Concentrations of oestrone sulphate during pregnancy in milk from Jersey and Friesian dairy cows differing in milk yields and composition

Oestrone sulphate concentrations were measured by radioimmunoassay in milk samples obtained weekly during pregnancy from Jersey and Friesian cows, with each breed grazed at two different stocking rates. Mean milk yields differed significantly (P<0.05) between the four herds, while mean percentage milk fat and protein values differed significantly (P<0.05) between the two breeds. In all four herds, oestrone sulphate concentrations in milk rose progressively during pregnancy from a mean value of approximately 80-100 pg/ml at 60-80 days of pregnancy to a plateau value of approximately 1 ng/ml at 181-200 days. In non-pregnant cows, oestrone sulphate concentrations in milk ranged from non-detectable to 110 pg/ml, with a mean +/- s.e.m. value of 59 +/- 4 pg/ml. There was considerable variation in milk oestrone sulphate concentrations between cows in each herd, and oestrone sulphate concentrations could also fluctuate markedly within cows from week to week. Despite this variation, the concentration of oestrone sulphate in 98% of milk samples obtained after 120 days of pregnancy was greater than the highest concentration found in milk from non-pregnant cows. Measurement of oestrone sulphate concentrations in milk samples taken at least 120 days after mating or insemination may provide an alternative, non-invasive means of determining or confirming pregnancy in New Zealand dairy cows.     

Changes in serum oestrone sulphate and progesterone levels of red deer hinds during pregnancy

Serum oestrone sulphate (E1S) and progesterone (P) levels were recorded from six red deer hinds throughout the first two-thirds of gestation. E1S was generally undetectable until 30 days post conception when levels rose, peaking between 60 and 80 days, and fell to lower values between 80 and 170 days post conception. P levels rose after conception and remained elevated for the remainder of the study. This study indicates that in general the presence of measurable E1S levels in serum of hinds is associated with pregnancy.     

不同品种及排酸对育肥牛肉嫩度影响的研究

为了研究品种对牛肉嫩度的影响以及在不同排酸时间中肉嫩度的变化,试验在内蒙古肉牛主产区选择了16月龄的红白花西门塔尔牛、夏洛莱牛、安格斯牛、黄白花西门塔尔牛等品种高代杂种牛以及草原红牛和蒙古牛,在相同饲养管理条件下育肥180 d后屠宰并测定肉的嫩度。结果表明:安格斯牛肉嫩度较其他品种肉牛好,蒙古牛肉嫩度较其他品种肉牛差;但经过一定的排酸期后,嫩度均可达较好水平。     

Influence of different calcium contents in diets supplemented with anionic salts on bone metabolism in periparturient dairy cows

At the initiation of lactation, Ca homeostatic mechanisms have to react to a tremendous increase in demand for Ca. Mobilization of Ca from bone and increased absorption from the gastrointestinal tract are required to re-establish homeostasis. It has been shown that dietary anions play an important role in the prevention of milk fever by mobilizing Ca from bone and by increasing Ca absorption in the GI tract. The purpose of the present study was to investigate the influence of different Ca contents in diets supplemented with anionic salts on bone metabolism of dairy cows. Twenty-four holstein cows (housed inside, second to fourth lactation) without a milk fever history were divided into four groups (A, B, C, D). Each group was fed a different diet which was given from day 263 of gestation till the day of parturition. Group A and B received a low calcium diet (4 g/kg DM) whereas group C and D received a high Ca diet (8 g/kg DM). In addition group B and D received anionic salts. The DCAD was calculated with the formula: DCAD (mEq/kg DM)=(0.2 Ca2++0.16 Mg2++Na++K+)-(Cl-+0.6 S2-+0.65 P3-). Blood and urine samples were collected on days 256, 270 and 277 of gestation, on the day of parturition as well as the following 5 days and on days 9, 14 and 19 after parturition. Serum Ca, P, Mg, ICTP, OC, VITD, PTH and urinary pH were analysed. The bone resorption marker ICTP showed a significant increase after parturition in all the groups. On the contrary, the bone formation marker OC decreased after parturition in all the groups. The VITD concentrations in group D and the urinary pH in group B were significantly lower compared to the other groups (p<0.05). The Ca concentrations tended to be higher in group B around parturition than in all the other groups. No significant influence of the four different diets on all the other parameters could be shown. In conclusion, this data showed that the addition of anions and the different Ca contents had no significant influence on bone resorption and bone formation markers. This may be because of the fact that the dietary cation-anion balance was not low enough (DCAD-group A: 181 mEq/kg DM, group B: -48 mEq/kg DM, group C: 210 mEq/kg DM and group D: 28 mEq/kg DM) to induce a metabolic acidosis with all its positive effects on calcium metabolism.     

Rumen microbiota succession throughout the perinatal period and its association with postpartum production traits in dairy cows:A review

The transition period for dairy cows usually refers to the 3 weeks pre-calving to the 3 weeks post-calving.During this period,dairy cows undergo metabolic and physiological adaptations because of their sus-ceptibility to metabolic and infectious diseases.Poor feeding management under these circumstances may adversely affect the health and subsequent production performance of the cows.Owing to long-term adaptation and evolution,the rumen has become a unique ecosystem inhabited by a complex microbial community closely associated with its natural host.Dietary components are metabolized by the rumen microbiota,and volatile fatty acids and microbial protein products can be used as precursor substances for synthesizing meat and milk components.The successful transition of perinatal dairy cows includes changes in diet,physiology,and the rumen microbiota.Rumen microbial profiles have been confirmed to be heritable and repairable;however,adverse circumstances affect rumen microbial composition,host digestion and metabolism,as well as postpartum production traits of dairy cows for a certain period.Preliminary evidence indicates a close relationship between the rumen microbiota and animal performance.Therefore,changes in rumen microbes during the transition period and the intrinsic links between the microbiota and host postpartum phenotypic traits need to be better understood to optimize production performance in ruminants.     

Udder health in beef cows and its association with calf growth

Background

Studies outside the Nordic countries have indicated that subclinical mastitis (measured by milk somatic cell count or the California Mastitis Test), intramammary infections (IMI), or blind quarters in beef cows may have negative effects on beef calf growth. Knowledge on prevalence of such udder health problems in Swedish beef cows is scarce. Therefore, the main aim of this study was to investigate subclinical mastitis, IMI and udder conformation in a number of beef cow herds. Production of β-lactamase in staphylococci was also investigated. Associations between certain cow factors and subclinical mastitis and IMI, and associations between cow and calf factors and 200 day calf weaning weight were also studied. The herds were visited once within a month after calving and once at weaning. Udder examination and quarter milk sampling, for somatic cell count and bacteriology, were performed in 8 to 12 cows per herd and occasion.

Results

Approximately 50%, 40% and 10% of the cows had subclinical mastitis, IMI, and at least one blind quarter, respectively, but the prevalence varied markedly between herds. Intramammary infections (mainly due to staphylococci) were identified in 13-16% of the milk samples. Less than 5% of the staphylococcal isolates produced β-lactamase. Approximately 11% of the cows sampled twice had the same IMI (mostly Staphylococcus aureus) at both samplings. Cow factors of importance for subclinical mastitis and/or IMI were teat and udder shape, breed, parity, presence of blind quarters, and cow hygiene. No significant associations were found between udder health parameters studied and calf weaning weights.

Conclusions

Subclinical mastitis and IMI, but not blind quarters, were common in beef cows, but the prevalence varied markedly between herds. Most IMI were caused by staphylococci and more than 95% of those were sensitive to penicillin. Cows with large funnel-shaped teats or pendulous udder after calving, and cows with blind quarters were at risk of having subclinical mastitis and/or IMI. Poor hygiene was also a risk factor for udder health problems. No significant associations were found between udder health and calf weaning weight. More studies on risk factors are warranted to improve advisory services on awareness and prevention of mastitis in beef cows.     

Oestrone sulphate measurement in bovine serum during late pregnancy and its relationship with the number of calves born

A radioimmunoassay developed for the measurement of oestrone sulphate in bovine serum was used to determine levels of hormone in cows. The cows were sampled as part of an embryo transfer programme designed to investigate the production of twin calves. The concentration of oestrone sulphate in serum was higher in cows carrying twin calves, but the difference did not become significant until around 220 days' gestation. The predictive value of the test could be used as a guide to increase feeding of cows pregnant with more than one calf.     

Vitamin D receptor amounts across different segments of the gastrointestinal tract in Brown Swiss and Holstein Frisean cows of different age

During different stages of lactation, different requirements of calcium have to be met depending on the milk amount. Vitamin D receptors (VDR) regulate calcium homeostasis by increasing the entry of Ca into blood from bone stores and dietary sources. The purpose of this study was to investigate if age and breed of cows influence VDR amounts across different segments of the gastrointestinal tract. Thirty-six cows were used (18 Brown Swiss, 18 Holstein Friesan, both > 5.5 years or < 4.5 years). Tissue specimens of the intestines were collected from the cows. Formaldehyde-fixed and microwave-treated paraffin sections were used for VDR immunohistochemistry employing a biotinylated monoclonal rat antibody and streptavidin peroxidase technique. The results showed that nuclei and cytoplasm of enterocytes stained positively for VDRs. Strongest immunoreactions were observed in intermediate and basal glandular cells. No significant differences were observed between the different groups. Vitamin D receptors immunoreactivities were prominent in duodenal mucosa, lower in jejunum and in colon, decreased further in ileum and were lowest in caecum. Decreases in number of positively marked cells and staining intensities resulted in reduced immunoreactions. The results of this study indicate that VDR are highly expressed at the site of maximal intestinal calcium absorption. No significant influence of age and breed was observed. The animals used were not in a negative Ca balance. The cows were all in the stage of late or mid lactation. During these periods, the Ca requirements are low and the diets are high in Ca concentration; and the animals are adapted to these circumstances. Passive absorption in adult animals seems to dominate when Ca intake is adequate or high. The active absorption may play a considerably more significant role during the peripartal period, when Ca homeostatic mechanisms are challenged because of tremendous Ca demand at the initiation of lactation.     

Behaviour of cows in cubicles and its possible relationship with laminitis in replacement dairy heifers

The behaviour of cows in cubicles was studied in two dairy herds which were under the same ownership and had similar buildings and management systems. One of the herds had an annual problem of lameness due to laminitis leading to solar ulceration in the replacement first lactation heifers. There were considerable behavioural differences between the cows in the two herds. In the problem herd the heifers and cows stood for significantly longer, more heifers were seen not to use the cubicles, and there were more examples of aberrant behaviour than in the other herd. Less straw was used for cubicle bedding in the problem herd and when the amount used was increased to one bale per 10 cows per day no new cases of laminitis and solar ulceration occurred in the heifers.     

烟酸及胆碱对围产期奶牛营养代谢的调控

围产期是奶牛泌乳周期中十分重要的时期,奶牛要经历生理、日粮、环境和管理等一系列变化,因此,采食量下降,机体处于能量和其他营养素的负平衡状态,易诱发多种代谢性疾病,如脂肪肝和酮病等。烟酸和胆碱能够调控脂肪代谢,提高产后泌乳性能,改善奶牛健康。本文总结了烟酸和胆碱的理化性质、生理功能及其对围产期奶牛营养代谢的调控机理,为进一步研究烟酸、胆碱在奶牛围产期合理应用及保障围产期奶牛健康提供参考。     

Concentrations of apolipoprotein C-III in healthy cows during the peripartum period and cows with milk fever.

Apolipoprotein (apo) C-III is a low-molecular-mass protein mainly distributed in the high-density lipoprotein fraction in cattle serum. We have recently shown that the apoC-III concentration is decreased in cows with fatty liver, ketosis, left displacement of the abomasum, retained placenta and milk fever. The decrease was most distinct in milk fever, thereby suggesting that apoC-III is particularly relevant to the development of milk fever and also that apoC-III is a candidate diagnostic marker for this disease. The purpose of the present study was to examine whether the apoC-III concentration in healthy cows is altered during the peripartum period, to assess the usefulness of apoC-III as a marker for milk fever. ApoC-III concentrations in 17 cows were monitored during the peripartum period (-48 to +12 days from parturition). Of the 17 cows, 14 were apparently healthy during the period. The apoC-III concentrations in the 14 healthy cows were unaltered during the period from -48 to -21 days, but thereafter showed individual variations. Compared with values during the period from -48 to -21 days, the apoC-III concentration was increased (137%) in 5 cows during the period from +1 to +12 days, whereas it decreased (60.7%) in 9 cows. Three cows suffered from milk fever at -3 to +10 days. Decreased apoC-III concentrations in diseased cows (15 to 37% of controls) were more distinct than in the 9 healthy cows. The apoC-III concentration was correlated with lecithin:cholesterol acyltransferase activity in cows with milk fever, but not in healthy cows. Correlation analysis also indicated that apoC-III and apoB-100 concentrations were negatively correlated in 5 healthy cows with increased apoC-III concentrations, but positively in 9 healthy cows with decreased concentrations and cows with milk fever. Determination of the apoC-III concentration during the peripartum period is suggested to be helpful in diagnosing milk fever. The possible relevance of apoC-III and apoB-100 in the development of milk fever is also implied.     

品种及杂交组合效应对育肥猪猪肉羟脯氨酸和pH值的影响

通过对不同品种及杂交组合氟烷基因显性纯合子育肥猪肌肉中羟脯氨酸和pH值2个指标的测定,来分析品种及杂交组合效应对猪肉质的影响。试验结果表明,品种及杂交组合效应对猪肉的嫩度有影响。在屠宰后的前4 d大长猪(大白猪×长白猪)猪肉中羟脯氨酸含量低于长大猪(长白猪×大白猪),说明其嫩度要好于长大猪;猪肉离体后pH值先下降后上升。随着冷藏时间的延长,长白猪和大白猪猪肉pH值的升高速度要比杜洛克猪、长杜猪(长白猪×杜洛克猪)、长大猪、大长猪的速度要慢,说明长白猪和大白猪肉的货架期较长。长白猪与大白猪正反交,对肌肉pH值影响差异不显著(P>0.05)。     

Effect of superovulation on uterine and serum biochemical parameters and its potential association with transferable embryos in Holstein dairy cows

The objective of this study was to determine the effects of superovulation (SOV) on serum and uterine biochemical parameters, uterine bacteriology and cytology and number of transferable embryos (TE). Dairy cows were placed on a Presynch/CIDR Synch protocol. The SOV group was superovulated, induced in estrus, and inseminated, whereas the control group was induced in estrus and inseminated without SOV. Uterine bacteriology and cytology and uterine and serum biochemical parameters were measured at day 7 of the estrous cycle to start the SOV protocol, as well as on the day of embryo recovery (DER). The SOV group produced 7.5 ± 6.7 oocytes/embryos, of which 3.4 ± 4.7 were TE. Serum urea and E2 and uterine Glu, CK, LDH, TP, P4 and PGFM in the control group and serum P4 and PGFM and uterine LDH and PGFM in the SOV group were significantly higher (p < 0.01) at DER than day 7. At DER, uterine urea, LDH, PGFM and TP and serum urea, LDH, PGFM, and P4 concentrations were higher (p < 0.01) in the SOV group than the control. There was no significant variation in uterine bacteriology or cytology. Overall, these results infer that SOV affects both serum profile and uterine secretions, and that these changes may influence the number of TE.     

鲁西黄牛发情周期和产后期外周血浆孕酮水平

在鲁西黄牛母牛的发情周期和产后期（产犊至产后６０ｄ）收集颈静脉血样，用放射免疫分析法测定血浆孕酮（Ｐ４）水平。结果表明，母牛的发情周期平均为（２１．２±１．６）ｄ，发情当天（０ｄ）外周血浆孕酮水平为（０．５２±１．４）μｇ／Ｌ，在周期的９～１５ｄ，孕酮水平较高，其峰值为（４．６２±１．５６）μｇ／Ｌ（ｎ＝１５），在周期的约１８ｄ以后，孕酮水平迅速下降，至周期的２１ｄ降至发情开始时的水平；母牛产后１０．６～１３．６ｄ以后，外周血浆孕酮水平开始升高，出现黄体周期，约有一半的母牛产后第１个黄体周期为（８．４±０．５）ｄ，显著短于正常周期（２０．１±３．２）ｄ（Ｐ＜０．０１）；在短周期中，孕酮峰值为（１．５２±０．７１）μｇ／Ｌ，亦显著低于正常周期孕酮峰值（３．８４±１．２５）μｇ／Ｌ（Ｐ＜０．０５）。除短周期外，产后发情周期中的孕酮水平变化与通常的发情周期基本相同     

归芎益母散对血瘀型胎衣不下临床疗效及与Th1/Th2细胞因子的相关性

筛选45头血瘀型胎衣不下奶牛,随机分为4组,分别为归芎益母散高、中、低剂量组(800,400,200 g/头)、药物对照组(250 g/头,益母生化散),经口灌服给药,用药1～3 d,另设1个空白对照组(健康奶牛10头)。结果表明,与空白对照组比较,用药前,血清中IL-2、TNF-ɑ显著降低(P0.01,P0.05),IL-4、IL-10显著升高(P0.01),Th1/Th2型细胞因子显著偏小(P0.01),用药后,高、中剂量组患牛日均产奶量,产褥期子宫炎发生率及产后180 d繁育性能指标与其相当(P0.05),血清IL-2、TNF-ɑ水平上升(P0.01,P0.05),IL-4、IL-10水平降低(P0.01),Th1/Th2细胞因子趋于平衡,其中,高剂量组Th1/Th2细胞因子与空白对照组差异不显著(P0.05);与药物对照组比较,高、中剂量组治愈率升高18.2%,19.7%,产褥期子宫炎发生率降低了9.1%,11.4%,归芎益母散中剂量组配种次数显著减少(P0.05),空怀时间明显缩短(P0.01),高剂量组空怀时间显著缩短(P0.05)。说明归芎益母散不仅具有调节患牛的子宫收缩和整体免疫机能的潜在药理效应,还促进滞留胎衣及早排出,降低受试奶牛继发感染产褥期子宫炎,有效提高了奶牛的繁殖性能,还具有促进患牛泌乳的作用。调节外周血中Th1/Th2细胞因子趋于平衡,是归芎益母散治疗奶牛胎衣不下重要机理之一。     

Pattern of change in the concentration of milk acetone and its association with ovarian activity for pasture-based cows in early lactation

The variation in milk acetone concentration between cows and the resumption of ovarian activity was determined in 68 Holstein–Friesian cows grazing pasture. Cows calved in two groups approximately three weeks apart and were assessed over the first 60 d of lactation.

The largest coefficient of variation (152%) for milk acetone concentration between cows was found in the first week of lactation. This variability in milk acetone concentration was largely explained by a consistent cyclic pattern, in relation to the day of the study, with regular peaks at 21–26 d intervals. These peaks were synchronised between cows, and cows in the second group synchronised with cows in the first group.

Milk acetone peaks greater than 0.4 mmol/L were associated with a significant drop in milk yield, possibly due to energy deprivation around this time. In this respect, liveweight change over the first 60 d of lactation was significantly negatively correlated (r = − 0.29, p < 0.05) with the mean milk acetone concentration taken over the same period. However, there was no significant relationship (p > 0.05) between mean or maximal milk acetone concentration and the resumption of ovarian activity for the cows that resumed ovarian activity in the first 9-weeks post-partum.

The results of this study suggest that the use of milk acetone as a practical indicator of energy balance is limited due to its variability over time. Milk acetone concentration may be useful in experimental situations or when regular milk samples can be obtained in the field, such as in-line analysis. There is a need to undertake more research to elucidate the implications of the cyclic pattern of acetone concentration in milk on reproductive performance.     

Expression of fibroblast growth factor 21 in the liver of dairy cows in the transition period and during lactation

Fibroblast growth factor 21 (FGF21) has been identified as a novel hormonal factor involved in the regulation of metabolic adaptations during energy deprivation. The present study aimed to investigate the expression of the FGF21 gene in the liver of dairy cows during the transition from pregnancy to lactation. Therefore, the relative mRNA abundance of FGF21 in liver biopsy samples of 20 dairy cows in late pregnancy (3 weeks pre‐partum) and early lactation (1, 5, 14 weeks post‐partum) was determined. It was observed that hepatic mRNA abundance of FGF21 at 1 week post‐partum was dramatically increased (110‐fold) compared to 3 weeks pre‐partum (p < 0.001). With progress of lactation, mRNA concentration of FGF21 was declining; nevertheless, mRNA abundance at 5 and 14 weeks post‐partum remained 25‐ and 10‐fold increased compared to 3 weeks pre‐partum (p < 0.001). Using a gene array technique, it was found that many genes involved in fatty acid oxidation, gluconeogenesis and ketogenesis were up‐regulated during early lactation compared to late pregnancy. Moreover, there were positive linear correlations between hepatic mRNA concentration of FGF21 and mRNA concentrations of genes involved in ketogenesis as well as carnitine synthesis and carnitine uptake at various time‐points during lactation, indicating that FGF21 could play a role in ketogenesis and carnitine metabolism in the liver of dairy cows (p < 0.05). In overall, the present study shows that expression of the FGF21 gene is strongly up‐regulated during the transition period. It is assumed that the up‐regulation of FGF21 might play an important role in the adaptation of liver metabolism during early lactation in dairy cows such as in other species.     

Nitrogen excretion at different stages of growth and its association with production traits in growing pigs

The objectives of this study were to determine nitrogen loss at different stages of growth and during the entire growing period and to investigate the associations between nitrogen excretion and production traits in growing pigs. Data from 315 pigs of an F(2) population which originated from crossing Pietrain sires with a commercial dam line were used. Nitrogen retention was derived from protein retention as measured using the deuterium dilution technique during different stages of growth (60 to 90 kg, 90 to 120 kg, and 120 to 140 kg). Pigs were fed ad libitum with 2 pelleted diets containing 17% (60 to 90 kg) and 16.5% (90 to 120 and 120 to 140 kg) CP. Average daily nitrogen excretion (ADNE) within each stage of growth was calculated on the basis of the accumulated difference between average daily nitrogen intake (ADNI) and average daily nitrogen retention (ADNR). Least ADNE, nitrogen excretion per BW gain (NEWG) and total nitrogen excretion (TNE) were observed during growth from 60 to 90 kg. In contrast, the greatest ADNE, NEWG, and TNE were found during growth from 120 to 140 kg. Statistical analyses indicated that gender, housing type, the ryanodine receptor 1 (RYR1) gene, and batch influenced nitrogen excretion (P < 0.05), but the degree and direction of influences differed between growth stages. Gender differences showed that gilts excreted less nitrogen than barrows (P < 0.05), which was associated with decreased feed conversion ratio (FCR; feed:gain) and lipid:protein gain ratio. Single-housed pigs showed reduced nitrogen excretion compared with group-housed pigs (P < 0.05). In comparison to other genotypes, pigs carrying genotype NN (homozygous normal) at the RYR1 locus had the least nitrogen excretion (P < 0.05) at all stages of growth except from 60 to 90 kg. The residual correlations indicated that NEWG and TNE have large positive correlations with FCR (r = 0.99 and 0.91, respectively) and moderate negative correlations with ADG (r = -0.53 and -0.48, respectively), for the entire growing period. Improvement in FCR, increase in ADG and reduction in lipid:protein gain ratio by 1 phenotypic SD reduced TNE per pig by 709 g, 307 g, and 211 g, respectively, over the entire growing period. The results indicate that nitrogen excretion changes substantially during growth, and it can be reduced most effectively by improvement of feed efficiency and to a lesser extent through the improvement of BW gain or body composition or both.