Blood sugar in dairy cows

Glycemia was found in 1270 cows and high-pregnant heifers fed summer feed rations and in 1981 cows fed winter feed rations, with the known levels of energy-yielding nutrients in feed rations for cows in the first (I) and in the second (II) lactation phases and cows and heifers in the eighth to ninth and a half month of pregnancy (III). The levels of glycemia were significantly lower after the summer feed rations than after the winter feed rations, both in the whole population and in all groups. The basic type of feed rations has a stronger influence on the level of glycemia than the phase of the reproduction cycle. In all groups, hypoglycemic deviations prevail over hyperglycemic ones. Hypoglycemia is most expressive in group I, least expressive in group III. The coefficient of glycemia variability is high (26.5 to 34.6); it is higher after the winter feed rations. Covering of the nutrient need is significantly higher in the summer period than in the winter period, the narrow calorie-protein ratio prevails over the increased ratio and is most obvious in groups II and III. Gaussian character of the glycemia distribution curves suggests a large number of independently acting factors, none of them prevailing over the others; the effects of these factors are mostly additive. This phenomenon limits strongly the employment of glycemic values as indicators of the energy balance in the organism. Glycemia is to be judged within the framework of the metabolic profile and nutritive indicators. Further study of glycemia should be performed by means of multivariate statistical methods.     

Immune response and milk production of dairy cows fed graded levels of rumen-protected glutamine

The objective of the study was to determine the effects of dietary supplementation with glutamine on the immune function and milk production of dairy cows. The experiment involved 24 Friesian cows, divided into three groups of eight each, according to the level of rumen-protected glutamine supplementation: a diet with no supplementation (Control), a diet supplemented with 160 g/day/cow (G160) and a diet supplemented with 320 g/day/cow (G320). At 0, 30, and 60 days of the experiment, lymphocyte response to phytohemoagglutinin (PHA) was determined in vivo for each animal. Humoral response to chicken egg albumin (OVA) and interleukin - (IL)-1β, IL-6 and IL-10 plasma levels were measured at 0, 15, 30, 45, and 60 days. Results demonstrate that supplementing 160 g/day/cow of glutamine can modulate immune responses of dairy cows and enhance the amino acid profile of cow milk.     

Association between anti-F. hepatica antibody levels in milk and production losses in dairy cows

This study was conducted to determine: (1) the associations between anti-Fasciola hepatica antibody levels in milk and some productive and reproductive parameters in dairy cattle, and (2) the threshold antibody level associated with loss of productivity, at both herd and individual level. Anti-F. hepatica antibodies were analysed by MM3-SERO ELISA in milk samples from the bulk tanks of 490 dairy farms and from 686 lactating cows. The results of general linear model analysis revealed a significant (P<0.05) negative association between the F. hepatica infection status at herd level, determined by analysis of specific antibodies in bulk tank milk, and the average herd milk production. Highly positive herds (MM3-SERO ELISA result>0.405) produced an average of 1.5 kg milk/cow per day less than the negative herds. At cow-level, the mixed model analysis also revealed a significant (P<0.05) association between anti-F. hepatica antibody levels and milk yield. A significant (P<0.05) average reduction of 2 kg milk/day was observed in cows with highly positive ELISA results (>0.762) in relation to cows with negative results. The results of the study led us to conclude that MM3-SERO ELISA is a powerful tool that can be successfully applied, if appropriate "economic thresholds" are established, to identify herds and cows suffering from milk production losses associated with natural infection by F. hepatica.     

The relationship between production and infertility in dairy cows

Extract

Each year increasing numbers of livestock are transported by land, rail, sea and air, vet documented observation of the behaviour of stock during transit has seldom been recorded. The trans-shipment of weaner calves between the North and South Islands of New Zealand provided an opportunity to gather information on conditions of travel and general adaptation to a journey of 1600 kilometres by road and air.     

Blood parameters in Swedish dairy herds with high or low incidence of displaced abomasum or ketosis

Sixty dairy herds were studied to investigate the association between long-term incidence of displaced abomasum and clinical ketosis and body condition score and blood profiles, including parameters estimating energy metabolism and hepatic lipidosis in the periparturient period and early lactation. Blood samples were taken around parturition and in early lactation from cows without apparent clinical symptoms of metabolic disorders. A difference in metabolism between high and low incidence herds was shown post-partum by a lower metabolic index (the revised Quantitative Insulin Sensitivity Check Index, RQUICKI), and tendencies for higher concentrations of glucose, insulin and non-esterified fatty acids in the high incidence herds. High incidence herds had more cows and produced on average 1400kg energy-corrected milk per cow per year more than the low incidence herds. No differences were found in parameters reflecting liver cell damage. In the first 3weeks post-partum the RQUICKI was a more sensitive marker of herds with a high incidence of displaced abomasum and clinical ketosis than any of the individual parameters, but further research is needed before practical applications of the RQUICKI can be foreseen.     

围产后期奶牛的血液生化指标特征

本试验旨在通过对围产后期奶牛进行血液生化指标检测,探讨奶牛血液生化指标的变化规律以及与疾病相关指标的发生特点,为围产后期奶牛产后保健提供理论依据。试验选择年龄、体况、胎次相近的二胎以上无疾病史的健康奶牛30头,于分娩当天(0d),产后1,2,3,7,14,21d清晨饲喂前尾静脉采血10mL,分离血清进行血液生化指标β-羟丁酸(BHBA)、游离脂肪酸(NEFA)、门冬氨酸氨基转移酶(AST)、葡萄糖(GLU)、血钙(Ca2+)、血磷(P3+)和血镁(Mg2+)的检测。结果显示:在试验期内30头试验奶牛脂肪肝的发病率为46.7%,酮病的发病率为40.0%,低血钙的发病率为33.3%;血液中NEFA的浓度在分娩当天最低为(0.33±0.17)mmol/L,与产后7,14,21d差异极显著(P0.01),血清中NEFA浓度从产后1d逐步升高。奶牛分娩当天血糖浓度最高为(6.40±1.55)mmol/L,与产后1,2,3,7,14和21天的血糖浓度差异极显著(P0.01),奶牛产后在7~21d时,血液中BHBA浓度逐步升高,其中第21dBHBA浓度最高为(0.84±0.68)mmol/L,与0,1,2和3dBHBA浓度差异极显著P0.01。分娩当天Ca2+浓度为(2.29±0.31)mmol/L,与其他各天差异极显著P0.01。产后0d起,血清中P3+浓度逐步升高,其中0d相对于3,7,14,21d差异极显著P0.01。血清中Mg2+浓度产后1d最低为(1.56±0.42)mmol/L,0d血清Mg2+浓度与产后1,2,3,7,14,21d血清Mg2+浓度差异极显著P0.01,产后1~21d血清Mg2+浓度逐步升高,并处于平稳趋势。结果表明,该牛场奶牛产后营养代谢性疾病发病率较高,应加强对围产期奶牛的饲养管理及保健,对于集约化高产奶牛场应制定合理的保健方案,通过饲料添加剂对分娩牛保健,来预防围产期常见营养代谢性疾病。     

Effects of low and high calcium intake prepartum on calcium mobilization rate around parturition in dairy cows

Forty-one dairy cows were fed a low (LCa-13 g/d) and a high (HCa-83.5 g/d) calcium ration in the 8 weeks prior to parturition and the effect on the Ca mobilization rate around parturition was studied. Plasma Ca values were stable in the LCa group around parturition. In the older cows of the HCa group a very slight decrease in the mean plasma Ca was observed: 2.58 mmol/l at 12-36 h ante partum decreased to 2.38 mmol/l at parturition. Hypocalcaemia, which commonly occurs around parturition, did not occur in 40 of the cows. A subclinical hypocalcaemia (1.8 mmol/l) occurred in one cow (parity 10) from the HCa group. To assess the efficiency of Ca mobilization, a severe hypocalcaemia (1.0 mmol/l) with clinical signs was induced by means of Na2EDTA infusion (0.90 mmol/min), starting at 10 h post-partum. The older cows in the LCa group required more Na2EDTA than those in the HCa group. Higher urinary hydroxyproline excretion in the week before parturition in the LCa than in the HCa group suggested a higher bone turnover. Plasma PTH levels around parturition were not significantly different between the groups. The amount of colostrum milked out in the first 10 h post-partum did not influence Ca homeostasis around parturition. The results contradict those of many other experiments in which hypocalcaemia was observed in cows ingesting high levels of Ca. It is concluded that the restricted feed intake prepartum possibly had a favourable effect on Ca homeostasis.     

The effects of high levels of rumen degradable protein on rumen pH and histamine concentrations in dairy cows

An experiment was conducted to test the hypothesis that the supplementation of crude protein (CP) results in rumen acidosis and increased histamine concentrations in dairy cows. Six ruminally fistulated, non-pregnant dry cows were fed three experimental rations in a replicated 3 × 3 Latin square design. The CP contents in the low-CP, the high rumen undegradable protein (high-RUP) and the high rumen degradable protein (high-RDP) rations were 112, 259 and 266 g/kg dry matter (DM) respectively. The cows were fed 7.7 kg DM of the concentrates and 2.7 kg DM of rice straw. High levels of RDP in the ration significantly increased the ammonia, total volatile fatty acid (VFA) and histamine concentrations in the rumen fluid. However, supplemental CP, whether degradable or undegradable, did not significantly affect the pH of rumen fluid. Plasma urea nitrogen concentration was higher in both high-RDP and high-RUP in relation to cows fed the low-CP ration. The rise in ruminal histamine concentrations was physiologically non-relevant, most likely because rumen pH was not affected by supplemental CP at the installed level of DM intake. Therefore, it can be concluded that the issue of supplemental CP, rumen pH and ruminal histamine concentrations has not yet been settled. Further research is warranted to understand these relationships.     

Cholic acid levels in the serum of dairy cows with metabolically-caused liver diseases

Three groups of freshly calved dairy cows suffering from fatty liver syndrome of different stages were examined for serum cholic acid (SCA) levels to assess the value of SCA-determination as a diagnostic approach to fatty liver syndrome. A. Comparison of the SCS levels between cows with and without ketonuria: Cows with ketonuria (n = 13) and with elevated plasma ASAT activity, indicating a moderate liver damage, showed a rise of their mean SCA level to 35.3 (+/- 14.9) mumol/l. Freshly calved cows without ketonuria (n = 10) had at the same time a mean SCA level of 17.9 (+/- 6.4) mumol/l, falling practically into the physiological range. The SCA level increased above the physiological range in 10 of the 13 cases with ketonuria, in seven of them even more than twice. B. Interrelationship between SCA level and hepatic lipid content: Increase in hepatic total lipid (TL) was always associated with SCA-elevation. The mean SCA level was 55 (+/- 22.0) mumol/l in cases of severe fatty liver (TL = 200-280 g/kg), and 39.5 (+/- 6.0) mumol/l in the moderate form (TL = 180-200 g/kg) of the syndrome. C. Peripartal SCA levels of cows with fatty liver: Clinically healthy cows (n = 6) with ketonuria and an elevation of serum ASAT and FFA concentrations had a mean SCA level of 35-45 mumol/l. One cow of this group, which developed acute fatty liver syndrome and died within the period of study, showed an extreme SCA level of 100 mumol/l in it's terminal stage.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reproductive performance of crossbred dairy cows reared under traditional low input production system in the eastern Himalayas

Reproductive performance of crossbred cows reared under traditional low input production system was assessed. A total number of 160 farmers were surveyed and traditional fodders were evaluated for proximate composition. Total protein, albumin and cholesterol concentrations in blood serum were analyzed. The age at first service, age at first calving, calving interval, calving to first service and calving to conception interval were calculated from records of 261 crossbred dairy cows. The crude protein, crude fiber, nitrogen free extract, ether extract and total ash content varied from 7.2 to 13.9, 18.2 to 34.4, 39.1 to 59.2, 2.1 to 4.1 and 7.2 to 17.9%, respectively. The total protein and albumin concentrations in blood serum were 7.6 ± 0.3 and 4.3 ± 0.3 g/dl, respectively. The cholesterol concentration was 221.1 ± 8.2mg/dl. The mean age at first service and age at first calving was 28.6 ± 1.0 and 40.7 ± 1.1months, respectively. The mean values for calving to first service and calving to conception intervals were 182 ± 14.5 and 224 ± 9.0days, respectively. The conception rate was significantly high among the cows that showed typical fern pattern of cervical mucus (56.6%). The conception rate based on 1^st insemination was 44.4%. The incidence of repeat breeders and anestrus among the crossbred cows were 12.8 and 14.1%, respectively.     

苜蓿添加量对高产奶牛泌乳性能和乳成分的影响

30头2～4胎的荷斯坦奶牛随机分为3组,各组产奶量、体质量、胎次和泌乳天数（DIM）差异不显著。3组奶牛日粮中苜蓿干草的添加量分别为2（对照）、4和6kg,相应的日粮干物质（DM）中粗蛋白含量分别为15．6％、17．2％和18．8％,各组间中性洗涤纤维（NDF）和产奶净能（NEL）含量相同,分别为37．4％和6．9MJ／kgDM。结果表明,在以苜蓿干草为主的奶牛日粮中提高粗蛋白含量能显著提高产奶量（P〈0．05）;干物质采食量（DMI）变化不显著（P〈0．05）,但有增加的趋势;乳脂率、乳蛋白、乳糖及干物质含量没有显著变化（P〈0．05）,在奶牛日粮中大量使用苜蓿干草并不增加日粮成本,可大幅度提高经济效益,6kg组与对照相比纯增效益最高。苜蓿干草在奶牛日粮中的适宜添加量为6kg。     

Relationships of metabolic profiles to milk production and feeding in dairy cows

The aim of this study was to assess the practicality of the metabolic profile test (MPT) for feeding evaluation in dairy cattle. Stepwise regression analysis was used to evaluate the relationships of MPT to feeding and milk production of 4,679 cows in 343 commercial dairy herds. Significant explanatory variables were determined by forward set-up selection, among the deviated values from the reference values of 10 blood metabolites and body condition score, to predict dependent variables, i.e., milk production and the rate of feeding to nutrient requirements, in each or all lactation stages and the dry period. The milk production model of the all-lactation stage showed the greatest goodness-of-fit (adjusted R(2)=0.214, p<0.0001) with high positive regression coefficients for serum cholesterol, magnesium, urea nitrogen and albumin, and negative for glucose and calcium. In the feeding models, goodness-of-fit of crude protein was relatively high (R(2)=0.072, p<0.0001) with a positive relationship to blood urea nitrogen. Although the other feeding models were low in goodness-of-fit, several significant explanatory variables to feeding were found. All feeding models in the late lactation stage and the dry period, in which the feeding was stable, had greater goodness-of-fit than those in the early lactation stage in which milk production varied. It was concluded that the values which deviated from the reference values for the MPT components could assess milk production and feeding, and the MPT is a practical tool for auxiliary feeding evaluation.     

影响奶牛生产性能及经济效益的因素

在规模化牛场的生产过程中,品种、营养、牛群结构、饲养管理、疾病防治等因素对奶牛生产及经济效益有很大影响.而选择高产品种、调整营养水平、建立合理的牛群结构、采取适宜的饲养管理和疾病防治措施,不仅能够提高奶牛的生产性能、繁殖性能,还能降低饲养成本、提高经济效益.文章对影响奶牛生产性能及经济效益的因素进行论述,为促进我国规模...     

Composition and milk cell characteristics in quarter milk fractions of dairy cows with low cell count

Variation in milk composition and milk polymorphonuclear neutrophil leukocyte (PMN) characteristics and functions among quarter milk fractions were investigated in order to evaluate the optimal fraction for the determination of local immune response. Five fractions were classified during milking: foremilk (I), cisternal milk (II), main milk (III), strippings (IV) and residual milk (V). Somatic cell count (SCC), fat, protein, lactose, sodium, potassium, chloride, polymorphonuclear leukocyte necrosis, apoptosis and oxidative burst were analysed in each fraction. The logSCC and fat concentration were highest in residual milk (P < 0.05), whereas protein and lactose concentration were highest in the earliest fractions (I, II, III) (P < 0.05). Polymorphonuclear neutrophil leukocyte necrosis was lowest in strippings and residual milk (P < 0.05), and PMN apoptosis was lowest in residual milk (P < 0.001). The highest percentage of PMN with oxidative burst was found in residual milk (P < 0.05), and was associated with the highest mean fluorescence intensity (MFI) (P < 0.05). In conclusion, late fractions have more PMN and more active PMN. Nevertheless, it is suggested that each fraction is appropriate in the study of local immune response of the mammary gland, however the fraction used in the study has to be specified.     

Low cortisol levels in blood from dairy cows with ketosis: a field study

Background

An elevated plasma glucose concentration has been considered to be a potential risk factor in the pathogenesis of left-displaced abomasums (DA). Therefore the present study was performed to investigate if spontaneous disease (parturient paresis, metritis, ketosis etc) in dairy cows results in elevated concentrations of glucose and cortisol in blood as cortisol is the major regulator of glucose in ruminants.

Methods

Cortisol, insulin, β-hydroxybutyric acid (BHBA), non esterified fatty acids (NEFA), and serum calcium were analyzed in blood serum and glucose, in whole blood, from 57 spontaneously diseased cows collected at different farms. The cows were grouped according to the disease; parturient paresis, recumbent for other reasons, mastitis, metritis, ketosis, inappetance and others.

Results

No elevated concentrations of cortisol or glucose were found in cows with metritis and mastitis but both cortisol and glucose were elevated in cows stressed by recumbency. Cows with ketonemia (BHBA > 1.5 mmol/l) did not have low concentration of glucose in blood but significantly low levels of cortisol. Some of these cows even had cortisol concentrations below the detection limit of the analysing method (< 14 nmol/l).

Conclusions

The study gives patho-physiological support to the treatment strategies of ketosis, recommending glucocorticoids, insulin etc. However further studies of this problem are needed to understand why cows with ketosis have low levels of cortisol and normal levels of glucose. To what extent elevated cortisol and glucose levels in hypocalcemic and recumbent cows are involved in the ethiology and /or the pathogenesis of DA also will need further research.     

Association between exposure to Neospora caninum and milk production in dairy cows

OBJECTIVE: To determine association between exposure to Neospora caninum and milk production in dairy cows. DESIGN: Prospective observational study. Animals: 565 Holstein cows. PROCEDURE: Cows were classified as seropositive or seronegative to N. caninum within 7 days after calving by use of a kinetic ELISA. Milk production was compared between seropositive and seronegative cows. RESULTS: On the basis of 305-day mature equivalent milk production data, seropositive cows produced less milk (2.8 lb/cow per day) than did seronegative cows. In addition, analysis of results throughout the first 300 days of lactation revealed that after adjusting for effects of lactation number, calving season, clinical mastitis, and lameness, milk weight of seropositive cows was 2.5 lb/cow per day less than that of seronegative cows. CONCLUSIONS AND CLINICAL RELEVANCE: Exposure to N. caninum was associated with a 3 to 4% decrease in milk production. A decrease in milk production of 800 lb/cow for a typical 305-day lactation represents a loss of $128/cow.