matter intake was positively correlated with water intake. Significant increase in dry matter intake was observed in ad libitum and thrice daily watering whereas, dry matter intake was decreased when frequency of watering adjusted to twice daily. The apparent digestibilities of all the nutrients including DM, CP, CF, EE and NFE was significantly improved due to restriction of drinking water to twice daily (T2). However, ad libitum and thrice daily watering were at par for DM, CP, CF and NFE digestibility except EE digestibility differ significantly in all the treatments.

Multiomics analysis revealed that the metabolite profile of raw milk is associated with the lactation stage of dairy cows and could be affected by variations in the ruminal microbiota

The nutritional components and quality of milk are influenced by the rumen microbiota and its metabolites at different lactation stages. Hence, rumen fluid and milk samples from 6 dairy cows fed the same diet were collected during peak, early mid- and later mid-lactation. Untargeted metabolomics and 16S rRNA sequencing were applied for analyzing milk and rumen metabolites, as well as rumen microbial composition, respectively. The levels of lipid-related metabolites, L-glutamate, glucose-1-phosphate and acetylphosphate in milk exhibited lactation-dependent attenuation. Maltol, N-acetyl-D-glucosamine, and choline, which are associated with milk flavor or coagulation properties, as well as L-valine, lansioside-A, clitocine and ginsenoside-La increased significantly in early mid- and later mid-lactation, especially in later mid-lactation. The obvious increase in rumen microbial diversities (Ace and Shannon indices) were observed in early mid-lactation compared with peak lactation. Twenty-one differential bacterial genera of the rumen were identified, with Succinivibrionaceae_UCG-001, Candidatus Saccharimonas, Fibrobacter, and SP3-e08 being significantly enriched in peak lactation. Rikenellaceae_RC9_gut_group, Eubacterium_ruminantium_group, Lachnospira, Butyrivibrio, Eubacterium_hallii_group, and Schwartzia were most significantly enriched in early mid-lactation. In comparison, only 2 bacteria (unclassified_f__Prevotellaceae and Prevotellaceae_UCG-001) were enriched in later mid-lactation. For rumen metabolites, LPE(16:0), L-glutamate and L-tyrosine had higher levels in peak lactation, whereas PE(17:0/0:0), PE(16:0/0:0), PS(18:1(9Z)/0:0), L-phenylalanine, dulcitol, 2-(methoxymethyl)furan and 3-phenylpropyl acetate showed higher levels in early mid- and later mid-lactation. Multiomics integrated analysis revealed that a greater abundance of Fibrobacter contributed to phospholipid content in milk by increasing ruminal acetate, L-glutamate and LysoPE(16:0). Prevotellaceae_UCG-001 and unclassified_f_Prevotellaceae provide substrates for milk metabolites of the same category by increasing ruminal L-phenylalanine and dulcitol contents. These results demonstrated that milk metabolomic fingerprints and critical functional metabolites during lactation, and the key bacteria in rumen related to them. These findings provide new insights into the development of functional dairy products.

The influence of different stress factors on the production and quality of sheep milk

Around 10.5 million tonnes of sheep milk are produced worldwide, and around 3.1 million tonnes in Europe. In Europe, sheep milk production has stagnated slightly in recent years and currently accounts for around 1/3 of the global production. Due to its high content of dry matter, milk fat, total protein and casein, sheep milk is an excellent raw material for cheese production. Milk processing and cheese making are not only economically important, but also part of the cultural heritage based on a long tradition, often taking place in rural and less developed areas. Milk production and quality are very complex and are influenced by numerous factors, the most important of which are breed, feeding and body condition, parity and stage of lactation, milking and udder health, and environmental factors. In addition, different types of stress such as heat stress, nutritional stress, weaning stress, shearing stress, stress of regrouping, etc. have a significant impact on the welfare and health of the sheep as well as on the quantity of milk produced, its chemical composition, processing characteristics and the economic efficiency of the flock. In recent years, due to climate change, there has been an increasing number of studies on the effects of heat stress on the reproductive and production characteristics of sheep, as well as on their welfare and health. In addition, heat stress is often associated to the feed and the lack of water. The effects of stress are particularly pronounced in extensive sheep farming and milk production, which are prevalent in sheep farming. The aim of this paper is to describe the effects of the main types of stress on the quantity and chemical composition of sheep milk and on animal welfare.

Analysis of 18 elements in Alpine goat milk in the first third of lactation

The research objective was to examine the influence of the first third of the lactation stage on 18 mineral elements in Alpine goat milk. The research was carried out on 20 goats of the French-Alpine breed, which were on average 5 years old and in the fourth lactation. The goats were monitored on the 30th and the 90th day of lactation. Their milk was analysed for chemical composition by the infrared spectroscopy. By means of inductively coupled plasma (ICP), a total of 18 minerals were analysed (Ca, P, K, Na, K, Mg, Fe, Zn, Cu, Se, Mn, Mo, Co, Cr, Ni, Cd, Pb, As and Hg). The period of milk sampling in the first third of lactation significantly influenced the changes in concentrations of Na, Se, Mo, Cr, Ni and As. Significantly higher concentrations of Na and As were determined in milk sampled on the 90th day, while lower concentrations of Se, Mo, Cr and Ni were determined in milk sampled on the 30th day of the first third of lactation. Analysis of the correlation coefficients between the investigated trace elements and the selected toxic elements in Alpine goat milk showed a significantly positive correlation between Ca:Mg, Ca:P, Ca:Co, Ca:Ni, Ca:Mo; Mg:P, Fe:As, Pb:Cd and P:Ni. In the first third of lactation, Alpine goat milk contained a very low concentration of heavy metals. The described changes indicate that Alpine goat milk is rich in essential elements, while the concentration of toxic elements is very low in the first third of lactation.