Treatment of cystic ovarian disease in dairy cattle

Fourty-four Holstein Friesian cows diagnosed as having ovarian follicular cysts from rectal palpation of the ovaries and observation of estrous behavior were used for the present experiments. Of the 16 cows injected intramuscularly (i.m.) with 110 mg of depot-progestins containing 100 mg of 17alpha-hydroxyprogesterone caproate and 10 mg of progesterone in oil, 8 cows responded with conception with 103 +/- 53 days in average after the treatment. The 8 cows not responding to depot-progestins were injected i.m. with 6,000 MU of HCG on the 10th day after the treatment. As a result, 2 cows of them conceived within 72 days in average after the initial treatment. Of the other 16 cows injected i.m. with 100 mg of progesteron in oil, 3 cows conceived. Interval between the treatment and conception was 36 +/- 9 days in average. In the 11 cows which failed to respond to progesterone treatment, an intramuscular injection of 6,000 MU of HCG on the 5th day after treatment resulted in conception of 7 cows within 42 +/- 10 days in average after the first treatment. Of the remaining 12 cows which received an i.m. injection with 10,000 MU of HCG, 4 cows responded with conception with 64 +/- 51 days in average after treatment. No remarkable rise in serum progesterone levels was observed either 10 days after depot-progestins injection or 5 days after progesterone treatment. Serum progesteron levels increased distinctly after HCG injections. The combined treatment with 100 mg of progesterone and 6,000 MU of HCG at 5 days interval gave the most successful results and this treatment was effective even when performed long after calving. Thus this method of treatment of cystic ovarian disease may be recommended for practical application.     

The relationship between oocyte morphology and ovarian status in cattle

We investigated the relationships between oocyte morphology, follicular size and follicular waves using bovine ovaries derived from local abattoirs. Ovaries at the recruitment and selection phases contained larger numbers of oocytes with good developmental ability, although ovaries at the recruitment phase contained the largest numbers of follicles compared with ovaries at the selection and dominant phases. Dominant phase ovaries contained a high percentage of oocytes with as good developmental ability as selection phase ovaries; however, they contained the lowest total number of oocytes with good developmental ability. Small follicles under 3.0 mm in diameter contained large numbers of small and degenerating oocytes. In contrast, follicles more than 3.0 mm in diameter contained a higher percentage of oocytes with good developmental ability.     

Risk factors associated with cystic ovarian disease in Norwegian dairy cattle

Background

The aims of this study were to establish the incidence of cystic ovarian disease (COD) and its geographical and seasonal variation in Norway, investigate the effect of COD on culling rates, and describe the effects of COD on subsequent reproductive performance and its association to twins.

Methods

Diagnosis of COD was made by veterinary surgeons in the field. Four statistical models were made all including herd as random effect: The four different dependent variables investigated were: 1) Diagnosis of COD between 40 and 165 days in milk or not; (n = 511,657); 2) Twins or singleton; data restricted to lactations with new calving (n = 156,661): 3) Culling/removal or not (n = 573,184): 4) Culling due to reproductive problems; data included only lactations which ended in culling (n = 234,232). Model 1, 3 and 4 applied Cox regression models, and model 2 logistic regression. Independent variables were parity, twins/singletons, calving season, herd size, region, COD occurrence in present lactation (if not dependent), and COD diagnosis in previous lactation.

Results

The incidence was 0.82% per lactation. COD increased with increasing parity, was smallest at herd size between 35 and 85 cows. Cows in 1^st parity and calved in spring had lowest hazard of COD and hazard for COD diagnosis was highest in autumn with HR = 2.6 (1.9 - 3.4) compared to spring. There was an interaction between parity and season. COD incidence was lower south of 60°N. Cows which experienced COD had an increased odds of giving birth to twins OR = 2.2 (1.7 - 2.7). Of those that were culled, those with COD were culled more frequently because of reproductive problems; HR = 2.1 (1.9 - 2.3) for higher parity than 2. Having COD diagnosed in the preceding lactation was a hazard for diagnosis in the lactation studied.

Conclusion

COD diagnosis is strongly associated with season (autumn calving) and parity. Herds north of 60°N have more COD. Occurrence of COD is associated with twin births as well as culling due to reproduction.     

The relationship between estimates of ovarian size in live cattle and subsequent measurements post mortem

The reproductive tract of each of 122 cows was palpated transrectally by a veterinarian on the day before they were slaughtered, to obtain estimates of ovarian size and to identify palpable ovarian structures. Reproductive tracts were then retrieved post mortem. Ovarian volumes were recorded and compared with in vivo size scores (coded 1–5; 1 being the smallest). Ovarian volumes averaged 4.0 ml (score l), 7.0 ml (2), 10.0 ml (3), 12.9 ml (4) and 15.9 ml (5). There was a linear increase in ovarian volume of 3.0 ± 0.1 ml per score unit (r² = 0.792). The curvilinear regression included a significant quadratic term (p<0.05), but only accounted proportionally for an additional 0.003 of the sums of squares. Ovarian size score was about proportional to volume and could be used as a non-surgical technique to measure ovarian volume in live cattle.     

The relationship between estimates of ovarian size in live cattle and subsequent measurements post mortem

The reproductive tract of each of 122 cows was palpated transrectally by a veterinarian on the day before they were slaughtered, to obtain estimates of ovarian size and to identify palpable ovarian structures. Reproductive tracts were then retrieved post mortem. Ovarian volumes were recorded and compared with in vivo size scores (coded 1-5; 1 being the smallest). Ovarian volumes averaged 4.0 ml (score 1), 7.0 ml (2), 10.0 ml (3), 12.9 ml (4) and 15.9 ml (5). There was a linear increase in ovarian volume of 3.0 +/- 0.1 ml per score unit (r2 = 0.792). The curvilinear regression included a significant quadratic term (p<0.05), but only accounted proportionally for an additional 0.003 of the sums of squares. Ovarian size score was about proportional to volume and could be used as a non-surgical technique to measure ovarian volume in live cattle.     

提高乳牛奶产量和奶品质的几项措施

自三鹿奶粉事件以后,人们对牛奶的品质要求更高,养牛户对乳牛的产奶量更加关注,那么我们怎样做才能更好的提高乳牛奶产量和奶品质呢?科学的饲养管理是提高乳牛的奶产量和奶品质的主要途径,喂给丰富的、易消化的饲料,可提高奶中脂肪和蛋白质的含量.     

不同粗饲料对奶牛乳产量和乳成分的影响

选择18头荷斯坦奶牛,设置3个处理,每个处理6个重复,每个重复1头奶牛,研究不同粗饲料对奶牛泌乳性能和乳成分的影响,3个处理的粗饲料分别为玉米秸(Ⅰ组)、玉米秸+青贮玉米秸(Ⅱ组)、羊草(Ⅲ组)。试验结果表明:①试验Ⅱ组与试验Ⅲ组平均产奶量差异不显著(P>0.05),试验全期分别比Ⅰ组提高了8.82%(P<0.05)和9.57%(P<0.05);②不同处理间的乳糖、乳脂含量差异不显著(P>0.05);对于乳蛋白,在试验40d时3个试验组差异不显著(P>0.05),在第15d时Ⅱ组、Ⅲ组分别比Ⅰ组降低了7.43%(P<0.05)和8.57%(P<0.05)。对于乳干物质,Ⅱ组与Ⅲ组差异不显著(P>0.05)。根据上述生产性能指标综合评定,玉米秸+青贮玉米秸可有效替代羊草饲喂奶牛,而不降低泌乳性能。     

Retrospective analysis of the efficacy of different hormone treatments of cystic ovarian disease in cattle

Cystic ovarian disease in cows was treated either with a single intramuscular injection of 500 micrograms cloprostenol, a prostaglandin F2 alpha analogue, in 77 cases of luteal cysts or with 500 micrograms gonadorelin or 20 micrograms buserelin, gonadotrophin releasing hormone or its analogue (GnRH), in 116 cases of follicular cysts. Recovery was defined as the absence of cysts and the formation of a corpus luteum either with or without observed oestrus within 10 days after treatment with cloprostenol and 15 days after treatment with GnRH. Recovery occurred in 65 per cent and 52.6 per cent of cases, respectively, in average times of 4.9 and 19 days. Fifteen days after treatment with GnRH, 20 cows with luteinised cysts were treated with cloprostenol and 15 recovered in a mean of 20.4 days, while 10 which still had follicular cysts, were given GnRH and one recovered 31 days after the beginning of treatment. Another 27 cows, in which cysts became luteinised, were treated with cloprostenol seven days after treatment with GnRH to give quicker (average 11.5 days) but poor (48 per cent) recovery and with a higher rate (33 per cent) of recurrence of cysts. A progesterone releasing intrauterine device was used in 25 cases of cystic ovarian disease, some of which had been previously treated. Sixty-eight per cent recovered in an average of 15 days. The proportions of cows becoming pregnant to one to three inseminations after the different methods of treatment were similar (77 to 94 per cent).(ABSTRACT TRUNCATED AT 250 WORDS)     

The complex relationship between welfare and reproduction in cattle

Using reproduction parameters as indicators for cattle welfare has limitations and, at best, these parameters should only be viewed as indirect indicators of welfare. On a farm level, measures such as fertility rates emphasize biological performance of the herd but fail to consider the welfare of individual animals. Even on an individual level, the relationship between reproductive effectiveness and animal welfare is complex. Good reproductive performance does not automatically signify good welfare, as domestication and targeted breeding programmes have led to prioritization of high productive and reproductive performance in most modern farm animal species. In this review, we synthesize literature regarding cattle husbandry, reproduction, welfare and their multidimensional relationships. We argue that practices such as artificial insemination or the use of sexed semen may provide potential welfare advantages as these practices reduce the risk of disease transmission and injury or enable selection of specific beneficial traits. Furthermore, they may offer a solution to current practices jeopardizing welfare, such as the management of surplus bull calves in the dairy industry. Conversely, the animals’ ability to perform natural behaviours such as oestrous expression, an aspect arguably contributing to welfare, is often limited on commercial farms; this limitation is particularly evident in housing systems such as tie stalls where movement is restricted. Moreover, common management practices such as oestrus manipulation may lead to negative attitudes in citizens who often regard naturalness as important element of animal welfare.     

The relationship between feeding and fertility in dairy cattle]

The possible relationship between nutrition and fertility in dairy cows are reviewed. Study of the literature shows that opinions on the effect of the various nutrients differ markedly. The conclusion which can be made is that in countries where standards of dairy farming are high, nutrition only plays a minor role in the problem of herd subfertility. In the course of time deficiencies in a large number of minerals, trace elements and vitamins have been stressed as a cause of inadequate fertility. However cows are at present generally fed with a lot of well balanced concentrates and therefore deficiencies are very unlikely to occur. During early lactation every high producing dairy cow has a negative energy balance. In a number of cows this results in anoestrus and in a long interval from parturition to first insemination. Overfeeding during late lactation and the dry period does not adversely affect subsequent reproduction but may cause puerperal disorders. The relation between protein nutrition and fertility is complex. Protein effects on fertility are minor. Problems can arise if there is a combination of a high percentage of crude protein (greater than 18%), a high rumen degradability of the protein and a low energy content of the diet. The value of metabolic profile tests is minimal because they do not differentiate between normal herds and herds with fertility problems.     

Cytoplasmic genetic effects on preweaning growth and milk yield in Hereford cattle

Performance records on Hereford cattle raised in two herds were used to evaluate cytoplasmic genetic effects on preweaning growth and milk production. Animals were traced through maternal lineage to foundation females to form cytoplasmic lines. Growth records were available on 1,189 calves at Raleigh and 1,599 at Plymouth representing 27 and 15 cytoplasmic lines, respectively. Milk records were available on 418 cows at Raleigh and 522 cows at Plymouth, representing 20 and 13 cytoplasmic lines. After adjustment for sire, cytoplasmic effects were significant for birth weight (BWT), average daily gain (ADG) and 205-d weight (WT205) in both herds. Cytoplasm accounted for 2, 5 and 5% of the variance for BWT, ADG and WT205 at Raleigh; and 1, 2 and 2% of the variance at Plymouth. After addition of maternal grandsire to the model, cytoplasm was still significant; however, variances were reduced at Plymouth. Cytoplasmic effects for milk yield were important at Raleigh (P less than .01) but marginal at Plymouth (P = .10). Variance components for cytoplasm accounted for 4 and 1% of the variance for milk yield at Raleigh and Plymouth, respectively. Ranges for least-squares constants for cytoplasmic lines corresponded to one of two standard deviations. Correlations among least-squares constants for ADG, WT205 and milk yield were high, suggesting that cytoplasmic effects were mediated through milk production. More research is needed to confirm these results before cytoplasmic inheritance is considered in breeding programs for beef cattle.     

Bovine respiratory syncytial virus reinfections and decreased milk yield in dairy cattle

Summary

The influence of Bovine Respiratory Syncytial Virus (BRSV) reinfections on the daily milk yield was studied by evaluating the milk production of 32 BRSV reinfected cows. For the estimation of milk production losses, four lactation curve models were used, including a gamma function, a second degree polynomial, and both of these models with a lag variable. Bovine respiratory syncytial virus reinfections seemed to have only a small effect on the daily milk production. Comparison of the true production with an estimated production according to the gamma function showed that the production for first lactation cows dropped 0.14 kg on average and for cows in their second or later lactation 0.56 kg on average, during 5 consecutive days in the infection period. For the second‐degree polynomial model these values were respectively 0.42 kg and 0.80 kg. All calculated average production losses were relatively small and not significant (P>0.15). The models without lag variable were more suitable than the models with the lag variable to estimate small production losses caused by BRSV reinfections. The power of this study was sufficient to detect a decrease in production of approximately 1 ‐ 1.5 kg milk per cow per day. It was therefore concluded that BRSV reinfections were not associated with an important loss of milkproduction.     

Chronic cystic ovarian disease in a Holstein cow

Cystic ovarian follicles are commonly found during rectal examination of early postpartum dairy cows, usually presenting with anoestrus and occasionally nymphomania. Most cases self cure with time, or respond to exogenous hormonal treatment. This case report describes a refractory case in a Holstein cow in which a novel treatment approach was used. A gonadotrophin releasing hormone agonist implant was inserted for 180 d in an attempt to suppress pituitary gonadotrophin output, arrest abnormal ovarian follicle growth and prevent steroidogenesis. Frequent serial blood samples were collected before and after implant insertion to monitor changes in pulse release of luteinising hormone. Follow up ultrasound scans and blood samples were done to monitor ovarian structures; progesterone and oestradiol were collected at various times over the 180 d period. A normal, cycling herdmate was enrolled as a control. Prior to implant insertion, high frequency and low amplitude luteinising hormone pulses were detected in the cystic cow. Insertion was followed by a sustained surge in the release of luteinising hormone in both cows, but ovulation was not induced in the cystic cow. Plasma oestradiol levels remained consistently elevated and signs of oestrous behaviour were observed. Long term gonadotrophin releasing hormone agonist treatment failed to suppress either ovarian steroid production or cause regression of the cysts by 180 d.     

The relationship between packed cell volume and the course of disease in milk fever in dairy cows

Results from a field investigation involving 1086 cows with clinical milk fever, revealed a clear relationship between PCV at the time of first treatment and the subsequent course of the disease. Average PCV was progressively higher as the cows required one, two, or more than two treatments before recovery, and was highest in cows which subsequently failed to recover. PCV in healthy, periparturient cows was considerably lower than in cows with milk fever. PCV was negatively correlated with plasma Ca, and varied, moreover, with the time of first treatment in relation to calving, and also with the length of time the cow had been recumbent before being treated for the first time. PCV was also measured during the further course of the disease in cows which received more than one treatment (2nd to 6th treatments).     

Prostaglandin treatment and subsequent cystic ovarian disease in Holstein cows

Using computerized herd health data, a prospective cohort study was devised to determine whether cows treated with prostaglandins had a higher incidence of cystic ovarian disease than comparable cows not treated. Of 744 cows selected as having diseases for which prostaglandin administration may be indicated, 240 received prostaglandin. Sixteen cows had cystic ovarian disease following prostaglandin administration. Chi-square analysis showed no association (P greater than 0.10) between cystic ovarian disease and the use of prostaglandin. Incidence of cystic ovarian disease within 150 days of calving in clinically normal cows was compared with that of cows with reproductive disorders. Cows with reproductive disorders had a significantly (P less than 0.01) higher incidence of cystic ovarian disease.