Progesterone responses to human chorionic gonadotropin in dairy cattle supplemented with beta-carotene

Twenty Holstein cows were assigned to one of four groups according to milk production and beta-carotene supplementation to evaluate effects of supplementation and milk production on reproductive performance and response of corpus luteum to human chorionic gonadotropin indicated by release of progesterone and secretion of luteinizing hormone in blood plasma. Cows were divided into groups of high and low production and divided further into beta-carotene supplemented and unsupplemented groups. Blood samples were taken 10 days postestrus at 10-min intervals from 1 h prior to injection of 5000 IU human chorionic gonadotropin until 5 h postinjection. Mean days to first detected estrus were 33, 37, 34, and 36 in supplemented, unsupplemented, high-production, and low-production cows. Treatment with beta-carotene and milk production did not affect days to first breeding (63, 67, 62, and 67), or services per conception (3.2, 5.1, 4.6, and 3.7). However, days open were reduced by supplementation (116 versus 186), but milk production had no effect (173 versus 129). Regressions of progesterone on sampling time within treatment and within milk production were significant. Regression of luteinizing hormone on time within production group was also significant. Neither beta-carotene nor milk production affected most reproductive measures, but differences were subtle in corpus luteum response to human chorionic gonadotropin, which may alter endocrine function.     

Peripartum serum vitamin E, retinol, and beta-carotene in dairy cattle and their associations with disease

Peripartum decreases in serum concentrations of vitamins A and E may contribute to impaired immune function in dairy cows. The objectives of this study were to describe peripartum serum concentrations of alpha-tocopherol, beta-carotene, and retinol and their associations with disease risk. On 20 farms over 1 yr, blood samples were collected weekly from 1057 cows from 1 wk before expected calving until 1 wk postpartum. Serum concentrations of alpha-tocopherol, beta-carotene, and retinol, as well as several biochemical variables were measured. Their associations with the risk of retained placenta or clinical mastitis were modeled separately with logistic regression, and the factors associated with the concentration of each vitamin were modelled with mixed linear regression. Differences in vitamin concentrations between 2 batches of sera analyzed 6 mo apart required stratification of statistical analyses. Accounting for the effects of parity, season, and twins, an increase in alpha-tocopherol of 1 microg/mL in the last week prepartum reduced the risk of retained placenta by 20%, whereas serum nonesterified fatty acid concentration > or = 0.5 mEq/L tended to increase risk of retained placenta by 80%. In the last week prepartum, a 100 ng/mL increase in serum retinol was associated with a 60% decrease in the risk of early lactation clinical mastitis. There were significant positive associations of peripartum serum concentrations among each of alpha-tocopherol, beta-carotene, and retinol.     

Effects of bioethanol plant and coproduct type on the metabolic characteristics of the proteins in dairy cattle

The dramatic increase in bioethanol production in Canada has resulted in millions of tonnes of different types of coproducts: wheat dried distillers grains with solubles (DDGS), corn DDGS, and blend DDGS (e.g., wheat:corn 70:30). The objectives of this study were 1) to investigate the effect of DDGS type and bioethanol plant on the metabolic characteristics of the proteins and the total truly digested and absorbed protein supply to dairy cattle using the DVE/OEB system and 2) to compare the metabolic characteristics of the proteins of original feedstock grains with their respective derived DDGS samples. The results showed that all types of DDGS are a good source of the truly digested and absorbed protein in the small intestine [DVE; 107 vs. 249 g/kg of dry matter (DM) for wheat and wheat DDGS; 108 vs. 251 g/kg of DM for corn and corn DDGS]. According to the DVE/OEB system, the predicted total DVE supply to dairy cattle differed among wheat DDGS (DVE = 249 g/kg of DM), corn DDGS (DVE = 251 g/kg of DM), and blend DDGS (DVE = 281 g/kg of DM) and, to a lesser extent, between the different bioethanol plants (DVE: 277 vs. 230 g/kg of DM for bioethanol plants 1 and 2). The results indicated the superior protein value of blend DDGS as well as that of the more optimum degraded protein balance (DPB) value for corn DDGS (DPB: 11 g/kg of DM in corn DDGS vs. 72 g/kg of DM in wheat DDGS and 55 g/kg of DM in blend DDGS). In addition, differences in the acid detergent-insoluble crude protein content of wheat DDGS samples were reflected in differing protein DVE values. In conclusion, it is inappropriate to assume fixed protein values for DDGS without considering factors such as DDGS type and bioethanol plant origin.     

Epidemiology of metabolic disorders in dairy cattle: association among host characteristics, disease, and production

Logistic regression was used to investigate the effects of host characteristics, production, and 23 veterinary diagnoses on the odds of contracting seven metabolic disorders among 61,124 Finnish Ayrshire cows that calved during 1983. Cows in higher producing herds were at increased risk of parturient paresis, udder edema, and ketosis. Cows that had higher previous yields were at increased risk of parturient and nonparturient paresis and ketosis. All of the metabolic disorders except udder edema were directly interrelated. Dystocia, prolapsed uterus, other infertility, and abortion were not risk factors for any of the seven metabolic disorders; however, retained placenta, early metritis, traumatic reticuloperitonitis, acute and chronic mastitis, and foot or leg injury each were direct risk factors for at least two metabolic disorders.     

Rumen pH and fermentation characteristics in dairy cows supplemented with Megasphaera elsdenii NCIMB 41125 in early lactation

This study investigated the effect of using the lactate-utilizing bacterium Megasphaera elsdenii NCIMB 41125 as a probiotic supplement on rumen fermentation and pH in dairy cows in the immediate postcalving period. Fourteen multiparous rumen-fistulated Holstein cows, blocked according to 305-d milk yield in the previous lactation, were used in a randomized complete block design. From d 1 to 28 postcalving, cows were fed ad libitum a total mixed ration with a forage to concentrate ratio of 392:608 and a starch concentration of 299 g/kg of dry matter. Treatments consisting of a minimum of 10¹⁰ cfu of Megasphaera elsdenii NCIMB 41125 or autoclaved M. elsdenii (placebo) were administered via the rumen cannula on d 3 and 12 of lactation (n = 7 per treatment). Mid-rumen pH was measured every 15 min, and eating and ruminating behaviors were recorded for 24 h on d 2, 4, 6, 8, 11, 13, 15, 17, 22, and 28. Rumen fluid for volatile fatty acid and lactic acid analysis was collected at 11 time points on each of d 2, 4, 6, 13, and 15. Yields of milk and milk protein and lactose were similar, but milk fat concentration tended to be higher in cows that received the placebo. Time spent eating and ruminating and dry matter intake were similar across treatments. Ruminal lactic acid concentrations were highly variable between animals, and no cases of clinical acidosis were observed. Both treatment groups had rumen pH <5.6 for more than 3 h/d (a commonly used threshold to define subacute ruminal acidosis), but the length of time with rumen pH <5.6 was markedly reduced in the days immediately after dosing and fluctuated much less from day to day in cows that received M. elsdenii compared with those that received the placebo. Ruminal total volatile fatty acid concentrations were similar across treatments, but the acetate:propionate ratio tended to be smaller in cows that received M. elsdenii. Despite the lack of a measurable treatment effect on ruminal lactic acid concentration, supplementation of early lactation dairy cows with lactate-utilizing M. elsdenii altered the rumen fermentation patterns in favor of propionate, with potential benefits for energy balance and animal productivity.     

Growth and reproduction characteristics of purebred and crossbred dairy cattle in first lactation

Breed additive, maternal, and heterozygotic effects on 11 monthly postpartum body weights, average size, weight gain, age at first calving, and days open were estimated by linear regression analyses from records of 680 purebred and crossbred animals. Calving year, age, and milk yield were significant environmental effects. Positive regressions of age on body weights indicated late calving cows were heaviest postpartum and had most days open. Negative regressions of milk yield on weight gain and postpartum weight showed greatest losses of weight associated with highest yields. There were breed differences in growth; purebreds highest to lowest were Brown Swiss, Holstein, Red Dane, Jersey, and Ayrshire and for weight gain, Brown Swiss, Ayrshire, and for weight gain, Brown Swiss, Ayrshire, Jersey, Holsteins, and Red Dane. Crosses were superior to purebreds in these traits. Additive effects of Holstein were greater than Ayrshire, Jersey, and Red Dane for postpartum body weights and average size. All constants for heterozygotic effect combinations were significant for postpartum weights and average size. Heterozygosity effects increased in magnitude with advancing lactation. Generally, age at first calving and postpartum interval to conception reflected little heterozygotic or maternal effects. There was some indication of breed differences in mean and additive effects for age at first calving.     

Fatty acid and sensory characteristics of beef from three biological types of cattle grazing cool-season forages supplemented with soyhulls

Over two consecutive years, the effects of allocating divergent biological types of cattle (n=107) to fescue pasture without supplementation, or fescue or orchardgrass pasture with soyhull supplementation on chemical, fatty acid and sensory characteristics were investigated. Cattle from the two supplemented treatments produced beef that had increased (P<0.05) percentage lipid and decreased (P<0.05) polyunsaturated and n-3 fatty acids compared to the control. However, the n-6 to n-3 ratio was still less than four in beef from the supplemented cattle. Additionally, supplementation did not decrease (P>0.05) the CLA present in the longissimus, which can commonly occur when forage-fed cattle are supplemented concentrates. Although supplementation did not impact (P>0.05) Warner-Bratzler shear force or tenderness, supplementation of soyhulls reduced (P<0.05) the grassy flavor intensity of rib steaks when compared to the control. Biological type did not have a significant influence on most traits analyzed in this study. These results suggest that supplementation of soyhulls to cattle grazing forage can reduce grassy flavor intensity without decreasing CLA proportions, but can reduce the n-3 fatty acid proportions present in the longissimus.     

Antioxidant and antigenotoxic effect of dairy products supplemented with red ginseng extract

The purpose of this study was to evaluate the antioxidant and antigenotoxic effect of dairy products milk (M) and yogurt (Y) after the addition of 2% red ginseng extract to milk (RM) and to yogurt (RY). Total phenolic content, total flavonoid content, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, oxygen radical absorbance capacity, and total radical trapping antioxidant potential were determined in the samples. Furthermore, antigenotoxic effect of samples was measured, using comet assay in human leukocytes. Total phenolic content and total flavonoid content of RM [38.3 ± 0.8 mg of gallic acid equivalents (GAE)/100 g, 23.6 ± 0.1 mg of quercetin equivalents (QE)/100 g] and RY (41.1 ± 0.9 mg of GAE/100 g, 18.7 ± 0.1 mg of QE/100 g), respectively, were higher than those of M (6.31 ± 0.2 mg of GAE/100 g, 10.4 ± 0.1 mg of QE/100 g) and Y (8.1 ± 0.9 mg of GAE/100 g, 8.4 ± 0.2 mg of QE/100 g), respectively. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and oxygen radical absorbance capacity values increased significantly after the addition of 2% red ginseng in both. Additionally, the total radical trapping antioxidant potential in RM (787.7 ± 7.0 μg/mL) was lower than in M (2074.0 ± 28.4 μg/mL). The H₂O₂-induced DNA damage in RY (0.1 ± 0.0 mg/mL) was less than the damage in Y (0.4 ± 0.0 mg/mL), but we found no significant difference between M and RM. This study indicates that supplementation with red ginseng can fortify the antioxidant and antigenotoxic effects of dairy products effectively.     

Ruminal fermentation characteristics and fatty acid profile of ruminal fluid and milk of dairy cows fed flaxseed hulls supplemented with monensin

Flaxseed hull, a co-product obtained from flax processing, is a rich source of n-3 fatty acids (FA) but there is little information on its value for dairy production. Monensin supplementation is known to modify biohydrogenation of FA by rumen microbes. Therefore, the main objective of the experiment was to determine the effect of feeding a combination of monensin and flaxseed hulls on ruminal fermentation characteristics and FA profile of ruminal fluid and milk. Four ruminally fistulated multiparous Holstein cows averaging 665 ± 21 kg body weight and 190 ± 5 d in milk were assigned to a 4×4 Latin square design (28-d experimental periods) with a 2×2 factorial arrangement of treatments. Treatments were: 1) control, neither flaxseed hulls nor monensin; 2) diet containing (dry matter basis) 19·8% flaxseed hulls; 3) diet with monensin (16 mg/kg dry matter); 4) diet containing 19·8% (dry matter basis) flaxseed hulls and 16 mg monensin/kg. Flaxseed hull supplementation decreased the acetate to propionate ratio in ruminal fluid and monensin had no effect. Concentrations of trans-18:1 isomers (trans9,trans11,trans13/14+6/8) and cis9,12,15-18:3 in ruminal fluid and milk fat were higher and those of cis9,12-18:2 in milk fat tended (P=0·07) to be higher for cows supplemented with flaxseed hulls than for cows fed no flaxseed hulls. Monensin had little effect on milk fatty acid profile. A combination of flaxseed hulls and monensin did not result in better milk fatty acid profile than when feeding only flaxseed hulls.     

Physicochemical assessment of fresh chilled dairy dessert supplemented with wheat germ

Wheat germ is an available and economical source of protein, vitamins and antioxidants with an increasing application in food products. The main aim of this study was to investigate the effects of different levels (0.0, 2.5, 5.0, 7.5 and 10.0%) and particle sizes (120, 210 and 354 μm) of wheat germ on physicochemical properties of fresh chilled dairy dessert. With increasing wheat germ level, dry matter of the dessert increased while the pH decreased. Particle size had no significant effect on these parameters. Increasing the wheat germ content and particle size enhanced darkness, hardness, cohesiveness and gumminess of the desserts while decreasing springiness and water release of the samples. Wheat germ level had greater effects on different quality aspects of the desserts than its particle size. The most acceptable dessert was produced with no more than 5.0% wheat germ with either of the particle sizes used in this study.     

Reproductive performance of lactating Holstein cows fed supplemental beta-carotene

Fifty-six Holstein cows were used in a replicated study to determine whether supplemental beta-carotene improved reproductive performance. Each of two replicates was of completely randomized design with 2 X 2 factorial arrangement of two diets with or without beta-carotene supplementation. On a dry matter basis, diet 1 was 5% hay, 20% haylage, 25% corn silage, and 50% concentrate. Diet 2 was 7.5% hay, 42.5% corn silage, and 50% concentrate. The diets contained adequate amount of vitamins A, D, and E. From 10 d postpartum until pregnancy was confirmed by rectal palpation, half the cows on each diet received a supplement of 400 mg beta-carotene per head daily. The remaining cows on each diet received a supplement of 160,000 IU vitamin A per head daily. Supplemental beta-carotene increased plasma beta-carotene throughout the trials. Median days to first ovulation, first service, days open, and mean services per conception were: 22, 77, 97, and 1.6 for cows receiving beta-carotene supplement compared with 19.5, 73, 82, and 1.9 in controls. Supplementation did not affect first service conception rate, uterine involution, or milk yield. Incidence of follicular cysts, luteal cysts, pyometra, and endometritis in cows fed beta-carotene were 11, 7, 0, and 7% compared with 8, 21, 4, and 13% in control cows. Supplemental beta-carotene did not improve the fertility of Holstein cows.     

Rumen function and grazing behavior of early-lactation dairy cows supplemented with fodder beet

Fodder beet (FB) is a source of readily fermentable carbohydrate that can mitigate early spring herbage deficits and correct the negative energy balance experienced during early lactation in pastoral dairy systems of New Zealand. However, the low-fiber and high-soluble carbohydrate content of both FB bulb and spring herbage are factors that promote subacute ruminal acidosis, impairing rumen function and limiting the marginal milk production response to supplement. In a crossover experiment, 8 Holstein Friesian × Jersey early-lactation dairy cows were used to test the effect of supplementing 16 kg of dry matter (DM) of a grazed perennial ryegrass herbage with 6 kg of DM/d of FB bulb (FBH) versus herbage only (HO) on changes in rumen function and grazing behavior. Following 20 d of adaptation to diets, DM disappearance (%) of FB bulb (FBH cows only) and herbage were measured in sacco, separately. Cows were fasted overnight, and the ruminal contents were bailed the following morning (~0930 h) again to determine the pool size of volatile fatty acids, ammonia, and particle size of digesta, as well as to estimate the rate of ruminal outflow and degradation of neutral detergent fiber. The FBH diet did not alter DM intake, milk yield, or milk solid (fat + protein) production compared with HO. Supplementation of herbage with FB reduced ruminal pH compared with HO between ~0800 h and 1300 h each day. During each period, 1 cow experienced severe subacute ruminal acidosis (pH <5.6 for >180 min/d) during final adaptation to the target FB allocation. The FBH diet reduced the ruminal pool of acetate and ammonia, but increased the ruminal pool of butyrate and lactate compared with HO. When fed FB, rumination and grazing time increased and grazing intensity declined compared with cows fed HO. Despite increased rumination, the comminution of large particles declined 28% between the first and second rumen bailing when cows were fed FB, and in sacco DM disappearance of perennial ryegrass declined 18% compared with cows fed HO. These results indicate that grazing dairy cows supplemented with FB (40% of daily intake) increase rumination and mastication intensity to counteract reduced ruminal degradation of ryegrass herbage due to low ruminal fluid pH.     

Sole ulcers in dairy cattle: associations with season, cow characteristics, disease, and production

Epidemiological associations, expressed as odds ratios between variables obtained from dairy cow records and sole ulcer occurrence at claw trimmings were estimated with logistic regression analysis on data from 2204 and 1124 cows in lactation 1 and lactations 2 to 9, respectively. Sole ulcer in one foot or more than one foot occurred in 20.0 and 29.7% of cows in lactation 1 and in 23.5 and 24.7% of cows in lactations 2 to 9. The analysis revealed several complicated interactions. Trimming or calving in summer to fall was strongly associated with sole ulcer. Trimming later than 1 to 2 mo after calving was positively associated with sole ulcer depending on milk yield, body weight, or season of calving. If lactation 1 cows were treated for disease (limb, metabolic, digestive, or severe reproductive disorders), sole ulcer in more than one foot occurred earlier in lactation. Milk yield in early lactation and body weight were positively associated with sole ulcer. Heel erosion was associated with sole ulcer depending on season of trimming and parity. Presence of sole ulcer but not heel erosion in a lactation increased the risk of sole ulcer in the subsequent lactation. The interval between trimmings appeared to be important.     

Diagnostic milk biomarkers for predicting the metabolic health status of dairy cattle during early lactation

Data on metabolic profiles of blood sampled at d 3, 6, 9, and 21 in lactation from 117 lactations (99 cows) were used for unsupervised k-means clustering. Blood metabolic parameters included β-hydroxybutyrate (BHB), nonesterified fatty acids, glucose, insulin-like growth factor-1 (IGF-1) and insulin. Clustering relied on the average and range of the 5 blood parameters of all 4 sampling days. The clusters were labeled as imbalanced (n = 42) and balanced (n = 72) metabolic status based on the values of the blood parameters. Various random forest models were built to predict the metabolic cluster of cows during early lactation from the milk composition. All the models were evaluated using a leave-group-out cross-validation, meaning data from a single cow were always present in either train or test data to avoid any data leakage. Features were either milk fatty acids (MFA) determined by gas chromatography (MFA [GC]) or features that could be determined during a routine dairy herd improvement (DHI) analysis, such as concentration of fat, protein, lactose, fat/protein ratio, urea, and somatic cell count (determined and reported routinely in DHI registrations), either or not in combination with MFA and BHB determined by mid-infrared (MIR), denoted as MFA [MIR] and BHB [MIR], respectively, which are routinely analyzed but not routinely reported in DHI registrations yet. Models solely based on fat, protein, lactose, fat/protein ratio, urea and somatic cell count (i.e., DHI model) were characterized by the lowest predictive performance [area under the receiver operating characteristic curve (AUC_ROC) = 0.69]. The combination of the features of the DHI model with BHB [MIR] and MFA [MIR] powerfully increased the predictive performance (AUC_ROC = 0.81). The model based on the detailed MFA profile determined by GC analysis did not outperform (AUC_ROC = 0.81) the model using the DHI-features in combination with BHB [MIR] and MFA [MIR]. Predictions solely based on samples at d 3 were characterized by lower performance (AUC_ROC DHI + BHB [MIR] + MFA [MIR] model at d 3: 0.75; AUC_ROC MFA [GC] model at d 3: 0.73). High predictive performance was found using samples from d 9 and 21. To conclude, overall, the DHI + BHB [MIR] + MFA [MIR] model allowed to predict metabolic status during early lactation. Accordingly, these parameters show potential for routine prediction of metabolic status.     

Major advances associated with reproduction in dairy cattle

The purpose of this overview is to review some of the major advances in reproductive technologies, and how they may be applied to meet the challenge of enhancing reproductive efficiency in the high-producing dairy cow of the 21st century. The current population of high-producing dairy cows is considered to be subfertile, as characterized by low pregnancy rates and high rates of embryonic mortality. Coordinated systems of reproductive management have been developed based upon a thorough understanding of the endocrine, cellular, and molecular factors controlling ovarian and uterine function. These systems will partially restore herd reproductive performance. Advances in other reproductive technologies offer possibilities for wider use of superior germplasm. Technologies such as sexed semen, cloning, transgenesis, and preimplantation genetic diagnosis offer the potential to enhance the influence of superior animals on production of food for human consumption. However, at this time, additional research is needed to counteract the higher rates of embryonic and fetal mortality associated with some of these technologies. Furthermore, use of genomics, proteomics, and bioinformatics in the study of reproduction will undoubtedly provide investigators with a greater understanding of the limitations to efficient reproductive processes in the subfertile lactating dairy cow.     

The effect of lameness on the resting behavior and metabolic status of dairy cattle during the transition period in a freestall-housed dairy herd

The objective of this observational study was to examine the effect of lameness on the resting behavior of dairy cattle through the transition period in a mattress-bedded commercial freestall facility, and explore the relationships between lameness, behavior, and metabolic indicators of disease. A convenience sample was used, comprised of 40 multiparous and 17 primiparous Holstein cows that were recruited as they entered the close-up pen and tracked through the maternity, hospital, and fresh pens. At recruitment, 87.5% of multiparous cows and 23.5% of primiparous cows showed evidence of abnormal gait. Lying time decreased from 16 d before calving from a least squares means ± standard error of 13.5 ± 0.6 h/d to a nadir of 10.6 ± 0.38 h/d on the day of calving. After a period of increased rest after calving, lying time stabilized by d 6 to between 9.8 and 10.8 h/d. This change was accompanied by an increase in the number of lying bouts per day from least squares means (95% confidence limits) of 11.2 (10.0 to 12.4) bouts per day to a peak of 17.7 (16.5 to 18.8) bouts per day on the day before calving, and a decrease in the duration of each lying bout. Resting behavior was influenced by calving month, temperature humidity index, body condition, parity, and lameness. Moderate and severely lame cows had significantly longer lying times throughout the transition period before and after calving, but most notable was a dramatic increase in the number of lying bouts observed 3 d before and after calving. In the straw-bedded, loose-housed maternity pen, moderate and severely lame cows had 20.3 (19.1 to 21.5) bouts per day, compared with 15.6 (14.3 to 16.8) bouts per day for nonlame cows. We hypothesized that this alteration in behavior may be associated with hypersensitivity to pain due to lameness. A total of 26.3% of cows tested above a threshold of 1,400 μM β-hydroxybutyrate. Moderate and severely lame cows had a least squares means (95% confidence limits) β-hydroxybutyrate concentration of 1,165 (1,037 to 1,291) μM that was significantly greater than 697 (560 to 834) μM for slightly lame cows and 687 (551 to 824) μM for nonlame cows. In summary, lameness significantly altered the resting behavior of cows during the transition period and was associated with elevated risk for ketosis in the study herd.     

Supplementing intensively grazed late-gestation and early-lactation dairy cattle with chromium

Two hundred thirty-two primiparous and multiparous cows were assigned to a study to determine the effect of supplementing 0 or 6.25 mg/d of Cr from Cr Met on lactation and reproductive performance. Cows received treatments from 6 wk precalving through 21 wk postpartum. Precalving, treatments were incorporated into a pelleted grain mixture and group-fed. Post-calving, cows received treatments via an individual oral drench once a day after the a.m. milking. Grazed herbage was the primary diet constituent for lactating cattle. Blood was collected from a predetermined group of cows before and immediately after calving. On 4 occasions during the treatment period, milk yield was recorded and samples collected for determination of composition. Chromium supplementation had no effect on yield of milk and milk components and milk composition. Chromium supplementation decreased serum nonesterified fatty acids (NEFA) concentration (0.60 vs. 0.68 mmol/L), with chromium supplementation having the greatest impact on serum NEFA concentrations at 1 wk prepartum. Greater percentages of cows supplemented with Cr were observed to be anestrus by dairy personnel (45.5 vs. 32.0%). However, Cr supplementation tended to increase the percentage of cows pregnant in the first 28 d of the mating season (50.0 vs. 39.2%). Results indicate that Cr Met supplementation of intensely grazed, late-gestation and early-lactation dairy cattle decreased serum NEFA concentrations and tended to increase pregnancy rates in the first 28 d of the mating season.     

A GC-MS based metabolic profiling of fermented sausage supplemented with pineapple

Food Science and Biotechnology - A GC-MS based metabolomic study was performed to understand metabolic changes during sausage fermentation and to investigate how the incorporation of pineapple...     

Influence of lactation on metabolic characteristics and embryo development in postpartum Holstein dairy cows

The aim of this study was to examine the direct effect of lactation on the ability of the reproductive tract of postpartum dairy cows to support early embryo development. Twenty-one primiparous Holstein heifers were used. Immediately after calving, half of the cows were dried off (i.e., never milked), and the other half entered the milking herd and were milked twice daily. Jugular blood samples were taken twice per week from 15 d before calving to approximately 100 d postpartum to measure nonesterified fatty acids, β-hydroxybutyrate, glucose, insulin, and insulin-like growth factor-I. At the same time, body weight and body condition score were recorded for each cow. At approximately 60 d postpartum (experiment 1), approximately 65 two- to four-cell embryos, produced by in vitro maturation and fertilization, were endoscopically transferred to the oviduct ipsilateral to the corpus luteum of all cows on d 2 of the estrous cycle. Five days later (d 7), the oviduct and uterus were flushed nonsurgically and the number of embryos developing to the blastocyst stage was recorded. At approximately 90 d postpartum (experiment 2), the estrous cycles of the same cows were resynchronized and 15 to 20 in vitro-produced blastocysts were transferred to the uterus of each recipient on d 7. All cows were slaughtered on d 14 to assess embryo survival and dimensions. Body weight and body condition score were significantly different between groups for the entire postpartum period of the study. Concentrations of nonesterified fatty acids and β-hydroxybutyrate were higher and concentrations of glucose, insulin, and insulin-like growth factor-I were lower in lactating compared with nonlactating cows. Embryo recovery rates from lactating and dry cows were similar. In experiment 1, fewer embryos developed to the blastocyst stage in the lactating cows compared with the nonlactating cows. In experiment 2, embryo survival and conceptus dimensions were not different between lactating and nonlactating cows. In conclusion, the data indicate that the reproductive tract of the lactating dairy cow is compromised in its ability to support early embryo development compared with that of matched dry cows and this may contribute to early embryo mortality observed in such animals.     

Physicochemical characteristics of rice starch supplemented with dietary fibre

Various dietary fibres (DF) from rice flours of Taichung Sen 10 (TCS10) and Tainung 67 (TNu67) rice cultivars were isolated while their roles in governing the pasting and the rheological properties of the rice starch were examined. The addition of DF (at 5 wt.% on dry starch basis), most notably from TCS10 cultivar generally caused significant increases in swelling power and pasting viscosities of 10 wt.% rice starch dispersions. Furthermore, the addition of DF was found to improve the rheological parameters of the 10 wt.% rice starch gel. Nuclear magnetic resonance (NMR) relaxation measurements revealed that the water mobility of starch gel was decreased with the addition of DF. The statistically significant factors were concluded to be arabinoxylan-related compositions for the increments of pasting and rheological characteristics, meanwhile the swelling power and setback viscosity mainly depend on β-glucan compositions and arabinose-to-xylose molar ratio (R_AX).