Primiparous Holstein Dairy Cows Research Articles

Untargeted Metabolomic Analysis of Lactation-Stage-Matched Human and Bovine Milk Samples at 2 Weeks Postnatal.

Epidemiological data demonstrate that bovine whole milk is often substituted for human milk during the first 12 months of life and may be associated with adverse infant outcomes. The objective of this study is to interrogate the human and bovine milk metabolome at 2 weeks of life to identify unique metabolites that may impact infant health outcomes. Human milk (n = 10) was collected at 2 weeks postpartum from normal-weight mothers (pre-pregnant BMI < 25 kg/m2) that vaginally delivered term infants and were exclusively breastfeeding their infant for at least 2 months. Similarly, bovine milk (n = 10) was collected 2 weeks postpartum from normal-weight primiparous Holstein dairy cows. Untargeted data were acquired on all milk samples using high-resolution liquid chromatography-high-resolution tandem mass spectrometry (HR LC-MS/MS). MS data pre-processing from feature calling to metabolite annotation was performed using MS-DIAL and MS-FLO. Our results revealed that more than 80% of the milk metabolome is shared between human and bovine milk samples during early lactation. Unbiased analysis of identified metabolites revealed that nearly 80% of milk metabolites may contribute to microbial metabolism and microbe-host interactions. Collectively, these results highlight untargeted metabolomics as a potential strategy to identify unique and shared metabolites in bovine and human milk that may relate to and impact infant health outcomes.

O48 Adaptation to grazing of primiparous Holstein dairy cows according to feeding strategy in the first 21 days postpartum

O48 Adaptation to grazing of primiparous Holstein dairy cows according to feeding strategy in the first 21 days postpartum

68 Characterization of Bovine Extracellular Vesicles Isolated from Colostrum

Abstract Bovine colostrum is composed of a variety of biologically active compounds including microRNAs (miRNA), which are found within extracellular vesicles (EVs). Newborn calves are agammaglobulinemic. Hence, the ability of the bovine neonate to fight off pathogens is therefore almost entirely dependent upon colostrum ingestion. Extracellular vesicle-derived miRNAs may have a crucial role in the regulation of the immune response. Thus, we aimed to characterize the EVs morphology from bovine colostrum using stimulated emission depletion (STED) super resolution microscopy. Bovine colostrum samples (approx. 3-4 h after parturition) were collected from primiparous Holstein dairy cows (n = 10) at a commercial dairy farm. Colostrum samples (15 mL) were subjected to a series of centrifugation steps to achieve defatted supernatant and to label EV pellets with EV specific markers. The EV pellets were resuspended in 100µL of 1 x PBS for EV staining methods or resuspended in 1 mL of trizol reagent for further miRNA isolation. The EVs suspensions were incubated with a primary polyclonal antibody anti-CD63 and with a secondary antibody (Alexa Fluor 594) for approximately 90 minutes each. Labeled EV-antibody complex were analyzed using confocal and STED microscopy. Based on the confocal and super resolution STED imaging capability obtained from the EVs-derived from bovine colostrum (Figure 1), labeled EVs with anti-CD63 and the enhanced resolution of STED over conventional confocal imaging, allowed to image the EVs at their actual size (30-200 nm). Further in-depth view on EV morphology, marker proteins expressed on the membrane, and size will contribute to our understanding of EVs-derived from colostrum and their functions. This will be crucial in studies to evaluate EVs uptake by intestinal cells for the correct identification of compartments involved in subcellular trafficking.

Effects of fennel (Foeniculum vulgare) seed powder addition during early lactation on performance, milk fatty acid profile, and rumen fermentation parameters of Holstein cows

IntroductionAromatic and herbal plants usage as feed additives have become a new tendency in dairy cows’ nutrition to enhance animal performance. This experiment was performed to study the effects of supplementing fennel seed powder (FSP) to diets during early lactation on performance, milk fatty acid (FA) profile, and rumen fermentation of Holstein dairy cows.MethodsTwenty-four primiparous Holstein dairy cows (10 ± 3 d in milk, 30 ± 2.1 Kg of milk/d, 610 ± 31 Kg body weight; mean ± SE) were balanced for actual milk yield and calving date (n = 8 per treatment) in a complete randomized design. Animals were allocated randomly to diets containing 0 g/d (0FSP), 25 g/d (25FSP), or 50 g/d (50FSP) FSP, individually top-dressed over the total mixed ration. The experimental period was 45 d consisting of the first 15 d for adaptation and the final 30 d for data collection and sampling.Results and discussionDry matter intake responded quadratically to FSP feeding, and cows fed 25FP treatment had greater DMI than 0FSP treatment. The average ruminal pH value decreased linearly as FSP increased in diets. Ruminal valerate and isovalerate proportion increased linearly as FSP inclusion in diets increased, while acetate proportion decreased and acetate:propionate ratio tended to decrease linearly. Increasing FSP in diets linearly increased serum glucose, globulin, and total protein concentrations. Milk yield increased linearly as FSP inclusion in diets increased, whereas milk composition was unaffected. Increasing FSP in diets linearly increased de novo and mixed FA and decreased preformed FA in milk. Dietary treatments did not affect saturated FA, whereas unsaturated FA, mono and poly unsaturated FA linearly decreased with increasing FSP inclusion in diets. Moreover, the content of C18:0 tended to decrease, and C18:1 cis-9 decreased linearly as FSP inclusion increased. Also, increasing the FSP level in diets decreased linearly non-esterified fatty acids and acetone concentrations in the milk. It could be concluded that FSP addition at 50 g/d could enhance performance of early lactating cows.

Feed intake, rumen fermentation and performance of dairy cows fed diets formulated at two starch concentrations with either conventional urea or slow-release urea

This study evaluated the effects of high and moderate starch diets by substituting corn grain with wheat and rice bran in diets containing slow-release urea (SU, protected into lipids matrix microencapsulation) or conventional urea (CU) on the performance of high producing dairy cows. Twenty-four multiparous (days in milk = 83 ± 14; milk yield = 47 ± 4.5 kg/d) and sixteen primiparous (days in milk = 83 ± 12; milk yield = 37.5 ± 2.5 kg/d) Holstein dairy cows were randomly assigned to 1 of 4 treatments in a 2 × 2 factorial arrangement of treatments with 2 dietary starch concentrations [moderate starch (MS; 260 g/kg of dry matter, DM) vs. high starch (HS; 320 g/kg of DM)] and two sources of urea (SU vs. CU). The experiment lasted 52 days (d), consisting of 10 d for covariate period, 21 d for adaptation, and 21 d for sampling. In a preliminary in vitro gas test, the gas production was higher for SU than CU at 0.5, 1, 2, 6, and 24 h post-incubation (P < 0.01). There were interactions between urea source and starch level for dry matter intake (DMI, P < 0.01), propionate proportion (P = 0.04), milk urea nitrogen (MUN, P = 0.09) and rumen NH3-N (P = 0.07) concentrations; the DMI (P = 0.01) was higher and propionate proportion (P = 0.05), MUN (tendency, P = 0.08) and rumen NH3-N (tendency, P = 0.06) were lower with high than moderate starch level in CU diet, but it was not different between the two starch levels in SU diet. Furthermore, the urea source and starch level interaction was significant for butyrate proportion (P = 0.04); the butyrate proportion (P = 0.03) was lower with high than moderate starch level in SU diet, but it was not different between the two starch levels in CU diet. Cows fed CU had greater milk fat (P < 0.01) and protein (P = 0.04) yield and milk fat content (P = 0.05) and tended to have a greater 35 g/kg fat corrected milk yield (P = 0.09) than cows fed SU. The total volatile fatty acids concentrations (P = 0.04) and milk protein content (P < 0.01) were greater in HS-fed cows than in MS-fed cows. Blood urea nitrogen concentration was higher at 2 (P = 0.02) and 4 (P = 0.03) h after feeding in CU-fed cows than in SU-fed cows. Apparent digestibility of starch was greater in HS-fed cows than in MS-fed cows (P < 0.01) and in CU-supplemented cows than in those who received SU (P = 0.05). Overall, the SU product used in this study reduced the rate of ruminal nitrogen release compared to CU; however, no advantages are observed with the addition of SU when compared with CU on high-production dairy cow performance. Moreover, the results suggest that the performance of high-producing dairy cows can be maintained when wheat and rice bran are used instead of corn grains at 150 g/kg of DM.

Effects of rumen-protected methionine and lysine on milk yield and milk composition inHolstein dairy cows consuming a corn grain and canola meal-based diet

Methionine (Met) and lysine (Lys) are thought to be the two most important amino acids for lactation performance. Met and Lys dietary supplementation can thus be an effective approach to improve amino acid balance for lactation performance, particularly in early lactation. The purpose of this study was to determine how rumen-protected (RP) Met + Lys affect milk production, milk composition, and feed efficiency in primiparous Holstein dairy cows fed a corn grain and canola meal-based diet for 60 days (8.5 weeks) following calving. Two hundred primiparous Holstein dairy cows were randomly assigned to one of two dietary treatments based on their expected calving date: 1) a basal diet; or 2) a basal diet supplemented with RP Met + Lys. Milk production and feed consumption were tracked on a daily basis, and milk components were tested once a week. During the trial, drinking water was always available in front of the dairy cows. The RP Met + Lys considerably increased (p < 0.05) milk yield (+ 2.20 kg/d), fat corrected milk yield (+ 2.18 kg/d) and feed efficiency but had no effect on dry matter intake (p > 0.05). There was no effect of treatment on either starting or final body weight (p > 0.05). Cows receiving RP Met + Lys, on the other hand, showed a tendency (p = 0.09) of reduced body condition score (BCS) losses between weeks 1 and 8. The RP Met + Lys increased (p < 0.05) the proportion of milk fat, but had no effect on the other milk composition markers (p > 0.05). Except for milk crude protein, the yields of fat, true protein, lactose, and energy in milk were higher (p < 0.05) in cows fed RP Met + Lys vs. control cows. The results indicate that supplementing with RP Met + Lys after the first calving has a considerable impact on subsequent milk and milk fat production, as well as the yield of the majority of milk nutrients.

Shifts in the Holstein dairy cow milk fat globule membrane proteome that occur during the first week of lactation are affected by parity

BackgroundThe milk fat globule membrane (MFGM) proteomes of colostrum and transition milk are rich sources of proteins that are likely important for neonatal calf health. In addition, characterization of these proteomes could also yield valuable information regarding mammary gland physiology of the early postpartum lactating cow. The objectives of this research were to characterize the MFGM proteomes of colostrum and transition milk through sample collections at four timepoints postpartum, including the first milking (M1, colostrum), second milking (M2, transition milk), fourth milking (M4, transition milk), and fourteenth milking (M14, mature milk), and compare these proteomes between multiparous (MP; n = 10) and primiparous (PP; n = 10) Holstein dairy cows. Isolated MFGM proteins were labeled using Tandem Mass tagging and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Protein identification was completed using MASCOT and Sequest in Proteome Discoverer 2.2. The scaled abundance values were analyzed using PROC MIXED in SAS to determine the effects of milking (MIL), parity (PAR), and MIL × PAR. The adaptive false-discovery rate (FDR)-adjusted P values were determined using PROC MULTTEST. Protein characterization and bioinformatic analysis were completed using a combination of PANTHER, Blast, and Uniprot.ResultsA total of 104 common proteins were identified in each of the MFGM samples. Statistical analysis revealed that 70.2% of identified proteins were affected by MIL. Of these, 78.1% were lower in M14 compared with M1, including immune-related proteins lactotransferrin, lactadherin and hemopexin. Parity affected 44.2% of proteins. Of the proteins affected by PAR, 84.8% were higher in MP cows compared with PP cows, including apolipoprotein E and histones 2A, 2B, 3, and 4 b. Butyrophilin subfamily 1 member 1A and annexin 5 were higher in samples from PP cows. Milking × parity affected 32.7% of identified proteins, including lactotransferrin, gelsolin, vitamin D binding protein, and S100 proteins.ConclusionsThis research supports previous findings that the Holstein MFGM proteome changes rapidly during the first week of lactation. In addition, this research identifies the impact of parity on the colostrum and transition milk MFGM proteomes, which may be important for milk-fed calf health or for the identification of protein biomarkers for mammary functionality.

Diet Composition Affects Liver and Mammary Tissue Transcriptome in Primiparous Holstein Dairy Cows.

Simple SummaryCorn stover (CS) diets are still adopted by small dairy farms in China. Compared with mixed forage (MF) diets, feeding CS diet affects milk composition, digestibility, feed intake, ruminal fermentation, and lactation performance. Mammary gland and liver are two of the most important organs for lactation in cows. However, research related to the effect of CS diet on the metabolism of liver and mammary tissues of dairy cows is limited. Overall evaluation of the biological response of liver and mammary tissues of dairy cows to changes in CS diet compared with MF diet is essential. Thus, the objective of the present study was to evaluate the overall adaptation of liver and mammary tissue to a CS diet in mid-lactation primiparous dairy cows. Modest effect on the transcriptome of the liver and mammary tissue by the CS diet was observed. The analysis of the genes affected by CS indicated mammary gland responding to lower level of linoleate from the diet (lower in CS vs. MF) by activating the associated biosynthesis metabolism while the liver adaptively activated potassium transport to compensate for a lower K ingestion. The results of this study may facilitate the development of better feeding and management strategies and the increase of profitability of dairy farms.The objective of the present study was to evaluate the overall adaptations of liver and mammary tissue to a corn stover (CS) compared to a mixed forage (MF) diet in mid-lactation primiparous dairy cows. Twenty-four primiparous lactating Holstein cows were randomly allocated to 2 groups receiving either an alfalfa forage diet (MF, F:C = 60:40) with Chinese wildrye, alfalfa hay and corn silage as forage source or a corn stover forage diet (CS, F:C = 40:60). A subgroup of cows (n = 5/diet) was used for analysis of liver and mammary transcriptome using a 4 × 44K Bovine Agilent microarray chip. The results of functional annotation analysis showed that in liver CS vs. MF inhibited pathways related to lipid metabolism while induced the activity of the potassium channel. In mammary tissue, fatty acid metabolism was activated in CS vs. MF. In conclusion, the analysis of genes affected by CS vs. MF indicated mammary gland responding to lower level of linoleate from the diet (lower in CS vs. MF) by activating the associated biosynthesis metabolic pathway while the liver adaptively activated potassium transport to compensate for a lower K ingestion.

Untargeted Metabolomic Analysis of Gestationally Matched Human and Bovine Milk Samples at 2-Weeks Postnatal

Abstract Objectives Human breast milk is the ideal nutrition source for infant development during the first year of life. Epidemiological data demonstrates that bovine whole milk is often substituted for human milk during the first 12-months of life and may be associated with adverse infant outcomes. The goal of this project is to interrogate the human and bovine milk metabolome at 2-weeks postnatal to identify unique and overlapping metabolites that may impact infant health outcomes. Methods Human milk (n = 10) was collected at 2-weeks postpartum from normal weight mothers (pre-pregnant BMI &amp;lt;25 kg/m2) that vaginally delivered term infants and planned to exclusively breastfeed for at least 2-months. Similarly, bovine milk (n = 10) was collected 2-weeks postpartum from normal weight primiparous Holstein dairy cows. Dairy cattle were housed in sand-bedded, shaded barns with access to fans and water soakers and fed a common transition cow total mixed ration. Untargeted metabolomics was completed on all milk samples using high-resolution mass spectrometry. Metabolomic analysis was implemented using an open-source containerized metabolomics pipeline. Data processing was completed using MZmine, mummichog and Python were used for statistical analysis. Results We detected 716 metabolomic features in human and bovine milk samples after quality control. Our analysis also revealed that 43% (312) of metabolomics features were present in both human and bovine milk, 23% (167) of metabolomics features were unique to human milk and 33% (237) of metabolomics features existed only in bovine milk samples. Pathway analysis revealed that sialic acid and glycosphingolipid metabolism (P &amp;lt; 0.0009) were common to human and bovine milk samples. We also found that amino acid (tryptophan, tyrosine, purine) metabolism (P &amp;lt; 0.005) was unique to bovine samples and vitamin B3 pathways (P = 0.03) was unique to human samples. Conclusions Our analysis revealed a core milk metabolome shared between human and bovine samples. Collectively, these results highlight untargeted metabolomics as a potential strategy to identify unique and overlapping metabolites in bovine and human milk that may impact infant health outcomes. Funding Sources Research was supported by NIDDK/K01; SECIM P&amp;F; CTSI Pilot Award; Robin Hood Foundation; NIH Loan Repayment Program.

Impact of the severity of negative energy balance on gene expression in the subcutaneous adipose tissue of periparturient primiparous Holstein dairy cows: Identification of potential novel metabolic signals for the reproductive system

The severity of negative energy balance (NEB) in high-producing dairy cows has a high incidence among health diseases. The cow’s energy status during early lactation critically affects metabolic and reproductive parameters. The first objective of this study was to investigate by RNA-seq analysis and RT-qPCR the gene expression profile in white adipose tissue and by gene ontology and upstream regulation tools the relationships with energy metabolism and reproduction in two groups of primiparous dairy cows with extreme NEB statuses (NEB < -9 Mcal/day vs. NEB > -9 Mcal/day) around parturition. The second objective was to determine the potential involvement of a new adipokine identified as a candidate for the regulation of ovarian function in our RNA-seq analysis by using bovine primary granulosa culture, thymidine incorporation to determine cell proliferation and ELISA assays to measure progesterone secretion. The RNA-seq analysis revealed that 514 genes were over-expressed and 695 were under-expressed in the adipose tissue of cows with severe NEB (SNEB) and cows with moderate NEB (MNEB) during the -4 and 16 wkpp period. In addition, 491 genes were over-expressed and 705 genes were under-expressed in the adipose tissue of SNEB cows compared to MNEB cows. Among these differently expressed genes (DEGs), 298 were related to metabolic functions and 264 to reproductive traits. A set of 19 DEGs were validated by RT-qPCR, including CCL21 (C-C motif chemokine ligand 21). Moreover, CCL21, a gene known to be secreted by adipose tissue, was chosen for further analysis in plasma and ovaries. The use of next-generation sequencing technologies allowed us to characterise the transcriptome of white adipose tissue from primiparous cows with different levels of NEB during lactation. This study highlighted the alteration of the expression of genes related to lipid metabolism, including CCL21, which is released in the bloodstream and associated with the in vitro regulation of ovarian functions.

PSI-18 Adiponectin serum concentrations in late pregnancy and early lactation in primiparous and multiparous Holstein dairy cows.

PSI-18 Adiponectin serum concentrations in late pregnancy and early lactation in primiparous and multiparous Holstein dairy cows.

Changes in rumen bacterial and archaeal communities over the transition period in primiparous Holstein dairy cows

In the present study, we hypothesized that the rumen bacterial and archaeal communities would change significantly over the transition period of dairy cows, mainly as an adaptation to the classical use of low-grain prepartum and high-grain postpartum diets. Bacterial 16S rRNA gene amplicon sequencing of rumen samples from 10 primiparous Holstein dairy cows revealed no changes over the transition period in relative abundance of genera such as Ruminococcus, Butyrivibrio, Clostridium, Coprococcus, and Pseudobutyrivibrio. However, other dominant genus-level taxa, such as Prevotella, unclassified Ruminococcaceae, and unclassified Succinivibrionaceae, showed distinct changes in relative abundance from the prepartum to the postpartum period. Overall, we observed individual fluctuation patterns over the transition period for a range of bacterial taxa that, in some cases, were correlated with observed changes in the rumen short-chain fatty acids profile. Combined results from clone library and terminal-restriction fragment length polymorphism (T-RFLP) analyses, targeting the methyl-coenzyme M reductase α-subunit (mcrA) gene, revealed a methanogenic archaeal community dominated by the Methanobacteriales and Methanomassiliicoccales orders, particularly the genera Methanobrevibacter, Methanosphaera, and Methanomassiliicoccus. As observed for the bacterial community, the T-RFLP patterns showed significant shifts in methanogenic community composition over the transition period. Together, the composition of the rumen bacterial and archaeal communities exhibited changes in response to particularly the dietary changes of dairy cows over the transition period.

Community structure of the metabolically active rumen bacterial and archaeal communities of dairy cows over the transition period.

Dairy cows experience dramatic changes in host physiology from gestation to lactation period and dietary switch from high-forage prepartum diet to high-concentrate postpartum diet over the transition period (parturition +/- three weeks). Understanding the community structure and activity of the rumen microbiota and its associative patterns over the transition period may provide insight for e.g. improving animal health and production. In the present study, rumen samples from ten primiparous Holstein dairy cows were collected over seven weeks spanning the transition period. Total RNA was extracted from the rumen samples and cDNA thereof was subsequently used for characterizing the metabolically active bacterial (16S rRNA transcript amplicon sequencing) and archaeal (qPCR, T-RFLP and mcrA and 16S rRNA transcript amplicon sequencing) communities. The metabolically active bacterial community was dominated by three phyla, showing significant changes in relative abundance range over the transition period: Firmicutes (from prepartum 57% to postpartum 35%), Bacteroidetes (from prepartum 22% to postpartum 18%) and Proteobacteria (from prepartum 7% to postpartum 32%). For the archaea, qPCR analysis of 16S rRNA transcript number, revealed a significant prepartum to postpartum increase in Methanobacteriales, in accordance with an observed increase (from prepartum 80% to postpartum 89%) in relative abundance of 16S rRNA transcript amplicons allocated to this order. On the other hand, a significant prepartum to postpartum decrease (from 15% to 2%) was observed in relative abundance of Methanomassiliicoccales 16S rRNA transcripts. In contrast to qPCR analysis of the 16S rRNA transcripts, quantification of mcrA transcripts revealed no change in total abundance of metabolically active methanogens over the transition period. According to T-RFLP analysis of the mcrA transcripts, two Methanobacteriales genera, Methanobrevibacter and Methanosphaera (represented by the T-RFs 39 and 267 bp), represented more than 70% of the metabolically active methanogens, showing no significant changes over the transition period; minor T-RFs, likely to represent members of the order Methanomassiliicoccales and with a relative abundance below 5% in total, decreased significantly over the transition period. In accordance with the T-RFLP analysis, the mcrA transcript amplicon sequencing revealed Methanobacteriales to cover 99% of the total reads, dominated by the genera Methanobrevibacter (75%) and Methanosphaera (24%), whereas the Methanomassiliicoccales order covered only 0.2% of the total reads. In conclusion, the present study showed that the structure of the metabolically active bacterial and archaeal rumen communities changed over the transition period, likely in response to the dramatic changes in physiology and nutritional factors like dry matter intake and feed composition. It should be noted however that for the methanogens, the observed community changes were influenced by the analyzed gene (mcrA or 16S rRNA).

Changes in circulating adiponectin and tumour necrosis factor-α and their relationship with insulin resistance in periparturient dairy cows

Abstract Introduction: The aim of the study was to investigate changes in the serum levels of adiponectin and TNF-α, as well as insulin sensitivity, and to elucidate the possible relationship among the parameters and negative energy balance during the periparturient period of dairy cows. Material and Methods: Thirty primiparous Holstein dairy cows were selected for the study. Blood samples were collected from each cow seven days before the expected calving date, on the calving day, and 7, 14, and 21 days after calving. Blood non-esterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), glucose, insulin, adiponectin, and TNF- α levels were measured. Revised Quantitative Insulin Sensitivity Check Index (rQUICKI) was calculated using data on NEFA, insulin, and glucose concentrations. Results: When compared to prepartum levels, serum concentration of adiponectin significantly increased on day 21 postpartum. The rQUICKI increased and NEFA levels decreased on day 7 after parturition. Insulin and glucose levels decreased on days 7, 14, and 21 postpartum when compared with prepartum levels. BHBA levels decreased on day 21 and TNF- α concentration also decreased on days 7, 14, and 21 postpartum. Adiponectin levels positively correlated with NEFA during the preparturient period. Negative correlation was detected between adiponectin and rQUICKI on calving day and on 14th day after parturition. TNF- α concentration positively correlated with glucose levels on day 7 prepartum and on 21st day postpartum and with rQUICKI on 21st day postpartum. Negative correlation was detected between adiponectin level and insulin sensitivity. Conclusion: Based on the results of the study, we concluded that adiponectin could possibly increase insulin sensitivity when blood NEFA concentrations are elevated.

Associations of selected bedding types with incidence rates of subclinical and clinical mastitis in primiparous Holstein dairy cows

The objective of this observational study was to determine the association of exposure to selected bedding types with incidence of subclinical (SM) and clinical mastitis (CM) in primiparous Holstein dairy cows housed in identical pens at a single facility. At parturition, primiparous cows were randomly assigned to pens containing freestalls with 1 of 4 bedding materials: (1) deep-bedded new sand (NES, n=27 cows), (2) deep-bedded recycled sand (RS, n=25 cows), (3) deep-bedded manure solids (DBMS, n=31 cows), and (4) shallow-bedded manure solids over foam-core mattresses (SBMS, n=26 cows). For 12mo, somatic cell counts of quarter milk samples were determined every 28d and duplicate quarter milk samples were collected for microbiological analysis from all quarters with SM (defined as somatic cell count >200,000 cells/mL). During this period, duplicate quarter milk samples were also collected for microbial analysis from all cases of CM. For an additional 16mo, cases of CM were recorded; however, no samples were collected. Quarter days at risk (62,980) were distributed among bedding types and most quarters were enrolled for >150d. Of 135 cases of SM, 63% resulted in nonsignificant growth and 87% of recovered pathogens (n=33) were identified as coagulase-negative staphylococci. The distribution of etiologies of pathogens recovered from cases of SM was associated with bedding type. Coagulase-negative staphylococci were recovered from 12, 38, 11, and 46% of quarters with SM from cows in pens containing NES, RS, DBMS, and SBMS, respectively. A result of nonsignificant growth was obtained for 81, 59, 89, and 46% of quarters with SM from cows in pens containing NES, RS, DBMS, and SBMS, respectively. Quarters of primiparous cows bedded with NES tended to have greater survival time to incidence of CM than quarters of primiparous cows bedded with RS or DBMS.

Effects of feeding dry glycerol on milk production, nutrients digestibility and blood components in primiparous Holstein dairy cows during the early postpartum period

The aim of this study was to evaluate the glucogenic property of glycerol supplementation in the dairy cow’s diet. Sixty primiparous cows (control, n=30, and glycerol supplemented, n=30) were used to measure milk yield and components, blood hormone and metabolite profiles, and body condition score. Feed intake and apparent total-tract digestibility were also measured using 10 primiparous cows (control, n=5, and glycerol supplemented, n=5). Dry glycerol was top dressed at 250 g/day/cow from parturition to 21 days postpartum. Average feed intake, milk yield and components were not affected by glycerol supplementation. Apparent total–tract digestibility of organic matter and neutral detergent fibre were not influenced by dry glycerol supplementation, but lipid digestibility was greater (p=0.01) in cows fed glycerol. The serum concentration of glucose and insulin tended to be higher in dry glycerol-supplemented cows (p=0.1; p=0.06, respectively). While, serum concentrations of nonesterified fatty acids and β-hydroxybutyrate were not affected. Supplemented cows had lower body condition loss during weeks 1 to 5 after calving (p=0.09). The glucogenic effect of glycerol did not affect milk yield during the first 3 weeks of lactation. However, daily milk yield during the 13 weeks recording period was higher in the glycerol-supplemented cows (28.5 vs. 30.3 kg, p&lt;0.001). Percentages of cows cycling at the planned breeding date was greater (p=0.01) for cows fed dry glycerol. The results demonstrated that feeding dry glycerol as a glucogenic supply could be useful in saving body reserves and improving energy balance of primiparous Holstein dairy cows during the early postpartum period.

Genetic relationship between heifers and cows fertility and milk yield traits in first-parity Iranian Holstein dairy cows

Relationship between reproductive characteristics of heifers and cows and milk production traits in Iranian primiparous Holstein dairy cows were investigated under a Bayesian approach using data collected from 1995 to 2014. The studied reproductive traits in heifers were success or failure at first insemination (SFH), number of inseminations for conception (INSH), and days to calving (DC). Considered reproductive traits in cows were success or failure at first insemination (SFC), number of insemination for conception (INSC) and days open (DO). Milk production traits were included 305-day adjusted milk yield (MY), fat yield (FY) and protein yield (PY). Linear models were used for the analysis of INSH, DC, INSC and DO, while threshold models were used for SFH and SFC. Direct heritability estimates were0.012, 0.029, 0.049, 0.006, 0.010, 0.039, 0.252, 0.167 and 0.214 for INSH, INSC, OD, DC, SFH, SFC, MY, FY and PY, respectively. Genetic correlation estimates between reproductive traits were high and negative for SFH and SFC with INSH, INSC, OD and DC; varying between −0.991 for INSC-SFC and −0.627 for OD-SFH. Genetic correlation estimates between INSC, INSH, OD and DC were high and positive, varying from 0.638 for INSH-OD to 0.932 for INSC-DC. A positive estimate of 0.613 was obtained for the genetic correlation between SFC and SFH. Genetic and phenotypic correlations between milk production traits were positive and high. Unfavorable genetic correlations were obtained between MY, FY and PY with reproductive traits, varying from −0.617 for SFC-PY to 0.593 for OD-MY. High genetic correlations were found for SFH-SFC (0.613) and INSH-INSC (0.862). The reproductive traits considered in heifers (except for DC) had medium to high genetic correlations with milk production and cow's reproduction traits. Furthermore, reproductive traits of heifers can be measured relatively early in the life. Therefore, it can be concluded that including reproductive traits of heifers in genetic evaluation programs can be useful of Iranian Holsteins.

Changes in various metabolic parameters in blood and milk during experimental Escherichia coli mastitis for primiparous Holstein dairy cows during early lactation.

BackgroundThe objective of this study was to characterize the changes in various metabolic parameters in blood and milk during IMI challenge with Escherichia coli (E. coli) for dairy cows during early lactation. Thirty, healthy primiparous Holstein cows were infused (h = 0) with ~20-40 cfu of live E. coli into one front mammary quarter at ~4-6 wk in lactation. Daily feed intake and milk yield were recorded. At –12, 0, 3, 6, 12, 18, 24, 36, 48, 60, 72, 96, 108, 120, 132, 144, 156, 168, 180 and 192 h relative to challenge rectal temperatures were recorded and quarter foremilk was collected for analysis of shedding of E. coli. Composite milk samples were collected at -180, -132, -84, -36, -12, 12, 24, 36, 48, 60, 72, 84, 96, 132 and 180 h relative to challenge (h = 0) and analyzed for lactate dehydrogenase (LDH), somatic cell count, fat, protein, lactose, citrate, beta-hydroxybutyrate (BHBA), free glucose (fglu), and glucose-6-phosphate (G6P). Blood was collected at -12, 0, 3, 6, 12, 18, 24, 36, 60, 72, 84, 132 and 180 h relative to challenge and analyzed for plasma non-esterified fatty acids (NEFA), BHBA and glucose concentration. A generalized linear mixed model was used to determine the effect of IMI challenge on metabolic responses of cows during early lactation.ResultsBy 12 h, E. coli was recovered from challenged quarters and shedding continued through 72 h. Rectal temperature peaked by 12 h post-challenge and returned to pre-challenge values by 36 h post-IMI challenge. Daily feed intake and milk yield decreased (P <0.05) by 1 and 2 d, respectively, after mastitis challenge. Plasma BHBA decreased (12 h; P <0.05) from 0.96 ± 1.1 at 0 h to 0.57 ± 0.64 mmol/L by 18 h whereas concentration of plasma NEFA (18 h) and glucose (24 h) were significantly greater, 11 and 27%, respectively, after challenge. In milk, fglu, lactose, citrate, fat and protein yield were lower whereas yield of BHBA and G6P were higher after challenge when compared to pre-challenge values.ConclusionsChanges in metabolites in blood and milk were most likely associated with drops in feed intake and milk yield. However, the early rise in plasma NEFA may also signify enhanced adipose tissue lipolysis. Lower concentrations of plasma BHBA may be attributed to an increase transfer into milk after IMI. Decreases in both milk lactose yield and % after challenge may be partly attributed to reduced conversion of fglu to lactose. Rises in G6P yield and concentration in milk after challenge (24 h) may signify increased conversion of fglu to G6P. Results identify changes in various metabolic parameters in blood and milk after IMI challenge with E. coli in dairy cows that may partly explain the partitioning of nutrients and changes in milk components after IMI for cows during early lactation.

Characterization of bacterial community of raw milk from dairy cows during subacute ruminal acidosis challenge by high-throughput sequencing.

Four cannulated primiparous Holstein dairy cows (84 ± 25 DIM) were used in a 2 × 2 crossover experimental design. The two diets contained 40% (low-concentrate diet, or control diet, LC) and 70% (high-concentrate diet, or SARA induction diet, HC) concentrate feeds respectively. Milk samples were collected on days 17, 18 and 19 of each experimental period. DNA was extracted from each milk sample, and pyrosequencing was applied to analyse the milk microbial community. Regardless of diet, the bacterial community of milk was dominated by Actinobacteria, Firmicutes, Proteobacteria and Bacteroidetes. HC feeding showed a higher proportion of some mastitis-causing pathogen bacteria, such as Stenotrophomonas maltophilia, Streptococcus parauberis and Brevundimonas diminuta, as well as of psychrotrophic bacteria, such as Pseudomonas, Brevundimonas, Sphingobacterium, Alcaligenes, Enterobacter and Lactobacillus. However, the diversity of the milk bacterial microbiota (ACE, Chao, and Shannon index) was not affected by HC feeding. To the best of our knowledge, this is the first report on the use of pyrosequencing for evaluating the impacts of nutrition on changes in the composition of milk microbiota. These findings indicate that HC feeding may increase the risk of dairy cows suffering from mastitis, decrease the organoleptic quality of raw milk and dairy products, and limit the shelf life of processed fluid milk.

Evaluation of test day daily milk yield and persistency of different milking times in primiparous Holstein dairy cows in Iran

Monthly test day records (morning, noon and night milk; 470,829) from 49,675 Iranian Holstein over 603 herds were used to study the characteristics of genetic parameters of milk yield at different milking times and evaluation of persistency in different milking times. According to the results, residual variance is high at the beginning of lactation(4.70 kg) and gradually decreases till the end of lactation in different milking times. Also the additive genetic variance increases till the end of lactation (especially morning milk and estimates are lower at the beginning of lactation (0.35 kg). Permanent environmental variance shows moderate increase, with peak value at the end of lactation. The trends of heritability at different milking times are similar but the morning milk has higher heritability during 260 to 290 days. Peak time of milk yield for morning time was 79 days but for noon and night milking curves was at 62 and 90 DIM. Genetic correlations of different milking times between test days as well as permanent environmental correlation of higher value (close to unity) in adjacent period but decreased with increasing period among test day yield. Morning milk yield was higher compared to noon and night milk but night milk curve showed better persistency.