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Residual feed intake (RFI) is an important trait of feed efficiency that has been increasingly considered in the breeding objectives for dairy cattle. The objectives of this study were to estimate the genetic parameters of RFI and its component traits, namely, dry-matter intake (DMI), body weight (BW), and energy-corrected milk (ECM), in lactating Holstein cows; we thus developed a system for genomic evaluation of RFI in lactating Holstein cows and explored the associations of the RFI of heifers and cows. The RFI values were calculated from 2,538 first (n = 2,118) and second (n = 420) lactation Holsteins cows between 2020 and 2024 as part of the STgenetics EcoFeed® program. Of the animals, 1,516 were heifers from the same research station with previously established RFI values. After quality control, 61,283 single-nucleotide polymorphisms were used for the analyses. Univariate analyses were performed to estimate the heritabilities of RFI and its components in lactating cows; bivariate analyses were then performed to estimate the genetic correlations between the RFI of heifers and lactating cows using the genomic best unbiased linear prediction method. Animals with phenotypes and genotypes were used as the training population, and animals with only genotypes were considered the prediction population. The reliability of breeding values was obtained by approximation based on partitioning a function of the accuracy of the training population's genomic estimated breeding values (GEBVs) and magnitudes of genomic relationships between the individuals in the training and prediction populations. The heritability estimates (mean ± SE) of the RFI, DMI, ECM, and BW were 0.43 ± 0.07, 0.44 ± 0.04, 0.40 ± 0.05, and 0.46 ± 0.04, respectively. The average reliability of the GEBVs for RFI from the training and prediction populations were 44% and 30%, respectively. The genetic correlations for the RFI were 0.42 ± 0.08 between heifers and first lactation cows and 0.34 ± 0.06 between heifers and first and second lactation cows. Our results show that the genetic components of RFI are not fully carried over from heifers to cows and that there is re-ranking of the individuals at different life stages. Selection of animals for feed efficiency on a lifetime basis thus requires accounting for the efficiencies during animal growth and milk production as a lactating cow. [ABSTRACT FROM AUTHOR]

On the basis of current growth trajectories, pasture-based dairies of the future are likely to be bigger, have higher stocking rates and feed more concentrate to cows. This review uses the five-domains framework to consider risks to the welfare of dairy cows in these larger intensified pasture-based production systems. The factors considered in this review can be broadly categorised as (1) emerging welfare risks that can be managed, (2) emerging welfare risks that require research to be managed, or (3) persisting and/or exacerbated welfare risks. First, large herds could be subject to welfare risks associated with more stock per labour unit, longer milking times and longer distances walked to and from the dairy. To counter this, the time that cows in large herds spend off pasture can be reduced by splitting the herd into several more manageable groups, and animal-monitoring technologies can help identify health challenges with a reduced stockperson to animal ratio. Cow body condition and productivity can be maintained at high stocking rates by improving pasture production and feeding a higher proportion of concentrate. The risk of ruminal acidosis may then be reduced by appropriate transition feeding regimes and rumen buffers. Second, ensuring social stability and reducing competition may become difficult as herd sizes increase and feeding becomes more intensive. The resulting variability in feed intake, increased agonistic behaviour and social stress present emerging risks to cow welfare. Research is needed to better understand the social behaviour of cows in large intensive pasture-based herds, and how the design of the pre-milking area, the feeding pad and pasture feeding regimes (i.e. quantity and timing of pasture allocation) can improve accessibility for more vulnerable animals. Finally, intensive pasture-based dairies of the future will continue to face welfare challenges relating to lameness, mastitis and cull-cow management, whereas risks due to environmental exposure may be exacerbated by the removal of shelterbelts to facilitate irrigation. These require continued efforts in research (e.g. ways of incorporating shelter into intensive grazing systems), development (e.g. pathway to market for aged beef) and extension (e.g. improved record keeping and benchmarking of lameness and mastitis). Pasture-based dairies of the future are likely to be bigger, have higher stocking rates and feed more concentrate. This review uses the five-domains framework to consider risks to the welfare of dairy cows in these larger pasture-based systems. Risks to cow welfare are broadly categorised as (1) emerging welfare risks that can be managed, (2) emerging welfare risks that require research to be managed, or (3) persisting and/or exacerbated welfare risks. Suggestions are made for future research, development and extension. [ABSTRACT FROM AUTHOR]

Residual feed intake (RFI) is an important trait of feed efficiency that has been increasingly considered in the breeding objectives for dairy cattle. The objectives of this study were to estimate the genetic parameters of RFI and its component traits, namely, dry-matter intake (DMI), body weight (BW), and energy-corrected milk (ECM), in lactating Holstein cows; we thus developed a system for genomic evaluation of RFI in lactating Holstein cows and explored the associations of the RFI of heifers and cows. The RFI values were calculated from 2,538 first (n = 2,118) and second (n = 420) lactation Holsteins cows between 2020 and 2024 as part of the STgenetics EcoFeed® program. Of the animals, 1,516 were heifers from the same research station with previously established RFI values . After quality control, 61,283 single-nucleotide polymorphisms were used for the analyses. Univariate analyses were performed to estimate the heritabilities of RFI and its components in lactating cows; bivariate analyses were then performed to estimate the genetic correlations between the RFI of heifers and lactating cows using the genomic best unbiased linear prediction method. Animals with phenotypes and genotypes were used as the training population, and animals with only genotypes were considered the prediction population. The reliability of breeding values was obtained by approximation based on partitioning a function of the accuracy of the training population’s genomic estimated breeding values (GEBVs) and magnitudes of genomic relationships between the individuals in the training and prediction populations. The heritability estimates (mean ± SE) of the RFI, DMI, ECM, and BW were 0.43 ± 0.07, 0.44 ± 0.04, 0.40 ± 0.05, and 0.46 ± 0.04, respectively. The average reliability of the GEBVs for RFI from the training and prediction populations were 44% and 30%, respectively. The genetic correlations for the RFI were 0.42 ± 0.08 between heifers and first lactation cows and 0.34 ± 0.06 between heifers and first and second lactation cows. Our results show that the genetic components of RFI are not fully carried over from heifers to cows and that there is re-ranking of the individuals at different life stages. Selection of animals for feed efficiency on a lifetime basis thus requires accounting for the efficiencies during animal growth and milk production as a lactating cow.

Simple Summary: Zinc is an essential nutrient for animals, the effects of zinc depend on factors such as level of supplementation and animal health. However, few studies have investigated its impact on cheese quality. This study aimed to evaluate the effect of Zinc Oxide (ZnO) supplementation in the diet of lactating Friesian cows on chemical composition, zinc content, fatty acid and proteic profile, ammine content, pH, aw, texture, and sensory profile of cheese. Zinc is known for its antimicrobial properties and can reduce microbial growth during ripening period. It also has antioxidant abilities and could reduce lipid oxidation by affecting oxidative stability. The results showed that ZnO supplementation improved the texture, the sensory profile and stability of caciotta cheese and reduced the production of biogenic amines. ZnO supplementation could be a promising strategy for improving the quality and shelf-life of caciotta cheese. Zinc is essential for animals, playing a vital role in enzyme systems and various biochemical reactions. It is crucial to ensure a sufficient intake of zinc through the diet to maintain efficient homeostasis. Only few studies on zinc effect in cow lactating diet evaluated the effects on milk and cheese quality, with conflicting findings. 24 cows of the Friesian breed were divided into two groups (CTR: control and TRT: treated group). Cows were selected for age, body weight, parity and phase of lactations (mid lactation, 140–160 days). CTR diet contained 38 mg/kg of Zn and TRT diet was supplied with 120 mg/kg of complete feed for 60 days. The objective of current investigation was to evaluate the impact of a dietary Zinc Oxide (ZnO) integration of lactating Friesian cows on chemical composition, zinc content, fatty acid and proteic profile, ammine content, pH, aw, texture, and sensory profile of cheese and to improve the chemical-nutritional quality of milk and cheese. The results showed that ZnO supplementation reduced mesophilic aerobic bacteria and Presumptive Pseudomonas spp. growth, proteolysis, biogenic amines content, lipid oxidation, odour intensity and sour and increased hardness, gumminess, chewiness, elasticity of cheese. Biogenic amines are considered an important aspect of food safety. ZnO integration in cow diet could represent a promising strategy for improving the quality, the safety and shelf-life of caciotta cheese. [ABSTRACT FROM AUTHOR]

The study presents the results of a survey of agricultural enterprises and peasant farms in the Sakhalin Oblast. The authors conducted the visual estimation of the feed consumption and cows’ overall health, revealed the chemical analysis of primary zootechnical parameters of the feed, compared the results with the rates and previous data, and gave recommendations. Moreover, the authors assessed the fodder, feed allowance and compared it with the nutritional rates using the software “Feeding rations” developed by the “Plinor limited liability company”. Furthermore, one can identify that the daily milk yield of Holstein cows doubled in the period 2001–2010, but the feed allowance of the Holstein cows during lactation and dry periods still did not meet nutritional requirements. The low nutritional value of green forage is caused by the small amount of legumes in the herbage. One should prepare winter forage earlier to improve the quality of ration (hay, haylage, silage). Mowing grasses ten days later than the optimal time leads to a protein decrease in forage by 30%–35%. It is crucial to balance the feed allowance with biological and mineral supplements, adding grain mixture or sunflower cake.

A steady-state process-based lactating cow thermal balance spreadsheet model developed by Nelson and Janni (2023) was compared to mean measured body temperatures, respiration rates, and skin temperatures from two published studies (Gebremedhin et al., 2010; Chen et al., 2015). Model body temperatures were also compared with reticular temperatures from cows standing in unshaded paddocks that were part of a solar shade study (Sharpe et al., 2021). Gebremedhin et al. (2010) reported measured mean rectal temperatures, 39.4 ± 0.5 C and 40.6 ± 0.4 C for hot and dry conditions with and without a solar load; model body temperatures for similar hot and dry conditions were 39.7 C and 40.6 C with and without a solar load, respectively. Model respiration rates were within one standard deviation of measured mean respiration rates (Gebremedhin et al., 2010). The model body temperature for a baseline condition was 39.1°C, which was within 0.1°C of the mean baseline temperature of 39.2 ± 0.6°C (Chen et al., 2015). The model respiration rate was 63 breaths per minute (bpm); much lower than the reported baseline respiration rate of 88 bpm (Chen et al., 2015). Model body temperatures were 0.1°C to 0.7°C lower than the measured mean reticular temperatures of standing cows in non-shaded paddocks with solar loads when ambient temperatures ranged from 24.4°C to 26.5°C. Model results compared well with mean measured parameters from three studies. The model can be used to assess the impact of factors affecting heat exchange (e.g., body mass, milk yield, solar load, air dry-bulb temperature, dew-point temperature, and air velocity) on heat exchange flux, cow respiration rate, and body temperature. [ABSTRACT FROM AUTHOR]

Dairy cow heat stress impacts cow well-being, reduces milk yield, and leads to economic losses. Understanding heat stress mechanics supports ongoing and future efforts to mitigate heat stress. The purpose of this project was to modify a steady-state heat transfer model developed by McGovern and Bruce (2000) by incorporating work by Berman (2005), McArthur (1987), Turnpenny et al. (2000a,b), Thompson et al. (2014), Gwadera et al. (2017), two new empirical relations for tissue insulation and sweat rate, and a new solution method that allowed for overlapping changes in heat exchange. The modified model describes heat exchange between a lactating cow and the environment through respiration, convection, sweating, and shortwave and longwave radiation. This article describes the process-based model equations, compares results from the two new empirical relations used to published work, and presents the inputs and results for a cow on pasture in sunlight. The modified model, which can be solved with a spreadsheet, provides insight into factors and processes that affect lactating cow heat exchange. A companion paper compares the modified model results with published average measured body temperatures, respiration rates, and skin temperatures and unpublished body temperature data for cows on pasture in the sunshine. [ABSTRACT FROM AUTHOR]

Objective The purpose of present study was to investigate the effects of condensed molasses fermentation solubles (CMS) on lactation performance, rumen fermentation, nutrient digestibility, and serum parameters of dairy cows. Methods A total of 75 healthy Holstein cows with the same parity (milk production = 35±2.5 kg, body weight = 570±28 kg) were randomly selected and divided into 5 groups. One group served as control group (CON; no CMS), whereas the other 4 groups were CMS1 (accounted for 1% of the diet), CMS2 (2%), CMS3 (3%), and CMS4 (4%). All cows were fed regularly three times each day at 0800, 1600, and 2400 h. Cows received diet and water ad libitum. The experiment lasted for 60 days. Results Results showed that the dry matter intake, milk yield, and protein of CMS2 were maximum and higher (p

Nitrogen (N) excretion from livestock production systems is of significant environmental concern; however, few studies have investigated the effect of dietary CP concentration on N utilisation efficiency at different stages of lactation, and the interaction between dietary CP levels and stages of lactation on N utilisation. Holstein-Friesian dairy cows (12 primiparous and 12 multiparous) used in the present study were selected from a larger group of cows involved in a whole-lactation study designed to examine the effect of dietary CP concentration on milk production and N excretion rates at different stages of lactation. The total diet CP concentrations evaluated were 114 (low CP), 144 (medium CP) and 173 (high CP) g/kg DM, with diets containing (g/kg DM) 550 concentrates, 270 grass silage and 180 maize silage. During early (70–80 days), mid- (150–160 days) and late (230–240 days) lactation, the same 24 animals were transferred from the main cow house to metabolism units for measurements of feed intake, milk production and faeces and urine outputs. Diet had no effect on BW, body condition score, or milk fat, protein or lactose concentration, but DM intake, milk yield and digestibilities of DM, energy and N increased with increasing diet CP concentration. The effect of diet on milk yield was largely due to differences between the low and medium CP diets. Increasing dietary CP concentration significantly increased urine N/N intake and urine N/manure N, and decreased faecal N/N intake, milk N/N intake and manure N/N intake. Although increasing dietary CP level significantly increased urine N/milk yield and manure N/milk yield, differences in these two variables between low and medium CP diets were not significant. There was no significant interaction between CP level and stage of lactation on any N utilisation variable, indicating that the effects of CP concentration on these variables were similar between stages of lactation. These results demonstrated that a decrease in dietary CP concentration from high (173 g/kg DM) to medium level (144 g/kg DM) may be appropriate for Holstein-Friesian dairy cow to maintain milk production efficiency, whilst reducing both urine N and manure N as a proportion of N intake or milk production.

The objective of the present study was to evaluate the suitability of environmental sampling to screen Czech dairy herds to detect Mycobacterium avium ssp. paratuberculosis (MAP) and to find the most convenient location for the MAP detection in the lactating cow area. Environmental samples (ES, n = 72) from milking parlour holding pens (n = 19), milking alleyways (n = 19) and free-stall alleyways (n = 34) from 19 herds were simultaneously tested to detect MAP by a quantitative PCR (qPCR) and bacterial culture. Eight and thirteen samples from the milking parlour holding pens, twelve and eleven samples from the milking alleyways and eleven and eighteen samples from the free-stall alleyways were qPCR and culture positive, respectively. A 4.6 times higher probability of being culture positive than qPCR positive was detected for the assessable MAP detection results from the free-stall alleyways [P = 0.008 6, odds ration (OR) = 4.572 8)] and no association was found between the results from the milking parlour holding pens (P = 0.191 4) and the milking alleyways (P > 0.999 9) and the diagnostic method used. The percentage of qPCR-positive samples in the tested locations was detected for the milking alleyways (63.2%), free-stall alleyways and milking parlour holding pens. The herd infectious status was in agreement with 16 (84.2%), 14 (73.7%) and 12 (63.2%) qPCR results from the milking alleyways, free-stall alleyways (32.4%) and milking parlour holding pens (42.1%), respectively. No statistically significant differences were detected for these results (P = 0.396 1). MAP was detected by the qPCR and bacterial culture in all three locations where the ES were collected. We suggest an environmental sampling followed by MAP detection by qPCR as an easy-to-perform time-saving protocol for MAP screening in Czech dairy herds. Although the milking alleyways seem to be the most convenient location for the environmental sampling, this assumption was not statistically supported.

Mathematical models for predicting P excretions play a key role in evaluating P use efficiency and monitoring the environmental impact of dairy cows. However, the majority of extant models require feed intake as predictor variable, which is not routinely available at farm level. The objectives of the study were to (1) explore factors explaining heterogeneity in P output; (2) develop a set of empirical models for predicting P output in feces (Pf), manure (PMa), and milk (Pm, all in g/cow per day) with and without dry matter intake (DMI) using literature data; and (3) evaluate new and extant P models using an independent data set. Random effect meta-regression analyses were conducted using 190 Pf, 97 PMa, and 118 Pm or milk P concentration (PMilkC) treatment means from 38 studies. Dietary nutrient composition, milk yield and composition, and days in milk were used as potential covariates to the models with and without DMI. Dietary phosphorus intake (Pi) was the major determinant of Pf and PMa. Milk yield negatively affected Pi partitioning to Pf or PMa. In the absence of DMI, milk yield, body weight, and dietary P content became the major determinants of Pf and PMa. Milk P concentration (PMilkC) was heterogeneous across the treatment groups, with a mean of 0.92 g/kg of milk. Milk yield, days in milk, and dietary Ca-to-ash ratio were negatively correlated with PMilkC and explained 42% of the heterogeneity. The new models predicted Pf and PMa with root mean square prediction error as a percentage of observed mean (RMSPE%) of 18.3 and 19.2%, respectively, using DMI when evaluated with an independent data set. Some of the extant models also predicted Pf and PMa well (RMSPE%=19.3 to 20.0%) using DMI. The new models without DMI as a variable predicted Pf and PMa with RMSPE% of 22.3 and 19.6%, respectively, which can be used in monitoring P excretions at farm level. When evaluated with an independent data set, the new model and extant models based on milk protein content predicted PMilkC with RMSPE% of 12.7 to 19.6%. Although models using P intake information gave better predictions, P output from lactating dairy cows can also be predicted well without intake using milk yield, milk protein content, body weight, and dietary P, Ca, and total ash contents.

Background: There are no in-depth research on commercial dairying management and performance of dairy cows under commercial dairying in Chittagong, Bangladesh. The good farming practice and cow's productivity leads the farm profitability. This study may assist to overcome the problems related to the profitability of dairy farms. Methods: The study was conducted in 28 commercial dairy farms based on two types of data. Primary data: generated from stock inventory and farm management information using a pretested survey questionnaire and analyzed data of average production performance and quality of milk traits indifferent crosses collected directly four times season wise (summer, monsoon and winter) from each selected farms of Chittagong, Bangladesh from 2014 to 2015. Result: Overall management system of irrespective categories of farms was in moderate condition with some exception. Highest number of milking animal was 50% HF x 50% L cross under all farm categories. Crosses of 75% HF x 25% L were highest in number under farm category A and lowest C. In terms of milk quality and quantity, farms with higher number of animals were in better condition. Daily average milk yield was significantly higher in monsoon followed by summer and winter. Therefore, this current study would be helpful for the dairy farmers to find out an expected solution to overcome the problems in this sector. [ABSTRACT FROM AUTHOR]

The current study was aimed to molecular detection of Coxiella burnetii in cattle of Al-Basra province for first time using the conventional polymerase chain reaction (PCR). Therefore, a total of 100 adult cows were selected randomly from different areas in Al-Basra province (Iraq) from October/2019 to May/2020 and subjected for jugular venous blood sampling. Targeting three specific genes for C. burnetii, the positive findings were 23% for 16 SrRNA gene, 16% for IS1111A-transposase gene, and 12% for com1 gene. All positive samples by IS1111A-transposase and com1 genes were also positives by 16SrRNA gene. Based on study findings, C. burnetii infection is endemic in cattle population, and it is better to screen large numbers using various types of samples. Furthermore investigations are required to fully recognize epidemiology of C. burnetii, and factors that affect the environmental survival of the bacterium. [ABSTRACT FROM AUTHOR]

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Deoiled soy lecithin is a feed additive enriched in phospholipids. Our study evaluated the effects of dietary deoiled soy lecithin supplementation on (1) milk production and composition, (2) plasma and milk fatty acid (FA) content and yield, and (3) apparent FA digestibility and absorption in lactating dairy cows fed fractionated palm fat. In a split-plot Latin square design, 16 Holstein cows (160 ± 7 days in milk; 3.6 ± 1.2 parity) were randomly allocated to a main plot receiving a corn silage and alfalfa haylage-based diet with palm fat containing either moderate (MPA) or high palmitic acid (HPA) content at 1.75% of ration dry matter (72 or 99% palmitic acid, respectively; n = 8/palm fat diet). On each palm fat diet, deoiled soy lecithin was top-dressed at 0, 0.12, 0.24, or 0.36% of ration dry matter in a replicated 4 × 4 Latin square design. Following a 14-d covariate period, lecithin supplementation spanned 14 d, with milk and blood collected during the final 3 d. Milk composition and pooled plasma markers were measured. The statistical model included the fixed effects of palm fat type, lecithin dose, period, and the interaction between palm fat type and lecithin dose. The random effect of cow nested within palm fat group was also included. Lecithin linearly decreased dry matter intake. In cows fed HPA, lecithin feeding reduced milk fat content and tended to decrease milk fat yield. Although no changes in milk yield were observed, a quadratic reduction in 3.5% fat-corrected milk was observed with increasing lecithin dose. Lecithin linearly increased energy-corrected milk efficiency in cows fed MPA. Lecithin supplementation also decreased milk urea nitrogen, relative to unsupplemented cows. The proportion of 16-carbon FA in milk fat decreased linearly with lecithin dose, whereas 18-carbon FA increased linearly. Lecithin reduced de novo FA (<16-carbon) content and tended to increase preformed FA (>16-carbon) content in a linear manner. Compared with MPA, HPA diets reduced apparent total and 16-carbon FA digestibility and absorption. Deoiled soy lecithin feeding did not modify FA digestibility or absorption. Our observations suggest that soy lecithin feeding modifies rumen digestion to reduce dry matter intake and change milk composition. [ABSTRACT FROM AUTHOR]

Five lactating Holstein cows in a 5×5 Latin square experiment were fed five high-concentrate total mixed rations (TMRs) to investigate the effects of step-wise improvement of forage combination on ruminal and milk fatty acid profiles. The ratio of concentrate to forage was fixed as 61:39, and the step-wise improvement of forage combination was applied as: TMR1, a ration containing corn stover; TMR2, a ration containing corn stover and ensiled corn stover; TMR3, a ration containing ensiled corn stover and Chinese wild ryegrass hay (Leymus chinensis); TMR4, a ration containing the ryegrass hay and whole corn silage; TMR5, a ration containing the ryegrass hay, whole corn silage and alfalfa hay. The TMRs were offered to the cows twice daily at 0700 and 1900 h. The entire experiment was completed in five periods, and each period lasted for 18 days. Diurnal samples of rumen fluids were collected at 0100, 0700, 1300 and 1900 h (day 16); 0300, 0900, 1500 and 2100 h (day 17); and 0500, 1100, 1700 and 2300 h (day 18). The step-wise improvement of forage combination increased energy and crude protein contents and decreased fibre content. As a result, the step-wise improvement of forage combination increased dry matter intake and milk yield (P

Medium-chain fatty acids (MCFAs) have antialgal, antibacterial, antifungal, anti-protozoan, and antiviral activities. However, antibacterial activities of MCFAs in the hindgut of pigs and cattle are still unknown. We report the effects of the supplementation of MCFAs on fecal bacteria of pigs, lactating cows, and Japanese Black calves. Lactobacillus spp., Bifidobacterium spp., eaeA(+) Escherichia coli, Salmonella spp., Campylobacter jejuni, and Clostridium perfringens in the feces of animals were quantified by real-time PCR assay. There was no significant increase or decrease in Lactobacillus spp. and Bifidobacterium spp. in the three animals. In the pig feces, eaeA(+) E. coli was reduced to less than a third in the treatment group (P < 0.01). C. jejuni in the pig feces was also significantly less in the treatment group compared with the control (P < 0.01). In the lactating cow, eaeA(+) E. coli was reduced to one fifth of that in the control (P < 0.01). Salmonella spp. was halved in calf feces (P < 0.01). Thus, a reduction in Gram-negative pathogenic bacteria was observed. In conclusion, supplementation of a MCFA calcium soap in the diet would be beneficial to growing pigs, lactating cow, and calves by reducing pathogenic bacteria. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of sodium butyrate supplementation on plasma glucose levels and lipid metabolism of the cow in the mid-lactation. For this, ten dairy cows (four Holstein and six Jersey, multiparous, 150 days in milk (DIM) were used and randomly divided into two groups: Control Group (CG, n = 5), which received the standard diet; Treatment Group (TG, n = 5), which received the standard diet plus 1.0 g/kg of body weight per day of butyrate over a 8 days period. Individual blood samples were collected once daily throughout the experimental period for analysis of ß-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), triglycerides, cholesterol and glucose. It can be observed that in TG the BHB blood levels were higher (0.64 ± 0.03 mmol/l and 0.91 ± 0.03 mmol/l, for CG and TG, respectively, P=0.001) and the glucose levels were lower than the CG (55.5 ± 0.84 mg/dL and 51.1 ± 0.75 mg/dL, for TG and CG, respectively, P<0.0001). The results show that supplementing cows with sodium butyrate may regulate the rate of lipolysis and the concentrations of NEFA improving the health status of the animal. [ABSTRACT FROM AUTHOR]

The objective of the present study was to evaluate the suitability of environmental sampling to screen Czech dairy herds to detect Mycobacterium avium ssp. paratuberculosis (MAP) and to find the most convenient location for the MAP detection in the lactating cow area. Environmental samples (ES, n = 72) from milking parlour holding pens (n = 19), milking alleyways (n = 19) and free-stall alleyways (n = 34) from 19 herds were simultaneously tested to detect MAP by a quantitative PCR (qPCR) and bacterial culture. Eight and thirteen samples from the milking parlour holding pens, twelve and eleven samples from the milking alleyways and eleven and eighteen samples from the free-stall alleyways were qPCR and culture positive, respectively. A 4.6 times higher probability of being culture positive than qPCR positive was detected for the assessable MAP detection results from the free-stall alleyways [P = 0.008 6, odds ration (OR) = 4.572 8)] and no association was found between the results from the milking parlour holding pens (P = 0.191 4) and the milking alleyways (P > 0.999 9) and the diagnostic method used. The percentage of qPCR-positive samples in the tested locations was detected for the milking alleyways (63.2%), free-stall alleyways and milking parlour holding pens. The herd infectious status was in agreement with 16 (84.2%), 14 (73.7%) and 12 (63.2%) qPCR results from the milking alleyways, free-stall alleyways (32.4%) and milking parlour holding pens (42.1%), respectively. No statistically significant differences were detected for these results (P = 0.396 1). MAP was detected by the qPCR and bacterial culture in all three locations where the ES were collected. We suggest an environmental sampling followed by MAP detection by qPCR as an easy-to-perform time-saving protocol for MAP screening in Czech dairy herds. Although the milking alleyways seem to be the most convenient location for the environmental sampling, this assumption was not statistically supported. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of partial replacement of wheat straw for corn silage and alfalfa hay at 7% diet dry matter (DM) on feed intake, nutrient digestibility, and milk production of late-lactation Holstein cows. Eight multiparous Holstein cows (averaging 2.9±0.35 parity; 43.6±2.6 kg/d milk yield; 214±18 d in milk) were used in a replicated 4x4 Latin Square design. During each of four 21-d periods, cows were fed total mixed rations varying in forage source: 1) control (13.5% alfalfa hay, 20% corn silage and 66.5% concentrate), 2) wheat straw replaced for corn silage, 3) wheat straw replaced for alfalfa hay 4) wheat straw equally replaced for corn silage and alfalfa hay. Diets were formulated to contain similar values of NDF, forage NDF and physically effective NDF. The DM intake, milk production and compositions as well as total tract digestibility of DM, organic matter, NDF, and crude protein were unaffected by treatments. Likewise, ruminal and blood parameters were not affected by experimental treatments. Body weight gain tended to be lower (P=0.06) for cows fed the wheat straw-included diets. These results indicated that, at 7% of diet DM, chopped wheat straw could be used as an alternative for major forage sources high concentrate diets for lactation cows yielding over 40 kg/d milk. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effects of the replacement of corn silage with barley silage on high producing dairy cow performance. Thirty six high-producing (57.3±3.9kg/d) dairy cow in mid-lactation (93±7 DIM) were assigned to one of three experimental treatments including (1) no barley silage (BS) and 30% corn silage (CS), (2) 10% BS and 20% CS, and (3) 20% BS and 10 % CS in the TMR over two 24-day periods. The results showed that replacement of corn silage with barley silage linearly increased fat corrected milk (FCM; P=0.04), fat yield (P=0.04) and fat corrected milk production efficiency (P=0.01). There was also a tendency for linear increase in milk fat percentage (P=0.08), and linear decrease in milk lactose percentage (P=0.05). Ruminal acetate proportion and pH increased with increasing barley silage and propionate proportion decreased. Increasing barley silage resulted in linear increase in dry matter, organic matter and neutral detergent fiber digestibility (NDF; P<0.05). This study showed that replacing corn silage with barley silage could be considered as a successful strategy to improve performance and forage provisions of high-producing dairy cows. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are small noncoding RNAs present in milk-derived extracellular vesicles and milk fat globules (MFG). Nucleic acid content between the lactating mammary tissue (MT) and MFG are quite similar but discrepancies exist in their miRNA content. Our objective was to identify the origin of these discrepancies, and to evaluate the existence of a possible mechanism sorting miRNAs that will or will not be exported from the mammary epithelial cells (MECs) in bovine MFG. miR-125b-5p, miR-126-3p, miR-141-3p, and miR-204-5p, chosen on the basis of their abundance in the MT, were quantified using RT-qPCR in lactating cow MT, MFG, and laser capture-microdissected MECs. Two miRNAs (miR-125b-5p and miR-141-3p) were detected in the MT as well as in MFG and MECs. miR-204-5p was detected only in the MT, suggesting that it is very likely expressed in a cell type other than MECs. miR-126-3p was detected both in the MT and in MECs but not in MFG, suggesting a targeting mechanism for miRNAs in MECs. These results highlights differences in miRNA content between MECs and MFG may be due to a possibly not random mechanism for loading MFG with miRNA cargos that could involve a variable distribution in MECs or a sorting mechanism. [ABSTRACT FROM AUTHOR]

Adrenal responsiveness was tested in nonpregnant, lactating Holstein dairy cows fed diets supplemented with OmniGen-AF (OG; Phibro Animal Health Corp., Teaneck, NJ), an immune modulator, and in nonsupplemented control (CON) cows following bolus infusions of a combination of corticotropin-releasing hormone (CRH; 0.3 µg/kg of BW) and arginine vasopressin (VP; 1.0 µg/kg of BW) or ACTH (0.1 IU/kg of BW) in 2 environments: thermoneutral [TN; temperature-humidity index (THI) <60] for 24 h/d and heat stress (HS; THI >68 for 17 h/d). Cows (506) were initially fed OG (n = 254) or CON (n = 252) diets for 44 d before selection of a subgroup of cows (n = 12; 6 OG, 6 CON) for the study. The 2 subgroups were balanced for parity, milk yield, and days in milk. All cows were transported to and housed in 2 environmentally controlled rooms at the University of Arizona Agricultural Research Complex (Tucson). Cows were given 3 d to acclimate to the rooms and then underwent 12 d of TN conditions and then 8 d of HS conditions for a total of 24 d on experiment. Cows were infused with CRH-VP on d 9 of TN and on d 1 of HS and with ACTH on d 10 of TN and on d 2 of HS. Hormone infusions took place at 1000 h (0 h) on each infusion day. Blood samples, taken in 30-min intervals, were first collected at 0800 h (−2 h) and were drawn until 1800 h (8 h). Before infusion, serum progesterone was elevated in OG cows compared with CON cows. Infusion of releasing factors (CRH-VP or ACTH) caused increases in serum cortisol and progesterone, but cortisol release was greater in CON cows than in OG cows during HS, whereas progesterone did not differ between the 2 treatments. Serum ACTH increased following infusion of releasing factors, but this increase was greater following CRH-VP infusion than ACTH infusion. Serum bovine corticosteroid-binding globulin also increased following infusion of releasing factors in both treatment groups, but this increase was greater during HS in cows fed OG. The free cortisol index (FCI) increased following CRH-VP and ACTH and was higher in HS than in TN for both OG and CON cows. However, the FCI response was blunted in OG cows compared with CON cows during HS. Heat stress enhanced the adrenal response to releasing factors. Additionally, the adrenal cortisol and FCI response to releasing factors was reduced during acute heat stress in cows fed OG. Collectively, these data suggest that OG supplementation reduced the adrenal responsiveness to factors regulating cortisol secretion during acute HS. [ABSTRACT FROM AUTHOR]

The present study was conducted to evaluate the effects of using raw or microwave irradiated safflower seed on dry matter intake, milk production and composition, milk fatty acid profile, blood parameters, and nutrient apparent digestibility in early lactation cows. Nine multiparous Holstein cows at early lactation were randomly assigned to one of three treatments based on 3 x 3 balanced latin square design. Dietary treatments included whole linted cottonseed (control), 40 g/kg DM raw safflower seed (RSS), and 40 g/kg DM microwave irradiated safflower seed (MSS). Results showed no significant effect of dietary treatments on milk production, milk fat, protein, and lactose content, and dry matter intake. Feeding RSS and MSS diets increased milk long chain fatty acids, C18:1 trans, C18:2, and polyunsaturated fatty acid concentrations, while milk C16 fatty acid (P<0.05) decreased. The cis-9, trans-11 conjugated linoleic acid (CLA) concentration tended to be higher in cows fed MSS diet. It was concluded that there are no negative impacts of raw and microwave irradiated safflower seed supplementation on lactation performance, while milk quality was meliorated by increasing unsaturated fatty acid concentrations. [ABSTRACT FROM AUTHOR]

Abstract Background A possible option to meet the increased demand of forage for dairy industry is to use the agricultural by-products, such as corn stover. However, nutritional value of crop residues is low and we have been seeking technologies to improve the value. A feeding trial was performed to evaluate the effects of four levels of Saccharomyces cerevisiae fermentation product (SCFP; Original XP; Diamond V) on lactation performance and rumen fermentation in mid-lactation Holstein dairy cows fed a diet containing low-quality forage. Eighty dairy cows were randomly assigned into one of four treatments: basal diet supplemented with 0, 60, 120, or 180 g/d of SCFP per head mixed with 180, 120, 60, or 0 g of corn meal, respectively. The experiment lasted for 10 wks, with the first 2 weeks for adaptation. Results Dry matter intake was found to be similar (P > 0.05) among the treatments. There was an increasing trend in milk production (linear, P ≤ 0.10) with the increasing level of SCFP supplementation, with no effects on contents of milk components (P > 0.05). Supplementation of SCFP linearly increased (P < 0.05) the N conversion, without affecting rumen pH and ammonia-N (P > 0.05). Increasing level of SCFP linearly increased (P < 0.05) concentrations of ruminal total volatile fatty acids, acetate, propionate, and butyrate, with no difference in molar proportion of individual acids (P > 0.05). The population of fungi and certain cellulolytic bacteria (Ruminococcus albus, R. flavefaciens and Fibrobacter succinogenes) increased linearly (P < 0.05) but those of lactate-utilizing (Selenomonas ruminantium and Megasphaera elsdenii) and lactate-producing bacteria (Streptococcus bovis) decreased linearly (P ≤ 0.01) with increasing level of SCFP. The urinary purine derivatives increased linearly (P < 0.05) in response to SCFP supplementation, indicating that SCFP supplementation may benefit for microbial protein synthesis in the rumen. Conclusions The SCFP supplementation was effective in maintaining milk persistency of mid-lactation cows receiving diets containing low-quality forage. The beneficial effect of SCFP could be attributed to improved rumen function; 1) microbial population shift toward greater rumen fermentation efficiency indicated by higher rumen fungi and cellulolytic bacteria and lower lactate producing bacteria, and 2) rumen microbial fermentation toward greater supply of energy and protein indicated by greater ruminal VFA concentration and increased N conversion. Effects of SCFP were dose-depended and greater effects being observed with higher levels of supplementation and the effect was more noticeable during the high THI environment.

Antibacterial factors act as innate immune components, which respond as soon as bacteria enter a living organism. To prevent and treat mastitis in cattle, understanding the concentrations of these substances inside the udder is important; however, they remain to be studied. In this investigation, the concentration of lingual antimicrobial peptide (LAP), S100 protein (S100A7), lactoferrin (LF), and immunoglobulin antibody were measured in the different fractions of foremilk. Lactating Holstein cows were examined, and 10 foremilk fractions were obtained from sequential samples up to 150 ml. The LAP concentrations in milk samples increased until 25 ml. The LF concentrations increased up to the 10 ml fraction, then stabilized at low level after the 50 ml fraction. For S100A7, some fractions had significantly higher (p < .05) concentrations than the 5 or 10 ml fractions. The IgA antibody concentration increased up to the 5 ml fraction, then after 50 ml fraction showed relatively low concentrations. This investigation determined the concentration patterns of LAP, LF, S100A7, and IgA antibody secreted in milk inside the udders of healthy lactating cows as baseline data. These distinct concentration patterns might indicate various protective responses. [ABSTRACT FROM AUTHOR]

Heat load is a challenge for high-producing dairy cows, with adverse consequences on production, reproduction, and welfare. The objectives of this observational study in 2 commercial dairy herds were to determine the effects of environmental heat stress on standing and lying behavior, to monitor the changes in core body temperature (CBT) of cows during lying and standing bouts, and to compare changes in CBT during standing bouts in freestall pens versus standing in holding pens. High-producing cows were selected for data collection over a period of 6 d of increasing heat stress during a heat wave to which they were not acclimated. A total of 20 cows were fitted with leg accelerometers that recorded lying behavior and with vaginal temperature loggers that recorded CBT. These data were recorded at 30-s intervals. Time in the parlor holding pen was calculated from automated parlor software that recorded milking unit attachment and removal times. Mean daily temperature–humidity index in the pens increased from 68.5 to 79.0 during the 6-d trial, whereas mean daily lying time decreased from 9.5 to 6.2 h/d. The mean number of lying bouts per day remained similar at 11.1 to 12.2, but duration of lying bouts decreased from a high of 49.7 min on the coolest day to 32.8 min on the hottest day. During lying bouts, CBT increased at a mean rate of 0.50°C/h. In contrast, CBT changed at a mean rate of −0.25°C/h when standing in the freestall pens and only −0.09°C/h when standing in the milking-center holding pens. Explanatory models for the CBT at which cows ended either standing or lying bouts were derived from 6 selected lying bouts and 3 selected standing bouts for each cow on each day. The CBT at which a cow ended a lying bout was positively related to CBT and temperature–humidity index at the start of the bout, bout duration, and rate of CBT change during the bout. The CBT at which a cow ended a standing bout was negatively related to bout duration and positively related to start CBT, start temperature–humidity index, and rate of CBT change. Insights into the thermodynamics of standing and lying behavior in dairy cows during periods of heat stress provided by this study may contribute to the development of more effective strategies to mitigate heat load in dairy cattle. [ABSTRACT FROM AUTHOR]

Exogenous enzymes have been used to improve nutrient utilization in several species of livestock, particularly swine and poultry. In addition, improved immunological and metabolic traits have been reported in nonruminants. The objective of this study was to determine the effects of β-mannanase supplementation on milk yield and composition, and immunological and metabolic responses in lactating Holstein dairy cows. Two weeks after calving, 20 Holstein cows (10 multiparous and 10 primiparous) were blocked by parity and assigned to 1 of 2 diets for 182 d. All cows were housed in the same environment and fed the same basal diet. The basal diet of the treatment group was supplemented with β-mannanase (CTCBio Inc., Seoul, South Korea) at 0.1% of concentrate dry matter. No differences were detected between the control and enzyme supplement groups in milk yield parameters or milk composition. Supplementation of β-mannanase enzyme reduced blood haptoglobin levels in supplemented multiparous cows compared with controls. Furthermore, nonesterified fatty acid concentration levels tended to be lower in cows fed β-mannanase, regardless of parity. Neither immunoglobulin G nor milk somatic cell count was affected by β-mannanase supplementation, regardless of parity. The number of insemination services tended to be lower in cows fed diets supplemented with β-mannanase. Results from this study suggest that supplementation of β-mannanase exogenous enzyme could help to reduce instances of systemic inflammation and decrease fat mobilization in lactating Holstein cows. Multiparous cows are considered susceptible to acute infections and inflammation; thus, the enzyme had a greater effect in multiparous cows. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the Chinese Society of Animal Science is the property of Chinese Society of Animal Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Residual feed intake (RFI) is the difference between actual and predicted dry matter intake (DMI) of individual animals. Recent studies with Holstein-Friesian calves have identified an ~20% difference in RFI during growth (calf RFI) and these groups remained divergent in RFI during lactation. The objective of the experiment described here was to determine if cows selected for divergent RFI as calves differed in milk production, reproduction or in the profiles of BW and body condition score (BCS) change during lactation, when grazing pasture. The cows used in the experiment (n=126) had an RFI of −0.88 and +0.75 kg DM intake/day for growth as calves (efficient and inefficient calf RFI groups, respectively) and were intensively grazed at four stocking rates (SR) of 2.2, 2.6, 3.1 and 3.6 cows/ha on self-contained farmlets, over 3 years. Each SR treatment had equal number of cows identified as low and high calf RFI, with 24, 28, 34 and 40/11 ha farmlet. The cows divergent for calf RFI were randomly allocated to each SR. Although SR affected production, calf RFI group (low or high) did not affect milk production, reproduction, BW, BCS or changes in these parameters throughout lactation. The most efficient animals (low calf RFI) lost similar BW and BCS as the least efficient (high calf RFI) immediately post-calving, and regained similar BW and BCS before their next calving. These results indicate that selection for RFI as calves to increase efficiency of feed utilisation did not negatively affect farm productivity variables (milk production, BCS, BW and reproduction) as adults when managed under an intensive pastoral grazing system.

ABSTRACT Objective. This study was conducted during winter season at rural livestock farm of district Sargodha, Pakistan, in order to define the macrominerals status in blood plasma of lactating and dry Desi breed cows . Material and methods. Twenty lactating and twenty dry cows were used and their blood plasma was analyzed for Ca, Mg, Zn, Cu and Fe using atomic absorption spectrophotometer. Results. In lactating cows, the plasma Ca concentration was lower than dry cows (6.8 vs. 7.6 mg/dl, p

The aim of current study was to determine the effect of dietary omega 3 fatty acids (FA) mainly eicosapentaenoic (EPA) and docosahexaenoic (DHA) on inflammatory response of post calving cows during transition to lactation. Twenty Holstein lactating cows were assigned into two groups (10 each). The two groups fed on the basal diet while one of them was supplemented with 70 g of omega-3 FA per cow. The supplement was added to the diet from the 1st day of calving till the 60th days of lactation. Blood samples were taken 3 times weekly from the 2nd to the 4th week post calving. The blood samples were analyzed for glucose, insulin, non-esterified fatty acids (NEFA), beta hydroxyl butyric acid (BHBA), C- reactive protein (CRP), haptoglobin, albumin and globulin. Feeding omega-3 FAs significantly increased (P<0.05) blood glucose level by 17.35%, 28.23% and 24.73% than the control at weeks 1, 2, 3 of the experiment, respectively. BHBA was lower in cows fed omega-3 at 1st and 2nd week then became nearly similar to the control at the end of experiment. At 1st and 2nd week, cows fed omega-3 FAs had significantly lower serum CRP than those fed the control diet and became nearly similar to control at the end of the experiment. Serum, globulin was significantly higher in cows fed omega 3 FAs at 2nd and 3rd week by 81.1% and 51.2%, respectively. Omega 3 FA improved energy status of fresh cow by increasing serum insulin and glucose levels while decreasing NEFA and BHBA parameters. Also, feeding omega 3 FA improved humoral immunity through increasing serum globulin and reduced inflammatory response by lowering CRP post calving. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Animal Production / Hayvansal Üretim is the property of Hayvansal Uretim (Journal of Animal Production) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study was to investigate the effect of diets containing roasted soybean (R), extruded soybean (E) or their combination (RE) on dairy cow performance and milk fatty acid (FA) profile. Nine multiparous lactating Holstein cows (680 ± 25 kg BW; 90 ± 10 DIM; means ± SD) were randomly assigned to a triple 3 × 3 Latin square design. Dry matter intake (DMI), apparent nutrient digestibility, milk yield, composition and FA profile and efficiency of nitrogen (N) utilization for milk production were measured. Cows fed R and RE had higher 4% fat corrected milk (FCM) yield and DMI compared to those fed the E (P<0.05). The efficiency of 4% FCM production per unit of DMI was not influenced by experimental diets (P>0.05). Experimental diets had no effect on milk fat and protein concentrations and nutrient digestibility (P>0.05). Milk fat concentrations of vaccenic acid (VA; C18:1 trans-11) and conjugated linoleic acid (CLA; C18:2 cis-9, trans-11) were higher for cows fed with RE compared to other groups (P<0.05). We concluded that cows fed with RE had similar milk production and fat content compared to those fed with R and a similar beneficial milk FA profile compared to those fed with E. Thus, feeding a diet with RE improved the quality and quantity of dairy cow milk. [ABSTRACT FROM AUTHOR]

Abstract: This study aimed to determine the effects of different forage combinations on in vitro gas production (GP) kinetics, ruminal and milk fatty acid profiles. Forty‐five lactating cows were randomly arranged into three groups and fed three total mixed rations (TMRs) with different forage combinations: TMR1, 23% alfalfa hay, 7% Chinese wild ryegrass hay and 15% whole corn silage; TMR2, 30% corn stover plus 15% whole corn silage; TMR3, 30% rice straw plus 15% whole corn silage. In vitro dry matter disappearance ranked: TMR1 > TMR2 > TMR3, and highest cumulative GP and asymptotic GP occurred in TMR1 while no difference occurred between TMR2 and TMR3. The average GP rate ranked: TMR1 > TMR2 > TMR3. TMR1 in comparison with TMR2 and TMR3 presented lower rumen contents of acetate and butyrate and greater rumen contents of propionate, valerate, C13:0, C14:0, C15:0, C18:1cis‐9, C18:2n‐6, C18:3n‐3, C20:0 and C22:0 as well as milk C18:2n‐6 and C18:3n‐3 proportions. Transfer efficiencies of C18:2n‐6 and C18:3n‐3 from diet to milk ranked: TMR1 > TMR2 > TMR3. The findings suggest TMRs containing alfalfa hay and Chinese wild ryegrass hay in comparison with corn stover or rice straw improve rumen fermentation and transfer efficiency of C18:2n‐6 and C18:3n‐3. [ABSTRACT FROM AUTHOR]

Mammary biopsy collection (MB) is a valuable approach for studying mammary gland biology, but it is unclear if repeated MB impair the performance of lactating dairy cows. The objective of this trial was to examine the effect of repeated MB during lactation on udder health, dry matter intake (DMI), and lactation performance of lactating dairy cows. Sixty-four multiparous, mid-lactation Holstein cows were enrolled in a 29-wk trial, and 32 cows were randomly selected for repeated MB. The MB and non-MB (NMB) cows had similar parity (2.6 ± 0.9) and days in milk (96.5 ± 56.3 d) at enrollment. All animals were housed in the same barn and managed in the same manner. Cows were milked 3 times daily with milk yield recorded at each milking. Milk composition was measured weekly and DMI recorded daily. Three MB were performed per cow: 1 wk after enrollment and at 15 and 24 wk. The first and third MB were performed on the left rear quarter, whereas the second MB was on the right rear quarter. The MB were performed based on previously described procedures using a rotating stainless steel cannula with a retractable blade connected to a cordless drill, with appropriate sedation and antiseptic treatment after each MB. After MB, udder health, surgical wound healing, and presence of blood in milk were visually examined at each milking. Blood was cleared from milk 3.86 ± 2.0 d after MB. During the experiment, 4 rear quarters of MB cows and 5 rear quarters from NMB cows were diagnosed and treated for clinical mastitis. No differences were observed in DMI, milk yield, somatic cell score, or milk concentration and yields of fat, protein, lactose, and solids-not-fat between MB and NMB. In conclusion, lactating cows recover rapidly from MB, and repeated MB have no long-term effects on DMI, milk yield and composition, or udder health of lactating dairy cows. [ABSTRACT FROM AUTHOR]

This study compared vaginal temperature, physiologic, and productive parameters in lactating dairy cows supplemented or not with Omnigen-AF (Phibro Animal Health, Teaneck, NJ) during the summer months in a tropical environment. Thirty-two lactating, primiparous (n = 16) and multiparous (n = 16) pregnant Holstein x Gir cows were ranked by parity, days in milk, body weight, and body condition score (BCS), and assigned to receive (SUPP; n = 16) or not (CON; n = 16) Omnigen-AF (Phibro Animal Health, Teaneck, NJ) at 56 g/cow daily (as-fed basis). During the experimental period (d -6 to 56), cows were maintained in a single drylot pen with ad libitum access to water and a total mixed ration, and milked twice daily. Cows received Omnigen-AF mixed with 200 g of corn (as-fed basis) after the daily morning milking through self-locking head gates, whereas CON cows concurrently received 56 g of kaolin mixed with 200 g of corn. For feed intake evaluation, cows from both treatments were randomly divided in 4 groups of 8 cows each, and allocated to 8 individual feeding stations for 3 d. Intake was evaluated 4 times per group from d 1 to 56. From d -6 to 0, d 15 to 28, and d 43 to 56, cow vaginal temperature was recorded hourly. Environmental temperature-humidity index (THI) was also recorded hourly from d 15 to 28 and d 43 to 56. Cows were evaluated for body weight and BCS on d -6 and 56, individual milk production was recorded daily from d -6 to 56, and milk samples were collected on d -6, 0, 7, 14, 21, 28, 35, 42, 49, and 56 for analyses of somatic cell count and milk components. Blood samples were collected on d -6, -3, 0, 9, 15, 18, 21, 24, 27, 36, 45, 48, 51, 54, and 56. Results from samples or observations collected from d -6 to 0 were included as an independent covariate in each respective analysis. Environmental THI was 74.2 ± 0.5 and cows were exposed to THI >68 for 633 h within a total of 672 h of evaluation. Cows assigned to CON had greater vaginal temperature on d 28, 43, 45, and from d 48 to 55 (by 0.38 to 0.52%), as well as greater mean somatic cell count (by 97%) and serum haptoglobin concentrations (by 89%) compared with SUPP cows. Cows assigned to SUPP had greater mean dry matter intake (by 7%), BCS on d 56 (by 11%), and mean serum insulin concentrations (by 35%) compared with CON cows. Hence, SUPP ameliorated hyperthermia, improved nutritional status, and modulated systemic and mammary gland immune parameters in lactating dairy cows exposed to heat stress conditions. [ABSTRACT FROM AUTHOR]

Background: A possible option to meet the increased demand of forage for dairy industry is to use the agricultural byproducts, such as corn stover. However, nutritional value of crop residues is low and we have been seeking technologies to improve the value. A feeding trial was performed to evaluate the effects of four levels of Saccharomyces cerevisiae fermentation product (SCFP; Original XP; Diamond V) on lactation performance and rumen fermentation in mid-lactation Holstein dairy cows fed a diet containing low-quality forage. Eighty dairy cows were randomly assigned into one of four treatments: basal diet supplemented with 0, 60, 120, or 180 g/d of SCFP per head mixed with 180, 120, 60, or 0 g of corn meal, respectively. The experiment lasted for 10 wks, with the first 2 weeks for adaptation. Results: Dry matter intake was found to be similar (P > 0.05) among the treatments. There was an increasing trend in milk production (linear, P ≤ 0.10) with the increasing level of SCFP supplementation, with no effects on contents of milk components (P > 0.05). Supplementation of SCFP linearly increased (P < 0.05) the N conversion, without affecting rumen pH and ammonia-N (P > 0.05). Increasing level of SCFP linearly increased (P < 0.05) concentrations of ruminal total volatile fatty acids, acetate, propionate, and butyrate, with no difference in molar proportion of individual acids (P > 0.05). The population of fungi and certain cellulolytic bacteria (Ruminococcus albus, R. flavefaciens and Fibrobacter succinogenes) increased linearly (P < 0.05) but those of lactate-utilizing (Selenomonas ruminantium and Megasphaera elsdenii) and lactate-producing bacteria (Streptococcus bovis) decreased linearly (P ≤ 0.01) with increasing level of SCFP. The urinary purine derivatives increased linearly (P < 0.05) in response to SCFP supplementation, indicating that SCFP supplementation may benefit for microbial protein synthesis in the rumen. Conclusions: The SCFP supplementation was effective in maintaining milk persistency of mid-lactation cows receiving diets containing low-quality forage. The beneficial effect of SCFP could be attributed to improved rumen function; 1) microbial population shift toward greater rumen fermentation efficiency indicated by higher rumen fungi and cellulolytic bacteria and lower lactate producing bacteria, and 2) rumen microbial fermentation toward greater supply of energy and protein indicated by greater ruminal VFA concentration and increased N conversion. Effects of SCFP were dose-depended and greater effects being observed with higher levels of supplementation and the effect was more noticeable during the high THI environment. [ABSTRACT FROM AUTHOR]

The present study was conducted on 24 lactating Sahiwal cows by dividing them into four homogeneous groups randomly. The cows of control were kept on cement concrete floor. The cows of treatment group (G-2) were kept in shed having rubber mat flooring, whereas G-3 group animals were reared on cement concrete floor with physical modification, in G-4 group providing rubber mat flooring with physical modification. The objective was to study the effect of improved shelter management on behaviours (lying time, standing time) of cattle. In hot-humid season (June to august), the overall mean values of standing time of cows housed under different shed were 776.69±1.45, 619.94±1.06, 728.06±1.01 and 545.24±1.34 minutes, in G-1, G-2, G-3 and G-4 group, respectively whereas in hot-humid season, the overall mean values of lying time of cows housed under different shed were 513.26 ±0.62, 662.04±1.4, 555.75±2.67 and 714.08±3.26 minutes, respectively. There was significant difference in animal behavior such as in standing time, lying time. Overall standing time (minute) in cows was significantly higher in G-1 group (776.69±1.45). All groups were significantly differ (P<0.05) in standing time as well as in lying time. Lying time was significantly higher (P<0.05) in G-4 group (714.08±3.26.). [ABSTRACT FROM AUTHOR]

The main aim of the present study was to examine the effects of long-term supplementing diets with saturated or unprotected polyunsaturated fatty acids from two different plant oils rich in either n-3 or n-6 fatty acids (FAs) plus docosahexaenoic acid (DHA)-rich algae on mammary gene expression and milk fat composition in lactating dairy cows. Gene expression was determined from mammary tissue and milk epithelial cells. Eighteen primiparous German Holstein dairy cows in mid-lactation were randomly assigned into three dietary treatments that consist of silage-based diets supplemented with rumen-stable fractionated palm fat (SAT; 3.1% of the basal diet dry matter, DM), or a mixture of linseed oil (2.7% of the basal diet DM) plus DHA-rich algae (LINA; 0.4% of the basal diet DM) or a mixture of sunflower oil (2.7% of the basal diet DM) plus DHA-rich algae (SUNA; 0.4% of the basal diet DM), for a period of 10 weeks. At the end of the experimental period, the cows were slaughtered and mammary tissues were collected to study the gene expression of lipogenic enzymes. During the last week, the milk yield and composition were determined, and milk was collected for FA measurements and the isolation of milk purified mammary epithelial cells (MECs). Supplementation with plant oils and DHA-rich algae resulted in milk fat depression (MFD; yield and percentage). The secretion of de novo FAs in the milk was reduced, whereas the secretion of trans-10,cis-12-CLA and DHA were increased. These changes in FA secretions were associated in mammary tissue with a joint down-regulation of mammary lipogenic enzyme gene expression (stearoyl-CoA desaturase, SCD1; FA synthase, FASN) and expression of the regulatory element binding transcription factor (SREBF1), whereas no effect was observed on lipoprotein lipase (LPL) and glycerol-3-phosphate acyltransferase 1, mitochondrial (GPAM). A positive relationship between mammary SCD1 and SREBF1 mRNA abundances was observed, suggesting a similar regulation for these genes. Such data on mammary gene expression in lactating cows presenting MFD contribute to strengthen the molecular mechanisms that govern milk fat synthesis in the mammary glands. In purified MEC, the dietary treatments had no effect on gene expressions. Differences between mammary tissue and milk purified MEC gene expression were attributed to the effect of lipid supplements on the number of milk purified MEC and its RNA quality, which are determinant factors for the analysis of gene expression using milk cells.

The effects of water restriction following feeding under heat stress conditions on nutrient digestibilities, milk yield and composition and some blood hormones in lactating Holstein cows were evaluated. The design was completely randomized with 30 high producing lactating Holstein cows (80.8±40.5 DIM) which were assigned to two treatment groups (15 cows per treatment). Treatments were free access to water (FAW) and 2 h water restriction (2hWR) following feeding. Average temperature-humidity index (THI) in the farm was over 80 throughout the experiment which defines heat stress conditions. Neutral detergent fibre, organic matter and ether extract digestibilities increased by water restriction (P0.05). Water intake was recorded daily during the digestibility period and was not different between FAW and 2hWR group (P>0.05). Fat corrected milk was higher in 2hWR group than FAW group (P0.05). Somatic cell counts were greater in 2hWR than FAW group (P0.05). Blood prolactin and growth hormone were higher in 2hWR group than the FAW group (P

The study investigated the relationship of markers of welfare and metabolism in milk, urine and blood with the genetic merit of Holstein and Simmental cows after the peak of lactation. Cows were selected from 3 Simmental (IS) and 2 Holstein (IH) commercial dairy farms. Within each farm, cows were ranked according to the estimated breeding value for milk protein yield (EBVp) from minus to positive and selected every 5 EBVps from minus to positive values (about 20% lactating cows for each farm). Milk was sampled and analyzed for protein, fat, lactose, cortisol contents and somatic cell count (SCC). Blood and urines were analyzed for biomarkers of metabolism and welfare. Significantly lower body condition score (BCS) was observed for IH in comparison to IS. Plasma creatinine was higher in IS, whilst Zn, total antioxidant status and glutathione peroxidase was higher in IH. The creatinine N to N ratio in urine was significantly higher for IS, while the purine derivatives (PD) N to creatinine N ratio was higher for IH. The EBVp was negatively related to BCS and glucose for IS and to plasma b-hydroxybutyrate in both breeds. EBVp was negatively related to urinary PD N to total N ratios for IS and to PD N to creatinine N ratio for IH. These preliminary results would indicate that the selection of cows for milk protein yield had minor effect on plasma and milk biomarkers of welfare. Instead, biomarkers of metabolism were more affected by breed and genetic merit.