Serum bile acid concentrations in clinically normal cattle: comparison by type, age, and stage of lactation.

Serum total bile acid concentrations were determined for various types and ages of cattle. There was extreme variability among all the cattle, but the variance was twice as large (0.50 vs 0.22 in logarithmic scale) for beef cattle than for dairy cattle. There was no significant difference in serum total bile acid concentrations between beef cattle and dairy cattle in midlactation. Values for calves < 6 weeks old and for 6-month-old heifers were significantly (P = < 0.05) lower than values for lactating dairy cows. The 5th to 95th percentile range of values (mumol/L) for beef cattle was 9 to 126; for lactating dairy cattle, 15 to 88; and for 6-month-old dairy heifers, 11 to 64.     

Efficacy of an intravaginal progesterone insert and an injection of PGF2alpha for synchronizing estrus and shortening the interval to pregnancy in postpartum beef cows, peripubertal beef heifers, and dairy heifers

The objective was to test the efficacy of an intravaginal progesterone insert and injection of PGF2alpha for synchronizing estrus and shortening the interval to pregnancy in cattle. Cattle were assigned to one of three treatments before a 31-d breeding period that employed artificial insemination. Control cattle were not treated, and treated cattle were administered PGF2alpha or an intravaginal progesterone-releasing insert (CIDR) for 7 d and treated with PGF2alpha on d 6. The treatments were applied in one of three experiments that involved postpartum beef cows (Exp. 1; n = 851; 56+/-0.6 d postpartum), beef heifers (Exp. 2; n = 724; 442.5+/-2.8 d of age), and dairy heifers (Exp. 3; n = 260; 443.2+/-4.5 d of age). Luteal activity before treatment was determined for individual cattle based on blood progesterone concentrations. In Exp. 1, there was a greater incidence of estrus during the first 3 d of the breeding period in CIDR+PGF2alpha-treated cows compared with PGF2alpha-treated or control cows (15, 33, and 59% for control, PGF2alpha, and CIDR+PGF2alpha, respectively; P < 0.001). The improved estrous response led to an increase in pregnancy rate during the 3-d period (7, 22, and 36% for control, PGF2alpha, and CIDR+PGF2alpha, respectively; P < 0.001) and tended to improve pregnancy rate for the 31-d breeding period for cows treated with CIDR+PGF2alpha, (50, 55, and 58% for control, PGF2alpha, and CIDR+PGF2alpha, respectively, P = 0.10). Improvements in rates of estrus and pregnancy after CIDR+PGF2alpha, were also observed in beef heifers. Presence of luteal activity before the treatment period affected synchronization and pregnancy rates because anestrous cows (Exp. 1) or prepubertal heifers (Exp. 2) had lesser synchronization rates and pregnancy rates during the first 3 d of the breeding period as well as during the entire 31-d breeding period. The PGF2alpha, and CIDR+PGF2alpha but not the control treatments were evaluated in dairy heifers (Exp. 3). The CIDR+PGF2alpha-treated heifers had a greater incidence of estrus (84%) during the first 3 d of the breeding period compared with the PGF2alpha-treated heifers (57%), but pregnancy rates during the first 3 d or during the 31-d breeding period were not improved for CIDR+PGF2alpha compared with PGF2alpha-treated heifers. In summary, the concurrent treatment of CIDR and PGF2alpha improved synchronization rates relative to PGF2alpha alone or control. Improved estrus synchrony led to greater pregnancy rates for beef cows and beef heifers but failed to improve pregnancy rates for dairy heifers.     

Study on prevalence of bovine viral diarrhoea virus (BVDV) antibodies in 29 Italian dairy herds with reproductive problems

An epidemiological survey on prevalence distribution of antibodies to BVDV was carried out in dairy cattle herds during 1995-1996 in northern Italy. A total of 704 serum samples from 29 non-vaccinated herds reported to have reproductive problems were tested for serum neutralising antibodies. In each herd, sampling was based on the stratification by age into five classes (< 6 months old calves, 6-12 months old calves, pregnant heifers, uniparous, pluriparous). Overall, 53.3% of samples were serologically positive, with the lowest ratio in 6-12 months old calves (37.9%) and the highest in pluriparous cows (71.2%).     

Prevalence of Cryptosporidium, Giardia and Eimeria infections in post-weaned and adult cattle on three Maryland farms

The prevalence of Cryptosporidium, Giardia and Eimeria, in healthy, asymptomatic, post-weaned and mature cattle was investigated on three Maryland farms. One farm, a dairy research facility, had 150 multiparous Holstein milking cows; 24 were examined and Cryptosporidium andersoni was detected in three (12.5%) but neither Giardia nor Eimeria was detected. The second farm, a commercial dairy, had 57 multiparous Holstein milking cows and an equal number of heifers. Of 19 cows examined, C. parvum, Giardia duodenalis, and Eimeria bovis and/or E. ellipsoidalis were detected in two (10.5%), two (10.5%) and one (5.26%) cow, respectively. Of 23 heifers examined, C. parvum, Giardia, and E. bovis and E. ellipsoidalis, was detected in two (8.7%), four (17.4%), and five (21.7%), heifers, respectively. The third farm, a beef cattle breeding and genetics research facility, had 180 7- to 9-month old purebred black Angus. Of 118 examined for C. parvum and Giardia, 34 (28.8%) and 44 (37.3%) were positive, respectively, of 97 examined for E. bovis and/or E. ellipsoidalis 32 (33.0%) were positive. These findings, based on a method with a minimum detection level of 100 oocysts of C. parvum/g of feces, which underestimates the number of infected cattle, clearly demonstrate the presence of low level, asymptomatic infections in post-weaned and adult cattle in the United States and indicate the potential role of such cattle as reservoirs of infectious parasites.     

Serum haptoglobin concentration in cattle

To obtain a basal concentration of serum Haptoglobin (Hp) in cattle in Taiwan, Hp concentrations were measured from serum samples collected from 10 healthy heifers, every week for one year. The values were also compared with those collected from 15 cows diagnosed with postpartum metritis. The heifers were successfully impregnated by artificial insemination six months after the tests. Hp concentrations were also measured in the serum collected from 11 other cows within 3 weeks after parturition. The Hp assay developed in this study gave a good correlation (r=0.893)with Western blotting. The Hp concentration of 454 serum samples from the 10 heifers had a mean value of 83.6 +/- 34.1 mg/l, and there was no significant difference among individual heifers. The basal value of Hp in heifers was calculated as less than 73.6 mg/l. No significant difference in Hp concentration was observed among the 10 heifers during cold and warm seasons (19.8 +/- 2.2 degrees C vs 27.3 +/- 1.4 degrees C), or before and after pregnancy. The mean serum Hp concentration from cows suffering from postpartum reproductive disorders was 1133.5 +/- 627.1 mg/l, which was significantly greater than the serum of healthy heifers and postpartum cows (104.6 +/- 61.0 mg/l) (P<0.05). These results demonstrate that Hp concentration may be a useful indicator for cows with postpartum reproductive disorders.     

The specificity of antibody responses in cattle naturally exposed to Fasciola hepatica

Fasciola hepatica causes significant morbidity and mortality in dairy cattle in the Andean region of Cajamarca, Peru, where prevalence of infection of up to 78% has been reported. ELISA and Western blot analyses were used to characterise antibody responses in dairy cattle to adult F. hepatica to excretory-secretory (E/S), somatic (SO) and surface (SU) antigens. Three groups of dairy cattle - calves, heifers and adult cows - naturally exposed to F. hepatica in this region, were monitored every 2 months over a 2-year period. Calves, heifers and adult cows all had antibodies which recognised a 28kDa protein in the SO preparation, whereas only adult cows had antibodies that recognised a 28kDa protein in E/S products. All three groups of cattle responded to a 60-66kDa group of proteins in E/S and SU preparations and a 17kDa antigen in SO products was recognised by antibodies from cows and heifers but not calves. The total antibody response to E/S antigens measured by ELISA, increased over time in calves and remained constantly high over the 2-year period in all three groups of cattle. Slight fluctuations in the antibody response occurred in the group of heifers and cows coinciding with seasonal changes in the level of challenge.     

The duration of expulsion and the separation of the afterbirth in breeding cows--a contribution to the improvement of parturition monitoring

The objective of this study was to obtain data on the duration of the expulsion and afterbirth stages and on the rate of contractions of the abdominal muscles in dams with eutocia (n = 81; heifers: 11; cows: 70). We also looked into the questions of whether and at which stage of expulsion there were differences in these parameters between cows and heifers as well as purebred Simmental (n = 49) and Simmental X Limousin (n = 21). The total period of expulsion (period from appearance of the phalanxes in the rima vulvae until the complete expulsion of the calf) was 19.7 +/- 2.1 minutes. It took 17.3 +/- 2.3 minutes for the head to emerge. Further expulsion required 1.9 +/- 1.7 minutes. At an average of 40.1 +/- 1.5 minutes, the expulsion stage was longer in heifers than in cows, in which it lasted 18 +/- 2.1 minutes (p < 0.01). The differences are due to the time that the head took to emerge. While this stage of labor lasted 15.3 +/- 2.3 minutes in cows, this interval was clearly longer in heifers, lasting 38.1 +/- 1.5 minutes (p < 0.01). No statistically significant difference was observed in the course of further expulsion and there were not any differences detected between purebred Simmental and Simmental X Limousin. An average of 67.5 +/- 1.6 abdominal contractions were required for complete expulsion, 56.5 +/- 1.7 contractions of the abdominal muscles were necessary until the head appeared. After 9.3 +/- 1.6 abdominal presses, the calf had completely emerged. There was a statistically significant difference between cows (52.8 +/- 1.7) and heifers (93.3 +/- 1.6) until the expulsion of the head (p < 0.01). No breed-specific differences were observed. Separation of the afterbirth was observed in 95.0% of the animals up to the eighth hour post partum. Retarded separation and retained placenta were recorded in 2.5% of the animals in each case. 82.7% of the animals performed placentophagy. No placentophagy was observed when the placenta was retarded. No differences were detected between heifers and cows and the breeds with regard to the separation of the afterbirth and the incidence of placentophagy.     

奶牛不同生理阶段血清微量元素含量和氧化状态

选择3～4月龄犊牛、后备母牛和成年母牛(产奶后期、产前及产后1月内).测定了血清Se、Cu、Zn、Mn、Fe含量厦谷胱甘肤过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量.结果表明,除Zn含量外,所测元素含量犊牛明显低于后备母牛和成年牛(P<0.05或P<0.01),后备母牛和成年牛之闻差异不显著(P>0.05),血清Se含量在产奶后期和产前明显下降(P<0.05),血清Cu、Mn含量在产后1月内有降低的趋势,但与产前相比均差异不显著(P>0.05);所测血清氧化状态指标与年龄无明显关系,在妊娠末期和泌乳早期发生改变,血清CAT、GSH-Px、SOD活性和MDA含量在产前和产后1月内最高.表明犊牛上述所测指标最低,奶牛产前和泌乳早期血清微量元素含量和氧化状态失衡.     

Effect of preoperative administration of erythromycin or flunixin meglumine on postoperative abomasal emptying rate in dairy cows undergoing surgical correction of left displacement of the abomasum

Objective: To determine whether preoperative administration of erythromycin or flunixin meglumine altered postoperative abomasal emptying rate, rumen contraction rate, or milk production in dairy cattle undergoing surgical correction of left displacement of the abomasum (LDA). DESIGN: Nonrandomized, controlled clinical trial. ANIMALS: 45 lactating Holstein-Friesian cows with LDA. PROCEDURES: Cows were alternately assigned to an erythromycin (10 mg/kg [4.5 mg/lb], IM), flunixin (2.2 mg/kg [1.0 mg/lb], IV), or control group (n = 15/group). Treatments were administered once 1 hour before surgical correction of LDA. D-Xylose solution (50%; 0.5 g/kg [0.23 g/lb]) was injected into the abomasal lumen during surgery, and venous blood samples were periodically obtained to determine time to maximum serum D-xylose concentration. RESULTS: Abomasal emptying rate was significantly faster in cows treated with erythromycin (mean +/- SD time to maximum serum D-xylose concentration, 149 +/- 48 minutes) than in control cows (277 +/- 95 minutes) but was not significantly different between cows treated with flunixin (230 +/- 49 minutes) and control cows. Cows treated with erythromycin had significantly greater milk production, relative to production before surgery, on postoperative days 1 and 2 than did control cows. Cows in the erythromycin and flunixin groups had a significantly higher rumen contraction rate on the first postoperative day than did control cows. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that preoperative administration of a single dose of erythromycin increased abomasal emptying rate, rumen contraction rate, and milk production in the immediate postoperative period in cows undergoing surgical correction of LDA.     

Rectal palpation and transmission of bovine leukemia virus in dairy cattle.

To determine whether rectal palpation, using common obstetrical sleeves, serves as a mode of transmission of bovine leukemia virus in dairy cattle, field studies were conducted at 2 dairies. At a commercial dairy, significant difference was not observed in rate of seroconversion in heifers and cows in which the same sleeve or new sleeves were used for palpations. At a university dairy, where cattle were used to teach dairy husbandry and veterinary procedures, significantly (P less than 0.02) greater rate of seroconversion was observed in heifers and cows palpated with unwashed common sleeves than that observed in heifers and cows palpated with sleeves washed between use. Although rectal transmission of bovine leukemia virus under field conditions was documented, it was related to frequency of palpation and age of cattle.     

Some Characteristics of Primary and Secondary Oestrous Signs in High-producing Dairy Cows

Shortened and weakened oestrous signs in dairy cows may cause a failure of oestrus detection and artificial insemination timing error leading to poor reproductive performance. The aims of this study were to investigate the duration of standing oestrus in high-producing dairy cows under a free stall system, to determine the duration of expression of secondary oestrous signs before and after standing oestrus (Expt 1) and to compare the duration and intensity of oestrus between cows and heifers (Expt 2). Cattle were checked for primary and secondary oestrous signs at an interval of 4 h. Heat detection aids were also used. In Expt 1, of 56 cows which were detected in oestrus, 36 cows (64.3%) showed standing oestrus and other 20 cows (36.6%) showed secondary oestrous signs only. Duration of the standing oestrus was 6.6 +/- 6.3 h on average (+/-SD), ranging between 2 and 32 h. The cows in standing oestrus showed secondary oestrous signs during a period from 9.6 +/- 8.1 h before onset of standing to 18.4 +/- 18.8 h after the end of standing oestrus. In the cows that did not show standing oestrus, expression of secondary oestrous signs were observed for 25.7 +/- 20.5 h, which was 7.5 h shorter than the average duration of oestrus in cows showing standing oestrus. In Expt 2, nine (82%) of the 11 lactating cows in oestrus showed standing, while all the 10 heifers exhibited standing oestrus. Average duration of standing oestrus was 6.4 +/- 4.3 h in cows and 6.2 +/- 3.9 h in heifers, respectively. It may be concluded that the duration of standing oestrus is substantially shortened in lactating dairy cows, and more than one-third of cows did not show standing oestrus. In cows showing standing oestrus, duration of expression of secondary oestrous signs before and after standing is not shortened. Duration of standing oestrus in heifers was as short as that in cows.     

荷斯坦青年牛初次配种妊娠月龄对头胎和二胎产奶量和繁殖性能的影响

旨在研究母牛初次配种妊娠月龄（age at first pregnancy,AFP）对其泌乳性能和主要繁殖性能的影响。本研究以我国北方地区2个规模化奶牛场13 927头荷斯坦母牛（A牧场8 091头,B牧场5 836头）的生产数据为基础,统计了母牛AFP、头胎和二胎的产奶量、产后首次发情时间、首次配种时间和首次受孕时间,然后将母牛根据AFP的早晚（12~19月龄）分为8组,对各试验组母牛的头胎和二胎产奶量和主要繁殖性能的数据进行比较分析。结果表明：1）2个规模化奶牛场荷斯坦青年牛AFP以13和14月龄为主（总占比70.1%）;2）AFP可显著影响荷斯坦青年牛头胎和二胎的305 d产奶量（P<0.05）,其中AFP为14月龄时A牧场头胎和二胎305 d产奶量均最高,分别为15 102和15 534 kg;3）AFP可显著影响荷斯坦青年牛头胎和二胎产后首次发情时间和受孕时间（P<0.05）,AFP为14月龄时头胎产后首次发情和受孕情况最优;4）对于产后首配时间,除A牧场头胎AFP为16月龄时产后首次配种时间显著高于AFP为17月龄时（P<0.05）外,其余各组间均无显著性差异（P ≥ 0.05）,并且各组间配种时间相差≤ 5 d;5）通过对A牧场在场牛（2 703头）与淘汰牛（660头）的AFP记录数据分析发现,在场牛的AFP为14.52月龄,显著高于淘汰牛的AFP（P<0.05）。因此,在北方地区现有的生产管理水平下,14月龄可能是荷斯坦青年牛最适宜的初次配种妊娠月龄,这对我国规模化奶牛场选择荷斯坦青年牛适宜的初次配种月龄具有一定参考价值。     

Insulin-like growth factor-I concentration in Holstein female cattle: variations with age, stage of lactation and growth hormone-releasing factor administration

Plasma insulin-like growth factor-I (IGF-I) concentrations were monitored in Holstein females through different periods of their growth, lactation and after acute or chronic growth hormone-releasing factor (GRF) administration. Plasma samples were radioimmunoassayed using a human IGF-I antibody after a 24 hr incubation in a HCl(.1N)-glycine(.2M) buffer (pH 2). In a first study, IGF-I concentrations were measured in Holstein females of different ages and(or) stages of lactation (n = 6 per group). The IGF-I concentrations in newborn calves (102.0 +/- 11.3 ng/ml) markedly decreased (P less than .01) in 1 mo old animals (50.2 +/- 7.1 ng/ml), then increased (P less than .01) to 137.0 +/- 5.1 and 137.4 +/- 11.0 ng/ml in 6 and 10 mo old heifers, respectively. In dairy cows, IGF-I concentrations were low 24 hr post-partum (44.7 +/- 7.6 ng/ml) and then increased (P less than .05) to remain stable throughout lactation (91.3 +/- 4.9, 92.8 +/- 12.9, 96.1 +/- 7.6, 90.7 +/- 8.8 ng/ml at 2, 3, 6 and 9 mo of lactation, respectively). There was a further increase (P less than .05) to 113.7 +/- 3.1 ng/ml during the dry period. In a second trial, blood samples were collected from lactating dairy cows every 2 hr for 24 hr following a sc injection of saline (n = 4) or human (h) GRF (1-29)NH2 (10 micrograms/kg BW, n = 4). The IGF-I peak concentration was reached on average 10 hr after the GRF injection and was higher (P less than .01) in treated cows than in control cows (135.4 vs 86.9 +/- 16.2 ng/ml). In the last trial, daily sc injections of 10 micrograms of hGRF(1-29)NH2 per kg BW to dairy cows (252 days of lactation) for 57 days, which increased milk production by 14% (2 kg/day), also increased (P less than .01) IGF-I concentration: 127.1 +/- 5.3 and 118.0 +/- 1.6 vs 90.7 +/- 4.7 and 96.0 +/- 5.0 ng/ml on days 29 and 57 of treatment for treated (n = 9) and control (n = 8) cows, respectively. Thus, the IGF-I concentration in dairy cattle varies with age and stage of lactation, and is increased by GRF administration in lactating dairy cows.     

Serological study of a dairy herd with a recent history of Neospora abortion

HERD HISTORY: A cluster of 19 abortions occurred in April and May 1994 on a seasonal dairy farm of 277 cows in Taranaki. Lesions consistent with neosporosis were seen in several foetuses. The age of the aborting cows ranged from 2 to 12 years. Pregnant rising 2-year-old heifers had been grazed off the main farm on a run-off' until returning in May, when they were replaced on the run-off by the rising l-year-old calves. None of these pregnant heifers aborted. METHODS: Sera were obtained from all calves (n = 32), 32 of 33 pregnant heifers, 59 of 60 3-4 year-old cows and 101 of 150 older cows, plus all cows that had aborted. Sera were tested using an indirect fluorescent antibody assay. Non-aborting cattle sera were screened at 1:400, and further dilutions were tested from 15 aborted cows. RESULTS: The percentages of seropositive cattle were: 32% of the calves, 3% of the heifers, 31% of the younger cows and 27% of the older cows. The proportion of seropositive heifers was significantly lower (p< 0.01) than in the other age classes. There was no significant difference in the proportion of seropositive animals between these other age classes (p >0.05). Of the 15 cows that aborted, and for which further dilutions were tested, nine had titres of 1: 12,800, four had titres of 1:6400, one had a titre of 1: 1600 and one had a titre of 1:400. Twenty cows were the dams of pregnant heifers. Six of these cows were seropositive but all their offspring were seronegative. Fifteen aborting cows were held over to the following year when 13 became pregnant and calved normally. There were only two to three abortions in the whole herd in this following year. CONCLUSION: These results suggest that either a point-infection occurred sometime in early 1994 with an infective period short enough so that the heifers did not get infected when they returned to the main farm, or some factor precipitated a recrudescence of latent infection with a subsequent rise in titres in about 29% of the animals on. the main farm only. Although neither hypothesis can be proven or disproven in this observational study, the former hypothesis seems more likely.     

An economic assessment of twin births in British dairy herds.

The effect of twinning on the subsequent health, production and reproductive performance of dairy cattle was studied by analysing the data derived from 19,755 calvings which occurred during three years on 37 farms. The data formed part of the database of a veterinary practice operating the DAISY dairy cow recording scheme for its dairy farmer clients. The average twinning rate was 2.5 per cent. For first calf heifers the rate was 0.9 per cent, and the rate increased with increasing parity to over 5 per cent for cows calving for their sixth and subsequent lactations. Although they produced more milk than their contemporaries, twin-bearing cows suffered an increased incidence of retained placenta and vulval discharges and their calving to conception interval was extended by 33 days. Furthermore, 35 per cent of these cows were culled compared with 21 per cent of their contemporaries. The benefit of having more calves for sale was reduced owing to 15 per cent of them being born dead. It is calculated that producing twins resulted in an average loss of income of 74 pounds/cow, a deficit of 15 per cent compared with cows having single calves.     

Insights into the dynamics of endemic Coxiella burnetii infection in cattle by application of phase-specific ELISAs in an infected dairy herd

Serological diagnosis of acute and chronic Q fever in humans relies on detection of antibodies to phase I (PhI) and II (PhII) antigens of Coxiella (C.) burnetii. Although phase-specific antigens are available, they are not yet used in ruminants as they are in humans. This study focuses on phase-specific serology as a tool for analysis of the dynamics of infection in cattle. As a prerequisite, sero-prevalence in Bavarian cattle (1) and sero-prevalences for age-groups (2) were determined by ELISA (CHEKIT Q-Fever; mix of PhI/PhII-antigen). Subsequently, phase-specific antigens were coated onto ELISA plates individually and tests were simultaneously applied in an endemically infected herd with about 90 dairy cows and 250 calves/heifers in April 2005, March 2006 and retrospectively in May and October 2004. From April 2005 onward, placentas were analysed for C. burnetii by PCR (3). (1) Sero- and herd prevalences based on 21,051 sera from 603 Bavarian dairy farms collected in 2003 were 14.8% ± 0.48% and 72.3% ± 3.6%, respectively. (2) Analysis of 3965 animals from 105 farms for which age was reported revealed a base level of sero-prevalence of less than 5% in 1-2 years old animals, it increased to 15% in 2-3 years old and reached a plateau (25-30%) in cows four years and older. (3) In May 2004 and April 2005 a peak of PhI(-)/PhII(+)-prevalence in primiparous cows (2.0-3.5 years) was observed; but not in October 2004 and March 2006. The PhI(-)/PhII(+)-pattern in primiparous cows changed to negative (one-third), PhI(+)/PhII(+) (1/3) or persisted (1/3). In contrast, sero-conversion was rare in multiparous cows (>3.5 years). If the PhI(-)/PhII(+) pattern was detected, it was due to an infection in preceding years. This pattern persisted (2/3) or changed to negative (1/3); a change to PhI(+)/PhII(+) did not occur. PhI(-)/PhII(+) in heifers (1-2 years) always changed to negative. Detection of PhII-antibodies was significantly associated with PCR-positive placentas. Remarkably, 45% of sera with the PhI(-)/PhII(+) pattern were negative for the CHEKIT Q-Fever ELISA, thus this test missed an important group of infected animals.     

Low Incidence of an Altered Endometrial Epidermal Growth Factor (EGF) Profile in Repeat Breeder Holstein Heifers and Differential Effect of Parity on the EGF Profile Between Fertile Holstein (Dairy) and Japanese Black (Beef) Cattle

A high incidence (about 70%) of alteration in endometrial epidermal growth factor (EGF) profile, i.e., loss of 2 peaks on days 2–4 and 13–14, has been linked to a reduced fertility in multiparous repeat breeder Holstein cows. However, the EGF profile in Holstein heifers and other breeds (types) of cattle has not been investigated. In study 1, EGF concentrations were determined using endometrial tissues obtained by biopsy on days 3, 7 and 14 from 84 fertile Holstein heifers to obtain a normal range and 53 repeat breeder Holstein heifers to estimate incidence of alterations in the EGF profile. In repeat breeder heifers, EGF concentrations were similar to fertile controls on 3 days and five animals (9.4%) had an altered EGF profile with EGF concentrations below the normal range on days 3 and 14. In study 2, EGF concentrations on day 3 were repeatedly examined from the nulliparous period to the third postpartum period in 28 Holstein (dairy) and 47 Japanese Black (beef) cattle. The effect of parity on EGF concentrations on day 3 was different between Holstein and Japanese Black cattle. In Japanese Black cows, the EGF concentrations were consistently high throughout the study period, while in Holstein cows, the EGF concentrations decreased after the second calving. In conclusion, unlike multiparous repeat breeder Holstein cows, an altered EGF profile may not be a major cause of repeat breeding in Holstein heifers, and the peak EGF concentrations around day 3 may decrease even in fertile populations of multiparous dairy cows, but not in beef cows.     

Survey of helminth infections in Maine dairy cattle.

The survey was done to determine the incidence and seasonal prevalence of the gastrointestinal helminths infecting Maine dairy cattle. Approximately equal groups of calves, heifers, and cows from 13 dairy farms, managerially and geographically representative of dairying in the state, were sampled at regular 2-month intervals over the period of a year. On the basis of fecal egg counts and identification of cultured larvae, the following results were obtained: Of the 94 adult cows, 78 heifers, and 91 calves sampled continuously in the course of the survey, 95.7%, 98.7%, and 96.7%, respectively, were strongylorid positive (infected with Ostertagia, Cooperia, Trichostrongylus, Haemonchus, and Oesophagostomun), with an overall incidence of 97%. Strongyloides papillosus eggs were in 64.6% of the cattle, Bunostomum in 40.3%, Nematodirus in 27.8%, Trichuris in 27.0%, Capillaria in 9.5%, Moniezia in 25.1%, and Dictyocaulus viviparus larvae in 2.7%. Worm burdens, as reflected by mean nematode egg production per gram of feces, varied. The greatest worm burdens were in the calves, followed by the heifers and the cows. A marked variation in egg production related to season was observed, particularly with the strongylorid worms. Peak strongylorid egg production was observed in the May-June sampling period. After the peak period, worm burdens decreased in all groups of cattle to their lowest point during the winter period of January-February. This pattern of egg production was similar to that reported by workers in other parts of the world. Farm management practices were shown to be related to the degree of parasitism existing in these herds. Those herds classed as poorly managed had significantly higher levels of parasitism in young animals than those classed as having fair or good management.     

The effect of Zindep inj. preparation on levels of zinc, T-lymphocytes and beta-lysine in the blood of pregnant dairy cows]

The effects of zinc administration at a rate of 3 mg/kg lw. in the preparation Zindep inj. ad usum vet. (Biotika, Slovenská L'upca) were evaluated as exerted on zinc concentrations in the blood serum of 16 dairy cows in the middle of the 7th month of pregnancy. With respect to zinc injection, T-rosetted lymphocytes and beta-lysine activity were inestigated. Blood was collected from all dairy cows from v. jugularis before the preparation was administered, on days 2, 5, 8, 15, 30 and 60 after Zindep administration. Atom absorption spectrophotometry, applying a flame technique on a Perkin Elmer 1100 apparatus (Bíres, 1986), was used to determine Zn concentrations in the blood serum of all dairy cows. T-lymphocytes were determined by a rosette test after Paul et al. (1977), and beta-lysine was detected spectrophotometrically after Bucharin et al. (1987). Zinc dynamics in the blood serum of dairy cows is presented in Fig. 1. The starting values of zinc in the test cows were 9.68 +/- 2.30 mumol/l and in the control ones 10.15 +/- 1.27 mumol/l. Zincaemia of experimental dairy cows was significantly lower (P less than 0.01) on day 2 after Zindep administration, in comparison with the control group. A significant increase in zinc concentrations in the blood serum of experimental animals, in comparison with the control ones, was observed from day 8 to day 60 (P less than 0.01). The maximum zincaemia values were recorded in experimental dairy cows within days 15 and 30 (15.65 +/- 3.33, and/or 14.55 +/- 2.10 mumol/l).(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of blood polymerase chain reaction and enzyme-linked immunosorbent assay for detection of Mycobacterium avium subsp. paratuberculosis infection in cattle and sheep.

A study was carried out to compare the performance of enzyme-linked immunosorbent assay (ELISA) and blood polymerase chain reaction (PCR) for diagnosis of paratuberculosis in cattle and sheep. For cattle, a set of 278 samples from 1 paratuberculosis-affected Friesian farm was used; it included 80 ELISA-positive samples and 198 ELISA-negative samples from an age-matched group. Ninety-four samples were from heifers and 184 were from 2-5-year-old cows. The overall analysis showed a clear association (Fisher exact test [FET] P = 0.0049) but a weak negative agreement (45.3%, kappa = -0.1665 +/- 0.0994) between the 2 tests. It reflected a moderate agreement among heifers (87.7%, kappa = 0.4471 +/- 0.2435) and a moderate disagreement among cows (62.7%, kappa = -0.3670 +/- 0.1057). For sheep, 496 blood samples from 53 Latxa dairy flocks were used; 180 of the blood samples were from dam/offspring pairs. The overall association between the 2 tests on ovine samples was strong (FET, P = 0.0005), whereas the agreement was low (kappa = 0.1622 +/- 0.1188). There was slightly better agreement for ewes (kappa = 0.2135 +/- 0.1992) than for lambs (kappa = 0.1193 +/- 0.1301). There was also a highly unlikely proportion of dam/offspring positive results (FET, P < 0.0001, kappa = 0.6269 +/- 0.1854). Four of 6 lambs that were necropsied 1 year after testing had paratuberculosis microscopic lesions in the ileocecal valve (3 lambs) or a PCR-positive result (4 lambs). These results suggest that blood PCR testing might be a potentially useful new approach in paratuberculosis diagnosis, especially in young animals.