Dry Milk Research Articles

Enteric methane emission of dairy cows supplemented with iodoform in a dose–response study

Enteric methane (CH4) emission is one of the major greenhouse gasses originating from cattle. Iodoform has in studies been found to be a potent mitigator of rumen CH4 formation in vitro. This study aimed to quantify potential of iodoform as an anti-methanogenic feed additive for dairy cows and investigate effects on feed intake, milk production, feed digestibility, rumen microbiome, and animal health indicators. The experiment was conducted as a 4 × 4 Latin square design using four lactating rumen, duodenal, and ileal cannulated Danish Holstein dairy cows. The treatments consisted of four different doses of iodoform (1) 0 mg/day, (2) 320 mg/day, (3) 640 mg/day, and (4) 800 mg/day. Iodoform was supplemented intra-ruminally twice daily. Each period consisted of 7-days of adaptation, 3-days of digesta and blood sampling, and 4-days of gas exchange measurements using respiration chambers. Milk yield and dry matter intake (DMI) were recorded daily. Rumen samples were collected for microbial analyses and investigated for fermentation parameters. Blood was sampled and analyzed for metabolic and health status indicators. Dry matter intake and milk production decreased linearly by maximum of 48% and 33%, respectively, with increasing dose. Methane yield (g CH4/kg DMI) decreased by maximum of 66%, while up to 125-fold increases were observed in hydrogen yield (g H2/kg DMI) with increasing dose of iodoform. Total tract digestibility of DM, OM, CP, C, NDF, and starch were unaffected by treatments, but large shifts, except for NDF, were observed for ruminal to small intestinal digestion of the nutrients. Some indicators of disturbed rumen microbial activity and fermentation dynamics were observed with increasing dose, but total number of ruminal bacteria was unaffected by treatment. Serum and plasma biomarkers did not indicate negative effects of iodoform on cow health. In conclusion, iodoform was a potent mitigator of CH4 emission. However, DMI and milk production were negatively affected and associated with indications of depressed ruminal fermentation. Future studies might reveal if depression of milk yield and feed intake can be avoided if iodoform is continuously administered by mixing it into a total mixed ration.

Feeding graded levels of camelina expeller meal up to 20% of dietary dry matter decreases feed intake and milk production but enhances concentration in milk fat of n-3 fatty acids in dairy cows

Eight Holstein cows were used in a replicated 4 × 4 Latin square design study to determine the effects of feeding 0%, 10%, 15%, and 20% camelina expeller meal (CEM) on production and milk fatty acid profiles. Dry matter intake (DMI) and milk fat content decreased linearly, whereas milk yield decreased quadratically, as CEM increased. Concentrations in milk fat of C18:2n-6 and cis-9, trans-11 C18:2 increased linearly, whereas those of C18:3n-3 and trans-10, cis-12 C18:2 increased quadratically as CEM increased. Results show that CEM levels up to 20% decrease DMI and milk yield but increase concentrations in milk fat of desirable n-3 fatty acids.

Оценка сбалансированности аминокислотного состава белка сухого кобыльего молока

Кобылье молоко, приближенное по своему составу к женскому молоку, и продукты его переработки (кумыс) активно используются в лечебно-профилактическом питании при бронхолегочных заболеваниях, патологиях ЖКТ, в реабилитации онкологических больных и для поддержания общего иммунитета. Биологическая ценность кобыльего молока определяется качеством белка и сбалансированностью его аминокислотного состава. В то же время производство кобыльего молока не получило широкого распространения (объемы производства составляют до 0,02 % от общего объема производства сырого молока) ввиду особенностей организации молочного коневодства, высокой себестоимости сырья, несовершенства логистических процессов, что требует изменения бизнес-процессов и перехода на производство сухого кобыльего молока, отличающегося пролонгированными сроками годности. Аминокислотный состав белка кобыльего молока сопоставим с идеальным белком, в нем не выявлена лимитирующая аминокислота, наряду с этим в сыром кобыльем молоке установлен минимальный аминокислотный скор по валину. Высокая сбалансированность аминокислотного состава позволяет улучшить синтез белка в организме человека при высоком коэффициенте утилитарности – от 0,9883 в сыром молоке до 0,9900 в сухом молоке. Аминокислоты белка сухого кобыльего молока практически полностью используются в анаболических целях, при этом показатель сопоставимой избыточности равен 0,0003, что в 14 раз меньше, чем в сыром молоке, тем самым обеспечивая более высокую усвояемость сухого молока – до 99,0–99,5 %. В условиях отсутствия регламентирующей нормативной документации по использованию сырого натурального кобыльего молока в питании человека оптимальным решением является производство сухого кобыльего молока способом сублимационной сушки на малых сельскохозяйственных предприятиях полного производственного цикла. Результаты проведенных исследований показывают более высокие характеристики сбалансированности аминокислотного состава сухого кобыльего молока. Рекомендуется проведение дальнейших исследований по углубленной оценке пищевой ценности сухого кобыльего молока. Mare's milk, which is close in composition to women's milk, and its processed products (koumiss) are actively used in therapeutic and preventive nutrition for bronchopulmonary diseases, gastrointestinal pathologies, in the rehabilitation of cancer patients and to maintain general immunity. The biological value of mare's milk is determined by the quality of protein and the balance of its amino acid composition. At the same time, the production of mare's milk has not become widespread (production volumes are up to 0.02% of the total production of raw milk) due to the peculiarities of the organization of dairy horse breeding, high cost of raw materials, imperfections in logistics processes, which requires changes in business processes and the transition to the production of dry mare's milk, characterized by prolonged shelf life. The amino acid composition of mare's milk protein is comparable to an ideal protein, there is no limiting amino acid in it, along with this, a minimum amino acid score for valine is established in raw mare's milk. The high balance of the amino acid composition makes it possible to improve protein synthesis in the human body with a high utilitarianism coefficient – from 0.9883 in raw milk to 0.9900 in powdered milk. Amino acids of mare's milk powder protein are almost completely used for anabolic purposes, while the index of comparable redundancy is 0.0003, whichis 14 times less than in raw milk, thereby providing a higher digestibility of milk powder – up to 99.0–99.5 %. In the absence of regulatory regulatory documentation on the use of raw natural mare's milk in human nutrition, the most optimal solution is the production of dry mare's milk by freeze-drying at small agricultural enterprises of the full production cycle. The results of the conducted studies show higher characteristics of the balanced amino acid composition of dry mare's milk. It is recommended to conduct further studies on the in-depth assessment of the nutritional value of dry mare's milk.

Association of dry matter intake, milk yield, and days to first ovulation with cytological endometritis in Holstein cows

Dry matter intake (DMI, kg/d) is closely related to the magnitude of negative energy and protein balance during the transition period, and the metabolic adaptations to support lactation in dairy cows. Thus, DMI might affect the development of cytological endometritis in the early postpartum period. Difficulty to adapt to these metabolic changes is related to impaired immune function and increased occurrence of reproductive disorders. We aimed to examine the association of pre- and postpartum DMI, body weight (BW), body condition score, milk yield and milk composition, and days to first ovulation with cytological endometritis at 15 (CYT15) and 30 DIM (CYT30). A second objective was to understand the association of vaginal discharge with CYT15 and CYT30 and performance. We conducted a pooled statistical analysis of 5 studies, including data from 280 multiparous Holstein cows. Based on the cutoffs for the percentage of uterine polymorphonuclear cells (PMN), determined by taking the median value of the data set for 15 and 30 DIM, cows were categorized as follows: LOW15 (PMN % at 15 DIM ≤24%; n = 125), HIGH15 (PMN % at 15 DIM >24%; n = 125), LOW30 (PMN % at 30DIM ≤7%; n = 141); and HIGH30 (PMN % at 30DIM >7%; n = 139). Cows in HIGH15 consumed an average of 1.97 ± 0.5 kg/d less DM than cows in LOW15 during prepartum, and 3.01 ± 0.5 kg/d less DM during postpartum. Dry matter intake (as a percentage of BW) was higher for cows in LOW15 during pre- and postpartum than for cows in HIGH15. Moreover, cows in HIGH15 tended to have lower milk yield than cows in LOW15 from the third until the fifth week postpartum. Although DMI was not associated with CYT30, DMI (as a percentage of BW) was lower for cows in LOW30 pre- and postpartum than for cows in HIGH30. There was no association between CYT30 and milk yield. Cows in LOW15 had greater days to first ovulation than cows in HIGH15, while cows in LOW30 also had greater days to first ovulation than cows in HIGH30. Simple regression analyses demonstrated linear associations of increased DMI, particularly postpartum, with decreased uterine PMN percentage and lower vaginal discharge score. Additionally, increased units of vaginal discharge score and increased percentage units of uterine PMN were linearly associated with decreased milk yield. Corroborating with the notion of the ovarian function being associated with uterine inflammatory status, cows in HIGH15 and HIGH30 ovulated on average 3 d before than cows in LOW15 and LOW30, respectively. Cytological endometritis at 15 DIM was associated with lower DMI from 4 wk before calving until 4 wk postpartum and was associated with lower milk yield. The association of vaginal discharge with cytological endometritis was variable and dependent on the day of evaluation.

Validation of the KangarooSci® Aerobic Count Plate for the Enumeration of Meosphilic Aerobic Bacteria in Selected Foods and on Stainless Steel Environmental Surfaces: AOAC Performance Tested MethodSM 062301.

The KangarooSci® Aerobic Count Plate is a sample-ready culture medium system, for direct counting of aerobic bacteria colonies after 48-72 h of incubation. The KangarooSci Aerobic Count Plate was evaluated for AOAC® Performance Tested Methods SM certification. The KangarooSci Aerobic Count Plate (ACP) was evaluated through matrix studies and product consistency/stability study and robustness testing. For the matrix study, nine food products (nonfat dry milk powder, fresh raw bovine milk, pasteurized liquid bovine milk, fresh raw ground beef, frozen uncooked chicken breast, cooked shredded pork, apple juice, ice cream, and fresh strawberries), and one environmental surface (stainless steel) were evaluated following the KangarooSci ACP product instructions and compared to the ISO 4833-1:2013-pat 1, Microbiology of food and animal feeding stuffs-Horizontal methods for the enumeration of microorganisms-Part 1: Colony count at 30 °C by the pour plate technique reference standard. The product consistency and stability testing evaluated three separate production lots of the KangarooSci ACP. The robustness testing examined three test parameters, volume of sample plated, incubation time, and incubation temperature using a factorial study design. Results from the matrix study demonstrated equivalent performance between the KangarooSci ACP and the ISO 4833-1:2013 reference standard. The product consistency and stability testing showed that the performance of the assay was equivalent over time up to 12 months and between production lots. Minor changes to the operational test conditions showed no significant impact on performance during the robustness testing. The KangarooSci ACP is an effective method for aerobic plate count for all matrixes evaluated. The KangarooSci Aerobic Count Plate allows for fast, reliable enumeration of aerobic bacteria. Utilizing the alternative method takes up less space in incubators, requiring no sample spreader, and requires less consumables compared to the reference method.

Mathematical Models to Predict Dry Matter Intake and Milk Production by Dairy Cows Managed under Tropical Conditions

This study aimed to create an equation to predict dry matter intake (DMI) and milk production and N-ureic in the milk of dairy cows managed in tropical conditions in Brazil. We used 113 observations from three experiments using lactating Jersey, Girolando, and Holstein cows. The goodness of fit of the developed equations was evaluated using the coefficients of determination (r2) and root mean square error (RMSE). There was a positive correlation between body weight and milk yield (MY) of r = 0.73. The equation considered DMI to be the most important variable to estimate the MY (r2 = 0.65). Four equations were adjusted to estimate the DMI, where, by a stepwise procedure, the first variable included in the equation was the neutral detergent fibre intake, which explained 92% of the DMI of the cows. However, when the variables BW, MY, and milk fat were included in the equation, there was a reduction of 0.06 in RMSE and an increase in precision (r2 = 0.94). The nutrient intake, milk production, and characteristics prediction equations present satisfactory precision and accuracy for dairy cows managed in tropical conditions in Brazil.

Transcriptomic regulations of heat stress response in the liver of lactating dairy cows

BackgroundThe global dairy industry is currently facing the challenge of heat stress (HS). Despite the implementation of various measures to mitigate the negative impact of HS on milk production, the cellular response of dairy cows to HS is still not well understood. Our study aims to analyze transcriptomic dynamics and functional changes in the liver of cows subjected to heat stress (HS). To achieve this, a total of 9 Holstein dairy cows were randomly selected from three environmental conditions - heat stress (HS), pair-fed (PF), and thermoneutral (TN) groups - and liver biopsies were obtained for transcriptome analysis.ResultsBoth the dry matter intake (DMI) and milk yield of cows in the HS group exhibited significant reduction compared to the TN group. Through liver transcriptomic analysis, 483 differentially expressed genes (DEGs) were identified among three experimental groups. Especially, we found all the protein coding genes in mitochondria were significantly downregulated under HS and 6 heat shock proteins were significant upregulated after HS exposure, indicating HS may affect mitochondria integrity and jeopardize the metabolic homeostasis in liver. Furthermore, Gene ontology (GO) enrichment of DEGs revealed that the protein folding pathway was upregulated while oxidative phosphorylation was downregulated in the HS group, corresponding to impaired energy production caused by mitochondria dysfunction.ConclusionsThe liver transcriptome analysis generated a comprehensive gene expression regulation network upon HS in lactating dairy cows. Overall, this study provides novel insights into molecular and metabolic changes of cows conditioned under HS. The key genes and pathways identified in this study provided further understanding of transcriptome regulation of HS response and could serve as vital references to mitigate the HS effects on dairy cow health and productivity.

Assessment of different dietary alfalfa hay to alfalfa silage ratios for dromedary camel feeding

ABSTRACT Two in vivo experiments studied the effects of different alfalfa hay (AH) to alfalfa silage (AS) ratios including 100:0 (AH100), 50:50 (AH50:AS50) and 0:100 (AS100) in total mixed rations (TMR) of dromedary camels. In experiment (Exp.) 1, a total of 18 multiparous Baluchi dairy camel [100 ± 5 days in milk (DIM); 3.65 ± 0.539 kg milk yield] were randomly allocated to one of the three groups (n = 6) for 42 d of experimental period. Dry matter intake (DMI) and milk yield were recorded daily, and blood samples were collected on days 0, 21 and 42. In Exp. 2, 18 male Baluchi camel calves [275 ± 14 days of old; 105 ± 8 kg BW] were housed in individual shaded pens for 150 days. DMI was recorded daily and individual weights of camels were recorded monthly. Blood samples were collected on days 0, 75 and 150. In Exp.1, feeding different dietary AH:AS ratios altered neither DMI (p = 0.351) nor milk yield (p = 0.667). Of all milk components, only the milk urea nitrogen (MUN) was increased (p = 0.015) by AS feeding (both AH50:AS50 and/or AS100). AS feeding tended to increase AST (p = 0.099) and ALT (p = 0.092) levels in lactating camels. In Exp. 2, DMI (p = 0.845), average daily gain (ADG; p = 0.092) and return per kg BW gain (p = 0.710) of silage-fed camels were similar to those of hay-fed group. The plasma concentration of BUN (p = 0.014) and AST (p = 0.014) were increased in camels fed AS100. Overall, the results suggest that both AS and/or AH could be used in dromedary camel diets based on the climatic condition, season and available facilities; however, the long-term use of AS (as sole forage) should done with caution due to the potential risk of impaired liver function. Further studies needed to explore the impact of hay versus silage feeding on digestibility, rumen function and nitrogen pollution in camel feeding.

The Impact on Cow Performance and Feed Efficiency When Individual Cow Milk Composition and Energy Intake Are Accounted for When Allocating Concentrates

The objective of this three-treatment, 12-week study (involving 69 dairy cows) was to test three methods of concentrate allocation on milk production efficiency. All treatments were offered a basal mixed ration of grass silage and concentrates, with additional concentrates offered to individual cows based on either milk yield alone (Control), milk energy output (Precision 1) or energy intake and milk energy output (Precision 2). Concentrate requirements were calculated and adjusted weekly. Control cows had lower concentrate dry matter intake (DMI; p = 0.040) and milk protein content (p = 0.003) but yield of milk and energy-corrected milk (ECM), energy balance, bodyweight and condition score were unaffected by treatment. Efficiency measures such as ECM/DMI and ECM/metabolizable energy intake were also unaffected by treatment. Less concentrates were used per kg ECM yield in the Control compared to the Precision treatments (p < 0.001). In conclusion, accounting for individual cow milk composition or milk composition combined with individual cow energy intake did not improve production efficiency compared to an approach based on individual cow milk yield only.

Effect of foot-and-mouth disease vaccination on acute phase response and milk production in the Holstein-Friesian crossbred cow

The study investigated the effects of FMD vaccination on acute phase response and milk composition in the HF crossbred cows (n = 12) using a cross-over experimental design. In trial 1, one group (n = 6) received inactivated trivalent oil-adjuvanted FMD vaccine [day post-vaccination, (dpv) 0], while the mock-vaccinated group received saline (n = 6). After a cooling period of 15 days, the trial was repeated by swapping groups. The body temperature, dry matter intake (DMI) and milk yield were recorded. Haemato-biochemical parameters, haptoglobin and cortisol concentrations were also assessed. A significant (p < 0.05) increase in the neutralizing antibody response to FMDV serotype O and Asia1 indicated a positive immune response. A significant (p < 0.05) increase of 0.4° to 0.6°C in the body temperature, decrease of 0.7–0.8 kg in DMI along with an increase in the serum haptoglobin, total leukocyte count and neutrophils within dpv 2 indicated acute phase response in the FMD vaccinated group. Among the milk constituents, only milk fat (p = 0.053) was significant. It was concluded that FMD vaccination induced acute phase response within dpv 3 in the crossbred cows and caused a non-significant reduction in the milk yield on the day of vaccination.

Efeito do estresse calórico e da insolação sobre consumo, indicadores bioquímicos, produção e qualidade do leite de vacas Holandês e Jersey

ABSTRACT The objective of this work was to compare the dry matter intake, milk yield and quality, physiological and biochemical parameters in Holstein (n=10) and Jersey (n=10) cows under heat stress and insolation, in two treatments: CL - cooling by ventilation and sprinkling and HS - heat stress and insolation. Data were submitted to ANOVA. There was an interaction between treatment and breed and day effect for dry matter intake. For consumption in % of body weight, CL and Jersey cows consumed more. CL cows produced more milk and 3.5% fat-corrected milk. Feed efficiency was similar between treatments and breeds. Fat, lactose, total solids, and somatic cell score did not differ. The concentration of milk urea nitrogen was higher for CL cows. Milk from Holstein cows had greater stability to alcohol, and from HT cows had a greater freezing point of milk. HT cows had higher respiratory rates in the morning and surface temperatures in the afternoon. There were no differences in beta-hydroxybutyrate and glucose concentrations. Heat stress, with insulation, reduces intake, especially in Holstein cows, as well as milk production and increases the freezing point of milk, respiratory rate, and surface temperature.

Assessment of function-technological and rheological parameters of consistency stabilisers for dairy protein-fat systems for the production of semi-smoked sausages

During the past few years, the world community has faced a number of problems related to the delivery and storage of milk and milk products. In particular, the situation provoked by quarantine restrictions in various countries of the world forces to look for solutions regarding the use of non-traditional raw materials for the production of classic or similar food products. As a result, it is quite promising to use dairy products with extended shelf life, in particular, dry milk concentrates as the main protein carriers for the production of stable protein-fat systems. The use of dry milk proteins makes it possible to manufacture restored structural products that can be used as an alternative to classic ones. Therefore, the object of research is food components of various origins, in particular food modified starches, food fibers and their modifications, hydrocolloids. Characteristic indicators of viscosity with increasing shear stress were determined for 5 % solutions of modified starches of various types after brewing at a temperature of 80 °C. It was found that when the shear stress increases to a value of 200 Pa, there is a significant decrease in viscosity, which generally characterizes them as structural systems. The functional and technological indicators of wheat (VF-200), bamboo (BAF-200) food fibers (fiber length 200 microns) and carboxyl methyl cellulose (CMC) were studied. Increased functional and technological capabilities of CMC compared to dietary fibers were revealed. The kinetics of swelling of dietary fibers and CMC were studied, while the period of maximum intensification of the process, which is between 5 and 15 minutes, was determined. The maximum value of the swelling coefficient is characteristic for CMC 4.4±0.04, for wheat fiber 4.01±0.06, for bamboo fiber 3.81±0.05. Using the method of mathematical and statistical processing of experimental data, optimization of concentration and technological modes was carried out to achieve maximum hydration and strength of iota-carrageenan gel. It was determined that at a concentration of 1 % during brewing at 80 °C and a time of 5 min. high enough gel strength can be achieved for optimum consistency in the overall system. The result of the work is a comprehensive study of the functional technological characteristics of food additives that will form the consistency of a structural protein-fat product of the cheese type, which can be used in sausage products as a filler, with the aim of improving the organoleptic, structural-mechanical and nutritional values of the finished products.

Effects of Two Levels of Dietary Energy Content on Milk Production and Serum Metabolites in Early Lactation Temperate Crossbred Dairy Cows Fed Guinea Grass (&lt;em&gt;Megathyrsus maximus&lt;/em&gt;) Based Diets

The current study investigated the association of two levels of metabolizable energy (ME) content on milk production, composition, and blood metabolites of temperate crossbred (Jersey x Frieician) dairy cows fed with Guinea grass (Panicum maximum) and concentrates (50:50 on a DM basis) based total mixed ration (TMR). Twelve multiparous temperate crossbred dairy cows were randomly allocated to each dietary treatment (n=6) in a randomized block design. The required energy diet (RE) was predicted to supply the recommended level (100%) of ME, and the high energy diet (HE) was predicted to supply 10% more than the recommended level (110%) of the daily ME requirements of the dairy cows. Dry matter intake, body weight, and milk yield were recorded, and feed and blood samples were obtained for proximate and blood metabolite analysis during the 14 weeks experimental period. No treatment effects were observed (P&gt;0.05) on BW, milk fat, SNF, protein, and milk urea nitrogen or on blood metabolites such as serum non esterified fatty acids, beta-hydroxy butyric acid, Albumin, Ca and P. Compared to the cows fed with RE, HE diet fed cows had high (P&lt;0.05) dry matter intake at 4, 10, 12, and 14 weeks but dietary treatment had no effect on dry matter intake (P&gt;0.05) at 2, 6, and 8 weeks of the experimental period. Until the 4th week of lactation, dietary treatment had no effect (P&gt;0.05) on milk yield, but from the 4th to the 14th week, cows fed with HE had a higher (P&lt;0.05) milk yield than those fed with RE. Thus, the cumulative milk yield of the cows fed with HE were higher (P&lt;0.05) than that of cows fed with RE from the 10th to 14th weeks of lactation. It was concluded that the milk yield of temperate crossbred dairy cows fed diets based on Guinea grass can be enhanced by incorporating high energy content into the diet.

Performance, milk fatty acid profile and oxidative status of lactating small ruminants supplemented with microalgae: A meta-analysis

Microalgae are considered an effective strategy to improve the polyunsaturated fatty acid profile of ruminant milk. This meta-analysis aimed to evaluate the effects of dietary supplementation with microalgae (MIAs) on milk yield, oxidative status, and milk quality of lactating small ruminants. The data used were obtained from 20 peer-reviewed scientific articles. The weighted mean difference between experimental treatments (diets added with MIAs) and control treatments (diets without MIAs) was evaluated using the random-effects meta-analysis model. Higher dry matter intake and milk yield were observed in response to MIAs supplementation (P < 0.05). In addition, MIAs supplementation increased (P < 0.05) the contents of conjugated linoleic, α-linolenic, γ-linolenic, eicosapentaenoic, docosahexaenoic, total polyunsaturated, and total omega-3 fatty acids in milk. In blood plasma, higher (P < 0.05) concentrations of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase were observed in response to MIAs supplementation. In milk, MIAs supplementation decreased fat content (P < 0.001) and increased SOD and CAT content (P < 0.05). In conclusion, the dietary inclusion of MIAs could be used as a nutritional strategy to improve the performance and fatty acid profile in the milk of small ruminants. Furthermore, MIAs supplementation could be used to improve the oxidative status of blood plasma and milk of lactating small ruminants.

Effects of heat stress on markers of skeletal muscle proteolysis in dairy cattle

Heat stress (HS) markedly affects postabsorptive energetics and protein metabolism. Circulating urea nitrogen increases in multiple species during HS and it has been traditionally presumed to stem from increased skeletal muscle proteolysis; however, this has not been empirically established. We hypothesized HS would increase activation of the calpain and proteasome systems as well as increase degradation of autophagosomes in skeletal muscle. To test this hypothesis, lactating dairy cows (~139 d in milk; parity ~2.4) were exposed to thermal neutral (TN) or HS conditions for 7 d (8 cows/environment). To induce HS, cattle were fitted with electric blankets for the duration of the heating period and the semitendinosus was biopsied on d 7. Heat stress increased rectal temperature (1.3°C) and respiratory rate (38 breaths per minute) while it decreased dry matter intake (34%) and milk yield (32%). Plasma urea nitrogen (PUN) peaked following 3 d (46%) and milk urea nitrogen (MUN) peaked following 4 d of environmental treatment and while both decreased thereafter, PUN and MUN remained elevated compared with TN (PUN: 20%; MUN: 27%) on d 7 of HS. Contrary to expectations, calpain I and II abundance and activation and calpain activity were similar between groups. Likewise, relative protein abundance of E3 ligases, muscle atrophy F-box protein/atrogin-1 and muscle ring-finger protein-1, total ubiquitinated proteins, and proteasome activity were similar between environmental treatments. Finally, autophagosome degradation was also unaltered by HS. Counter to our hypothesis, these results suggest skeletal muscle proteolysis is not increased following 7 d of HS and call into question the presumed dogma that elevated skeletal muscle proteolysis, per se, drives increased AA mobilization.

Effect of diets enriched in n-6 or n-3 fatty acids on dry matter intake, energy balance, oxidative stress, and milk fat profile of transition cows

The objective of this study was to determine the effect of dietary supplementation of n-3 polyunsaturated fatty acids (PUFA) and n-6 PUFA on dry matter intake (DMI), energy balance, oxidative stress, and performance of transition cows. Forty-five multiparous Holstein dairy cows with similar parity, body weight (BW), body condition score (BCS), and milk yield were used in a completely randomized design during a 56-d experimental period including 28 d prepartum and 28 d postpartum. At 240 d of pregnancy, cows were randomly assigned to one of the 3 isoenergetic and isoprotein dietary treatments, including a control ration containing 1% hydrogenated fatty acid (CON), a ration with 8% extruded soybean (HN6, high n-6 PUFA source), and a ration with 3.5% extruded flaxseed (HN3; high n-3 PUFA source). The HN6 and HN3 diets had an n-6/n-3 ratio of 3.05:1 and 0.64:1 in prepartum cows and 8.16:1 and 1.59:1 in postpartum cows, respectively. During the prepartum period (3, 2, and 1 wk before calving), DMI, DMI per unit of BW, total net energy intake, and net energy balance were higher in the HN3 than in the CON and NH6 groups. During the postpartum period (2, 3, and 4 wk after calving), cows fed HN3 and HN6 diets both showed increasing DMI, DMI as a percentage of BW, and total net energy intake compared with those fed the CON diet. The BW of calves in the HN3 group was 12.91% higher than those in the CON group. Yield and nutrient composition of colostrum (first milking after calving) were not affected by HN6 or HN3 but milk yield from 1 to 4 wk of milking was significantly improved compared with CON. During the transition period, BW, BCS, and BCS changes were not affected. Cows fed the HN6 diet had a higher plasma NEFA concentration compared with the CON cows during the prepartum period. Feeding HN3 reduced the proportion of de novo fatty acids and increased the proportion of preformed long-chain fatty acids in regular milk. In addition, the n-3 PUFA-enriched diet reduced the n-6/n-3 PUFA ratio in milk. In conclusion, increasing the n-3 fatty acids concentration in the diet increased both DMI during the transition period and milk production after calving, and supplementing n-3 fatty acids was more effective in mitigating the net energy balance after calving.

Lying posture as a behavioural indicator of heat stress in dairy cows

Dairy cows tend to stand as a heat stress response, but the increased tendency to stand adversely affects their productivity and welfare. Thus, taking measures against heat stress before cows spend more time standing is important. Therefore, this study focused on the lying postures of cows (lying with the head turned back (HB) and lying with the head up and still (HS)) as behavioural indicators of countermeasures. It is predicted that if cows adopt a posture that exposes a large body surface area to the outside air as an adaptive response to heat stress when they are in a lying position, the expression time of HB will decrease. Six Holstein dairy cows which had calved two or three times were observed using video filming, and their behaviour was recorded for 12 days throughout the year. The temperature and humidity in the cow barn were measured and used to calculate the temperature-humidity index (THI). Standing, lying down, rumination, and HB were recorded continuously, and HS was instantaneously sampled every 30 s. Lying, standing, and rumination durations, and the time ratios of HB and HS while lying down were calculated. The data obtained from 19:30 h to 4:30 h and from 10:00 h to 15:00 h were used as nighttime and daytime data, respectively; however, data obtained from the dry milk period were excluded. Data on each behaviour during the daytime or nighttime were applied to four linear mixed models (linear, quadratic, and cubic regressions, and broken stick), including THI and milk yield as explanatory variables, and the model with the lowest value of Akaike’s information criterion was selected. A broken-stick model was selected for the analysis of lying and THI in the nighttime, and the result showed that lying time decreased with a THI value of 75 as a boundary. A linear model was selected for the analysis of HB and THI in the nighttime, and the result showed that the time ratio of HB while lying down decreased with increasing THI. These results suggest HB may be a behavioural indicator of heat stress before cows spend more time standing as a heat stress response.

Enhancement of the quality attributes and health benefits synbiotic yoghurt from cow's milk

The present work delighted on extraction of galactomannan polysaccharide from guar gum beans and microbial galactomannan source. Effect of replacing non-fat dry milk that used to fortify cow's milk in yoghurt industry with the two extracted galactomannans and commercial galactomannan as food additives was studied. Control yoghurt treatment was made from 3.0% fat cow's milk that was fortified with 1.5% non-fat dry milk. Another 6 yoghurt treatmentwas fortified with 0.15, 0.25% of commercial, guar and microbial galactomannan respectively. All treatments were cultured with the probiotic starter (1.0% Streptococcus thermophilus + 1.0% Lactobacillus delbrueckii subsp. Bulgaricus + 1.0% Bifidobacteriumbifidum). The obtained results indicated that yoghurt supplementation with the three types of galactomannans increased the acidity, curd tension, total solids content, decreased pH values and syneresis of yoghurt treatments. Control yoghurt and commercial galactomannan yoghurt were not significantly different from the corresponding batches those made with either guar galactomannan and microbial galactomannan in fat, protein and ash content. Yoghurt treatments which supplemented with the three types of galactomannans have higher bifidobacteria counts and organoleptic scores than the control treatment yoghurt.

Effects of forage and grain legume-based silages supplemented with faba bean meal or rapeseed expeller on lactational performance, nitrogen utilization, and plasma amino acids in dairy cows

The objective of this experiment was to investigate the effect of forage type [red clover (51%)-grass silage, i.e., RCG; vs. faba bean (66%)-grass silage, i.e., FBG] and concentrate type (faba bean, FB; vs. rapeseed expeller, RE) on lactational performance, milk composition and nitrogen (N) utilization in lactating dairy cows. Eight lactating multiparous Nordic Red cows were used in a replicated 4 × 4 Latin Square experiment, with 21-d periods, in a 2 × 2 factorial arrangement of treatments. The experimental treatments were as follows: (1) RCG with RE, (2) RCG with FB, (3) FBG with RE, and (4) FBG with FB. Inclusion rates of RE and FB were isonitrogenous. Crude protein contents of the experimental diets were 16.3, 15.9, 18.1, and 17.9% of dry matter, respectively. All diets included oats and barley and were fed ad libitum as total mixed rations with forage-to-concentrate ratio of 55:45. Dry matter intake and milk yield were recorded daily, and spot samples of urine, feces, and blood were collected at the end of each experimental period. Dry matter intake did not differ across diets, averaging 26.7 kg/d. Milk yield averaged 35.6 kg/d and was 1.1 kg/d greater for RCG versus FBG, and milk urea N concentration was lower for RCG compared with FBG. Milk yield was 2.2 kg/d and milk protein yield 66 g/d lower for FB versus RE. Nitrogen intake, urinary N, and urinary urea N excretions were lower, and milk N excretion tended to be lower for RCG compared with FBG. The proportion of the dietary N excreted as fecal N was larger in cows fed RCG than for those fed FBG, and the opposite was true for urinary N. We detected an interaction for milk N as percentage of N intake: it increased with RE compared with FB for RCG-based diet, but only a marginal increase was observed for FBG-based diet. Plasma concentration of His and Lys were lower for RCG than for FBG, whereas His tended to be greater and Lys lower for FB compared with RE. Further, plasma Met concentration was around 26% lower for FB than for RE. Of milk fatty acids, saturated fatty acids were decreased by RCG and increased by FB compared with FBG and RE, respectively, whereas monounsaturated fatty acids were increased by RCG versus FBG, and were lower for FB than for RE. In particular, 18:1n-9 concentration was lower for FB compared with RE. Polyunsaturated fatty acids, such as 18:2n-6 and 18:3n-3, were greater for RCG than for FBG, and 18:2n-6 was greater and 18:3n-3 was lower for FB versus RE. In addition, cis-9,trans-11 conjugated linoleic acid was lower for FB compared with RE. Faba bean whole-crop silage and faba bean meal have potential to be used as a part of dairy cow rations, but further research is needed to improve their N efficiency. Red clover-grass silage from a mixed sward, without inorganic N fertilizer input, combined with RE, resulted in the greatest N efficiency in the conditions of this experiment.

Correction to: Palmitic- and Stearic Acid-based Dry Vegetable Fat Prills Augment Milk Performance of Crossbred Dairy Cows

Correction to: Palmitic- and Stearic Acid-based Dry Vegetable Fat Prills Augment Milk Performance of Crossbred Dairy Cows