Dairy Cow Diets Research Articles

The Effects of Incremental Doses of Aflatoxin B1 on In Vitro Ruminal Nutrient Digestibility and Fermentation Profile of a Lactating Dairy Cow Diet in a Dual-Flow Continuous Culture System.

Aflatoxin B1 (AFB1) is a mycotoxin known to impair human and animal health. It is also believed to have a deleterious effect on ruminal nutrient digestibility under in vitro batch culture systems. The objective of this study was to evaluate the effects of increasing the dose of AFB1 on ruminal dry matter and nutrient digestibility, fermentation profile, and N flows using a dual-flow continuous culture system fed a diet formulated for lactating dairy cows. Eight fermenter vessels were used in a replicated 4 × 4 Latin square design with 10 d periods (7 d adaptation and 3 d sample collection). Treatments were randomly applied to fermenters on diet DM basis: (1) 0 μg of AFB1/kg of DM (Control); (2) 50 μg of AFB1/kg of DM (AF50); (3) 100 μg of AFB1/kg of DM (AF100); and (4) 150 μg of AFB1/kg of DM (AF150). Treatments did not affect nutrient digestibility, fermentation, and N flows. Aflatoxin B1 concentration in ruminal fluid increased with dose but decreased to undetectable levels after 4 h post-dosing. In conclusion, adding incremental doses of AFB1 did not affect ruminal fermentation, digestibility of nutrients, and N flows in a dual-flow continuous culture system fed diets formulated for lactating dairy cows.

Efficiency of using different levels of mixed ligand complexes of Zinc, Manganese, and Cobalt in cow feeding

To increase productivity and reduce the negative impact on the environment, it is necessary to investigate the most optimal ratios of organic trace elements in the diets of cows involved in the production cycle, considering their physiological state and lactation stage. The purpose of the study was to determine the economic profitability of using mixed complexes of zinc, manganese, and cobalt in the diets of dairy cows. The experiment was carried out under production conditions on Holstein cows. 100 cows were divided into two groups. Cows of the control and experimental groups consumed feed mixtures made according to the same recipes, supplemented with mixed ligand complexes of zinc, manganese, and cobalt. It was found that with the optimal content of mixed ligand complexes of zinc, manganese, and cobalt in cows of the experimental group, body weight loss during the first hundred days of lactation was 16.4 kg or 2.88% less than in the control. Analysis of performance indicators of cows during the dry period and the first hundred days of lactation showed that in animals of the experimental group, whose diet contained mixed ligand complexes of trace elements at the rate of 54.7 mg of zinc and manganese and 0.7 mg of cobalt per 1 kg of dry matter, milk yields of natural fat content increased by 4.1 kg or 9.2%, the fat content in milk – by 0.02% compared to cows of the control group, whose diets provided the content of zinc and manganese at the level of 60.8 mg, cobalt – 0.78 mg/kg of dry matter due to mixed ligand complexes. There was also a decrease in the duration of the service period by 9 days and the insemination index by 0.17 semen doses. The cost of production remained unchanged, and the additional profit with a reduced concentration of these elements in the diet of cows of the experimental group amounted to EUR 27.24 or 9.7%. Thus, optimisation of mineral nutrition of cows by introducing mixed ligand complexes of zinc, manganese, and cobalt to achieve the concentration of trace elements of zinc and manganese – 54.7 mg each, and cobalt – 0.7 mg per 1 kg of dry matter of the feed mixture will improve milk production and reproductive capacity of cows and allow obtaining additional profit

Влияние танинов коры лиственницы даурской (Larix dahurica Turez) в составе энерго-протеиновой кормовой добавки в рационе молочных коров на гомеостаз организма и молочную продуктивность

Research has been carried out. at the Federal State Budgetary Institution Federal Research Center for Animal Husbandry named after. L. K. Ernst.The purpose of the study was to increase the energy-protein value and use of nutrients in the diet in the nutrition of dairy cows by introducing into it an energy-protein concentrate and an extract of Dahurian larch bark (Larix dahurica Turez), ExtraKor, (EPC + EB, produced by Ametis JSC), which includes proanthocyanidins (condensable tannins) – 65 %, dihydroquercetin – 16 % and phenolic acids in terms of ή-hydroxybenzoic acid – 14 %. The research was carried out on the dairy farm of the collective farm named after. M. A. Guryanova, Zhukovsky district, Kaluga region, on two groups of kholmogor × black-and-white crossbred cows in free-stall conditions with the formation of production and technological groups according to calving dates in an amount of 20–25 heads with milking in the milking parlor on a milking machine that takes into account daily milk yield . In the control and production groups, analogs by age of 10 animals each were selected to study the state of metabolism and chemical composition of milk. The main diet for feeding cows consisted of traditional feed and was designed to produce 25 kg of milk per day. The cows of the experimental group were additionally included in the diet with 1 kg of EPC+EB, made from recycled products of the confectionery industry and microbiological synthesis protein with the inclusion of Dahurian larch bark extract (Larix dahurica Turez) in dosages per 1 kg of product 682, 300 and 12 respectively. 1 kg of concentrate contained 957 g of dry matter, protein 137,8 g, fat 51,7 g, fiber 19,8 g, BEV 602,4 g, incl. sugar 167,9 g, calcium 25,0 g, phosphorus 4,6 g, magnesium 0,55 g, metabolic energy 11,18 MJ/kg. The inclusion of EPC+EB in the diet of dairy cows during the transit period of the production cycle balanced the energy-protein nutritional value of the diet and had a positive effect on protein-nitrogen, lipid-carbohydrate, mineral metabolism, on the functional state of the liver and on morpho-hematological parameters, which generally reflected on the productive health of cows, which led to a higher realization of the bioresource potential of milk productivity in relation to the control ones. As a result, the cows of the experimental group have an average daily milk yield at the 1st, 2nd and 3rd months. lactation was 20,7; 23,8 and 24,5 kg, which was 11,5; 24,6 % (p<0,01) and 20,0 % (p<0,05) higher than in controls, respectively. The fat content in milk in cows of the experimental group was 4,49 (p<0,02) and 3,83 % (p<0,01) versus 3,91 and 3,26 %, and protein 3,32 (p<0,001) and 2,95 % (p<0,001) versus 2,91 and 2,63 in cows of the control group, respectively, in the 1st and 2nd month of lactation.

ВЛИЯНИЕ МИНЕРАЛЬНО-ВИТАМИННОЙ ДОБАВКИ НА ИНФУЗОРНУЮ ФАУНУ РУБЦА И МОЛОЧНУЮ ПРОДУКТИВНОСТЬ КОРОВ

The article presents the results of research on the use of mineral and vitamin supplements in the diets of dairy cows and its effect on the microfauna of the rumen and dairy productivity of animals. The object of research was highly productive cows during the period of milking. As a result of the conducted studies, it was found that the use of a feed additive contributed to the optimization of digestive processes by increasing the density of rumen infusoria in 1 ml of rumen fluid in lactating cows of the experimental groups compared with peers from the control group by 22.6–23.1 %, which is reliable (p ≥ 0,95). The feed additive had a positive effect on increasing the biodiversity of infusoria in the rumen of ruminants, creating more favorable conditions for the formation and growth of microfauna, and, consequently, for improving the digestibility of nutrients consumed feed, as evidenced by data on the dairy productivity of animals. During the period of the experiment, the average daily milk yield according to the results of control milkings of cows receiving «Minvit 6.1-Mama» in the amount of 150 g was 31.0 ± 0.6 kg, which is 8.0 % (p ≥ 0.99) more than animals from the control group. Cows of the experimental group 2 had an average daily milk yield of 31.8 ± 0.71 kg, which is 10.8 % (p ≥ 0.99) higher than the same indicator compared to peers from the control group. Thus, the use of mineral and vitamin supplement «Minvit 6.1-Mama» in the feeding of dairy cows contributes to the optimization of scar digestion while increasing the milk productivity of animals. The maximum biological and zootechnical effect is manifested by the introduction of a feed additive in the amount of 200 g per head per day

Influence of dietary oils rich in omega-6 or omega-3 fatty acids on rumen microbiome of dairy cows.

The objective of this study was to compare the effect of supplementing dairy cow diets with contrasting sources of omega-6 (soybean oil) and omega-3 (fish oil) PUFA on rumen microbiome. For 63 d, 15 mid-lactating cows were fed a control diet (n = 5 cows; no fat supplement) or control diet supplemented with 2.9% dry matter (DM) of either soybean oil (SO; n = 5 cows) or fish oil (FO; n = 5 cows). Ruminal contents were collected on days 0, 21, 42, and 63 for 16S rRNA gene sequencing. Beta diversity and Shannon, Simpson and Chao1 diversity indices were not affected by dietary treatments. In terms of core microbiome, Succiniclasticum, Prevotella, Rikenellaceae_RC9_gut_group, and NK4A214_group were the most prevalent taxa regardless of treatments. Bifidobacterium was absent in SO diet, Acetitomaculum was absent in FO, and Sharpea was only detected in SO. Overall, results showed that at 2.9% DM supplementation of either SO or FO over 63 days in dairy cow diets does not cause major impact on bacterial community composition and thus is recommended as feeding practice.

Dietary citrus flavonoid extract improves lactational performance through modulating rumen microbiome and metabolites in dairy cows.

The effects of dietary supplementation with citrus flavonoid extract (CFE) on milk performance, rumen fermentation, rumen microbiome, rumen metabolome, and serum antioxidant indexes were evaluated. Eight multiparous lactating cows were allocated to a replicated 4 × 4 Latin square with 25-d periods consisting of 20 d of adaptation and 5 d of sampling. Experimental treatments included a control diet (CON) and CON supplemented with 50 g d-1 (CFE50), 100 g d-1 (CFE100), and 150 g d-1 (CFE150). Feeding CFE to dairy cows increased milk production and milk lactose. Milk somatic cell count linearly reduced with increasing CFE amount. Supplementing CFE linearly increased the ruminal concentrations of total volatile fatty acids, acetate, propionate, butyrate, and microbial crude protein. Ruminal lipopolysaccharide linearly decreased with increasing CFE amount. Compared with CON, CFE150 cows exhibited a greater abundance of Firmicutes and a low abundance of Bacteroidetes. Cellulolytic bacteria (genera Ruminococcus, Clostridium, and Butyrivibrio) and carbohydrate metabolism were enriched in the CFE150 cows. For archaea and viruses, major methanogens (genera Methanobacterium and Methanosarcina) and phylum Uroviricota were inhibited in the CFE150 cows. Compared with CON, the ruminal concentrations of tyrosine, proline, pyruvate, glucose, and glucose-6-phosphate were higher in the CFE150 cows. The metabolites of citrus flavonoids, such as hippuric acid, hesperetin, and naringenin, were increased in the CFE150 cows. Supplementing CFE significantly improved the antioxidant capacity of the dairy cows. This study highlighted that dietary supplementation with CFE led to significant changes in the rumen microbial composition and metabolites, and consequently resulted in an improved lactational performance of dairy cows.

ВЛИЯНИЕ АЛИМЕНТАРНОГО ФАКТОРА НА ГЕМАТОЛОГИЧЕСКИЙ ПРОФИЛЬ У МОЛОЧНЫХ КОРОВ

The article shows the findings of the research of the effect of the dietary factor on the hematological parameters of Holstein cows. We carried out the analysis of winter dairy food, general and biochemical blood test. The food analysis showed an excess of dry matter and a lack of raw and digestible protein, crude fiber, crude fat, a lack of macronutrients Ca and P, carotene. The relationship between the food quality of and the biochemical composition, as well as the complete blood count of cows, was established. The research revealed that deviations in the diet of dairy cows affect their hematological parameters. Thus, in the blood serum of experimental animals, there was a pronounced deficiency of glucose, iron, manganese, calcium, zinc, copper, nickel and cobalt. All these deviations from the physiological norm are directly dependent on the chemical composition of the food. The insufficiency of these elements is responsible for the development of osteodystrophy, disruptions in sex hormone production (due to a manganese deficiency), and, as a result, an extension of the open period due to repeat breeding. These deficiencies lead to disturbances in the body's metabolic processes in animals, consequently affecting their fertility. Hematological parameters indicate a decrease in segmented neutrophils, along with elevated levels of leukocytes and monocytes. Other parameters (platelets and white blood cell (stab cells, basophils, lymphocytes, erythrocyte sedimentation rate) were found to comply with physiological standard.

In vitro evaluation of microencapsulated organic acids and pure botanicals as a supplement in lactating dairy cows diet on in vitro ruminal fermentation.

The utilization of microencapsulated organic acids and pure botanicals (mOAPB) is widely used in the monogastric livestock industry as an alternative to antibiotics; in addition, it can have gut immunomodulatory functions. More recently, an interest in applying those compounds in the ruminant industry has increased; thus, we evaluated the effects of mOAPB on ruminal fermentation kinetics and metabolite production in an in vitro dual-flow continuous-culture system. For this study, two ruminal cannulated lactating dairy Holstein cows were used as ruminal content donors, and the inoculum was incubated in eight fermenters arranged in a 4 × 4 Latin square design. The basal diet was formulated to meet the nutritional requirements of a 680-kg Holstein dairy cow producing 45 kg/d of milk and supplemented with increasing levels of mOAPB (0; 0.12; 0.24; or 0.36% of dry matter [DM]), which contained 55.6% hydrogenated and refined palm oil, 25% citric acid, 16.7% sorbic acid, 1.7% thymol, and 1% vanillin. Diet had 16.1 CP, 30.9 neutral detergent fiber (NDF), and 32.0 starch, % of DM basis, and fermenters were fed 106 g/d split into two feedings. After a 7 d adaptation, samples were collected for 3 d in each period. Samples of the ruminal content from the fermenters were collected at 0, 1, 2, 4, 6, and 8 h postmorning feeding for evaluation of the ruminal fermentation kinetics. For the evaluation of the daily production of total metabolites and for the evaluation of nutrient degradability, samples from the effluent containers were collected daily at days 8 to 10. The statistical analysis was conducted using MIXED procedure of SAS and treatment, time, and its interactions were considered as fixed effects and day, Latin square, and fermenter as random effects. To depict the treatment effects, orthogonal contrasts were used (linear and quadratic). The supplementation of mOAPB had no major effects on the ruminal fermentation, metabolite production, and degradability of nutrients. The lack of statistical differences between control and supplemented fermenters indicates effective ruminal protection and minor ruminal effects of the active compounds. This could be attributed to the range of daily variation of pH, which ranged from 5.98 to 6.45. The pH can play a major role in the solubilization of lipid coat. It can be concluded that mOAPB did not affect the ruminal fermentation, metabolite production, and degradability of dietary nutrients using an in vitro rumen simulator.

Effects of exogenous amylolytic or fibrolytic enzymes inclusion on in vitro fermentation of lactating dairy cow diets in a dual-flow continuous-culture system

The objective of this study was to determine the effects of including exogenous amylolytic or fibrolytic enzymes in a diet for high-producing dairy cows on in vitro ruminal fermentation. Eight dual-flow continuous-culture fermentors were used in a replicated 4 × 4 Latin square. The treatments were control (CON), a xylanase and glucanase mixture (T1), an α-amylase mixture (T2), or a xylanase, glucanase, and α-amylase mixture (T3). Treatments were included at a rate of 0.008% of diet dry matter (DM) for T1 and T2 and at 0.02% for T3. All treatments replaced the equivalent amount of soybean meal in the diet compared with CON. All diets were balanced to have the same nutrient composition [30.2% neutral detergent fiber (NDF), 16.1% crude protein (CP), and 30% starch; DM basis], and fermentors were fed 106 g/d divided into 2 feedings. At each feeding, T2 was pipetted into the respective fermentor and an equivalent amount of deionized water was added to each fermentor to eliminate potential variation. Experimental periods were 10 d (7 d for adaptation and 3 d for sample collection). Composite samples of daily effluent were collected and analyzed for volatile fatty acids (VFA), NH3-N, and lactate concentrations, degradability of DM, organic matter, NDF, CP, and starch, and flow and metabolism of N. Samples of fermentor contents were collected from each fermentor at 0, 1, 2, 4, 6, and 8 h after feeding to determine kinetics of pH, NH3-N, lactate, and VFA concentrations over time. All data were analyzed using PROC GLIMMIX of SAS (SAS Institute Inc.), and the repeated variable of time was included for kinetics measurements. Treatment did not affect mean pH, degradability, N flow and metabolism, or the concentrations of VFA, NH3-N, or lactate in the effluent samples. Treatment did not affect pH, acetate:propionate ratio, or the concentrations of lactate, NH3-N, total VFA, acetate, propionate, butyrate, isobutyrate, valerate, or caproate. However, the concentration of total VFA tended to change at each time point depending upon the treatment, and T2 tended to have a greater proportion of 2-methylbutyrate and isovalerate than CON, T1, or T3. As 2-methylbutyrate and isovalerate are branched-chain VFA that are synthesized from branched-chain amino acids, T2 may have an increased fermentation of branched-chain amino acids or decreased uptake by fibrolytic microorganisms. Although we did not observe changes in N metabolism due to the enzymes, there could be changes in microbial populations that utilize branched-chain VFA. Overall, the tested enzymes did not improve in vitro ruminal fermentation in the diet of high-producing dairy cows.

Varying plantain content in temperate ryegrass-white clover pastures affects urinary-nitrogen excretion of non-lactating dairy cows

Dairy cow urine patches contain high rates of nitrogen (N; >500 kg N/ha) and represent the main source of N loss from grazed pastoral systems. Emerging research has identified plantain (Plantago lanceolata) as a key forage to potentially reduce urine N (UN) losses from dairy cows. This experiment examined the effect of increasing proportions of plantain in the diet of dairy cows on UN excretion relative to a ryegrass-white clover diet. Twenty mixed aged non-lactating dairy cows were randomly assigned to one of five treatment diets; 0 %, 20 %, 40 %, 60 % or 100 % plantain (dry matter basis), with the remainder comprised of ryegrass-white clover pasture and grass-silage. Cows were fitted with urine sensors to measure urination event N concentration, volume and frequency. Daily N intake increased with increasing proportions of plantain in the diet due to the greater N concentration of plantain. Conversely, mean UN concentration was reduced as the proportion of plantain in the diet increased. Urine-N concentration was >40 % lower for cows on 100 % plantain compared with 0 % plantain (0.46 and 0.81 % N respectively). There was no treatment effect on the total daily amount of UN excreted, indicating a dilution effect of plantain as total daily urine volumes markedly increased with increasing plantain diets. Nitrogen load per urination event was lower for cows on 100 % plantain than 0 % despite greater N intake, with no significant difference for the intermediate treatment groups. The reduced N load per event for cows on >60 % plantain could help to reduce N leaching losses at the urine patch level. This experiment suggests that a reduction in UN concentration can be achieved on low levels of plantain (20 % of the diet), but >60 % plantain diets are required to reduce N load per event.

Alterations in nutrient digestibility and performance of heat-stressed dairy cows by dietary L-theanine supplementation

The purpose of this study was to investigate the effects of dietary L-theanine supplementation on apparent nutrient digestibility, milk yield, milk composition, and blood biochemical indices of dairy cows under heat stress. Thirty Chinese Holstein cows (19.84±2.42kg milk/d, 192.36±40.77d in milk and 2±0.93 parities) were divided into 3 groups of 10 animals each. The control group was fed a basal total mixed ration (TMR) diet, while treatment 1 (LTA16) and treatment 2 (LTA32) groups were fed a basal TMR diet supplemented with L-theanine at 16 and 32 g/cow per day, respectively. The results showed that feeding the dairy cows with LTA16 treatment decreased (P<0.05) their rectal temperature, whereas feeding with LTA32 treatment decreased (P<0.05) their rumen fluid ammonia nitrogen content. In comparison to the control group, the supplementation of L-theanine had no significant effect (P>0.05) on the dry matter intake, nutrient digestibility, total volatile fatty acid (TVFA) concentration and molar proportion of volatile fatty acid, milk yield, milk composition, feed efficiency and antioxidant capacity of the dairy cows. The triglyceride (TG) content of the LTA32 group was significantly greater (P=0.014) than that of the control group. With the increase in L-theanine dosage, the serum cholesterol (CHOL) content significantly increased (P=0.013). The serum albumin (ALB; P=0.067), low-density lipoprotein cholesterol (LDL-C; P= 0.053), and high-density lipoprotein cholesterol (HDL-C; P=0.067) contents showed an upward trend as L-theanine dosage increased. Ultimately, the results of this study show that supplementing dairy cow diet with L-theanine could decrease dairy cow rectal temperature, affect lipid metabolism, and potentially relieve the heat stress of dairy cows to some extent.

Economic, zootechnical and radiological efficiency of the feed additive “Antiket” with the introduction of ferrocin

Presents the results of a comprehensive study of the production test of the feed additive “Antiket” with the introduction of ferrocin in the diet of dairy cows during the summer-pasture keeping of animals. The results of its radiological, zootechnical and economic efficiency are presented.

Biorefined press cake silage as feed source for dairy cows: effect on milk production and composition, rumen fermentation, nitrogen and phosphorus excretion and in vitro methane production

The objective of this study is to investigate the effect of replacing grass silage with biorefined grass silage (press cake silage) on dry matter intake (DMI), milk production and composition, rumen fermentation parameters, nitrogen and phosphorus excretion of early lactation Holstein Friesian dairy cows. An in vitro experiment using the rumen simulation technique (RUSITEC) also investigated the in vitro dry matter disappearance and methane (CH₄) production of these feedstuffs. In this study, press cake silage was made from perennial ryegrass (Lolium perenne) using a novel biorefining process. Thirty early-lactation cows (Bos taurus strain Holstein Friesian) were used in a randomized complete block design experiment (n = 15) and offered two dietary treatments for a 56 d period: Grass silage (GS): 14 kg dry matter (DM) grass silage + 7.2 kg DM of concentrate + 0.44 kg DM of soyabean meal; Press cake (PC): 5 kg DM grass silage + 9 kg DM press cake silage + 7.2 kg DM concentrate + 0.44 kg DM soyabean meal. The dietary treatments were also incubated in vitro for a period of 18 days using the RUSITEC. In the in vivo study, DMI was lower for PC compared to GS. No difference was observed between the treatments for milk yield and milk quality; however, milk fat yield was lower and milk solids yield tended to be lower in PC compared to GS. Cows offered PC had higher N use efficiency (NUE, milk N/N intake), lower total N excretion and lower N excretion in feces and urine compared to cows offered GS. Total and fecal P excretion was lower in cows fed PC compared to cows fed GS. Ruminal NH₃-N concentration was lower when PC was offered. In vitro rumen fermentation parameters such as pH, volatile fatty acids and CH₄ output were not affected by treatment. In vitro dry matter disappearance and NH₃-N concentration were lower for PC compared to GS. This study suggests that press cake silage can partially replace grass silage in the diet of dairy cows with beneficial effects on the environment and without compromising animal productivity.

Starch and Cellulose Degradation in the Rumen and Applications of Metagenomics on Ruminal Microorganisms.

Carbohydrates (e.g., starch and cellulose) are the main energy source in the diets of dairy cows. The ruminal digestion of starch and cellulose is achieved by microorganisms and digestive enzymes. In order to improve their digestibility, the microbes and enzymes involved in starch and cellulose degradation should be identified and their role(s) and activity known. As existing and new analytical techniques are continuously being developed, our knowledge of the amylolytic and cellulolytic microbial community in the rumen of dairy cows has been evolving rapidly. Using traditional culture-based methods, the main amylolytic and cellulolytic bacteria, fungi and protozoa in the rumen of dairy cows have been isolated. These culturable microbes have been found to only account for a small fraction of the total population of microorganisms present in the rumen. A more recent application of the culture-independent approach of metagenomics has acquired a more complete genetic structure and functional composition of the rumen microbial community. Metagenomics can be divided into functional metagenomics and sequencing-based computational metagenomics. Both approaches have been applied in determining the microbial composition and function in the rumen. With these approaches, novel microbial species as well as enzymes, especially glycosyl hydrolases, have been discovered. This review summarizes the current state of knowledge regarding the major amylolytic and cellulolytic microorganisms present in the rumen of dairy cows. The ruminal amylases and cellulases are briefly discussed. The application of metagenomics technology in investigating glycosyl hydrolases is provided and the novel enzymes are compared in terms of glycosyl hydrolase families related to amylolytic and cellulolytic activities.

Partial replacement of canola meal with dried dairy waste as a protein source in the diet of dairy cow: Effects on lactation performance, ruminal measurements, nutrient digestibility, and nitrogen balance

The potential nutritive values and in vivo responses of dried dairy waste (DDW) as a protein substitution for canola meal (CM) in the diet of early lactating Holstein dairy cows were evaluated. Twenty-four dairy cows were assigned to three treatments in a complete randomized design with eight replicates for 35 days. The treatments consisted of a control (without DDW), a low level of DDW (50% of dietary CM content was replaced by DDW), and a high level of DDW (100%). Dry matter intakes averaged 26.9 and 24.9 kg per day for control and DDW supplemented diets. Cows showed similar total-tract digestibility values for dry matter, organic matter, neutral detergent fiber, and ether extract. Ruminal pH and individual volatile fatty acids were not affected by the inclusion of DDW. There were no significant differences among the treatments for raw milk, fat, or energy corrected milk, as well as milk fat and protein yield by dietary replacement of CM with DDW. When compared to the control, feeding DDW enhanced feed efficiencies determined using raw milk and milk that has had its fat or calorie content adjusted. As the quantity of dietary DDW increased, urinary urea-N (g/d) decreased. Reduced urinary urea and manure nitrogen excretion are based on reduced dry matter intake, and 0.42 kg less crude protein intake when DDW replaced CM. DDW, as an alternative available protein source, could replace 50% of dietary CM. If milk production is maintained, DDW may be an eco-friendly supplement in lactating dairy cows by reducing feed and crude protein intake.

Macromineral and trace element concentrations in milk from Finnish Ayrshire cows fed microalgae (Spirulina platensis) and rapeseed (Brassica napus).

Given the lack of research regarding the effect of microalgal supplementation in dairy cows on milk mineral concentrations, this study investigated the effect of feeding different protein supplements in dairy cow diets on milk, feces, and blood plasma mineral concentrations, associated milk and blood plasma transfer efficiencies, and apparent digestibility. Lactating Finnish Ayrshire cows (n = 8) were allocated at the start of the trial to 4 diets used in a replicated 4 × 4 Latin square design experiment: (1) control diet (CON), (2) a pelleted rapeseed supplement (RSS; 2,550 g/d), (3) a mixture of rapeseed and Spirulina platensis (RSAL; 1,280 g of RSS + 570 g of S. platensis per day), and (4) S. platensis (ALG; 1,130 g of S. platensis per day). In each of the 4 experimental periods, a 2-wk adaptation to the experimental diets was followed by a 7-d sampling and measurement period. Feed samples were composited per measurement period, milk, and feed samples (4 consecutive days; d 17-20), and blood plasma samples (d 21) were composited for each cow period (n = 32). Data were statistically analyzed using a linear mixed effects model with diet, period within square, square and their interaction as fixed factors, and cow within square as a random factor. Cows fed ALG were not significantly different in their milk or blood plasma mineral concentrations compared with CON, although feeding ALG increased fecal concentrations of macrominerals (Ca and Mg) and trace elements (Co, Cu, Fe, I, Mn, and Zn), and reduced their apparent digestibility, compared with CON. When compared with CON and ALG, milk from cows fed RSAL and RSS had lower milk I concentrations (-69.6 and -102.7 μg/kg of milk, respectively), but total plasma I concentrations were not affected significantly. Feeding S. platensis to dairy cows did not affect mineral concentrations in cows' blood or milk, but care should be taken when rapeseed is fed to avoid reducing milk I concentrations which may in turn reduce consumers' I intake from milk and dairy products.

Actualidades en el uso de aminoácidos en la industria lechera

The constant demand for high quality dairy products has driven significant changes in the productive capacity of dairy cows in the last 50 years. To maintain high volumes of milk production and quality in terms of the level of protein, fat, and other milk components, it is common to use high levels of crude protein in the diet. However, this practice generates N residues in feces and urine that cause environmental pollution and high costs. Balancing diets to cover metabolizable protein and limiting amino acid requirements allows feeding low-protein diets resulting in higher N utilization efficiency, lower environmental impact, and higher profitability. Lysine, methionine, and histidine are the most limiting amino acids in diets for dairy cows based on corn silage and alfalfa hay. The use of rumen-protected lysine and methionine in transition cow diets positively affects dry matter intake, milk production and milk quality. Whereas supplementation with rumen-protected methionine to cows prior to calving improves metabolic immune status and genetic expression of offspring, which show better productive performance after birth.

Assessment of nutritional approaches to nutritional requirements

The article presents the results of scientific, economic and physiological experiments conducted on Ukrainian black-spotted and red-spotted cows in different phases of lactation: Ukrainian (2009), English FIM (2004) and US NRC (2001) feeding standards. It was found that feeding dairy cows according to the Ukrainian (2009) English (FIM, 2004) and US NRC (2001) provides almost the same productivity.&#x0D; In general, in all diets, the ratio between Calcium and Phosphorus was more than 2: 1, due to the excess in the diets of Calcium in two or more times. The ratio of Potassium to Magnesium in all diets was more than three, which is recommended for cows. It was found that the cation-anion balance in the diets of dairy cows was within physiological limits. Alkaline elements were predominant acidic, ie the balance was positive.&#x0D; The concentration of crude fat in the NRC, 2001 and FIM, 2004 was significantly lower (26.3 - 53.0 %), and that the content of Calcium, Phosphorus, Sulfur, Iron, Cobalt, Manganese, Iodine and Selenium compared to Ukrainian standards in all phases of lactation. Cows that received rations according to NRC and FIM norms had higher milk productivity than Ukrainian ones, but unevenly during lactation phases.&#x0D; Thus, in the first phase of lactation, according to English standards, milk yields were 3.3% higher, and according to US standards - 3.4% lower compared to Ukrainian standards. In the second phase of lactation milk yields according to Ukrainian and English standards were almost the same. Whereas under US standards, milk yields were 6.6% higher than in Ukraine.&#x0D; In the third phase of lactation, milk yields were 3.9% higher in English standards and 8.1% higher in US standards than in Ukrainian standards.

Nitrogen balance and microbial protein synthesis in dairy cows fed with peanut meal to replace soybean meal.

This research was carried out to evaluate the effect of replacing dietary soybean meal with peanut meal, on intake and digestibility, microbial protein synthesis, and nitrogen balance in lactating cows. Twelve crossbred Holstein × Gyr cows at 84days in milk (DIM) were distributed in a triple 4 × 4 Latin square. The treatments consisted of increasing peanut meal levels (0, 330, 670, and 1000g/kg dry matter basis) in replacement of soybean meal in the diet. Replacing soybean meal with peanut meal had no effect on the intake and digestibility of dry matter and nutrients. Nitrogen balance and percentage of retained were similar among treatments. Microbial nitrogen synthesis and microbial protein synthesis efficiency were similar among treatments. Thus, in regions where its cost is lower, peanut meal can totally replace soybean meal in dairy cow diets without affecting nitrogen balance and microbial protein synthesis.

Metagenomic insights into the modulatory effects of kelp powder (Thallus laminariae)-Treated dairy milk on growth performances and physiological lipometabolic processes of kunming mice.

Kelp powder, supplemented with a dairy cow diet, effectively improved the milk polyunsaturated fatty acids (PUFAs) content. However, little information exists on the downstream effects of the kelp-treated milk on body health, gut microbiota, and nutrient metabolism. For this purpose, 48 3-week old Kunming (KM) male mice with an average body weight of 16.1 g ± 0.2 g were randomly divided into the control treatment (CON, fed with standard chow), the common milk supplement treatment (Milk), and the kelp powder-treated milk supplement treatment (KPM). The experiment lasted for 35 days, with a 7-day long adaptive period and a 28-day long main trial. Phenotypic parameters including growth performances and serum lipids-related parameters were first measured, and results indicated that Milk and KPM supplement significantly promoted the total body weight gain (P < 0.05), while significantly decreasing the feed conversion ratio compared with CON (P < 0.05). No significant differences were observed in the blood lipids content among all three treatments, however, the triglyceride content showed a decreasing trend after KPM supplement treatment. Further, activities of liver lipometabolic-related enzymes were investigated to determine the underlying factors that impacted physiological lipid metabolism. KPM treatment showed a significant reductive effect on the activity of lipogenesis-related enzymes, such as FAS and ACC, while a significant stimulative effect on the activity of lipolysis-related enzymes included the ATGL and CPT1 compared with CON (P < 0.05). Finally, gastrointestinal tract development and cecal microbiota community that correlated with body lipid degradation and absorption were measured to determine the underlying mechanism of KPM supplementation on physiological lipid metabolism. Results indicated that supplementation with KPM significantly enhanced cecal bacteria diversity which was reflected in the significant increase of Chao1 and ACE indexes. Besides, starch-degraded bacteria such as Faecalibacterium, Ruminococcaceae, and Streptococcus are significant decreased (P < 0.05), while cellulose-degraded bacteria including Parabacteroides, Prevotella, Lactobacillus, Clostridium, and Bifidobacterium are significantly increased (P < 0.05) after KPM supplement, which may further restrict the energy generation and therefore reduce the lipid deposition. In summary, kelp supplement helped increase the milk PUFAs content, enhance the bacterial diversity and relative abundances of probiotics, which finally modulated physiological lipid metabolism, and promote growth performances.