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This article was published in 1957
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INSTITUTE OF INSPECTORS OF STOCK OF N.S.W. YEAR BOOK.
Notes on Infertility in Dairy Cattle
A. V. MEDENIS, V.M.D. (Riga), Veterinary Surgeon, Gerringong.
From the economical point of view, every farmer wishes his cows to produce a calf in every 12 months in order to get the greatest return in the form of milk, with the least expenditure on food. If ideal conditions prevail on the farm this aim is not unobtainable, but to achieve the ideal breeding conditions one has to appreciate the common breeding troubles. These can be caused by:
1. Hormonal sub or hyper-functions.
2. Ovarian disorders.
3. Uterine; and
4. Vaginal abnormalities and abnormal functions.
The hormones are important in regulating the oestrus cycie. Ovaries produce two hormones; oestrogenic hormone for follicular growth stimulation and progesterone for corpus luteum (CL) maintenance. These hormones are governed by the anterior Pituitary (AP) hormones: F.S.H. and L.H.
Ovarian sub-function is marked in winter, especially in heifers. When there is a deficiency of green feed. The ovaries are small, both the same size usually and hard. Many animals so affected fail to come in oestrus; or if in oestrus fail to conceive. This ovarian hypo-function has been found through the whole herd on three farms at the end of summer. Heifers failed to come on heat, and although cows were in season they failed to conceive owing to lack of ovulation. Per rectum the ovaries were as described above; with very few palpable indications of any stage of C.L. The opinion was formed that this state of "quiescent ovaries" was due to a deficiency and, accordingly, it was decided to feed a mineral (Ca and P) and trace element (Co and Cu) mixture. In a very short time both heifers and cows showed normal signs of oestrus, and all conceived. Much more work would have been necessary, of course, to determine the exact cause of the mineral deficiency in the cases quoted, but Hignett (Vet. Rec., 62:652), describing P. deficiency diseases in New Zealand, refers to symptoms similar to those seen by the writer. However, a secondary cause, low nutrition, could be playing a part, but Hignett does state that high Ca can cause low fertility: and that the ideal ratio of CaO to P2O3. is 1:1. It is known, too, that follicle growth does not take place when there is a P. deficiency.
Davies (J.A.V.M.A., 897:450) claims that female cattle fail to come in season on Cu deficient pastures in the U.S.A. Both copper and cobalt deficiencies can be found on many of our South Coast farms, and consequently it is considered advisable to add both these trace elements to any mineral mixture supplied to correct ovarian function. In this connection, the present tendency to use Mo superphosphate for pasture growth well may prove to be the cause of some of our infertility troubles. Excess molybdenum decreases copper storage in the liver, so at least it would be wise to use the molybdenised super. with discretion.
On each of the three farms referred to, injections of stilboestrol or serum gonadotrophic hormone (P.M.S.) failed to produce normal oestrus and ovulation. However, in sporadic cases of quiescent ovaries (showing oestrus but failure of ovulation) best results were achieved with P.M.S. (1000 1.u.); about 75% showing oestrus with follicular development. Cases which received 30-50 mg. (according to size) of Stilboestrol showed clinical signs of oestrus but in 80% of these there was no follicular development; while only 75% continued the cycle. PMS is used also in cows which come in season but fail to show a normal development of the Graafian follicle, with consequent sub-normal ovulation. It must be noted though that this treatment must not be used during the C.L. phase; when it can cause a complete cessation of oestrus. Use P.M.S. only after the 17th day in the oestrus cycle, or immediately after enucleation of the C.L; and then serve or inseminate at the next oestrus.
Better feeding and an adequate supply of minerals will do much to prevent ovarian dysfunction (or semi-function); while it is recognised that vitamin A also plays an important part in reproduction. For this reason, when there is ample green feed (usually during the summer on the South Coast) both cows and heifers conceive more readily. On the other hand, when pregnancy does ensue, in the absence of sufficient vitamin A calves may be born dead, or very weak. On poor farms one has seen a succession of dead calves; until additional vitamin A was supplied in the feed.
On one particular farm it was noted that when there was a plentiful supply of subterranean clover the cows failed to conceive; though conception was normal during the following month-when the clover had died off. This suggests the presence of excess oestrogenic factors in the clover; causing an imbalance in the oestrogen-progesterone level. The ovum can be speeded down the tube by an excess of oestrogens. This results in failure of fertilization, or a too rapid passage to the uterus; with consequent degeneration.
Injections of oestrogenic substances such as stilboestrol fail to bring cows or heifers to a correct oestrus cycle when the ovarian hypofunction is due to mineral deficiency (e.g., phosphorus) or lack of vitamins; but is of real benefit when absence of oestrus is due to hormonal sub-function; for example, in old animals or during high production after calving.
Cystic Ovaries. The result of excess oestrogenic substances; where the tertiary follicle does not rupture. As a rule, the affected animal is in continuous heat; though several cases have been seen, especially when one ovary only was cystic, in which there were not any signs of either normal oestrus or nymphomania. In such cases the animals usually breed normally following squeezing out of the cyst. This sequence is considered to indicate that there was not any excess of oestrogen, but rather a subsidence of the hormone reproductive system; due probably to the high production of the animal. It is well known that nature tends to prevent reproduction in any animal in low condition, or in a stage of high milk production.
When the primary or secondary follicle becomes cystic, one finds the small cystic degeneration of the ovary; resulting in irregular, and mostly slight, oestrus. In this type, treatment usually is unsuccessful; in fact, in any cases of cystic ovaries the prognosis is unpromising.
Roberts (Cornell Vet., Oct., 1955) claims that of his cases (146) treated with sheep pituitary gonadotrophin, 71.2% conceived; while the conception rate was 75.6% following treatment with 2,500 to 3,000 i.u. of chorionic gonadotrophin (PU) intravenously. He claims, too, that the results were slightly better when cysts were not removed manually before treatment. This author states, though, that of these cases of cystic ovaries, 73.6% displayed nymphomania, while the remainder failed to show any oestrus. These latter (26.4%) could have been cases such as described above; in which the only abnormality was cessation of ovarian function at the follicular phase. As stated, these respond well to treatment; and so increase the percentage of recoveries. One's own experience is that such a high recovery rate (71-75%) could not be achieved in treating true cases of cystic ovaries.
Usually it is considered advisable to use smaller doses (500 i.u.) of P.U., and to repeat the injection weekly. However, as frequent visits increase the cost of treatment the usual practice is to inject 3,000 i.u. intravenously and express the cyst at the same time, if possible: repeating the treatment after one week. When the ovary shows any sign of a C.L. after this treatment, the indications are that the treatment will be successful. Express the C.L. and mate at the next heat period; usually on the third or fourth day after enucleation. In cases which did not respond to this treatment, the advice of German scientists (Goetze et al.) was applied successfully; that is, the use of vitamin E in the form of alpha-tocopherol via intramuscular injections (150-300 mg.). (Kuest and Schaetz also claim that high doses of vitamin E have a beneficial influence in controlling cystic changes in the ovaries.)
Corpus Luteum persistens. Occurs when the oestrus cycle is stopped at the C.L. phase or the C.L. persists in the ovary following death of the embryo.
Usually, expression of the corpus is sufficient to achieve a return to the normal oestral cycle, but one has found, especially on poor farms, that this retention is a quite common cause of infertility. The usual story by the owner is that the cow was served several months previously (probably six or seven), but is thought not to be in calf. Such cases make it advisable to recommend strongly that dairy cows should be checked for pregnancy regularly as a common practice. In every batch of animals, even on the best farms, one can find at least one cow thought to be in calf, but empty. Following discovery and treatment (probably merely by enucleation), the cow is ready for service or insemination, and an otherwise certain loss of lactation is avoided.
Cystic corpora lutea are not uncommon; a layer of C.L. tissue being found under the cyst. The animal does not come in season, but again enucleation of the mal-formation usually results in a restoring of fertility.
Delayed Ovulation. Ovulation takes place only after oestrus has ceased. In the cow it occurs 12-16 hours after the end of heat (J. Hammond, 1927; Cassida, 1942); in heifers, seven-nine hours. The normal duration of the oestral period is 24 hours, but often it can be 18 hours only, and sometimes less (Trimberger and Davis, 1943). Fertility is low when insemination or mating takes place at the onset of oestrus, rises to a peak at or just after the end of oestrus; not beginning to drop off until 8-12 hours after the end of oestrus. The growth and development of the Graafian follicle takes place during the last hours of oestrus, and can be determined by palpation per rectum. As the sperm remains capable of fertilizing the ovum for up to 28 hours only (Laing. 1945), it is of the greatest importance not to inseminate too soon after the commencement of oestrus.
In some cows the time at which ovulation occurs is delayed; the writer having found, in fact, Graafian follicles which have not burst 48 hours after the end of the heat period. Injection of small doses of stilboestrol or P.U. will promote the rupture of the ripe follicles (this treatment is particularly advisable in the mare; with a much longer oestral period). Goetze claims good results following rupture of the Graafian follicle by rectal manipulation about six hours after the end of oestrus; in cows serviced by a bull previously and which have failed to conceive on previous services and which are diagnosed as "repeat breeders".
Summarising, the best time for insemination is shortly after the end of oestrus; and for mating-second half of oestrus period. And it is well to keep in mind that where other causes of infertility cannot be detected, a large percentage of cases will be found due to ovulation abnormalities; either delayed or no ovulation at all.
Embryonic Death. Is a quite common cause of infertility in cattle. The normal conception rate after first mating is 55-65%, but it is considered that this does not represent the fertilization rate; this being much higher, 80% or more. This means that in normal conditions embryonic death can account for up to 25% of fertilizations. C.L. persistens beyond the normal oestral cycle (which is usually 21 days, with a variation from 18-24 days) is due to embryonic death; resulting from one of the following: defect in sperm or ovum, unsuitable tubal or uterine environment, or luteal deficiency. When after four days the tiny embryo travels down to the uterus and later endeavours to attach to the uterine wall, conditions must be suitable. Any factors which, in particular, tend to alter the pH toward the alkaline (spermatozoa survive in pH 7.4-6.4) will be unfavourable and the embryo will perish.
Following embryonic death, the cow usually will return to oestrus in 35 to 56 days, but there are many cases in which the cycle will not reappear for up to six months; there being a CL. persistens for this period.
Endometritis:
Although there are some less common but important causes, infertility in dairy cows results most often from conditions which set up pathological changes in the uterus. Inflammation of the uterus or endometritis is encountered very frequently in the normal dairy practice, and in a wide variety of forms, ranging from non-catarrhal to severe purulent and even septicaemic. Almost all forms are due to a uterine infection; becoming evident clinically following abortion and/or retention of the foetal membranes. In abortions resulting from a Brucella infection the membranes very seldom are expelled normally, and the natural course of events is invasion by secondary organisms, endometritis and infertility.
In the writer's experience Brucellosis is by far the most common cause of infertility. In fact, when this infection is brought under control or eradicated the conviction is that there will be a marked decrease in infertility cases. For instance, on one farm carrying 150 cows, and heavily infected with Brucella abortus, the normal expectation was about 25 abortions in any period of 12 months. All adult cattle were inoculated with Strain 19 as non-pregnant animals; while all heifers were inoculated both before and after the first calving. In addition, and of the greatest importance in any control programme, there was strict isolation of known carrier and all aborting animals until foetal membranes had been expelled or removed and discharges had ceased. This course of action reduced abortions to four only in the first twelve months; and to none at all in a period of three years. As a natural result of this decrease in abortions, and the consequent absence of retention of placentae, sterility cases on this farm decreased in three years by at least 90%.
Similar prophylactic measures on another farm in the same district produced a similar result. Brucella abortions disappeared completely.
In all cases of abortion, from any cause whatever, foetal membranes are retained in approximately 80%; and very seldom can be removed easily. It is considered that to use any degree of force in the removal is wrong: since as a result of the injuries which occur the natural protective barrier is broken, easy access for secondary invaders is provided and metritis, often severe, follows as a matter of course.
The treatment of choice is to insert proven anti-bacterial pessaries into both horns of the uterus. By the tenth day post-abortion or post-partum the dissolution and detachment of the caruncular stalx is complete and the after-birth, if still in one piece, can be removed manually with very light traction. However, some organic fluid or fragments of membrane will be left in the uterus; and will provide an excellent breeding medium for bacteria unless further treatment is carried out without delay. One further warning; up to 16 days postpartum the walls of the uterus remain soft and susceptible to injury. and during this time the use of strong disinfectant solutions, and even massage, is contra-indicated. After that time involution and demarcation have progressed so far that lavage and massage can be undertaken. The aim is to avert an endometritis, and to this end success can be expected following injection into the uterus of a mild disinfectant solution (such as a weak Lugol's) per catheter, and then massaging the uterus per rectum with the object of removing all foreign matter, and concurrent infective organisms. Among the latter, Corynebacterium pyogenes and haemolytic streptococci can cause very severe injuries, including ulceration, to the mucous membrane of the uterus; an irreparable endometritis often resulting if these organisms are not removed promptly.
At times a second treatment-irrigation and massage may be required. This is given at about 14 days after the first; the strength of the disinfectant solution being increased.
DRUGS. Preparations suitable for the treatment of endometritis are, in the writer's experience, comparatively very few. "Versotrane" is one which is compartively new, but which has had a very wide use during recent years. Personal opinion is that it is most effective in the treatment of purulent metritis; especially cases in which C. pyogenes is present. Good results have been obtained also with the use of Versotrane and Lugol's solution alternately in purulent cases; the latter used 14 days after the former being found normally to be suficient to resolve the inflammation,
"Lugols", which has been in use for at least 50 years, is the preparation of choice for the average case. It has been found especially effective in catarrhal metritis; since it not only influences beneficially the healing process in inflamed mucous membranes, but also has a powerful bactericidal action when used in correct concentration. In this regard there are various opinions; the proportion of lodine to potassium iodide to water varying with different "authorities" through the range from 1:3:100 to 1:3:400. Goetze, of the Hanover Cattle Disease Clinic, states that any solution weaker than 1:3:200 is ineffective; Kuest and Schaetz in their publication on Sterility in Cattle claim that best results are obtained with the 1:3:100 solution; but warn that when using Lugol's at this strength it is important to limit the quantity used not more than 4 oz. for heifers and, according to the size of the uterus, from 4 to 8 oz. only for cows. There are claims (Rowson Vet. Rec., 65 (1953)) that strong Lugol's itself can cause sterility, especially when applied during the C.L. phase, but it is believed that any such effect would be transient only; especially if the corpus were expressed at the time of treatment. It has been claimed also (Moberg-Vet. Rec., Febr., 1954) that strong Lugol's results in inflammation of the uterine tubes; this author warning against the use of any type of strong solution, for this reason.
One's own experience is that Salpingitis results from infective organisms ascending from the uterus; and that Lugol's, in controlling the infection, must at the same time assist in restoring the salpinx to normal status. In any case, however, if salpingitis is diagnosed it is advisable to warn the owner early that the prognosis is not good; and so avoid probable disappointment later.
When the present practice was commenced in the Gerringong area, 1:3:400 Lugol's was used. The strength was increased later to 1:3:200, but for the last two years the 1:3:100 preparation has been in general use; and it is believed that best results are being obtained from this strongest recommended solution.
Comparing one's personal experiences with these two preparations (Versotrane and Lugol's) most commonly used in the treatment of abnormal conditions of the uterus and salpinx, it is felt that too little thought is given to the histological changes occurring in the uterine walls and mucous membranes. In many cases of apparently resolved endometritis the mucous membranse still will not commence to secrete and function normally to the extent of enabling the attachment of a fertilized ovum; even though all organisms have been killed. In such instances there is a residual inflammation, causing a thickening of the walls which can be palpated per rectum. It has been found that such conditions yield most readily to treatment with Lugol's; the iodine having a unique effect in healing and restoring the pathological membranes to the normal state. On the other hand, Versotrane is considered to be contra-indicated in endometritis cases showing a low degree of secretion; due to possible adhesion of uterine or cervical endometrium, especially if some injury has been caused by the end of the catheter. In general, one's own experience has been that iodine activates the mucus production, and consequently the "cleaning-out" process; while Versotrane, probably through a protein coagulant action, suppresses secretion. This has been felt when passing the catheter through the cervix 7-14 days after Versotrane treatment; the cervical canal and the uterine horns giving the impression of being in a dry state.
Other preparations which have been used are glycerine, iodine plus glycerine, acriflavine, even saline solution alone; but the results obtained have not been encouraging. It must be remembered, of course, that all these drugs, as also Versotrane and Lugol's solutions, act on the living tissue as well as on the bacteria present.
In another group are the safe and non-irritating drugs such as the sulphonamides and the antibiotics; which act only in controlling bacterial growth and do not exert any direct effect on inflamed membranes. However, the marked bactericidal effect no doubt is the reason for good results obtained when treating with antibiotic or sulpha drug solutions the comparatively simple cases of infertility in which mucous membranes are functioning normally but bacteria are present and causing the death of male and/or female cells, or preventing nidation of the embryo.
It has been found that the most effective solution of these drugs is:
1 million units crystalline Penicillin and
1 gm. Streptomycin: dissolved in
30 ml. saline solution.
Then add sufficient 33⅓% Sulphadimidine to fill a 50 ml, syringe, and inject in the corpus uteri and both horns. Then massage thoroughly per rectum to ensure an even distribution throughout the uterus. (NOTE: Some workers have found ½ m. Penicillin sufficient in the above preparations).
It sterile water is used instead of saline, it has been claimed by Lindley (J.A.V.M.A., 924 (1954)) that conception rates are 10% lower; and still lower if the Sulphadimidine is not added.
This type of treatment can be carried out both before and after insemination (or service). Due to the fact that the spermatozoa reach the tubules in from 2 to 5 minutes, the infusion could be given safely at from 10-15 minutes after insemination; while as the fertalized ova does not reach the uterus until the fourth day, infusion is effective on the second or third day post-insemination. However, as there always must be a possibility that conception is not taking place because of the slowing down, or even destruction, of the spermatozoa by a uterine infection or bacterial toxins, one prefers to carry out "antibiotic" treatment before insemination. In fact, when called as one frequently is, to the cow which has returned for the third or fourth time and asked whether further insemination is worthwhile, the usual procedure, if the uterus appears normal on palpation, is to apply the antibiotic infusion at once; to save a further visit. This treatment has been found effective when given only four hours before insemination.
Infusion during the C.L. phase is considered by many authors to be inadvisable owing to excess progesterone activity, and the fact that in this phase conditions in the uterus are ideal for bacterial growth. Under the influence of oestrogens, mucin forms a barrier to infection, so if treatment is considered necessary at this time it is advisable to express the corpus luteum; with a view to inseminating during the next oestrus-in approximately four days. It is a fact, of course, that due to oestrogenic action an infection often will disappear during the course of several normal oestral periods This fact is the basis of control of Trichomoniasis; the infection disappearing from female animals given three months sexual rest; provided that oestrus is regular during that time. It has been found in practice, though, that irrigation of the uterus with Lugol's shortens remarkably the recovery time. On the other hand, experience has shown that a severe purulent metritis cannot be expected to clear up without irrigation; even though the C.L. periodicum is expressed to obtain the beneficial effect of a temporary excess of oestrogens, and the infected animal is in season regularly.
In enucleating the corpus luteum it is essential that this be carried out correctly; to avoid damage to ovarian tissue, and probable adhesion in the ovarian bursa and blocking of the Fallopian tube. If the C.L. will not slide out easily, as it usually will during the period 4-10 days after oestrus, do not use sufficient force to cause bleeding in the ovary. If difficulty is experienced and expression of the C.L. is considered advisable, wait for a more suitable time.
In earlier years it was quite a common practice when irrigating an inflamed uterus to express the C.L. at the same time. The trend at present is to avoid expression of the C.L. as much as possible; in fact, express only when really necessary. There are a number of cases, and every practitioner finds them, in which sterility results from adhesions of the ovarian bursa, or scar tissue formation after improper or too forceful enucleation of the C.L. Some authors (for example, Kuest and Schaetz) consider expression of the C.L to be contraindicated. However, since in every instance of differing opinions, there usually are two extremes, it has been found that a middle course can be followed with safety. When carried out correctly and at the proper time, enucleation can be effected without any damage. If the C.L. is not expressed the bactericidal effects of the natural oestrogens can be induced by injections of, for instance, stilboestrol. Firstly, though, the ovaries must be palpated to determine an exact diagnosis of their development; since if synthetic oestrogens are used in the follicular phase, cystic ovaries can result.
Whenever any treatment involving irrigation or infusion is undertaken, it is most necessary that strict attention be given to cleanliness. Use sterile instruments and wash the labiae thoroughly before introducing the catheter. In fixing the cervix the old method of grasping with forceps and retracting has been discarded in favour of holding with the hand per rectum; the latter method having been found much safer. Damage to the uterus is avoided and infection is not transferred from cow to cow; provided that a separate, sterile catheter is used for each animal. With the cervix grasped per rectum the catheter is unger good control throughout the operation and there is no danger of perforating, or even injuring, the uterine wall. If the catheter cannot be passed with comparative ease, do not use force. Defer the treatment until the next oestrus, when the cervix will be open and the catheter can be introduced with ease.
In passing, it is stressed that the necessity for strict cleanliness is essential also, of course, in artificial insemination. Any carelessness can, and does, lead to the introduction of infection mainly from the labiae-which may be responsible for non-conception, or death of the embryo.
Vaginitis. Inflammations of the mucosa of the vagina are in most cases a descending process from the uterus. When the uterus has been "healed". then also will the vaginitis disappear. An exception is found in a specific disease of the vagina, such as Granular Vaginitis, which is quite a common condition in dairy practice. It becomes manifest in cows as small granules on the mucosa of the vulva and vagina; in bulls on the sheath and glans penis. Troutman (J.A.V.MA, 924:184) followed the conception results in 4,616 cows, suffering from Granular Vaginitis and not treated before insemination, and stated that there were 68.9% of non-returns in cows free of the disease, 65.7% in mild infections and 58.1% in severe cases; demonstrating that in the latter cases only is the fertility rate lowered to an appreciable extent. It has been found that treatment of severe cases locally with various drugs does not influence resolution markedly: the uterus must be treated at the same time.
As a final remark, one must emphasize the absolute need for the keeping of records of every case treated. Quite often an animal is handled on several occasions, and over an extended period, before complete recovery is effected. Without a written record of the various treatments carried out, and the findings of each examination, it is impossible, when hundreds of cattle are handled each month, to maintain a picture of the progress of any particular case. Further, do not be afraid to vary the treatment in cases found difficult to resolve. Where one drug, however well proven, apparently is failing, change to another; even though the latter may not normally be favoured.