Affect Milk Composition Research Articles

Effects of seasonal factors on the milk composition of dairy cows in Tafawa Balewa L.G.A, Bauchi State

This study compared the nutrient composition of milk between cattle breeds of Bunaji, Rahaji, Sokoto gudali and Adamawa gudali for both rainy and dry season. One hundred questionnaires were administered to respondents and 5% had milk yield of 3litre/day. 55% recorded 2 litre/day of milk while 40% had the least yield of 1litre/day. That early lactation produces highest milk quantity. The result of laboratory analysis showed that season have effect on nutrient composition of cow milk. It was observed that the early dry season milk composition was better for Bunaji, Rahaji, Sokoto gudali except for Adamawa gudali. For rainy season comparison, early rainy season milk composition was better for Bunaji, Sokoto gudali, Adamawa gudali except for Rahaji. Moisture content in dry season (70.08%) was lower (P>0.05) than moisture content in rainy season (87.36%) for Bunaji breed, similar result was obtained for Rahaji, Sokoto gudali and Adamawa gudali. The energy content and carbohydrate were higher (P<0.05) in the dry season for Bunaji(132.15KCal and 14.06%), Rahaji (126.20KCal and 14.55%), Sokoto gudali (148.00KCal and 22.05%) and Adamawa gudali (135.18KCal and 20.99%). The crude protein of analysed milk was slightly higher (P<0.05) in rainy season for Bunaji (5.64%), but higher in dry season for Rahaji (5.48%), Sokoto gudali (7.47%) and Adamawa gudali (6.01%). ether extract were all higher in dry season for breeds except Sokoto gudali. crude fibre was higher (5.34% Bunaji, 5.28% Rahaji, 3.45% S. gudali, 4.04% A. gudali) in dry season for all breed. Milk in all the four breeds of cattle have more of the nutrient composition in dry season at a higher level. Seasonal variation and climatic factors like rain, humidity and wind affects milk composition and cattle production in terms of pasture availability and the quality. The herders need to be encouraged to engaged in modern way of herding by possessing land for farming, they can rent it in exchange of crop residues and they can cultivate their personal farm produce and faster yielding pasture can be cultivated.

Steady-state modeling of water-splitting and multi-ionic transport of skim milk electro-acidification by bipolar membrane electrodialysis

Electrodialysis has become a relevant technology in promoting sustainability within the food industry. Bipolar membrane electrodialysis offers an efficient and eco-friendly alternative for skim milk acidification, eliminating the need for added acids that affect milk composition and properties. For the first time, this study presents a comprehensive 2-D computational model to investigate the multi-ionic transport and dynamics of skim milk electro-acidification using bipolar membrane electrodialysis. The model is based on conservation equations for mass-charge transport, coupled with the description of water-splitting through the second Wien effect. The primary focus of the analysis was on the skim milk pH evolution and the concentration profiles of the major ions. The results showed that ion concentration values varied due to concentration polarization and differences in ion mobilities. The simulations were compared with experimental data, showing reasonable agreement, particularly for Ca2+ ion concentration. Despite excluding organic components in its analysis, this model offers a novel and valuable approach to the study of skim milk electro-acidification using bipolar membrane electrodialysis, providing essential insights for process understanding and optimization.

PSX-16 The Effects of Vaccination Program and Grazing Season on Beef Cattle Milk Fatty Acid Composition When Grazing Native Rangeland in New Mexico

Abstract The objectives of this study were to evaluate the impact of vaccine program and progression of grazing season on beef cow milk fatty acid composition. In 2015, Fifty-one Angus-crossed beef heifers were randomly assigned to receive a modified-live viral vaccine (MLV; Bovishield Gold 5 FP) or killed viral vaccine (KV; Cattlemaster Gold 5 FP) against BVDV beginning at 3 months of age and for the duration of their lifespan in the herd. In 2019, 2020, and 2021, milk samples were collected on days 1, 63, and 205 of lactation. Milk samples were subjected to fatty acid analysis using Gas Chromatography. Data were analyzed as a completely randomized design with repeated measures using SAS. Milk concentrations of 16:0, 18:0, 18:1n-9, 18:2n-6, 18:3n-3, or total fatty acids when expressed as mg/g were not affected by vaccine treatment (P ≥ 0.58). However, milk 16:0 concentrations decreased linearly (P < 0.0001) as the grazing season progressed from day 1 to day 205 of lactation. This was despite a linear increase (P = 0.05) in forage concentrations of 16:0. Milk concentrations of 18:0 decreased linearly throughout lactation (P = 0.002). Likewise, milk concentrations of 18:1n-9 decreased throughout lactation (P < 0.0001). Milk concentrations of 18:2n-6 declined linearly (P < 0.0001) as the grazing season progressed into the fall weaning period. Interestingly, milk concentration of 18:3n-3 did not change (P = 0.62) with time. Biohydrogenation intermediates were reduced in concentration and did not vary across grazing season (P ≥ 0.06) Total fatty acids decreased throughout lactation (P < 0.0001). Total fatty acid content of forage did increase linearly (P = 0.02), which would suggest milk production (volume) and de novo milk fatty acid synthesis altered milk composition more so than forage fatty acid composition. In conclusion, vaccine treatment did not affect milk composition. However, grazing season progression resulted in decreased milk fatty acid concentrations from day 1 to day 205 of lactation.

Effect of betel leaf meal (Piper Betle L.) as feed additive on milk composition and somatic cell count of subclinical mastitis

The aim of this experiment was to study the effect of betel leaf meal (BLM) as feed additive on milk composition and somatic cell count of subclinical mastitis infected cow. The experiment design was a completely randomized design with five dietary treatments of BLM level and four replications in concentrate feed. The treatments were T0 (without betel leaf meal, as control), T1 (2% of betel leaf meal every day), T2 (4% of betel leaf meal every day), T3 (2% of betel leaf meal skip two days), and T4 (4% of betel leaf meal skip two days). Milk samples from the infected quarter would be analyzed every week of the experiment. Parameters measured were milk composition and somatic cell count. Data were analyzed by using analysis of variance (ANOVA) and the differences among treatments were examined by Duncan's multiple range test. Results showed that in T1 decreased somatic cell count by 83%, but the addition of BLM did not significantly affect milk composition. It could be concluded that the addition of 2% of BLM as a feed additive has the potency to prevent mastitis in lactating cows.

Factors affecting milk composition in dairy farms located in Northern, Thailand

The objectives of this study were to investigate variations in the milk composition and somatic cell count (SCC) from dairy cooperatives in Northern Thailand from January 2017 to December 2021. Milk composition among dairy cooperatives was also compared. The dataset included monthly milk composition (total solid (TS)%, fat%, protein%, lactose%, solid not fat (SNF)% and SCC) data from 15 dairy cooperatives, 2 private organizations, and their milk collection centers (1,800 records) collected in five provinces, including Chiang Mai, Chiang Rai, Lampang, Lamphun, and Phrae. The seasons were cold season (November to February), hot season (March to June), and rainy season (July to October). The dataset was compared among dairy cooperatives using a general linear mixed model. To detect a correlation, spearman correlation coefficients were calculated between SCC and milk composition. Results showed that the season significantly affected milk composition. The hot season appeared as the most critical season for all the parameters examined, showing the significantly lowest values (P < 0.001) of TS (12.33±0.3%), fat (3.79±0.27%) and protein (3.02±0.07%) whereas, a significantly highest SCC was obtained in the rainy season (321.21±3.93 x 1,000 cell/ml). Milk collecting centers of dairy cooperatives located in many districts had significantly different milk composition and SCC values. Lactose is the milk component that undergoes the greatest variation in response to the increase in SCC. This study highlighted the variations influencing milk composition and provided information for stakeholders and their roles in the dairy sector at the farm, dairy cooperative, and provincial levels.

Methodological guidelines: Cow milk mid-infrared spectra to predict reference enteric methane data collected by an automated head-chamber system.

Various methodological protocols were tested on milk samples from cows fed diets affecting both methanogenesis and milk synthesis to identify the best approach for the prediction of GreenFeed system (GF) measured methane (CH4) emissions by milk mid-infrared (MIR) spectroscopy. The models developed were also tested on a data set from cows fed chemical inhibitors of CH4 emission [3-nitrooxypropanol (3NOP)] that just marginally affect milk composition. A total of 129 primiparous and multiparous Holstein cows fed diets with different methanogenic potential were considered. Individual milk yield (MY) and dry matter intake were recorded daily, whereas fat- and protein-corrected milk (FPCM) was recorded twice a week. The MIR spectra from 2 consecutive milkings were collected twice a week. Twenty CH4 spot measurements with GF were taken as the basic measurement unit (BMU) of CH4. The equations were built using partial least squares regression by splitting the database into calibration and validation data sets (excluding 3NOP samples). Models were developed for milk MIR spectra by milking and on day spectra obtained by averaging spectra from 2 consecutive milkings. Models based on day spectra were calibrated by using CH4 reference data for a measurement duration of 1, 2, 3, or 4 BMU. Models built from the average of the day spectra collected during the corresponding CH4 measurement periods were developed. Corrections of spectra by days in milk (DIM) and the inclusion of parity, MY, and FPCM as explanatory variables were tested as tools to improve model performance. Models built on day milk MIR spectra gave slightly better performances that those developed using spectra from a single milking. Long duration of CH4 measurement by GF performed better than short duration: the coefficient of determination of validation (R2V) for CH4 emissions expressed in grams per day were 0.60 vs. 0.52 for 4 and 1 BMU, respectively. When CH4 emissions were expressed as grams per kilogram of dry of matter intake, grams per kilogram of MY, or grams per kilogram of FPCM, performance with a long duration also improved. Coupling GF reference data with the average of milk MIR spectra collected throughout the corresponding CH4 measurement period gave better predictions than using day spectra (R2V = 0.70 vs. 0.60 for CH4 as g/d on 4 BMU). Correcting the day spectra by DIM improved R2V compared with the equivalent DIM-uncorrected models (R2V = 0.67 vs. 0.60 for CH4 as g/d on 4 BMU). Adding other phenotypic information as explanatory variables did not further improve the performance of models built on single day DIM-corrected spectra, whereas including MY (or FPCM) improved the performance of models built on the average of spectra (uncorrected by DIM) recorded during the CH4 measurement period (R2V = 0.73 vs. 0.70 for CH4 as g/d on 4 BMU). When validating the models on the 3NOP data set, predictions were poor without (R2V = 0.13 for CH4 as g/d on 1 BMU) or with (R2V = 0.31 for CH4 as g/d on 1 BMU) integration of 3NOP data in the models. Thus, specific models would be required for CH4 prediction when cows receive chemical inhibitors of CH4 emissions not affecting milk composition.

Effects of dietary branched-chain amino acid supplementation on serum and milk metabolome profiles in dairy cows during early lactation.

The 3 branched-chain AA (BCAA), Val, Leu, and Ile, are essential AA used by tissues as substrates for protein synthesis and energy generation. In addition, BCAA are also involved in modulating cell signaling pathways, such as nutrient sensing and insulin signaling. In our previous study, dietary BCAA supplementation was shown to improve protein synthesis and glucose homeostasis in transition cows. However, a more detailed understanding of the changes in metabolic pathways associated with an increased BCAA availability is desired to fine-tune nutritional supplementation strategies. Multiparous Holstein cows (n = 20) were enrolled 28 d before expected calving and assigned to either the BCAA treatment (n = 10) or the control group (n = 10). Cows assigned to BCAA were fed 550 g/d of rumen-protected BCAA mixed with 200 g/d of dry molasses from calving until 35 DIM, whereas the cows assigned to the control were fed only 200 g/d of dry molasses. Serum samples were collected on d 10 before expected calving, as well as on d 4 and d 21 postpartum. Milk samples were collected on d 14 postpartum. From a larger cohort, we selected 20 BCAA-supplemented cows with the greatest plasma urea nitrogen concentration, as an indicator for greater BCAA availability, for the metabolomics analysis herein. Serum and milk samples were subjected to a liquid chromatography-mass spectrometry-based assay, detecting and measuring the abundance of 241 serum and 211 milk metabolic features, respectively. Multivariable statistical analyses revealed that BCAA supplementation altered the metabolome profiles of both serum and milk samples. Increased abundance of serum phosphocholine and glutathione and of milk Val, Ile, and Leu, and decreased abundance of milk acyl-carnitines were associated with BCAA supplementation. Altered phosphocholine and glutathione abundances point to altered hepatic choline metabolism and antioxidant balance, respectively. Altered milk acyl-carnitine abundances suggest changes in mammary fatty acid metabolism. Dietary BCAA supplementation was associated with a range of alterations in serum and milk metabolome profiles, adding to our understanding of the role of BCAA availability in modulating dairy cow protein, lipid, and energy metabolism on a whole-body level and how it affects milk composition.

Use of differential somatic cell count, somatic cell score, and milk mid-infrared spectral analysis for monitoring mastitis in dairy cows during routine milk recording

Routine mastitis screening is crucial on dairy farms, and it usually involves analysis of somatic cell count (SCC), which serves as an indicator of mastitis. Milk mid-infrared (MIR) spectral analysis, the standard method to determine milk components, was evaluated as an additional tool for the prediction of mastitis, since health condition of a cow is affecting milk composition. Differential somatic cell count (DSCC), the percentage of SCC due to polymorphonuclear leukocytes (PMN) and lymphocytes, is another new indicator to detect cows having an infected udder mammary gland. In a previous study we developed mastitis prediction models based on somatic cell score (SCS) and MIR spectral data from routine milk recording. The present study compared various models to predict clinical mastitis based on the parameters DSCC, SCS and MIR spectral data, alone or in combination. Data on DSCC, SCC, MIR spectral data and mastitis diagnosis by veterinarians were extracted for 40,332 dairy cows of the breeds Fleckvieh, Brown Swiss and Holstein Friesian from the Austrian milk recording and health monitoring systems. Three data subsets were created based on whether test-day records were classified as “mastitis” when they occurred 21 days (subset 1), 14 days (subset 2), or 7 days (subset 3) before or after diagnosis of mastitis; all other records were classified as “healthy”. The performance of seven models (DSCC alone, SCS alone, MIR alone, DSCC+SCS, DSCC+MIR, MIR+SCS and DSCC+SCS+MIR) was assessed in these subsets using partial least squares discriminant analysis. In all subsets, the DSCC model showed the highest sensitivities (0.710 to 0.792) but lowest specificities (0.564 to 0.562) during external validation. The SCS model showed lower sensitivities (0.624 to 0.662) but higher specificities (0.725 to 0.769) than DSCC. The MIR model showed sensitivities from 0.598 to 0.617 and specificities from 0.668 to 0.681. The models combining multiple predictors showed the highest balanced accuracies: the MIR+SCS model in subset 1 (0.697), DSCC+SCS+MIR in subset 2 (0.712) and MIR+SCS in subset 3 (0.744). Taken together, our analyses suggest that DSCC, SCS and MIR spectral data are useful for routine mastitis screening, with SCS performing as the best single predictor and the MIR+SCS model performing best overall.

Non - genetic factors affecting milk composition traits and association of milkquality parameters with udder and teat type traits of Sahiwal and Karan Friescows

The study was carried out to determine the effect of season of calving, stage of lactation and parity on 207 cattle compromising of Sahiwal (107) and Karan Fries cattle (100) of different parities and lactation stages.In Karan Fries cows, Season had significant effect on all milk composition traits viz., average test day milk yield (ATDMY), average test day fat yield (ATDFY), average test day solid not fat yield (ATDSNFY), average test day protein percentage (ATDP%) and average test day lactose yield (ATDLY). In Sahiwal cows, parity had non-significant effect on all milk composition traits whereas, in Karan Fries cows, parity had significant effect on milk composition traits viz., ATDMY, ATDFY, ATDSNFY, ATDP%, ATDLY and average test day protein yield (ATDPY). In Sahiwal cows, Season had non-significant effect on all milk composition traits whereas, in Karan Fries cows (KF) had significant effect on milk composition traits viz., ATDMY, ATDFY, ATDSNFY, ATDP% and ATDLY in Karan Fries cows. In Sahiwal cows, parity had non-significant effect on all milk composition traits whereas in Karan Fries cows, parity had significant effect on milk composition traits viz., ATDMY, ATDFY, ATDSNFY, ATDP%, ATDLY and ATDPY. The phenotypic correlation between udder and teat type traits and composition were low in magnitude. It can be concluded that changing patterns of milk composition with different seasons and parities provide scientific evidence to improve the nutrition management.

Prediction of Acute and Chronic Mastitis in Dairy Cows Based on Somatic Cell Score and Mid-Infrared Spectroscopy of Milk.

Simple SummaryMid-infrared (MIR) spectroscopy is the method of choice to determine milk components like fat, protein and urea. We examined the potential of MIR spectra analyses for the prediction of clinical mastitis events of dairy cows additionally, or alternatively, to somatic cell count, which is routinely used as an indicator for mastitis monitoring. Prediction models based on MIR spectra and a somatic cell count-derived score (SCS) were developed and compared. A model based on MIR spectra and SCS proved more accurate at predicting mastitis than models based on either indicator alone. Consequently, MIR spectra analyses add extra value in the prediction of clinical mastitis, making them potentially useful for dairy farm management and as an auxiliary trait for the genetic evaluation of udder health.Monitoring for mastitis on dairy farms is of particular importance, as it is one of the most prevalent bovine diseases. A commonly used indicator for mastitis monitoring is somatic cell count. A supplementary tool to predict mastitis risk may be mid-infrared (MIR) spectroscopy of milk. Because bovine health status can affect milk composition, this technique is already routinely used to determine standard milk components. The aim of the present study was to compare the performance of models to predict clinical mastitis based on MIR spectral data and/or somatic cell count score (SCS), and to explore differences of prediction accuracies for acute and chronic clinical mastitis diagnoses. Test-day data of the routine Austrian milk recording system and diagnosis data of its health monitoring, from 59,002 cows of the breeds Fleckvieh (dual purpose Simmental), Holstein Friesian and Brown Swiss, were used. Test-day records within 21 days before and 21 days after a mastitis diagnosis were defined as mastitis cases. Three different models (MIR, SCS, MIR + SCS) were compared, applying Partial Least Squares Discriminant Analysis. Results of external validation in the overall time window (−/+21 days) showed area under receiver operating characteristic curves (AUC) of 0.70 when based only on MIR, 0.72 when based only on SCS, and 0.76 when based on both. Considering as mastitis cases only the test-day records within 7 days after mastitis diagnosis, the corresponding areas under the curve were 0.77, 0.83 and 0.85. Hence, the model combining MIR spectral data and SCS was performing best. Mastitis probabilities derived from the prediction models are potentially valuable for routine mastitis monitoring for farmers, as well as for the genetic evaluation of the trait udder health.

Assessment of blood and productive parameters in mid-lactation dairy cows fed different diets: replacement of corn silage with triticale silage.

Corn crops require large amounts of resources that affect the environmental sustainability of dairy cow farming systems. The aim of the study was thus to investigate the effects of the replacement of corn silage (CS) with triticale silage (TS) by evaluating blood and productive parameters. The study lasted 7 weeks and involved two groups of 20 Italian Holstein Friesian dairy cows that were homogeneous in terms of parity (), days in milk (DIM) (), and daily milk production ( kg).Chemical analysis of feeds was carried out weekly. Dry-matter intake was estimated daily. At the beginning and end of the trial, haematological, metabolic, and immunological parameters were analysed. At the same, time body weight and body condition score were measured. Milk characteristics were also analysed weekly. Statistical analysis was performed by ANOVA on data of the second sampling, and a non-parametric test was performed to analyse BCS.Regarding the haematological parameters in the two groups, only lymphocyte values were not in the normal range (2.86 and L for CS and TS, respectively). Metabolic parameters were in the normal range except for blood ureic nitrogen (BUN; 13.65 and 14.04 ), non-esterified fatty acids (NEFAs; 21.40 and 31.93 ), and Cl (91.99 and 93.50 ). Hair cortisol was low (0.94 and 0.91 ), indicating the absence of stress signs, as confirmed by the results of other immunological parameters (serum lysozyme (SL), bactericidal activity (SBA), haptoglobin (HP), and oxygen free radicals (OFRs)).Statistical differences were not found either for haematological or biochemical parameters. The total replacement of CS with TS did not affect milk yield and composition.In conclusion, the replacement of CS by TS did not give rise to significant modifications in the parameters investigated and did not alter the health status of the animals, thus suggesting the feasibility of its introduction into the diet of mid-lactation dairy cows.

Detailed comparison between organic and conventional milk from Holstein-Friesian dairy herds in Italy

Several studies have reported gross composition differences between organic and conventional milk; however, most studies have not considered other factors such as breed and diet ingredients, which are known to influence milk composition. Thus, this study aimed to provide a detailed characterization of Holstein-Friesian cow milk from organic (ORG) and conventional (CONV) herds with similar diet ingredients and in the same geographic area. Bulk milk samples (n = 225) of 12 ORG and 12 CONV farms were collected from September 2019 to August 2020. Farms were located in Northern Italy, included corn (meal, silage, or both) in the lactating diets, and had similar management conditions, but ORG herds spent a period on pasture. Factors affecting milk composition were tested using a linear mixed model, which included calendar month, farming system (ORG and CONV), and their interactions as fixed effects, and farm nested within farming system as random effect. Results showed that total fat, lactose, vitamin E, and AA did not significantly differ between farming systems. Total protein and casein contents were significantly lower in ORG than CONV herds, and somatic cell score (SCS) was greater in ORG than CONV. Among minerals, differences were observed for Fe, K, Mg, and S in some months, being lower in ORG than CONV for K, Mg, and S and greater or lower for Fe depending on the month. Among fatty acid (FA) groups, index, and ratios, only polyunsaturated FA and n-3 FA tended to be greater in ORG than CONV, and cis-FA were greater in ORG than CONV during October. Among the most abundant individual FA, only C16:1n-9 differed, being lower in ORG than CONV. The calendar month (and hence seasonal feed ration) was significant for milk gross composition, SCS, vitamin E, mineral profile (except for Mo, Sr, and Zn), AA profile, FA groups (except for medium-chain FA), FA index and ratios, and individual FA (except C16:0). We conclude that the overall milk composition was quite similar between the 2 farming systems. This could be related to the similarity of the selected farms, the Holstein-Friesian breed, and generally high level of intensity in both farming systems.

Novel functional mutation of the PDIA3 gene affects milk composition traits in Chinese Holstein cattle

Protein disulfide isomerase family A member 3 (PDIA3) is a multifunctional protein, and it plays a vital role in modulating various cell biological functions under physiological and pathological conditions. Our previous study on Mediterranean buffalo demonstrated that PDIA3 is a potential candidate gene associated with milk yield based on genome-wide association study analysis. However, the genetic effects of the PDIA3 gene on milk performance in dairy cattle and the corresponding mechanism have not been documented. This study aims to explore the genetic effects of PDIA3 polymorphisms on milk production traits in 362 Chinese Holstein cattle. The results showed that 4 SNPs were identified from the 5' untranslated region of the PDIA3 gene in the studied population, of which 2 SNPs (g.-1713 C>T and g.-934 G>A) were confirmed to be significantly associated with milk protein percentage, whereas g.-434 C>T was significantly associated with milk fat percentage. Notably, linkage disequilibrium analysis indicated that 3 SNPs (g.-1713 C>T, g.-934 G>A, and g.-695 A>C) formed one haplotype block, which was found to be significantly associated with milk protein percentage. The luciferase assay demonstrated that allele C of g.-434 C>T exhibited a higher promotor activity compared with allele T, suggesting that g.-434 C>T might be a potential functional mutation affecting PDIA3 expression. Furthermore, overexpression of the PDIA3 gene was found to induce higher levels of triglyceride and BODIPY fluorescence intensity. In addition, PDIA3 overexpression was also found to positively regulate the synthesis and secretion of α-casein, β-casein, and κ-casein, whereas knockdown of this gene showed the opposite effects. In summary, our findings revealed significant genetic effects of PDIA3 on milk composition traits, and the identified SNP and the haplotype block might be used as genetic markers for dairy cow selected breeding.

Jackfruit leaves can totally replace traditional grass in the diet of lactating dairy goats

ABSTRACT This study aimed to evaluate the effect of replacing jackfruit leaves (JF) for Para grass (PG) on intake, digestibility, nitrogen balance, ruminal fermentation, milk yield and composition in lactating goats. Four crossbred Saanen lactating goats in mid-lactation and milking 1676 ± 112 g/day were used in a 4 × 4 Latin square design. A basal diet consisted of concentrate and PG (C:F 40:60). Treatments were dietary replacement of JL for PG at ratios of 0, 50, 75 and 100% corresponding to JL0, JL50, JL75 and JL100 diets, respectively. Feeding JL increased linearly (P < 0.01) DM intake, but decreased linearly (P < 0.05) nutrient digestibility. A linear increase in fecal N (P < 0.01) and N retention (P = 0.04), but a linear decrease in urinary N (P = 0.03) was detected when increased the JL in the diets. Total VFA concentration increased quadratically (P = 0.04), and the highest value was observed in JL75 compared with JL0 (85.9 vs. 72.8 mM). Milk production increased linearly (P = 0.03), but no change was observed in milk composition and blood urea nitrogen (BUN). Overall, combined data suggest that the substitution of JL for PG in lactating goat diets is effective in the improvement of nutrient intake, N retention, ruminal VFA concentration and milk yield without affecting milk composition and BUN.

Environmental factors affecting milk composition in Holstein cattle breed

The incidence of mastitis in dairy herds is one of the main difficulties faced by dairy farmers, with a negative effect on the productivity of the herd and the welfare of the animals. Somatic cell count in milk is an indicator of udder health and frequency of clinical and subclinical mastitis incidence in dairy herds, and it is also often used to determine quality payments to dairy producers. Milk urea can be an indicator of the nutritional status of the dairy cows. The interpretation of these parameters assists in making important management decisions with regards to the health status and nutrition of dairy cattle. The objective of this study was to identify and evaluate environmental factors (farm, season, parity and stage of lactation) which affect the milk production and composition of Holstein breed, using field data. The presented research included 25,460 individual milk samples which were analysed as part of the Dairy Herd Improvement program, from 11 Holstein dairy farms in the region of Vojvodina, Northern Serbia. Analyses of raw milk samples were carried out on the FOSS instruments - CombiFossTMFT+, a combination instrument consisting of the MilcoScanTMFT+ and the FossomaticTMFC. Statistical data processing was carried out by applying General Linear Model procedure, Statistics 13. Farm, season of milk control, parity and stage of lactation were included in the models as fixed effects. Significant differences in milk urea concentrations and somatic cell count were observed between farms (P&lt;0.01), seasons (P&lt;0.01), parity (P&lt;0.01) and stage of lactation (P&lt;0.01). Results showed that there were a highly significant (P&lt;0.01) positive relationships between milk urea (MU) concentration and milk yield, MU and milk fat content, and between MU and solids non-fat (SNF), also between somatic cell count (SCC) and milk fat content, between SCC and protein content, as well as in between SCC and SNF. Highly significant negative relationships were found between milk urea and protein content and SCC, and between SCC and daily milk yield and lactose content. Proper analyses and interpretation of obtained results of milk samples obtained within the Dairy Herd Improvement program could contribute to better health management on the farms and it could have a positive impact on composition and nutritional value of milk, as well as on milk safety. It would be important to carry out further research in order to facilitate the detection of subclinical mastitis with MU as a potential indicator.

Effects of calcium propionate on milk performance and serum metabolome of dairy cows in early lactation

Calcium propionate is a source of energy and calcium for alleviating negative energy balance and hypocalcemia. The objective of this study was to investigate changes in milk composition and serum metabolites associated with calcium propionate fed to postpartum dairy cows for 5 weeks. Thirty-two multiparous Holstein cows after calving were randomly allocated to control (CON), low calcium propionate (LCaP), medium calcium propionate (MCaP) and high calcium propionate (HCaP) groups. The dairy cows in the four groups were given oral drench with 0, 200, 350, 500 g/d calcium propionate per cow, respectively, from calving to d 35 in early lactation. Milk yield increased quadratically with increasing amounts of calcium propionate; being the greatest in the MCaP group. Supplementation with calcium propionate did not affect milk composition of dairy cows in early lactation. Serum glucose, insulin, glucagon, β-hydroxybutyrate, calcium, magnesium, calcitonin and calcitriol were not affected by calcium propionate supplementation. Serum non-esterified fatty acid tended to decrease linearly and parathyroid hormone increased quadratically with treatment. Serum alanine aminotransferase concentration was the lowest in the MCaP group and aspartate aminotransferase was the highest in the HCaP group among the four groups. Compared with the CON group, serum alkaline phosphatase activity decreased linearly and quadratically with the increasing calcium propionate supplementation. Supplementation with increasing amounts of calcium propionate quadratically decreased the activity of serum total antioxidant capacity, glutathione peroxidase, superoxide dismutase and catalase, however, quadratically increased concentration of malondialdehyde. Calcium propionate affected serum metabolites were mainly involved in bile acid metabolism from the metabolomic results. The 350 g/d calcium propionate feeding level could significantly improve milk performance but decrease antioxidant capacity of dairy cows as well. The effects of calcium propionate on milk performance and serum metabolites in early lactation cows was related to the regulation of serum bile acids metabolism.

Genetic variation in the OPN gene affects milk composition in Chinese Holstein cows

The aim of this study was to investigate the association between genotypes and haplotypes of OPN, and milk composition in dairy cows. A total of 317 Chinese Holstein cows were genotyped via DNA sequencing in this study. Three single nucleotide polymorphisms (SNPs), g.2916G > A, g.58675C > T and g.58899C > A, and eight haplotypes were identified. Of the eight possible haplotypes, four haplotypes i.e., Hap2 (ACC; 55.30%), Hap6 (GCC, 15.6%), Hap1 (ACA, 13.6%) and Hap4 (ATC, 5.70%), were considered to be major with a cumulative estimated frequency of >90%. Single markers (g.2916G > A and g.58899C > A) and Haplotype Hap6/4 were found to be associated with an increase in butter-fat percentage (p < 0.05). Taken together, our results provided evidence that polymorphisms in OPN are associated with milk composition, and could potentially be used for marker-assisted selection in Chinese Holstein cows.

The role of melatonin implantation and the associated effect of insulin-like growth factor-1 on milk composition of Barki ewes

Context Manipulation of milk composition in lactating ewes represents an important mechanism by which sheep breeders can improve profits through increased milk prices for cheese making and higher lamb growth rates. To this end, melatonin implantation may affect milk composition by alleviating reproductive seasonality and augmenting insulin like growth factor-1 (IGF-1). Aims This research aimed to evaluate the effects of melatonin administration on hormone levels and milk composition, and to determine its potential to manipulate milk composition of lactating Barki ewes. Methods Fifty lactating Barki ewes were divided into two groups of 25. One group received 18 mg melatonin in a single implant at 40 days after delivery, and the other group served as an untreated control. Over the following 8 weeks, milk components (fat, protein, lactose and total solids percentages), milk energy value, and blood serum hormones including IGF-1 were measured. Key results Melatonin implantation increased (P &lt; 0.05) IGF-1 concentration, which showed continued elevation (P &lt; 0.05) throughout the treatment period (from Day 14 to Day 56) relative to the control. Analysis of milk composition of implanted ewes revealed higher (P &lt; 0.05) milk fat, protein, lactose and total solids percentages as well as milk energy value than in milk of control ewes. Conclusion An integrated effect of melatonin and IGF-1 successfully improved milk composition of lactating Barki ewes. Implications Melatonin implantation can be used to improve milk composition of lactating Barki ewes, potentially increasing profits from cheese making and lamb production.

PSIV-11 Effects of feeding a 50% cranberry vine pellet on milk components during lactation in sheep

Abstract The objective of this study was to examine the effect of feeding cranberry vine (CV) on milk components during early lactation as part of a larger study on the antiparasitic efficacy of CV supplementation on ewes during the periparturient period. Ewes were fed a 50% CV pellet (CVP; n = 12) or a control pellet (CON; n = 13) beginning at 102±1 d of pregnancy until d 65±1 postpartum. The CV pellet fed was formulated to be equivalent in digestible dry matter to the control pellet. BW was determined weekly during the study and milk samples were collected weekly during lactation. Data were analyzed in SAS with repeated measures. Ewe BW were similar at the start of study (180.36lbs ± 4.70lbs; P = 0.43) however by wk 8 postpartum CVP ewes weighed less than CON ewes (CON: 212.31lbs±7.86lbs; CVP: 185.58lbs±8.00lbs; P = 0.04). There was a treatment*wk effect observed for milk fat, protein and MUN (P ≤ 0.05). Ewes fed CVP exhibited reduced milk fat at wks 2 (CON: 6.75%±0.63%; CVP: 6.06%±0.58%; P = 0.03) and 5 (CON: 6.66%±0.37%; CVP: 5.54%±0.26%; P = 0.05), milk protein was reduced in CVP ewes at wk 2 (CON: 4.92%±0.12%; CVP: 4.72%±0.19%; P = 0.05) and MUN was greater at weeks 4 (CON: 22.89±0.7mg/dL; CVP: 27.93±0.85mg/dL; P = 0.01) and 8 (CON: 24.80±0.51mg/dL; CVP: 26.64±0.86mg/dL; P &amp;lt; 0.01) in CVP ewes. Somatic cell analysis is pending. In conclusion, CVP supplementation during lactation affects milk composition in sheep. Studies are underway to determine the effect of CV supplementation on additional metabolic parameters in pregnant and lactating ewes.

Potential Benefits of Boswellia sacra Resin on Immunity, Metabolic Status, Udder and Uterus Health, and Milk Production in Transitioning Goats

As an attempt to prevent transition-period-associated metabolic disorders and/or diseases, the potential benefits of Boswellia sacra (Bs) resin on hematology, immunity, metabolic status, udder and uterus health biomarkers, and milk production were examined in transitioning goats. From 2 weeks prepartum to 7 weeks postpartum, goats (n = 7/treatment) orally received 0 (control, nBS), 2 (BsL), or 4 (BsH) g of Bs resin/goat/day. The results showed that both Bs treatments significantly improved the activity of phagocytes. Both Bs treatments significantly decreased the concentrations of blood plasma urea, non-esterified fatty acids, hydroxybutyric acid, and interleukin-1β, whereas they increased the total antioxidant capacity compared with the nBS treatment. Both Bs treatments significantly decreased the uterine horn diameter and tended to decrease the intrauterine fluid content, indicating improved uterine involution compared with no treatment. Compared with the nBS treatment, both Bs treatments significantly decreased the milk somatic cell count. The lowest milk interleukin-1β content was observed in goats that received the BsL treatment, followed by those that received the BsH and nBS treatments. The BsL treatment significantly increased the concentration of immunoglobulin M (IgM) in the colostrum compared with the other treatments. Both Bs treatments significantly increased the daily milk yield compared with the nBS treatment but did not affect milk composition or the fat-to-protein ratio. In conclusion, supplementing lactating goats in the transition period with Bs resin at a dose of 2 g/goat/day positively affected the body lipid metabolism, udder and uterus health, colostrum IgM content, and milk yield due to its antioxidant and anti-inflammatory effects.