Section 3

Reproductive Management Programme

 

Pragati Buffalo Farm is a commercial farm with 300 buffaloes. Last year, the farm faced problems of utero-vaginal prolapse in more than 20 per cent animals and lower pregnancy rate (less than 50 per cent) in spite of using bulls for natural service. Visits of veterinarians for treatment were not of much help and many animals became repeat breeders due to chronic endometritis. The problem persisted even after prolonged treatment with antibiotic and many buffaloes had to be culled. The farm ultimately closed down due to heavy economic losses.

The Bhagyoday Dairy Cooperative Society (BDCS) consists of 300 farmer-members tending to 2,000 dairy animals as primary vocation since agriculture is irregular as the area is drought-prone. On an average farmers hold 5-7 crossbred cows/buffaloes. Considering the enthusiasm and commitment of these farmers, a bank has provided credit to purchase additional crossbred animals to increase income and boost milk production. Things were fine in the first six months as animals were producing milk and the farmers were receiving regular income. Suddenly the farmers realised that even post-mid lactation very few animals were pregnant. Conceptions rates were low since many animals required 5-6 AI per conception. Many animals had open period longer than 140 days and more than 60 per cent of those remained unbred post-calving. The farmers are worried that once the animals go dry there will be no income to repay the loan.

Fertility problems are not very uncommon in dairy animals but it is very difficult to get such farms or farmers out of crisis situation once the damage is already done and the recovery would require additional investment and longer time. The Pragati Farm initially did not investigate the problems properly but relied on AI technicians and para-vets and spent lot of money on drugs. Later investigations revealed that the problem was associated with feed containing 26 per cent crude protein. This led to high blood urea (detected as milk urea). When protein content in feed was brought down to 16 per cent, the problem appeared to be resolved but it was already too late. In case of BDCS, the problem was found to be longer post-calving wait period and after educating the farmers on this aspect the calving to conception interval and pregnancy rates increased significantly.

These two cases emphasise the importance of proper investigations of herd fertility problems focused at detecting the root cause and associated factors to develop rational long-term strategy to address the current issue and prevent occurrence of the problem in future. Since dairy animals produce milk only after calving, it is important that estrus is detected regularly, animals are bred at right time and pregnancy is ensured in minimum services within a stipulated time (calving to conception period). If conception is delayed there are more open cows which affect milk production efficiency. Many farmers think of only milk production without bothering about the lactation length. They are under a myth that longer lactation length would mean more milk production hence insemination after calving is delayed inordinately.

Reproductive inefficiencies have profound adverse impact on farm economics. For example, with longer lactation length, milk yield per day would decrease and more cows/buffaloes would remain open and dry period would also be longer (see Box).

Put it in Box

Consequences of low reproductive efficiency in dairy animals

  • A false impression of increase in milk production.
  • Long calving interval results in more milk in lactation but less milk per day of life because cows spend more time in late lactation and dry period.
  • When calving interval is long fewer calves are born so culling is slow and genetic progress is slow.
  • Culling due to reproduction failure is high so increased cost of replacement.
  • High veterinary, semen costs, over conditioning of cow/buffalo due to long dry period.

 

If cows or buffaloes are not pregnant beyond the stipulated period, farmers are forced to exercise either dry off the animal since milk yield has gone down substantially, or, continue to milk even though milk yield is less. In both cases, farmers are at loss. An intelligent dairy farmer should strive to have high milk production and restrict average lactation length to between 305-330 days without compromising on average dry period. Efficient reproductive management leads to a number of benefits, such as reduced culling rate, reduced cost of treatment in repeat breeders, earlier first calving heifers for replacement and faster genetic improvement. It has been demonstrated globally that to increase farm efficiency and profitability, the easiest and practical way is to improve reproduction. To achieve this, farmers and the veterinarians will have to go beyond the traditional passive crisis management approach to a holistic ‘Reproductive Management Programme (RPM). This programme encourages planned efforts to achieve: (a) predefined breeding targets, and, (b) reduce reproductive disease problems at herd level to prevent the use of drugs, hormones, etc. The programme consists of following components:

  1. Record keeping and data interpretation

Figure 8: Herdman screen of a buffalo file showing the lifetime events such as dates of first estrus, all AI, all PD tests, abortions, calving, drying off, etc.

 

 

RMP is a proactive programme focused on detection of reproductive problems and inefficiencies before these are expressed as clinical symptoms. The problem detection in initial stage is based on trend analysis for which it is critical to collect as much breeding records as possible from individual cows and buffaloes. This is followed by periodic analysis to understand the problems. The web-server version of software ‘Herdman’ described earlier is quite convenient to achieve this objective. As shown in Figure 8 the individual animal file provides access to registered animals’ lifetime of breeding and other events. The programme also generates daily action and alert lists based on analysed information which is communicated to registered farmers and veterinary service providers. The data can be analysed periodically for breeding performance as shared with the farmers and the veterinarians. Advantage of this approach is that with availability of real-time records rational decision support based on accurate diagnosis is possible.

  1. Set up RMP targets

It is important that commercial or cooperative dairies first decide on fertility goals and targets. The basic objectives of reproductive management are to have first calf born to heifers at 26-30 months in cow and 36-40 months in buffalo. In breeding animals, calving to conception period of 110-120 days and calving rate of 85-90 per cent should be achieved. The overall reproduction planning can also be manipulated to get more cows in lactation during specific period when milk prices are attractive by synchronising estrus. The chronology of planning is: first set up record keeping system, analyse the data to generate benchmark status and based on this and economic feasibility set up breeding efficiency targets. Table 5 gives details of various parameters, indices and the target values in cows and buffaloes. The targets provided are not absolute and should be based on benchmark values at the time of first analysis. These can be revised periodically as the targets are achieved.

  1. Scheduled examination of animals

To develop and implement a sound pro-active system, a schedule for regular reproductive examination by expert veterinarian should be put in place to ensure that animals with underlying problem do not go undetected. The examination of animals is recommended at the following stages of post calving:

  1. At 45-60 days for cows/buffaloes that have not shown heat symptoms, they should undergo per rectal or sonography examination to ascertain post-parturient infection/abnormalities.
  2. At the stage when animals are not bred for >90 days post-calving for ovarian and uterine status.
  3. At 45-60 days for cows and buffaloes inseminated but having not returned to heat since then, for pregnancy check, ovaro-uterine pathologies.
  4. Animals that are negative at pregnancy check should be thoroughly examined to evaluate the status of ovaries and uterus to identify if the problem is due to animal factor or heat detection.
  5. The window period 7-10 days post-calving and 21-40 days post-calving are also important to detect animals with problems of metritis or endometritis.

In addition to above scheduled examinations cows or buffaloes that had abortion, retained placenta, uterine infection with abnormal discharge or abnormal length of estrus cycle, should be flagged and examined at the earliest. A red to reddish brown discharge from uterus is normal during 7-14 days after calving but if this persists beyond two weeks and has abnormal color or smell, such animal must be examined thoroughly. Although AI technicians and para-veterinarians services can be availed for AI and pregnancy checks the pathological conditions should be handled and treated by expert veterinarian only.

  1. Improved estrus detection

For accurate estrus detection, committed management staff is necessary. This is the single most crucial factor that can derail the reproduction targets of the farm. In many cases problem of sub-fertility is not due to pathologies but faulty estrus detection. Estrus detection efficiency in the farm can be improved by using breeding calendars, to predict the estrus day for each cow. This is a cumbersome and manual method hence not popular. The ‘Herdman’ software offers facility of generating daily action list of animals expected to be in estrus and accordingly the predicted animals can be observed or examined for heat. For intensive mechanised dairy farms pedometer can be used but for buffaloes these are not yet standardised. For use of pedometers precondition is that animals are not tied but reared loose. The time of taking round of farm for estrus detection is also critical. Estrus detection routine must be when animals are resting and ruminating after the feeding session since estrus discharge can be observed. When the animals are loose, mounting behavior is also indicative of estrus. From data analysed for various dairy cooperative it became evident that apart from feeding, two major causes of sub-optimum fertility are: (a) faulty voluntary wait period (short or very long) and (b) not proper heat detection by farmers and not carrying out AI at the correct time.

Voluntary wait period (VWP) is the period after calving to the time when it is bred for the first time. For VWP there are no industry standards. The guiding objective is to keep balance between fertility and milk production. After calving the cow/buffalo achieve peak milk between days 40-60 post-calving and the peak is maintained up to 100-110 days with gradual and regular decline until the animal is dried. General principle is that animals should be mated in last part of the peak lactation coinciding with physiological decline. This is because pregnancy is antagonist to lactation hence if animal gets pregnant there would be some reduction in milk production. Considering that a cow/buffalo after calving would express first heat on day 30 the subsequent three estruses would be on days 51, 72 and 93 days. If first two estruses are skipped and the cow is mated on third estrus (day 72) the animal is likely to conceive (implantation) around 100-105 days. If the cow is inseminated on fourth estrus (day 93), conception would be somewhere around 110-115 days in milk. In both cases it would be past peak period hence would not lead to drastic decline. In high yielding animals with consistent peak yield first insemination can be delayed to fourth estrus and the first three estruses can be skipped. Most of the researchers agree that VWP in dairy cows and buffaloes should be between 70-90 days. In case it is delayed open period would be longer without any compensation in terms of milk production. In such cases, the dry period would also increase which will cause economic burden on the farmer. If VWP is shortened, then pregnancy would hinder peak yield.

If proper data is available, heat detection efficiency can be calculated using different methods. The first accurate method is to enumerate animals that have actually shown estrus and divide this number with the actual expected animals in estrus during the period. In a good farm, this ratio should be more than 0.7 and ideally 0.8. When a large number of animals are involved, enumerating cows expected in heat is difficult and time-consuming. In such cases it is advantageous to use ‘Herdman’ software which supports direct calculation.

The second method is to calculate proportion of animals diagnosed as negative at the time of pregnancy examination. For example, in a farm at the weekly visit of a veterinarian, 20 animals (after 40-45 days of breeding) were presented for pregnancy test, out of which 10 animals were found to be not pregnant. Here the ratio 10/20 (that is 0.5) would indicate proportion of animals not found positive is very high and indicates inefficient estrus detection system. This means that in those ten non-pregnant cows more than two estruses must have gone unnoticed. In a good farm, a target of 0.15-0.2 should be set. This simple calculation can be done each time a veterinarian is examining animals for pregnancy.

The third method to calculate average inter-estrus interval, is on the basis of 18-24 days but this can be confounded due to early embryonic deaths. The longer estrus intervals indicate problem in estrus detection in the farm whereas lower intervals indicate problems such as cystic ovaries. In larger farms or dairy cooperatives that are facing problem of repeat breeders and variable estrus periods, serum progesterone determination in cows/buffaloes on the day of estrus is an important investigation. The procedure is to collect serum of animals at the time of insemination and save it at -20oC. When sufficient samples are collected, these can be sent to laboratory for progesterone determination. On the day of true estrus, progesterone levels should be very low (almost zero). The proportion of animals that are having high progesterone would indicate the inaccuracy of estrus detection and time of insemination.

  1. Optimise nutrition and monitor adequacy

For efficient fertility management, nutrition plays an important role. Since nutrition is a common factor in the herd it will be regarded as common source. Such problems can be predicted during data analysis. For example, when mean value of a parameter is abnormal but the standard error is narrow (less than 20 per cent of the mean) it indicates common source factor. Sufficient literature is available to propose that high protein intake, especially rumen degradable protein, is an important factor compromising fertility in ruminants. In many organised farms the problems of repeat breeding were found to be associated with high protein content of feed leading to high blood urea. It is important to ascertain that feeding practices are balanced and that the farm is constantly monitored for inadequacies.

Feeding of low energy feed leads to low blood glucose that ultimately affects reproductive efficiency. Macro and micro mineral deficiencies have also been shown to adversely affect fertility. Special attention should be paid to phosphorus in feed. Our work has shown that in the event of phosphorus deficiency not only blood but even cellular phosphorus levels are decreased. Excess mineral mixture feeding is also harmful for farm animals.

The correct procedure is to ascertain if additional mineral mixture is necessary by running a major metabolic profiling. ‘The Metabolic Profiling Module’ of software ‘Herdman’ facilitates random selection of animals and also helps in data analysis. Many companies have now come up with area-specific mineral mixture which is a rational practice.

  1. Reducing infectious abortions

The farm should have a well defined policy of testing the herd animals and new entrants for diseases that lead to abortion. In this context brucellosis and leptospirosis are of economic importance to the farmers. The salient features of these diseases are given separately. Under Indian conditions culling of a sero-positive cow is always a problem. There is now scientific evidence that diseases such as brucellosis are self-limiting and hence there is no need to press for panic sale. Leptospirosis is curable if diagnosed and treated at an early stage. There are also other causes of abortions and in case of any problem the veterinarian can be consulted for diagnosis. In order to control these diseases yearly screening of animals by serological tests is necessary. Testing only once is not enough to label an animal positive; rather it should be done for at least three times and preferably with an additional high-specificity test, to confirm. In case of brucellosis since there is no national control programme and the issue of inability to cull cows (due to legal hurdle) the farmer is faced with a dilemma as to what should be done with a cow diagnosed positive for brucellosis. The veterinarian should ensure that reporting of sero-positive cases should not result in distress sale by the farmer which otherwise would result in dissemination of infections to new areas. At the dairy cooperative level bulk tank milk testing for brucellosis has been recommended in India. This avoids labeling animals as brucella- positive instead control strategy can be adapted for sero-positive villages.

 

  1. Monitoring herd reproductive health

After analysis of data and considering all the indices, it is easier to determine if a problem is common to herd or pertains to individual animal (if S.E. is less than 20 per cent of the mean it is considered as uniform, hence common). The veterinarian should become adept in handling data sorting and analysis for various factors and cut-off limits. For example once a problem is detected in a herd, data sorting can ascertain if the problem is in pregnant/open/lactating/dry groups. Its impact can also be assessed by analysing the same data for say 100-day milk production/peak yield/days-to-peak, etc. This helps in monitoring

the farm fertility performance on a continuous basis. To understand the underlying problems generating of profile graphs for fertility parameters is also helpful. The graph generated in ‘Herdman’ (Figure 9) illustrates herd profile pregnancy with number of AI/services. The data shows that with first AI around 64 per cent animals have conceived whereas with second AI additional 18 per cent animals (total 82 per cent) became pregnant. High conception rate in this farm was due to use of bull for natural service and reflects that bulls used in the farm are fertile. But this rosy picture changes if interval calving to first service and caving to conception is considered. The calving to first service period was calculated to be average >140 days which was quite long compared to the standard. This was also the reason for longer calving to conception interval. After introducing shorter VWP its impact can be assessed by monitoring calving to first service interval.

Figure 9: Herd profile for AI conception.

Monitoring herd for reproduction parameters also helps in assessing progress and impact of various fertility initiatives. Figure 10 illustrates profile of pregnant animals in a herd for various gestation phases. In a good farm distribution of pregnancies should be uniform in all phases to ensure calving and milk production throughout the year. The data shows that there has been fluctuation especially in the gestation phase 120-180 days which means that during last 3-6 months there were underlying problems due to which pregnancy rates have come down. The farm management can be warned that in next six months the calving numbers would decrease hence milk production will be affected.

Impact of management decisions implemented in the farm can be monitored by periodic data analysis by keeping an eye on herd indices. In order to monitor the herd’s reproduction efficiency the data can be converted to ‘reproduction performance indices’. The indices are for estrus detection efficiency, conception efficiency and management efficiency (Table 5).

Figure 10: Profile of animals for pregnancy phases.

  1. Strategic treatment

In farms or cooperatives, due to inherent shortfalls in management around the time of calving uterine infections such as endometritis are common. When there are cases of retained placenta and abortion chances that the animals would end up with endometritis are very high. In such cases early treatment is crucial otherwise it would lead to long open period. In farms where sanitation practices at calving are defective, strategic treatment with broad-spectrum antibiotics has yielded good results. Strategic use of drugs such as prostaglandins can be initiated to optimise uterine involution and estrus expression. This should be done in consultation with veterinarian and the matter should be evaluated from economic point of view.

In fast changing world when new concepts are setting aside old views in every field, reproductive health management of dairy cattle should also be redefined to make it more efficient. Dairying in India could become competitive and economical if our approach to veterinary and extension services is radically changed on the lines of those countries where time-tested preventive systems have been used.

Table 5: Important breeding indices and their interpretation.

Index

Description Target values

Interpretation

   

Cattle

Buffalo

 
Mean age at first estrus (months) It is the age at which heifers exhibit first estrus

10-12

14-18

This index indicates the heifer management programme in the farm, especially the heifer nutrition. If the period is longer, calf management and heifer nutrition aspects should be reviewed.
Mean age at first breeding (months) Age at which the heifer is first bred

15 -17

20-28

This depends on the age at which the heifer exhibits estrus and her weight at the time of breeding. Higher value indicates heifer nutrition problems.
Mean age at first calving (months) Age at which the heifer calves

24-26

30-38

This depends on the above two indices.
Mean days first heat after calving Number of days the animals exhibit first estrus after calving

21-30

21-30

This indicates the cyclicity in calved animals and largely depends on good peri-parturient practices and nutrition in early lactation.
Average calving to first breeding interval (days) Number of days after calving the animal is first bred

50-70

50-70

This largely depends on the voluntary wait period policy of the farm and the estrus cycle in animals.
Average days open The number of days animals in herd require for conceiving

110-130

120-140

The open period depends on number of factors, such as, first estrus and subsequent intervals, heat detection efficiency, conception rate, etc.
Mean calving interval (months) Average interval between two calving

13-14

18-20

This is regarded as the golden standard index for reproduction efficiency of the herd.
Mean first service conception rate (percentage) This indicates the number of animals becoming pregnant with only first insemination

50-60

40-50

The index is in animals that are fertile hence also reflects the male side of the fertility, heat detection efficiency, time of insemination and the efficiency of the inseminator.
Mean services per conception (number) This indicates the fertility efficiency in all breedable animals of the herd

2-2.5

2.5-3

In case it is higher it indicates that there are problematic animals in the herd. Herdman software also calculates fertility rates for 2,3,4,5 and more inseminations.
Non-pregnant while pregnancy tests (percentage) This indicates the proportion of animals that are diagnosed negative at pregnancy diagnosis

10-20

10-20

If the proportion is higher it indicates poor estrus detection in the farm or early embryonic mortality.
Abortion rate (percentage) This indicates number of animals aborted out of number of calving

3-5

3-5

If higher it indicates infection, such as, brucellosis, IBR, BVD, leptospirosis, etc. Serological diagnosis.
Percentage animals pregnant in herd This indicates number of animals pregnant out of the herd and generally used as index when breeding bull is used for natural service

65

65

If lower bull should be tested or females should be screened for endometritis, high rumen degradable protein intake, etc.
Retention of placenta (percentage) This indicates animals with retained placenta out of total calving

Less than 8

Less than 8

Higher rates indicate calcium deficiency, brucellosis, low nutrition plane in dry period (lower body score at calving).
Endometritis (percentage) Animals with endometritis out of total calving

Less than 10

Less than 10

Higher rates indicate poor practices around calving time or faulty insemination technique leading to introduction of infection, more cases of retention of placenta.
Cystic ovaries (percentage) Animals with cystic ovaries out of total breedable animals

Less than 5

Less than 5

Higher rates indicates genetic problem.
Repeat breeders (percentage) Animals not conceived to three or more inseminations out of total breedable animals

Not more than 15

Not more than 15

Higher rate indicates lower reproductive efficiency which needs diagnosis considering other indices, laboratory investigations, etc.