Evaluation of real time B-mode ultrasound scanning for detecting early pregnancy in cows

A real time B-mode ultrasound scanner with a 7.5 MHz rectal linear transducer was used in two trials to detect whether dairy cows, less than 25 days after insemination at standing oestrus, were pregnant. In the first trial 17 cows were inseminated on the same day, and their reproductive tracts were examined 14, 15, 16 or 17 days after insemination. All the cows were diagnosed accurately as either pregnant or not pregnant. In the second trial 22 cows were inseminated on the day of observed oestrus while 14 were observed at oestrus but not inseminated. The animals were kept as a mixed group and an experienced operator scanned the uterus of each cow on one occasion, without knowing either the dates of observed oestrus or which cows had been inseminated. The rate of correct diagnosis was only 33 per cent in cows up to 16 days after oestrus, but increased markedly after 17 days and was 100 per cent by day 20.     

Oestrus during pregnancy in the cow

Forty-three oestruses were observed in 35 pregnant cows in one beef suckler herd and 17 dairy herds; at each oestrus the pregnant cow stood willingly to be mounted by another cow or bull. Such oestruses were observed at all stages of pregnancy, although more often between 121 and 240 days, occurred more than once per pregnancy and were also seen in successive pregnancies. On one farm where the dairy cows were observed for four 30 minute periods daily, oestrus was recorded in 5.7 per cent of pregnant cows. The behavioural signs associated with oestrus during pregnancy were indistinguishable from those of true oestrus in non-pregnant animals and although its duration was shorter (mean 5.6 hours), its intensity was comparable to that of the true oestrus. Pregnant cows showing oestrus were usually seen interacting with other oestrous cows in the sexually active group. Pregnant cows showing oestrus had a higher mean condition score (3.9 +/- 0.64) than control pregnant cows (3.0 +/- 0.36). Physiological changes in the genital tract normally associated with true oestrus were not observed in pregnant cows showing oestrus. There was no ovulation or metoestrous bleeding. The characteristics of cervical mucus, including ferning patterns, were similar to those of pregnant cows at the same stage of pregnancy. Hormonal changes associated with oestrus in non-pregnant cows were not observed in the pregnant cows exhibiting oestrus. Seven of nine pregnant cows at oestrus stood willingly to be mounted by a bull. On seven occasions, bulls exposed only to cervical mucus from pregnant cows showing oestrus did not display flehmen.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lungworm outbreaks in adult dairy cows: estimating economic losses and lessons to be learned

Two lungworm outbreaks in dairy herds were investigated in order to estimate the resulting economic costs. On the two farms, with 110 and 95 cows, total costs were estimated at ?59 and ?67 per cow, respectively. Overall, milk production reduced by 15 to 20 per cent during the outbreaks. Five cows died on one farm, while on the other farm seven cows died as a result of the lungworm outbreak. On one farm, 51.7 per cent of the total costs was due to reduced milk production and 33.1 per cent was due to disposal of dead animals. On the other farm, it was 36.3 and 50.9 per cent, respectively. The remaining 13 to 15 per cent of the total costs were due to extra inseminations, laboratory diagnosis and treatments. The history and development of the outbreaks are described. One lesson from these outbreaks is that recognising that potentially lungworm-na?ve animals are to be introduced into the adult herd allows for timely measures (for example, vaccination) to prevent a lungworm outbreak.     

Comparison of a camera - software system and typical farm management for detecting oestrus in dairy cattle at pasture

AIM: To compare the sensitivity, specificity, predictive values and accuracy of detection of oestrus using a novel oestrus detection strip (ODS) and a camera-software device (CSD) with typical farm management practices of visual observation and use of tail paint in dairy cattle at pasture. METHODS: Dairy cows (n = 480) in a seasonal-calving herd managed at pasture under typical commercial conditions in New Zealand were stratified by age, body condition score and days in milk, then randomly allocated to one of two groups prior to the planned start of mating (PSM). Tail paint was applied to all cows and oestrus detected by visual observation of oestrous behaviour and removal of paint, by farm staff. One group (n = 240) was fitted with ODS and also monitored for signs of oestrus using a CSD, while the Control group (n = 240) was monitored using tail paint and visual observations only. Cows detected in oestrus were artificially inseminated (AI), and pregnancy status determined using rectal palpation and ultrasonography, 51-52 days after the end of a 55-day A period. Results of pregnancy diagnosis were used to confirm the occurrence of oestrus, and the sensitivity, specificity, predictive value and accuracy of detection of oestrus compared between oestrus detection methods. RESULTS: The sensitivity and accuracy of oestrus detection in the Control group, using visual observation and tail paint, were low. Compared with the Control group, detection of oestrus using the ODS and CSD resulted in greater sensitivity (85% vs 78%; p = 0.006), specificity (99.6% vs 98.0%; p < 0.001), positive predictive value (PPV; 88% vs 51%; p < 0.001) and overall accuracy (99.0% vs 98.0%; p < 0.001). Negative predictive value (NPV) did not differ significantly between groups (99.4% vs 99.3%; p = 0.28). Pregnancy rate to first service was higher in the CSD group than in the Control group (72% vs 39%; p < 0.05). Use of the CSD significantly increased the cumulative proportion of cows pregnant to AI over the breeding period (p = 0.044). CONCLUSION AND CLINICAL RELEVANCE: The ODS and CSD was satisfactory for detection of oestrus in seasonal calving dairy herds grazing on pasture and could improve the sensitivity and accuracy of detection of oestrus in herds where these are low.     

北京地区荷斯坦奶牛皮肤褶皱厚度与泌乳性能关系的研究

本研究通过测定荷斯坦奶牛肋部和颈部皮肤褶皱厚度,探究了皮肤褶皱厚度的影响因素及其与泌乳性能的关系。利用数显游标卡尺测量荷斯坦奶牛肋部和颈部皮肤褶皱厚度,评定奶牛体况,并收集皮肤褶皱厚度测量月份试验牛场的奶牛生产性能数据,共得到2 519头奶牛的数据用于分析。利用固定效应模型分析胎次、牛场、测定人、泌乳阶段、体况评分对奶牛皮肤褶皱厚度的影响,皮肤褶皱厚度对泌乳性能影响的分析模型中同样包括上述固定效应。结果表明胎次、牛场、测定人、泌乳阶段、体况评分对荷斯坦奶牛皮褶厚均有极显著影响（P < 0.01）,肋部皮肤褶皱厚度对泌乳性能无显著影响（P > 0.05）,而颈部皮肤褶皱厚度对日产奶量、乳脂率影响显著（P < 0.05）,颈部皮肤褶皱厚度对乳蛋白率、尿素氮无显著影响（P > 0.05）。颈部皮褶厚为7.20 mm的个体日产奶量最高;颈部皮褶厚为6.00 mm的个体,乳脂率最低。本研究进一步阐明了荷斯坦奶牛泌乳期内不同部位皮肤褶皱厚度的影响因素,并首次利用大群数据区分不同部位研究了皮肤褶皱厚度对泌乳性能的影响,为利用皮肤褶皱厚度提高奶牛管理效率提供科学依据。     

Post-partum Reproductive Performance of Crossbred Dairy Cattle on Smallholder Farms in Sub-humid Coastal Tanzania

The objective of this study was to monitor the reproductive performance of dairy cows in smallholder farms under the Tanga Dairy Development Project (TDDP). The findings can be used to improve reproductive efficiency. Dates of oestrus, artificial insemination (AI) or service by bull and calving were recorded, and pregnancy was diagnosed by rectal palpation. Daily milk yields, monthly body condition score (BCS) measured on the scale of 1-9, feed availability, calf rearing, and diseases were also recorded. Milk progesterone (P4) concentration was measured by radioimmunoassay (RIA) in 1327 sequential samples collected between day 15 and 120 in 46 post-partum Zebu x Friesian crossbred dairy cows. The mean interval from calving to first P4 rise above 2 nmol/L (cyclicity) was 66.1 +/- 6.8 days. Resumption of ovarian activity postpartum was early (< 60 days) in 45%, and late (> 60 days) in 55% of the cows. In about 45% of the cows the first post-partum ovarian cycles were short (< 14 days) and had low P4 concentrations. Oestrus was missed once or several times in 34.7% of the cows, most likely indicating poor oestrus detection, silent oestrus, or farmers deliberately not taking or reporting their cows for insemination. The mean interval to conception was within 130 days postpartum. Average daily milk production was 5.7 +/- 2.2 L and the mean BCS Was 3.1 +/- 1.3. Both milk production and BCS had no clear influence on the measured reproduction parameters. Clinical uterine involution was complete within 29 +/- 2.6 days of calving in the majority of cows. Progesterone profiles and rectal palpation revealed various causes of infertility, which included anoestrus, silent oestrus, irregular oestrous cycles, and infection of the uterus. The major causes of animal culling, death, slaughter or sales include tick-borne diseases and trypanosomiasis, which have high prevalences in the area, infertility, low productivity and old age. Greater attention should be focused on reproduction and its interaction with nutrition and disease control.     

Oestrus detection in dairy cows by milk temperature measurement

The milk and body temperatures of 15 cows were monitored twice daily at milking times, over a total of 30 oestrous periods. The best determination of oestrus was based on a temperature rise of at least 0.2 degree C over the corresponding mean temperature of the three preceding days. This resulted in 72 +/- 16 per cent of oestruses, predicted by serial progesterone assays, being successfully detected by serial progesterone assays, being successfully detected and 11 +/- 3 per cent of false positives. The variable extent of the temperature rise at oestrus and the large daily fluctuations in temperature for individual cows, resulted in a moderate oestrus detection rate accompanied by an unacceptable level of false positives.     

Economic and reproductive consequences of retained placenta in dairy cattle

The financial losses due to retained placenta in Dutch dairy cattle were estimated by using two different methods of calculation. A data-set containing the birth records of 160,188 Meuse-Rhine-Yssel cows provided data on the reproductive performance of cows with and without retained placenta. The fertility of cows after retention of the placenta appeared to be affected. An economic calculation made by adding the losses due to increased calving interval, increased culling rate, loss of milk production and the costs of veterinary treatment and drugs revealed that the total loss due to retained placenta was 471 pounds per year for a 100-cow farm with an average incidence of the condition (6.6 per cent). For a 'problem' farm with a 30 per cent rate, the loss was 2139 pounds per year. A computer farm simulation model, based on a stochastic determination of events, was used to make calculations for circumstances closely resembling those on farms. A 6.6 per cent rate of retained placenta caused a small but significant decrease in net return on labour and management; however, a 30 per cent rate caused highly significant changes. The economic effects of retained placenta were similar in magnitude in herds of high or low productivity and high or low fertility. Sensitivity analysis showed that the greatest financial losses were caused by loss of milk production, followed by the number of animals suffering from complications. The financial losses in herds with an average rate of retained placenta were thus of limited economic importance and therapeutic measures alone should be adequate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Role of the sensitivity of detection of oestrus in the submission rate of cows treated to resynchronise oestrus

OBJECTIVE: To determine if failure to detect oestrus in cows treated to resynchronise oestrus leads to fewer cows being inseminated than are truly in oestrus. PROCEDURE: Cows in three herds were enrolled in a controlled breeding program that involved synchronisation of oestrus for a first round of artificial insemination (AI) followed by resynchronisation for a second round of AI. Just before oestrus was expected at the second round of AI, aids for the detection of oestrus were fitted, which included pedometers, radiotelemetric transmitters (HeatWatch), tail-paint and heatmount detectors. Milk samples were collected at the second round of AI (day 33, herds A and B; day 35, herd C of the treatment program) and were used in combination with pregnancy testing to determine the number of cows that were in oestrus (milk progesterone < 2.0 ng/mL) and cows that were not in oestrus (milk progesterone > 2.0 ng/mL or pregnant at second round of AI) at the time samples were collected. RESULTS: The mean sensitivity of detection of oestrus at the resynchronised oestrus was 92.5% and did not differ significantly between herds (P = 0.19). A total of 75% (60/80) of cows that were retrospectively determined to be not pregnant at the time of the second round of AI were classified as having high (> or = 2.0 ng/mL) concentrations of progesterone in milk at that time. Pregnancy testing of cows about 35 days after AI suggested that early pregnancy loss also contributed to a reduction in submission rates at the resynchronised oestrus. CONCLUSION: Failure to submit cows for insemination at a resynchronised oestrus was mainly due to cows not being in oestrus rather than due to a failure to detect oestrus.     

荷斯坦牛泌乳前期体况评分及其对泌乳性能和离群寿命的影响

为了探究荷斯坦牛泌乳前期体况评分（body condition score,BCS）的影响因素及BCS对生产性能和离群寿命的影响,本研究收集江苏省某大型牛场2018年1月至2020年12月共7 811头荷斯坦牛泌乳前期BCS、生产性能测定（dairy herd improvement,DHI）结果及淘汰记录,利用多因素方差分析法在分析奶牛泌乳前期BCS变化及影响因素基础上,重点分析泌乳前期BCS及其变化对泌乳性能和离群寿命的影响,利用Cox回归对泌乳前期不同BCS的荷斯坦牛生存曲线进行绘制,并对不同BCS荷斯坦牛的淘汰原因进行卡方检验。结果表明,全群泌乳前期BCS均值为（2.95 ±0.32）。胎次、产犊季节和泌乳天数对泌乳前期BCS有极显著影响（P<0.01）,1胎牛和夏季产犊的母牛泌乳前期BCS均最高;5~30、31~60、61~100 d BCS呈显著下降。泌乳前期BCS对产奶量、乳脂率、乳蛋白率、体细胞评分等均有极显著影响（P<0.01）。产奶量和高峰奶量随BCS的增加呈极显著下降（P<0.01）。泌乳前期BCS与产奶量、高峰奶量呈极显著负相关（P<0.01）,与乳蛋白率呈极显著正相关（P<0.01）。泌乳前期BCS的变化对SCS和高峰奶量均有显著影响（P<0.05）。泌乳前期BCS对离群胎次和淘汰月龄有极显著影响（P<0.01）。生存分析表明,BCS为2.75的牛只生存概率最大。2胎和4胎母牛、冬季产犊的母牛不同BCS淘汰比例均呈极显著差异（P<0.01）;低产淘汰的牛只泌乳前期BCS淘汰分布具有极显著差异（P<0.01）。在本研究牛群中,当泌乳前期BCS为2.75时,牛只生产性能较佳且淘汰风险最低,本研究为规模化牛场荷斯坦牛泌乳前期的饲养管理提供了参考。     

体况评分与步态评分对奶牛生产性能的影响

为探究体况评分(Body Condition Score,BCS)和步态评分(Locomotion Score,LS)对奶牛泌乳性能的影响,本试验在2016年7月至8月通过对北京地区7个奶牛场近5 000头泌乳牛进行体况和步态评分并收集相关的DHI数据,采用固定模型分析BCS和LS的影响因素及场、胎次、泌乳阶段、LS和BCS对日产奶量、体细胞数及乳成分的影响。结果表明:BCS和LS对日产奶量均有极显著影响(P0.01),BCS对乳蛋白率有显著影响(P0.05);胎次对LS有极显著影响(P0.01),而对BCS无显著影响,场-测量人、泌乳阶段对BCS和LS均有极显著影响(P0.01);LS与BCS之间回归关系显著,LS较高的个体BCS较低。在生产上可以综合运用BCS和LS加强管理,提升产奶量,改善乳品质量,使牛场获得更大的经济利益。     

Herd-level risk factors for the mortality of cows in Danish dairy herds

The factors affecting the mortality of cows in Danish dairy herds were investigated by analysing data from 6839 herds. The mean risk of mortality during the first 100 days of lactation was 2.5 per cent. The risk of mortality increased with increasing herd size (odds ratio [OR] 1.05 for an increase in herd size of 50 cows), with the proportion of purchased cows (OR 1.05 for an increase in the proportion of purchased cows of 0.1), and with increases in the somatic cell count (OR 1.16 for an increase in average weighted mean somatic cell count of 100,000 cells/ml). The risk decreased with increasing average milk yield per cow (OR 0.93 for an increase in mean yield per cow-year of 1000 kg). The risk was lower in free-stall barns with deep litter (OR 0.79) than in barns with cubicles (OR 1) or tie-stalls (OR 1.04). Herds with Danish Holstein (OR 1) or Danish Jersey (OR 0.93) cows as the predominant breed had a higher risk of mortality than herds of the Danish red dairy breed (OR 0.67). The risk of mortality was lower in organic herds (OR 1) than in conventional herds (OR 1.17), and lower in herds that grazed pasture during the summer (OR 0.78).     

Fertility of dairy cows in Northern Ireland

A comprehensive database was established on the milk production and reproductive performance of dairy cows in 19 selected herds in Northern Ireland, varying in size, management system and genetic merit. Data were obtained for 2471 cows, 1775 of which calved in a second year, and 693 were culled from the herd for specific reasons. The estimated mean rate of heat detection (assessed by the interheat interval during the main breeding season) in all the herds was 71 per cent, with a range from 53 to 92 per cent The average conception rate to first insemination was 37.1 per cent (range 21 to 66 per cent). The average calving interval for the retained cows was 407.2 days (range 359 to 448 days). Twenty-eight per cent of the cows that calved were culled, with infertility being the largest single reason (26.8 per cent of the cows culled). There were major differences in reproductive performance between the herds, but heat detection rate, conception rate and calving interval did not appear to be affeded by a herd's genetic merit. The herds with shorter calving intervals were characterised by better heat detection efficiency (83 v 61 per cent, P<0.01), a shorter interval from calving to first insemination (74 v 97 days; P<0.05), a higher conception rate to first insemination (45 v 34 per cent, P>0.10) and a lower removal rate (23 v 37 per cent, P<0.01). Furthermore, the cows in these herds had lower body condition scores (BCS) in the dry period (3.0 v 3.3; P<0.05) but lost less body condition in early lactation (0.3 v 0.6 BCS units, P<0.05). These results show that dairy herd fertility in Northern Ireland is generally low and similar to that previously reported for England and the USA, but that in some herds changes in herd management practices improved the cows' fertility.     

Survey of the incidence and aetiology of mastitis on dairy farms in England and Wales

A survey of clinical and subclinical mastitis was carried out on 97 dairy farms in England and Wales, selected at random from members of a national milk recording scheme. The farmers were asked to collect aseptic milk samples from five consecutive cases of clinical mastitis and from five quarters with high somatic cell counts using a defined protocol, and they completed a questionnaire that included information on the cows sampled, the herd and the history of mastitis in the herd. The samples were collected throughout the year. The mean incidence of clinical mastitis was 47 cases per 100 cows per year (estimated from historic farm records) and 71 cases per 100 cows per year (estimated from the samples collected). Streptococcus uberis and Escherichia coli were isolated in pure culture from 23.5 per cent and 19.8 per cent, respectively, of the clinical samples; 26.5 per cent of the clinical samples produced no growth. The most common isolates from the samples with high cell counts were coagulase-negative staphylococci (15 per cent), S uberis (14 per cent) and Corynebacterium species (10 per cent). Staphylococcus aureus and coagulase-positive staphylococci together accounted for 10 per cent of the samples with high somatic cell counts; 39 per cent produced no bacterial growth.     

Body Condition Change Ante- and Postpartum, Health and Reproductive Performance in German Holstein Cows

The effects of body condition score (BCS) change and status ante‐ and postpartum (pp) on health and reproductive performance in 234 German Holstein cows from eight dairy farms were evaluated. BCS was determined from 6 weeks antepartum until 20 weeks pp in 2‐week intervals. Three and 5 weeks pp progesterone concentrations in blood serum were determined to detect the presence of luteal tissue as an indicator of cyclicity. The incidence of various diseases, percent cycling cows, reproductive measures and culling rate were assessed. Data were subjected to logistic regression to account for possible herd and lactation number effects. Cows with a low BCS status (<3.0) at calving and during early lactation (4–10 weeks pp) were at a higher risk of suffering from lameness (OR 2.9–9.4), not being cycling at 3 and/or 5 weeks pp (OR 2.24–3.99) and being culled (OR 2.56–2.79) than cows in better body condition (≥3.0) In addition, cows with a low BCS status at parturition were at a higher risk of developing endometritis (OR 2.95) and becoming pregnant later than 105 days pp (OR 5.92) than cows with a BCS ≥ 3.0. At 10 weeks pp, the risk of dystocia (OR 4.10) or retained placenta (OR 2.78) at the preceding calving and not being pregnant at 200 days pp (OR 2.42) was higher in cows with a BCS < 3.0 than with a BCS ≥ 3.0. Cows with no BCS loss antepartum were more likely to have an interval from calving to first artificial insemination of <80 days and <105 days open, to be cycling at 3 and 5 weeks pp and to be pregnant at 200 days pp than cows with a BCS loss of >0.25 (OR 2.44–6.67). Furthermore, cows with no BCS loss from calving to 4 weeks pp had a lower risk of suffering from displaced abomasum than cows with a slight or a severe BCS loss (OR 0.09–0.07 respectively). In conclusion, our results suggest that body condition loss during the antepartal period affected BCS status at parturition and to a certain extent during lactation which was linked to a higher incidence of reproductive disorders and lameness, a higher culling rate and lower reproductive performance.     

Prevalence of subclinical mastitis and associated risk factors in smallholder dairy cows in Tanzania

A cross-sectional study was carried out on 200 randomly selected farms in each of the Iringa and Tanga regions of Tanzania to estimate the prevalence and risk factors for subclinical mastitis in dairy cows kept by smallholders. Subclinical mastitis was assessed using the California mastitis test (cmt), and by the bacteriological culture of 1500 milk samples collected from 434 clinically normal cows. The percentages of the cows (and quarters) with subclinical mastitis were 75.9 per cent (46.2 per cent) when assessed by the cmt and 43.8 per cent (24.3 per cent) when assessed by culture. Factors significantly associated with an increased risk of a cmt-positive quarter were Boran breed (odds radio [or]=3.51), a brought-in cow (rather than homebred) (or=2.39), peak milk yield, and age. The stripping method of hand milking was associated with a significantly lower prevalence of cmt-positive quarters (or=0.51). The cmt-positive cows were more likely to be culture positive (or=4.51), as were brought-in (or=2.10) and older cows.     

Seroprevalence of Neospora caninum and abortion in dairy cows in northern Spain.

The seroprevalence of Neospora caninum infection was estimated from a sample of 889 cattle from 43 dairy herds in three counties in the Asturias region of Spain. The true prevalence of infection was estimated to be 30.6 per cent (95 per cent confidence interval (CI) 27.6 to 33.6). Seropositivity was associated with abortion during the previous year (odds ratio (OR)=3.31, P<0.001) and was slightly higher among purchased cattle (37.6 per cent), than among cattle raised on the farm (29.1 per cent) (P=0.078). Seropositive cows were more likely than seronegative cows to have had a seropositive dam (OR=2.3, P=0.011), suggesting that congenital transmission contributed to about 56 per cent of the infections. Herds with a true seroprevalence above 10 per cent had more dogs on the farm, than herds with a lower prevalence (P=0.032). The ORS relating abortion to seropositivity in individual herds ranged from 0.7 to 19, indicating that some herds experienced few abortions caused by N. caninum, while others experienced more abortions due to the organism. Overall, 38.7 per cent of the abortions were estimated to have been attributable to N. caninum.     

Use of a heat detection paste on dairy cattle in France

The aim of the present study was to evaluate the merits of a coloured paste applied to cows as an aid to heat detection in a dairy herd. It was performed on 110 French Friesian cows under a loose housing system over one year. For comparison, the results of the previous year, with no paste application, were also computed. Results of heat detection by the herdsman and by paste removal were compared to expected ovulations assessed by regular rectal palpation and, or, plasma or milk progesterone patterns. The paste system improved the percentages of oestrus detection of post partum and post inseminated cyclic cows by 26 and 22 per cent respectively, compared to the previous year. Overall missed heat incidence was 15 per cent and over estimation was negligible (less than 5 per cent). The mean durability period of the paste in the absence of mounting was 13 days. This suggests that to achieve the above mentioned results, application of paste should be performed at least every two weeks when no previous heat has been recorded, or only once, two weeks after service to check for non-pregnancy.     

Effects of prostaglandin on the reproductive performance of dairy cows

A single injection of a synthetic analogue of prostaglandin F2 alpha (fenprostalene; Syntex) on the day of calving or between days 14 and 21 after calving did not affect the calving to first service interval, the number of services per conception or the conception rate of dairy cows. In a second trial, cows calved more than 45 days were injected once weekly with prostaglandin F2 alpha (dinoprost; Upjohn) or fenprostalene until served at the first detected oestrus. The calving to first service interval and the conception rate were not affected. Following injection of either prostaglandin, the spread in the pattern of onset of oestrus and the range in the proportion of cows (75 to 98 per cent) seen in oestrus within seven days were similar. This variation in the time of onset of oestrus after the administration of prostaglandin precludes limiting oestrus detection to four or five days per week, and is a major limitation to the use of prostaglandins in breeding programmes in dairy cows.     

Effect of three programmes for the treatment of endometritis on the reproductive performance of a dairy herd

Three management programmes to improve the reproductive performance of a dairy herd were compared in a prospective controlled field study on one commercial farm. A total of 542 cows were examined for endometritis 22 to 28 days postpartum and assigned to one of three treatment groups: in group 1 the cows with signs of endometritis were treated with an intrauterine infusion of 100 ml of a 2 per cent polycondensated m-cresolsulphuric acid formaldehyde solution; in group 2 the cows with signs of endometritis were treated with an intrauterine infusion of 125 ml of a 20 per cent eucalyptus compositum solution; and in group 3 all the cows were injected intramuscularly with 0.75 mg of tiaprost, an analogue of prostaglandin F2alpha (PGF2alpha) at two-week intervals, starting on day 43, until they were inseminated. Thirty-four per cent of the cows showed signs of endometritis. In group 3, oestrus detection efficiency was significantly higher than in groups 1 and 2 (P<0.05), the interval to first service was shorter, and the cows had fewer days open than the cows in groups 1 and 2 (P<0.05). The results indicate that management programmes based on the strategic use of PGF2alpha are an effective alternative to traditional programmes based on rectal palpations and intrauterine infusions to control endometritis at a herd level.