Electroretinogram and visual-evoked potential measurements in sheep.

Electroretinogram (ERG) and visual-evoked potential (VEP) recordings were taken from ten Suffolk-cross sheep. Stimuli for VEP were 1.5 flashes of white light/s; ERG stimuli were single flashes. The ERG measurements of the a and b wave latencies and a-to-b amplitude were measured between the lower eyelid and the vertex, with ground on the nuchal crest. The VEP after monocular stimulation were measured between the nuchal crest and the interorbital line, with ground on the vertex. Measurements consisted of the latencies to seven alternating positive and negative peaks P1, N1, P2, N2, P3, N3 and P4, and six amplitudes, P1-N1, N1-P2, P2-N2, N2-P3, P3-N3 and N3-P4. Average latencies for the a and b waves were 13.6 and 28.2 ms; the mean ab amplitude was 131.68 microV. Average latencies for the seven VEP peaks were 35.0, 43.1, 52.8, 64.1, 74.5, 90.4 and 112.2 ms. Mean amplitudes ranged from 3.90 to 8.29 microV.     

Postnatal development of the visual-evoked potential in dogs

Recordings of visual-evoked potentials that were induced by flashes of white light were obtained from 13 Beagle pups to document the development of the response from age 7 to 100 days. Responses were recorded between needle electrodes placed on the nuchal crest and the interorbital line, with ground at the vertex. Five alternating positive (P) and negative (N) peaks were observed in most visual-evoked potentials: P1, N1, P2, N2, and P3. Responses were recorded from 2 pups prior to opening of the eyelids. Recordings were performed without sedation or dark adaptation. Peak latencies were essentially mature (equal to those of adult dogs) by day 11 for P1, and by day 38 for N1 and P2. The latencies to N2 and P3 did not reach adult values by day 100, but did reach plateau values by day 43. The P1-N1 amplitude measurements reached mature levels by day 14, whereas N1-P2 amplitudes were mature by day 32. The P2-N2 and N2-P3 amplitudes reached plateaus that greatly exceeded adult amplitudes by days 50 and 58, respectively. Maturation of visual-evoked potential responses paralleled reported morphologic development of the visual cortex. All of the measured latency and amplitude values had significant (P less than or equal to 0.004) linear regression lines of latency vs age or amplitude vs age.     

Chronic copper poisoning in two Holstein cows

Chronic copper poisoning with an acute hemolytic crisis is described in 2 mature Holstein dairy cows from separate herds. Toxic concentrations of copper were present in the serum and in liver and kidney tissues of each cow. There was no history of environmental or dietary exposure to excessive quantities of copper. No further clinical cases of chronic copper toxicosis were observed in the herds. As well as massive hemolysis, in both cows there was involvement of other organ systems including the liver and kidneys which contributed to the clinical course of the disease.     

Lifetime performances in Carora and Holstein cows in Venezuela

A study was conducted in the Central-western region of Venezuela to investigate the lifetime performances of 7918 Carora and 3501 Holstein cows under two different levels of management (low and high) and covering a period from 1961 to 1995. Traits analysed were: herd life, productive life, number of calvings, lifetime milk yield, days in lactation over all lactations and daily milk yield. In Carora cows born from 1961 to 1986 a decrease in herd life, productive life and number of calvings was observed, whereas cows born between 1971 and 1972 showed the lowest lifetime productive traits. Performances of Holstein cows born in the 1981–1986 period were analysed and all traits decreased during this time period. In low level herds, Holsteins remained longer (98.5 months vs. 83.3 in herd life; 69.5 vs. 54.3 months in productive life) and had higher lifetime yield (20 925 vs. 18 589 kg) than those in high level herds, but daily milk yield was lower (8.4 vs. 11.0 kg/day). All lifetime performances were higher for Carora cows under the high level management: 116.8 vs. 112.1 months of herd life, 81.8 vs. 77.1 months of productive life, 5.8 vs. 5.2 calvings, 1616 vs. 1299 days of lactation, 16 194 vs. 11 912 kg of milk over all lactations and 6.5 vs. 4.6 kg milk/day. Survival estimates for year of birth were more variable in Holsteins than in Carora cows. Management influenced survival in Holsteins only, the low level showing higher values.     

Omasal dilation and displacement in 4 Holstein dairy cows

Cases of omasal dilation and displacement in 4 dairy cows are described. The disease was initially diagnosed by a combination of history and clinical signs that included right-sided abdominal distension, rectal palpation, and decreased milk production. The condition was confirmed by laparotomy or necropsy.     

Reproductive performance of Holstein dairy cows in Iran

The objectives of the present study were to describe the current reproductive parameters of Holstein dairy cows in Iran and to determine factors which have a significant effect on reproductive performance with emphasis on high-producing dairy cows. Five large Holstein dairy herds from the major milk production areas of Iran were selected for this study. Reproduction data including parity of dam, calving date, days to first service, days open, number of services, dry period, and occurrence of diseases for cows that calved from 2004 to 2007 were collected from the herds' databases. To determine the effects of year and season of calving, disease status, level of milk production, and parity of dam on reproductive parameters, the proc-mixed procedure in SAS software was used. Overall, data about 8,204 lactation were collected for the study. Results showed that mean (±SD) days open, calving interval, and days to first service for study herds were 134 (±89), 403 (±86), and 67 (±38) days, respectively. Conception rates at the first service and the overall service-conception rate were 41.6% and 41%, respectively. The level of milk production and diseases had significant negative effects on days open and service per conception (P < 0.05); statistical analysis showed that for every 100-kg increase in milk yield, days open will increase by about 0.3 days. However, no significant effect of level of productivity was observed on days to first service. The results of this study indicate that high milk production is a risk factor for decreasing fertility in Iran, like many other parts of the world.     

奶牛子宫复旧的B-超影像学研究

应用Ｂ型实时超声断层扫描仪（Ｂ－ 超）,对奶牛子宫复旧过程进行研究。对３８ 头中国荷斯坦奶牛,用Ｂ－ 超和连续检查法监测了子宫复旧过程。结果,经连续直肠检查法监测,受试牛子宫孕角、空角和子宫颈复旧的平均时间分别为（３７ ．４±３．１）、（３１．４ ±４．９）和（３６．８ ±４．９） ｄ;用Ｂ－ 超监测则为（３５ ．５±４．５） 、（３０．８ ±５．９）和（３７．５ ±５．０）ｄ。并且Ｂ－超监测还发现,分娩当天子宫肌层平均厚度为１．６５ ｃｍ ,产后２３ ｄ 时减少到１．３５ｃｍ ;产后第５ 天在超声影像上可见子宫内膜,平均厚度为０ ．３ ｃｍ ,第１５ 天为０ ．６ ｃｍ ,而到产后２３ ｄ 平均增厚到１．０２ ｃｍ ,子宫复旧完成时,子宫壁平均厚度为１ ．０ ｃｍ ;两子宫角的横切面轮廓清晰,大小基本相同,超声影像变白。研究表明Ｂ－ 超监测奶牛子宫复旧过程是可行的。     

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.     

Pharmacokinetics of ketamine in plasma and milk of mature Holstein cows

Sellers, G., Lin, H. C., G. Riddell, M. G., Ravis, W. R., Lin, Y. J., Duran, S. H., Givens, M.D. Pharmacokinetics of ketamine in plasma and milk of mature Holstein cows. J. vet. Pharmacol. Therap. 33 , 480–484. The purpose of this study was to evaluate the pharmacokinetics of ketamine in mature Holstein cows following administration of a single intravenous (i.v.) dose. Plasma and milk concentrations were determined using a high‐performance liquid chromatography assay. Pharmacokinetic parameters were estimated using a noncompartmental method. Following i.v. administration, plasma T_max was 0.083 h and plasma C_max was 18 135 ± 22 720 ng/mL. Plasma AUC was 4484 ± 1,398 ng·h/mL. Plasma t_½β was 1.80 ± 0.50 h and mean residence time was 0.794 ± 0.318 h with total body clearance of 1.29 ± 0.70 L/h/kg. The mean plasma steady‐state volume of distribution was calculated as 0.990 ± 0.530 L/kg and volume of distribution based on area was calculated as 3.23 ± 1.51 L/kg. The last measurable time for ketamine detection in plasma was 8.0 h with a mean concentration of 24.9 ± 11.8 ng/mL. Milk T_max was detected at 0.67 ± 0.26 h with C_max of 2495 ± 904 ng/mL. Milk AUC till the last time was 6593 ± 2617 ng·h/mL with mean AUC milk to AUC plasma ratio of 1.99 ± 2.15. The last measurable time that ketamine was detected in milk was 44 ± 10.0 h with a mean concentration of 16.0 ± 9.0 ng/mL.     

对当前中国荷斯坦牛育种工作的建议

改革开放以来,我国奶牛养殖业得到了突飞猛进的发展。2003年我国奶牛存栏数已达到893.2万头,牛奶总产达到1746.3万t,人均占有牛奶量达到12kg,取得了可喜的成绩。但是,成年母牛平均单产仅有3200余kg,同国际奶牛业发达国家平均9000～10000kg相比较,差距很大,仅是人家的三分之一左     

Pharmacokinetics of lidocaine in serum and milk of mature Holstein cows

The purpose of this study was to evaluate the pharmacokinetics of lidocaine in mature Holstein cows following an inverted L and caudal epidural nerve block. Plasma and milk concentrations were determined using high-performance liquid chromatography assay. Pharmacokinetic parameters were estimated using a noncompartmental method. Following administration via inverted L nerve block, serum T_max was 0.521 ± 0.226 h and serum C_max was 572 ± 207 ng/mL. Serum AUC was 1348 ± 335 ng·h/mL. Apparent serum t_½β was 4.19 ± 1.69 h and MRT was 5.13 ± 2.33 h with clearance uncorrected for the extent of absorption of 2.75 ± 0.68 L/kg/h. The last measurable time of lidocaine detection in serum was 8.5 ± 1.4 h with a mean concentration of 51 ± 30 ng/mL. Milk T_max was detected at 1.75 ± 0.46 h with C_max of 300 ± 139 ng/mL. Milk AUC till the last time was 1869 ± 450 ng·h/mL with the mean AUC milk to AUC serum ratio of 1.439 ± 0.374. The last measurable time of lidocaine detection in milk was 32.5 ± 16.2 h with a mean concentration of 46 ± 30 ng/mL. There was no detectable lidocaine concentration in any samples following caudal epidural administration.     

Genetic and environmental impact on auction prices for Holstein cows

The aim of the present analysis was to determine the impact of a variety of traits and effects (i.e. production, type, health, management effects, pedigree information) on prices of Holstein cows sold at auction, and to estimate genetic (co)variance components between type traits and auction price. Results were used to derive economic weights for type traits. Data of 1565 cows in first parity were collected at six monthly auction sales from August 2005 through January 2006. Seventeen linear type traits and body condition (scale 1 to 9), and four type composites (dairy character, body, feet and legs, and udder; scale 65 to 88) were scored by two classifiers in the auction hall before cows were sold. Analysis of variance revealed a highly significant impact (P < 0.001) of auction date, test day milk yield, stage of lactation, origin of sire, and miscellaneous defects on auction price. The most expensive cows were sold in August, they were from foreign proven sires, they had a high level of test day milk yield, and they were free from defects related to udder, feet and legs, or milkability. The feet and leg, udder, and body composite also had a significant effect on the price (P < 0.001), with higher scores being associated with higher prices. The opposite association was found for dairy character (P < 0.01). Utilizing results from regression analysis, economic weights per genetic standard deviation were highest for linear scored rear udder height (1.23 €), front teat placement (0.97 €), and strength (0.80 €), but were negative for dairy character (− 0.69 €). Genetic parameters for linear type traits scored at the auction date were consistent with literature reports. Heritability for auction price was 0.27, and auction price was genetically positively related to the feet and leg (0.55), udder (0.55), and body composite (0.21). A relative breeding value for auction price was estimated for 27 influential sires, and correlated with official indices for production, conformation, somatic cell count, functional herd life, fertility, and the total net merit index. Correlations were 0.15, 0.21, 0.11, 0.03, 0.05, and 0.19, respectively. Auction price in combination with type scores and information related to farm management provide valuable information for genetic analysis in dairy cattle, and results can be used to increase dairy cow profitability.     

荷斯坦奶牛乳腺上皮细胞的体外培养

用外科手术的方法采取健康的泌乳期荷斯坦奶牛乳腺组织,采用机械剪切结合酶消化的方法,在体外进行原代乳腺上皮细胞分离培养。结果成功地培养出荷斯坦奶牛原代乳腺上皮细胞。显微镜下观察,细胞形成单层呈鹅卵石样;角蛋白免疫组化染色后,呈现阳性反应。经数次传代后,细胞增殖依旧旺盛。     

荷斯坦奶牛体型线性性状与产奶量的相关性分析

对新疆荷斯坦奶牛的产奶量与体型线性性状进行了相关。通径分析。结果表明,荷斯坦奶牛的乳房纵沟深,后乳房宽,后乳房高与产奶量呈中等正相关,体高,体长,尻宽,尻长与产奶量呈弱相关;后乳房宽,乳房纵沟深是直接影响产奶量的重要性状,且是正身作用;后乳房高对产奶量起负面影响。其间接作用大。     

荷斯坦母牛超数排卵及胚胎移植试验初报

应用FSH对3头荷斯坦母牛进行超数排卵处理,在母牛发情后第7天,2头共冲出11枚卵子,其中受精卵2枚（1枚桑椹胚,另1枚退化）。将回收的胚胎移植给1头受体牛,2个月后直检怀孕。     

荷斯坦奶牛瘤胃微生物分离鉴定及多样性分析

研究为分离获得荷斯坦奶牛瘤胃内容物中的细菌,建立系统进化树,获取有益菌种。采用培养组学技术和16S rDNA分子鉴定方法相结合,对3头健康荷斯坦奶牛瘤胃内容物中细菌进行分离培养。共分离得到105株细菌,包括肠球菌属(Enterococcus)共15株14.29%,芽孢杆菌属(bacillus)共11株10.48%,不动杆菌属(Acinetobacter)共14株13.33%,葡萄球菌属(Staphylococcus)共22株20.95%,梭菌属(Clostridium)共1株0.95%,狭义梭菌属(Clostridium sensu stricto)共2株1.90%,短杆菌科(Brevibacteriaceae)共2株1.90%,链球菌属(Streptococcus)共11株10.48%,气球菌属(Aerococcus)共4株3.81%,柠檬酸杆菌属(Citrobacter)共14株13.33%,杆菌属(Brachybacterium)共1株0.95%,克雷伯氏菌属(Klebsiella)共1株0.95%,普罗维登斯菌属(Providencia)共3株2.86%,沙雷氏菌属(Serratia)共4株3.81%。结果中所占比例最高的菌属是葡萄球菌属;系统进化树分析和GenBank中的同源性比对结果发现,从细菌门、纲、目、科、属、种分析,分支明确;26个菌种同源性都在95.01%~100%之间。分离纯化出11株芽孢杆菌属(Bacillus)细菌具有潜在益生菌活性。可作为饲料添加剂饲喂荷斯坦奶牛。     

Trends in the reproductive performance of Holstein dairy cows in Iran

The study was undertaken to determine the trends in the reproductive performance of Holstein dairy cows in Iran during 1994 to 2008. Reproductive performance data for 528,034 lactations of 246,132 cows in 1,822 Holstein dairy herds of Iran were used. The potential effect of calving season, herd, parity, calving year, as well as herd size and 305-day milk production on reproductive performance traits was investigated using multiple regression models. The least squares means of age at first calving decreased by 3.1 (±0.06) days per year from 806.5 (±96.3) days in 1994 to 788 (±89.9) days in 2008. The least squares means of calving interval increased 1.02 (±0.03) days per year from 394.1 (±65) days in 1994 to 413.2 (±81) days in 2008. Greater 305-day milk production was associated with an average increase of 6.55 (±0.08) days in calving interval per 1,000-kg increase in milk yield. Larger herd size was associated with an average decrease of 0.22 (±0.02) days in calving interval per 50 cows per herd. The mean number of days dry was 88.6 (±51.3) days and increased by 0.82 (±0.02) days per year. In conclusion, reproductive performance in Holstein dairy herds has generally decreased, whereas herd size and milk production have increased over time. Producers may make significant improvements in herd reproduction by reviewing management strategies including the sire selection, reproductive management, inseminator training and techniques, and improved estrous detection. Moreover, it may be advisable for the fertility traits to be included in the genetic selection indices to reduce the rate of reproductive decline.     

影响荷斯坦牛妊娠期长短的因素分析

妊娠期长短是影响奶牛繁殖性能以及牧场经济效益的重要性状之一。为探索影响荷斯坦奶牛妊娠期长短的因素,本文收集了江苏省某奶牛场2016年1月至2017年4月正常健康产犊的荷斯坦牛产犊记录共7 164条。用一般线性模型对犊牛性别、胎次、产犊季节、是否产双犊、犊牛初生重、产犊时母牛体况评分和是否使用性控精液对妊娠期长短的影响进行分析。结果表明:胎次、犊牛性别、产犊季节、产犊时母牛体况评分、犊牛初生重以及是否使用性控精液极显著影响妊娠期长短(P0.01),2胎母牛的妊娠天数显著高于1胎和3胎;产公犊牛母牛的妊娠期显著高于产母犊的奶牛;春季产犊的奶牛妊娠期最长,冬季则最短;产犊时母牛体况评分越高,其妊娠期越短;犊牛初生重越大,则母牛的妊娠期越长;采用性控精液的奶牛妊娠期显著短于非性控精液配种的奶牛;是否产双犊对妊娠期长短无显著性影响(P0.05)。该结果为控制荷斯坦奶牛妊娠期长短,提高其繁殖性能和经济效益等方面提供了科学依据。     

Associations between periparturient disorders and reproductive efficiency in Holstein cows in northern Mexico

Interrelationships among parity, twinning, retained placenta, abortion, metritis, cystic ovaries, milk fever and postpartum reproductive events were investigated in Holstein cows in northeast Mexico. Data were from 6565 lacations from a large commercial dairy herd. Path analysis was used to model the direct and indirect effects of these variables. The risk of reproductive disorders in cows having a particular periparturient complication was assessed by odds ratio analysis. Milk fever was dropped out of the restricted model, mainly because of the low lactational incidence of this disease (0.5%).

The most important implied cause and effect relationships among the periparturient events were twinning causing retained placenta and retained placenta causing metritis (odds ratio = 5.2 and 4.7, respectively; P * 05). Excluding abortion, most reproductive disorders and twinning increased the days from parturition to first estrus (from 4.4 to 9.2 days), the days from parturition to conception (from 1.3 to 21.4 days), the services per conception (from 0.28 to 0.5) and the calving interval (from 14.7 to 21.3 days). Only in associations between retained placenta and reproductive parameters were the indirect components an important part of the total causal association.