CATTLE PRACTICE VOL 5 PART 4 “Play the Odds to Get Results” Milk Progesterone Sampling and Fertility Control in the Dairy Cow Watson C.L., Wood Veterinary Group, 124 Stroud Road, Gloucester, GL1 5JN SUMMARY There is a definite need to find systems that will deliver “fixed” improvements in most large dairy herds. Routine veterinary fertility visits by their nature concentrate on individual problem cows but often fail to tackle overall herd management defects. A system of collecting milk progesterone samples (mps) was put in place on 2 large herds during the 1994/95 calving season. The normal routine visit protocol was left in place and progesterone samples were taken on days 0, 19, and 24 after service. The aim was to monitor heat detection, possible embryo loss and obtain a very accurate and early recognition of pregnancy and absence of it. All positive pregnancies were confirmed at a later date by manual examination. The system was then used to feed information back to the stockperson to improve fertility control. The results were:- ¾ accurate determination of the oestrous cycle ¾ more than 75% of all returns could be predicted ¾ improvements in heat detection of returns ¾ improvements in accuracy of heat detection ¾ very accurate early pregnancy diagnosis ¾ help quantify later embryo loss The sampling regime was also extended to supply progesterone results for “key” cows examined at the routine veterinary visit to improve diagnosis and treatment regimes. INTRODUCTION Routine herd fertility visits are now an established part of dairy cattle practice and though the national uptake is still only around 15% (Wassell and Esslemont 1992) they have now become a matter of course for the large dairy herd. There is however a great danger that too much effort is put into treatment of the individual without any consideration of overall performance. Individual diagnosis and treatment is the basis of any routine visit but without any thought of where they are going, or what they are achieving there is the danger of this crucial veterinary involvement becoming a missed opportunity. In this Gloucestershire practice herds are recorded in using the DAISY herd health programme (University of Reading and National Milk Records) and analysed regularly throughout the year for fertility performance and other health parameters. The aim is to encourage client involvement, generate enthusiasm and to assess the success or otherwise of the herd. Often the same basic faults show through in some herds - poor heat detection and poor conception rates. When looking at the performance of some herds it is difficult to see any change in response to fertility visits. Table 1 shows the overall level of performance in all the DAISY recorded herds in the practice. Table 2 shows the changes in a fairly typical large dairy herd over a 5 year period . It is difficult to see any benefit from veterinary involvement in this herd. The results for herd 4 show that fertility is deteriorating in key areas such as conception rate, and numbers of cows actually becoming pregnant. Much of this poor performance is due to outside influences such as quota management, cattle prices and changes in herd size but the end result is a considerable economic loss with increased calving to conception intervals and increased culling despite routine veterinary involvement There is the danger that veterinary treatment was concentrating too much on the individual and not tackling the main problems on some units - heat BCVA 1997 373
CATTLE PRACTICE VOL 5 PART 4 Table 1. All Herds 1991/92 1992/93 1993/94 1994/95 1995/96 DAISY AVG.* HERD SIZE 117 115 119 129 119 152 ALL SERVES P.R. 46 46 46 43 45 46 %CO of CALVED 81 76 77 76 (59)** 82 SERVES/CO 2.1 2.1 2.1 2.2 2.2 2.1 CA-CO 109 96 92 101 (91)** 99 HEAT DETECT. 47 48 48 48 55 Table 2 Herd 4 1991/92 1992/93 1993/94 1994/95 1995/96 DAISY AVG.* HERD SIZE 155 152 184 204 225 152 ALL SERVES P.R. 47 45 35 30 32 46 %CO of CALVED 88 80 85 83 76 82 SERVES/CO 2.1 2.1 2.8 3.2 2.8 2.1 CA-CO 111 112 111 131 132 99 HEAT DETECT. 42 36 52 55 48 55 *Average result from DAISY herds - DAISY Report No. 4 (Reading University) detection and conception rate. There is also a tendency to look at records and say “I told you so” instead of trying to get them to get positive improvement at the time. A system for assessing fertility management, and more important, capable of giving positive feedback of practical useful information was needed to try and control and improve the situation. The objective was a system to “play the odds” to get results using known established principles to give predictable results. Progesterone levels in milk have been recognised for many years as a possible key to monitoring fertility as it reflects what is happening in the cows ovaries (Laing and Heap 1971). A system of progesterone sampling simple enough to be done on the farm without any special control was used to firstly monitor what was going on in the herd and then to provide the stockperson with practical help to improve fertility. A trial study was carried out between February and May 1995 on cows presented for service on 2 large dairy herds in the practice. THE SYSTEM Milk samples were taken from the afternoon milking by air mixing the bulk milk jar and drawing off an aliquot of about 20 - 30ml of milk in a similar fashion to the routine milk quality recording system. This sample was then tested for progesterone by the use of a microtitre ELISA test kit with a strong visible pink indicator (Ridgeway Science - Dropper Kits, Alveney, Glos). High (H) and Low (L) levels of progesterone were determined purely from the visual colour change without the need for any plate reader to determine precise levels. Three categories of cows were tested :- 1. Cows observed in oestrous which were to be served (day 0) 2. Cows at day 19 after service 3. Cows at 24 days after service Lists for sampling were produced by a combination of the stockman determining the day-of-service cows (day 0) and the 19 and 24 day samples from a 2 weekly DAISY print out. A simple recording form was devised with a decision flow chart to summarise what action was needed in response to the progesterone results (See appendix). Weekly routine visits continued as normal with manual pregnancy testing being carried out between 38 and 45 days post service with individual problem cows being examined and appropriate treatments used. Some progesterone sampling of problem cows was also done. RESULTS The progesterone levels at these marker times fall into characteristic combinations. Table 3 Shows the Table 3. Number of cows sampled with the patterns shown and the actions taken BCVA 1997 374
CATTLE PRACTICE VOL 5 PART 4 DIAGNOSIS DAY RESULT 0 19 24 TOTAL RETURNA.I. MANUAL PD -ve MANUAL PD+ve RETURN L L L 17 11 6 0 RETURN L H L 5 0 5 0 PREGNANT L H H 48 0 1 47 INACCURATE HEAT H ? ? 2 2 0 0 number of cows sampled with the repeat services used and the result of manual Pregnancy Diagnosis (PD). BCVA 1997 1. Day 0 samples – these establish a starting point for defining the oestrous cycle. Without an accurate start then any samples taken subsequently are meaningless. It adds accuracy to the other samples taken. A Low reading at day 0 establishes a diagnosis of oestrous to start the cycle. A High at this point indicates inaccurate heat detection and means further samples are unnecessary. 2. The key samples are at day 19 and 24. These are the essential action areas of the system. 19 day 24 day Interpretation L L Predicted Return H L Non Predicted Return H H Pregnant From the progesterone patterns, the numbers of cows actually reserved and the manual pregnancy test it is possible to estimate the accuracy of heat detection, pregnancy diagnosis and the level of heat detection and possible embryo loss. Accuracy of :- • PD +ve by progesterone 98% • PD -ve by progesterone 100% • heat detection at day 0 service 97% • heat detection at return service 50% • Possible later embryonic loss 2% The overall performance of the herd over this calving season is shown in table 4. Table4. Herd 4 TRIAL 1994/95 All services PR 50% 42% CA-CO 104days % CO of Calved 75% Serves per CO 2.3 Heat Detection 50% 44% DISCUSSION The use of milk progesterone analysis succeeded in producing valuable information in key areas involving heat detection and Pregnancy Diagnosis. Such as :- 1. Accuracy of heat detection at service 2. Level of heat detection of repeat services 3. Quantification of possible embryo loss 4. Accuracy for both PD+ve and PD-ve 5. Prediction of return service The system was initially used to monitor what was happening in the herd as a means of investigating the poor fertility performance. Information was then fed back to the farm to produce results. Heat detection. Both accuracy and quantity of heat detection can be assessed from these results and it shows a quite surprisingly high level of accuracy in choosing cows for service. National figures suggest at least 10% of cows are not in heat at service but the level here is 3%. There is certainly a positive response from the cowman perhaps as a result of knowing he was being monitored but also possibly because he was given some enthusiasm to “beat the system” or simply increase his awareness of what was happening. Borsberry (1995) described this effect in dairy herds which changed to DIY AI. The stock personnel only served cows which were bulling as it was perceived as reflecting on their performance. The effect was to improve conception rates and herd performance. There is a significant increase in the pregnancy rate over the trial period in this study (50% versus 44%). The level of heat detection of return services during the study period was an improvement over the base level for the whole season (50% versus 44%). Again there is the factor that producing lists of cows to be 375
CATTLE PRACTICE VOL 5 PART 4 sampled at day 19 and 24 highlighted the fact that there was something to be looked for from these animals. It became obvious that there was a benefit in feeding information back to the cowman rather than simply trying to monitor the situation as this was likely to produce results rather than answers. The results show that 77% of all cows that did repeat showed a low progesterone level at day 19 and that this information could be used to highlight cows worth observing closely. Increased observation and heat mount detectors could then be used. Some authors have shown the possibility of using milk progesterone for actually detecting oestrous and determining the time for AI (Foulkes et Al, 1982, Foulkes 1986, and McLeod et al, 1991). This formed the basis of the DAISY “MOIRA” scheme (Williams and Esslemont 1993) to take over complete control of oestrous detection and insemination to prevent any human error or interference. The problem with this is the amount of work involved usually results in a lack of co-operation in the farm staff - without which the system will fail. This level of progesterone sampling was enough to interest and give encouragement without being a complication and confusion. The simple fact that a herdsperson can be alerted to the possibility of a cow likely to repeat in a period of a few days is extremely valuable. McIntosh (1984) and others inferred this effect with cows and heifers after prostaglandin treatment. There was an apparent lift in conception rate possibly due to the better observation and timing of heat. With this system of progesterone profiling used in this study it should be possible to achieve levels of around 80% for heat detection. Pregnancy testing. Milk progesterone samples (mps) were first commercially used to provide a pregnancy testing service. It proved to be a relatively inaccurate method for positive diagnosis based purely on a day 24 sample (77% - Esslemont 1995). Pregnancy testing is a vital function for improving herd fertility. Esslemont (1995) constructed a model to measure the cost benefits and effects of various PD strategies. The basic variables are :- 1. How soon 2. How accurate 3. What action to take The sooner a PD can be done the less likely there is for any loss in Calving to Conception interval. However there needs to be a high degree of accuracy if some treatments such as prostaglandin are to be used on negatives. There is also the question of embryo loss after PD and inaccuracies involved in early detection. Mee and others (1994) have used real time ultrasound scanning at between 28 and 42 days of pregnancy with results that show there is a 2% loss between scanning and 120 days with a further loss of 2% between 120 days and term. These sort of results are within what would be expected after a manual examination carried out later and thus the scanning showed the possibility of substantial financial benefit. However Logue (1994) has reported quite severe apparent embryo losses after scanning with 26% losses between scanning and term. There is definitely a need to assure that the early detection of pregnancy does not result in high levels of loss later, which would negate any benefits of early detection of negatives. The best option is an early PD with a high degree of accuracy, a follow up manual veterinary check on all positives for embryo loss, and an efficient treatment regime for negative animals to ensure early accurate re-service. In this trial the use of 3 progesterone samples at 0,19 and 24 days produced a very high degree of accuracy for PD. The spread of samples over 24 days clearly defined the normal cycle and allowed very accurate interpretation of the resulting pattern. Coupled with a later manual pregnancy detection on the positives and a system of handling the negative animals it helped lift performance. The system on negative animals was at first rather cautious and a non-aborting treatment regime was used. A progesterone device was inserted as soon as possible after the negative mps result which was left in place till the next routine when an early manual test could back up the diagnosis. A dose of prostaglandin was then given and the device removed 24 hours later. Some cows had the progesterone device in place for 12 days before removal without prostaglandin. With this level of accuracy the use of a prostaglandin alone at an early stage would now be considered. Routine policy without any mps information was that prostaglandin by itself was not used unless the cow was over 45 days from service. Esslemont in his calculations (1995) showed that the combination of an early PD, action taken on the negative cows and a follow up check at a later date on the positives could be worth £60 per cow. The aim is simply to reduce calving to conception interval by giving the empty cows more chances to become pregnant without being penalised by the possibility of later embryo loss. A further benefit from this sort of routine sampling was that it identified problem cows such as cystic ovarian disease and anoestrous cows when coupled with a fertility examination at the routine visit. Samples were also taken from problem cows (primarily “non bullers”) on the day prior to the BCVA 1997 376
CATTLE PRACTICE VOL 5 PART 4 routine visit, which helped with diagnosis and simplified treatment options. This technique showed a possible route for better control of herd fertility and could deliver guaranteed results such as 95% of the herd pregnant with a calving to conception interval of 90 days (calving index 370 days). REFERENCES Borsberry, S., Catle Practice (1994), 2:53 Esslemont, R.J. The Veterinary Annual (1995) 35: 243-280 Foulkes, J.A. State Vet. J. (1986), 40:31-39 Foulkes, J.A. et al, Vet. Rec. (1982), 111:302-303 Laing, J.A., Heap, R.B., Brit.Vet.J. (1971) 127:19-22 Logue, D. Vet. Rec. (1994) McIntosh,D.A.D., Lewis, J.A., Hammond, D., Vet. Rec. (1984) 115: 129-130 McLeod, B.J., et al, Anim. Prod. (1991) 52:1-9 Mee, J. Vet. Rec. (1994) Wassell, T.R., Esslemont, R.J., Vet. Rec. (1992) 130:260-263 Williams, M.E., Esslemont, R.J., Vet. Rec. (1993)132:503-506 BCVA 1997 377
CATTLE PRACTICE VOL 5 PART 4 System for sequence of tests and action to be taken. Day 0 is the day of service Day 19 and 24 are days after service Start the sequence again after any service. Any irregular bulling should be presented at a routine visit FLOW CHART DAY 0 H - put out at routine visit and DONOT SERVE L - test and serve DAY 19 H - No action L - Likely to Bull if L observe or apply Kamar - put out at routine visit if not served. Start sequence again if served DAY 24 H - will come up at Routine visit for PD > 42 days L - Likely to Bull if L observe or apply Kamar - put out at routine visit if not served. Start sequence again if served Summary DAY TEST ACTION NEXT STEP NEXT STEP 0 H DO NOT SERVE ROUTINE VISIT PD OR CHECK L SERVE DAY 19 TEST 19 H OK NO ACTION DAY 24 TEST L HEAT LIKELY KAMAR/OBSERVE SERVE - START AGAIN NO SERVE - ROUTINE VISIT 24 H OK ROUTINE VISIT PD AT >42 DAYS L NOT PREGNANT HEAT LIKELY KAMAR/OBSERVE SERVE - START AGAIN NO SERVE - ROUTINE VISIT Recording form Cow No. Day 0 Serve Day 19 Day 24 PD Result 23 1.1.97 L: 20.1.97 H 25.1.97 H 25.3.97 +ve BCVA 1997 378
CATTLE PRACTICE VOL 5 PART 4 Ultrasound Studies of Persistent Large Follicles (Follicular Cysts) in Cattle Noble K1 , Douthwaite R2 and Dobson H1 1 Department of Clinical Veterinary Science & Animal Husbandry, University of Liverpool, Leahurst, Chester High Road, Neston, S.Wirral, L64 7TE. Tel. 0151 794 6080 2 The Laurels Veterinary Centre, 4, Ryeland Street, Hereford. HR4 0LA. Tel. 01432 354433 INTRODUCTION Ovarian follicles are transient endocrine glands. The use of ultrasound since 1986, has allowed researchers to sequentially monitor the growth and regression of follicles in cows, and relate the development of normal follicles to their endocrine function. For example, the final maturation of the ovulatory follicle is dependant upon an increasing frequency of "pulses" of LH from the anterior pituitary, whereas ovulation is dependant upon a "surge" of LH. BCVA 1997 The most frequently recognised ovarian disorders in cows are cysts. A follicular cyst is traditionally defined as an anovulatory follicle, greater than 25mm that persists for at least 10 days in the absence of a corpus luteum. The following is a review of recent experimental work and its implications to the veterinary practitioner concerning :- 1. The aetiology of follicular cysts 2. Their changing structure and endocrine function 3. Prediction of the endocrine function of cysts at a single ultrasound examination 1. Aetiology of follicular cysts A normal LH surge response to oestradiol in cows develops within 30 days after calving (Alam and Dobson, 1987). However, Nanda et al. (1991) found that 50% of cows with naturally occurring follicular cysts failed to produce an LH surge in response to exogenous oestradiol. Clinical cases of cysts are presented an unknown time after cyst formation, and the absence of these LH surges may be due to the cyst itself or events that led to its development. Ribadu (1993) investigated the effect of ACTHinduced stress on the naturally occurring LH surge of the oestrous cycle. ACTH was given (100 iu, injected twice daily for 7 days starting on Day 15 of the cycle) to seven heifers. Treatment resulted in a reduction in LH pulsatility, absence of an LH surge and prolonged growth of a dominant follicle. In three heifers, a follicular cyst developed. The ACTH treatment elevated plasma cortisol values for 14 days, and there was a small increase in plasma progesterone concentration for 7 days. 2. The changing structure and endocrine function of cysts. An experimental model was developed to reliably induce follicular cysts and study their structural and endocrine progression in detail. Heifers were administered a gradually decreasing low dose of progesterone (0.5 PRID) from Day 15 (Harvey et al., 1996; Fig 1). In all treated heifers, a follicle developed to greater maximum diameter than control ovulatory follicles. These abnormal follicles persisted on the ovary for up to 50 days and had 2 distinct seqential phases:- i) Firstly functional - plasma oestradiol concentration was high and the follicle was functionally dominant (i.e. there was no development of additional follicles greater than 5mm on either ovary). ii) Then structural - the follicle was structurally present but additional follicular wave activity resumed; in some cases this resulted in ovulation of another follicle and formation of a corpus luteum. These functional and structural phases may explain the two types of responses of animals observed by Nanda et al. (1991). Animals with a functional, oestradiol-producing, follicular cyst being less likely to respond to exogenous oestradiol than those with cysts in the structural phase. 379
CATTLE PRACTICE VOL 5 PART 4 In addition, Noble (1996: Fig. 1) showed that oestradiol secretion from a functional cyst ceased when plasma progesterone concentration was slightly increased (0.5 PRID inserted on Day 15 and exchanged for a new, soaked 0.5 PRID on Day 28). This effect was probably due to the progesteroneinduced suppression of LH pulsatility required for oestradiol production. Spontaneous follicular cysts are often treated with exogenous progesterone. These may act by curtailing the function of the cyst on the first day of treatment and then synchronising the successive follicular wave. 3. Prediction of the endocrine function of cysts at a single ultrasound examination Of interest to practioners, based on the above information, Douthwaite (1996) showed that the functional status of spontaneously occurring follicular cysts could be predicted at a single ultrasound examination. Non-functional (structural) cysts were associated with the simultaneous presence of medium-sized follicles (>5mm diameter) and had lower plasma oestradiol concentrations than functional cysts (7.9 ± 1.8 pg/ml vs 19.5 ± 3.3 pg/ml, p < 0.03 ). In the presence of the latter there were no other follicles > 5mm on either ovary. CONCLUSIONS Ultrasound and endocrine studies on both naturallyoccurring and experimentally-induced follicular cysts are helping to explain clinical findings (e.g. the simultaneous presence of a cyst and a CL) and to understand the rational behind available treatment. A better understanding of cystic follicles will afford better diagnosis and treatment of clinical cases, and may ultimately aid in their prevention. ACKNOWLEDGEMENTS We are grateful to our farming clients for access to animals, and the technical staff of the Department of Veterinary Clinical Science & Animal Husbandry, University of Liverpool all of whom have put in such effort to help over the years. The work by Karen Noble and Ralph Douthwaite was undertaken in partial fulfilment of requirements for the DBR course, University of Liverpool. REFERENCES Alam, M. G. S. and Dobson, H. (1987). Pituitary response to a challenge test of GnRH and oestradiol benzoate in postpartum and regularly cyclic dairy cows. Animal Reproduction Science 14 1-9. Douthwaite, R. (1996) Bovine cystic ovarian disease : a comparison of different methods of diagnosis, and assessment of treatment with a PRID. DBR dissertation, University of Liverpool. Harvey D., Noble K. & Dobson H., (1996) Structure and endocrine function of persistent follicles in cattle. Proceedings of British Society of Animal Science Annual Meeting (poster). Nanda, A.S., Ward, W. R. and Dobson, H. (1991): Lack of LH response to oestradiol treatment in cows with cystic ovarian disease and effect of progesterone treatment or manual rupture. Research in Veterinary Science 51 180-184. Noble K., Harvey D., Tebble J., Deacon S., Jones N. & Dobson H. (1996). Structure, endocrine function and progesterone treatment of persistent follicles in cattle. Proceedings of 19th World Buiatrics Congress, Edinburgh 1996 (poster). Ribadu, A. Y. (1993). Ultrasonography and Endocrinology of Ovarian Cysts in Cattle. PhD Thesis, University of Liverpool. BCVA 1997 380
CATTLE PRACTICE VOL 5 PART 4 Do-It-Yourself Artificial Insemination:The Influence of the Number of Training Days Spent in an Abattoir with Access to Live Cows. Howells H.M.J1 ., Davies D.A.R2 ., Dobson H2 . 1 Four Dales Veterinary Practice, Station Road, Helmsley, York YO6 5BZ. 2 Department of Veterinary Clinical Science and Animal Husbandry, University of Liverpool, Leahurst, Neston, South Wirral L64 7TE. ABSTRACT Data relating to 14,258 inseminations performed in the first 3 years after training were collected by postal questionnaire from 94 DIY AI personnel within the UK. The mean calving rate from 14,528 inseminations performed by 94 DIY personnel on 92 farms in the first year after training was 59.4% (range 5% to 92%). In the second year (n=64), the mean calving rate from 11,515 inseminations was 62.3% (range 33% to 88%) and in the third year (n=49) 64.6% (range 41% to 92%) from 9,346 inseminations. There was a 5.2% increase in the mean calving rate over the three years with an overall mean calving rate of 61.5%. Each inseminator served an average of 172 cows (range 20 to 800) over the three year period. Thirteen instructors were responsible for the tuition, of which a mean of 2.88 days (range 0 to 5 days) per course took place in an abattoir with access to live cows. The number of training days spent in an abattoir with access to live cows significantly affected the calving rate achieved by the first year's inseminations. Within the range of the data, in the first year after training a 3.7% increase in calving rate was observed for each day spent training in an abattoir with access to live cows (p<0.0001). There were no significant effects on the outcome of the second or third year inseminations. INTRODUCTION The Chief Veterinary Officer's Annual Reports show that between 1984 and 1994 the number of Farm Storage Licence holders increased from 2,704 to 6,144. The continued demand for training suggests that owner/herdsman inseminators are achieving satisfactory results, but there has been little evaluation of the effectiveness of training courses. Legislation dictates that teaching should be spread over 5 days, trainees receiving lectures covering rudimentary anatomy and physiology, then practising with bench specimens before using live cows. The standard method of appraising trainees involves ''dye testing'' (Graham 1966). Reproductive tracts are recovered from cows inseminated with standard AI guns using plastic French straws filled with a distinct coloured dye. This facilitates individual evaluation of the distribution of the inseminate and assessment of trauma and other subtle faults in technique. Such a valuable aid to teaching assessment is unavailable when training ''On Farm''. Novice inseminators are inevitably slow. Prolonged manipulation of the reproductive tract per rectum causes discomfort and may lead to trauma to the anal sphincter or rectum. Injury to the reproductive tract may result in adhesions affecting the ovaries, ovarian bursae, Fallopian tubes or uterus, leading to subfertility. The present study stemmed from a conviction that regard for animal welfare dictates that instruction in the technique of rectovaginal artificial insemination should only be undertaken when there is a plentiful supply of cows which are destined for slaughter on the day on which they are used for training. The objective was assess the inclusion of a live cow component in training courses by examining consequent performance rates. MATERIALS AND METHODS A database of 542 farms thought to be practising DIY AI in the UK was compiled with the assistance of cattle breeding organisations. A questionnaire (Figure 1) was designed to collect data by postal survey between October 1994 and January 1995. Statistical analyses were carried out using the Minitab Release 9.2 software program. Categorisation of the qualitative data was checked by a second investigator to ensure that agreement of the distinctions and descriptions exceeded 70% (Riley 1990). RESULTS The mean calving rate from 14,528 inseminations performed by 94 DIY personnel on 92 farms in the first year after training was 59.4% (range 5% to 92%). In the second year (n=64), the mean calving rate from 11,515 inseminations was 62.3% (range 33% to 88%) and in the third year (n=49) 64.6% (range 41% to 92%) from 9,346 inseminations. There was a 5.2% increase in the mean calving rate over the three years with an overall mean calving rate of 61.5%. Each inseminator served an average of 172 cows (range 20 to 800) over the three year period. In each herd, the mean number of sires used was 7.5 (range 1 to 25), mean management policy for earliest service post-partum was 47.1 days (range 20 to 80 BCVA 1997 381
CATTLE PRACTICE VOL 5 PART 4 days) and the mean milk yield per cow per lactation was 6,310 litres (range 4,200 to 9,000 litres). Figure 1: Questionnaire to DIY AI trained personnel: Name and Address:...................................................................................................................................................... Please attempt to complete ALL questions. 1) What was the name of your course instructor ? .................................................................. 2) When did you train ? Month..........Year........... 3) How many days were spent in an abattoir with access to live cows ? ................................ 4) Which abattoir did you visit ? ............................................................................................ 5) How old were you when you trained ? Under 20 / 20-30 / 30-40 / 40-50 / over 50 years (please ring appropriate figure) 6) Have you attended a refresher course(s) ? If so please give date(s) ................................... 7) Do you serve cows (a) once daily ? * (b) twice daily ? * *delete as applicable 8) What is the earliest time after calving at which you serve cows ? ..................................... 9) Do you (a) block calve ? * or (b) calve all year round ? * *delete as applicable In the first year after training, (repeated for second and third years) a) How many straws of semen did you use ? ............... b) How many of these services were heifers ? ............ c) How many of these services were cows ? ............. d) How many different A.I. sires were used for these services ? .............. e) How many heifers gave birth as a result of your inseminations this year ? ........... (exclude calves born as a result of natural service or other A.I.) f) How many cows gave birth as a result of your inseminations this year ? ........... (exclude calves born as a result of natural service or other A.I.) g) How many heifers were inseminated by a commercial A.I. service ? ............. h) How many cows were inseminated by a commercial A.I. service ? .............. i) How many heifers were served by a bull ? .............. j) How many cows were served by a bull ? ............ Over these three years , what was your average lactation yield per head ? .......................... If you no longer practise DIY A.I., a) When did you give up ? ........................... b) Why did you give up? Please record your comments on a) The advantages of DIY A.I. as you see them................................................................................................................... b) Problems associated with DIY A.I. which you have encountered..................................................................................... BCVA 1997 382
CATTLE PRACTICE VOL 5 PART 4 Thank you very much indeed for your time and effort. Thirteen instructors were responsible for the tuition, of which a mean of 2.88 days (range 0 to 5 days) per course took place in an abattoir with access to live cows. The mean calving rate achieved by DIY AI personnel in the first year following training increased with the number of training days which the inseminator spent in an abattoir with access to live cows (Figure 2 ANOVA, p<0.01). The number of trainees who received 0, 1, 2, 3, 4 & 5 days of abattoir based training was 25, 7, 4, 10, 15 and 33; performing a total of 3,675, 1,101, 1,258, 1,529, 1,832 and 5,133 inseminations, respectively. Multiple regression analysis demonstrated that, of the variables considered, the only significant (p<0.01) influence upon the inseminator's calving rate achieved in the first year was the number of training days in an abattoir with access to live cows. The variables for which data was available accounted for 25.2% of the total variation within the sample. No significant effects emerged in the second or third year following training. Linear regression analysis within the range of the data revealed a 3.7% increase in the calving rate in the first year following training for every day spent training in an abattoir with access to live cows (p < 0.0001). This effect accounted for 18.0% of the variation in the calving rate. In the first year after training, the calving rate achieved by inseminators who had spent 5 days training in an abattoir with access to live cows (n=33 farmers; 5,133 inseminations) exceeded that of personnel taught entirely on farm (n=25; 3,675 inseminations) by 18.5% (Figure 3). In the second year, this difference diminished to 3.0% (n=28; 4,522 inseminations and n=11; 2,195 inseminations, respectively), but in the third year, increased to 7.7% (n=19; 3,085 inseminations and n=11; 2,149 inseminations, respectively). It was noted that only 31% of the respondents (29/92; 2 missing values) utilised DIY AI to serve heifers, and that less than 1% (1/149) had attended a refresher course. A total of 321 advantages of DIY AI were cited by the respondents (Figures 4 & 5). BCVA 1997 383
CATTLE PRACTICE VOL 5 PART 4 Table 1: Hypothetical farm with 50% Pregnancy Rate Service No No served Cumulative Services No Pregnant Cumulative Pregnant Calving to conception Total Calving Interval P (C-C) (PxC-C)+(Px280) 1 100 100 50 50 65 17250 2 50 150 25 75 86 9150 3 25 175 12 87 107 4644 4 13 188 6 93 128 2448 5 7 195 4 97 149 1716 6 3 198 1 98 180 460 Total calving Interval for year 35668 days Table 2: Hypothetical farm with 68.4% Pregnancy Rate Service No No served Cumulative Services No Pregnant Cumulative Pregnant Calving to conception Total Calving Interval P (C-C) (PxC-C)+(Px280) 1 100 100 68 68 65 23460 2 32 132 22 90 86 8052 3 10 142 7 97 107 2709 4 3 145 2 99 128 816 5 1 146 1 100 149 429 Total calving Interval for year 35466 days Improved timing of service, reduced stress caused by segregation from herdmates, savings made on AI fees and not having to waste time waiting for the AI technician to arrive featured prominently. In contrast, only 94 examples of problems associated with the practice of DIY AI were noted. Fitting one more job into a busy routine, the demanding nature of the task in the absence of a relief inseminator, difficulty serving maiden heifers and some cows, problems obtaining semen and lack of confidence appeared to be the most frequently perceived drawbacks. DISCUSSION A superficial examination of the relationship between calving rate and the number of abattoir-based training days suggests that there is little additional benefit after 3 days abattoir training. The relationship appears to be non-linear, but substituting exponential and natural logarithmic functions into the regression equation did not significantly improve the model. From the results of this study, personnel trained in an abattoir with access to live cows for 5 days would be predicted to attain a calving rate to all services of 18.4% higher in the first year compared to those trained only on farm. The effects on reproductive performance and financial consequences can be compared for a hypothetical 100 cow herd in which the average calving rate to all services is 50% or 18.5% higher (i.e. 68.5%) with the following constants: oestrus detection rate 100%, the average gestation length 280 days, the calving to first service interval 65 days and a management policy which allows 6 inseminations per cow prior to culling as barren. The calving index would be shortened by 9 days, semen usage decreased by 52 straws, 2 cows saved from culling and the calving period tightened by 21 days (figures in Tables 2 subtracted from Table 1). Assuming that each culled cow costs £770 to replace, each day added to the calving index costs £3 per cow (Esslemont and Kossaibati, 1995) and that the average price of the semen used is £10 per straw, the predicted improved calving rate would be worth £4,760 after the first year inseminations. No value has been attached to the 21 day tightening of the BCVA 1997 384
CATTLE PRACTICE VOL 5 PART 4 calving period and consequent saving in labour which results from reducing time spent on oestrus detection and serving cows. CONCLUSION The relationship between success and the number of training days spent in an abattoir with access to live cows was highly significant and provides a persuasive economic argument towards abattoirbased DIY AI training. From a consideration of animal welfare, training should be restricted to nonpregnant cull cows in the lairages of abattoirs as close as possible to the point of slaughter. Unfortunately access to cull cows has been restricted by the repercussions of the ''British beef ban'' (E.E.C. Commission Decision 96/239/E.C. as amended 11/6/96) and the demand for on farm training is likely to increase. ACKNOWLEDGEMENTS This study was undertaken in part fulfilment of the Diploma in Bovine Reproduction, University of Liverpool. The database was compiled with assistance from Avoncroft Cattle Breeders Ltd., Progen Ltd., Semex U.K. Ltd., and Taurus Cattle Breeding Services Ltd. I am grateful to Jack Astin for discussion and guidance on the treatment of the raw data. BCVA 1997 385
CATTLE PRACTICE VOL 5 PART 4 REFERENCES Esslemont, R.J., and Kossaibati, M.A., (1995), Wastage in dairy herds. DAISY report number 4. Graham, E.F.,( 1966 ) The use of a dye indicator for testing, training, and evaluating technicians in A.I. Proceedings of the first technical conference on artificial insemination and bovine reproduction, pp 57 - 60. Riley, J., (1990), Getting the most from your data: a handbook of practical ideas on how to analyse qualitative data. Technical and educational services, Bristol. BCVA 1997 386