Swamp buffalo breeding: catching quiet heats and planning calving

A buffalo cow gives you very few clues about her breeding. Her heat is short and quiet and often happens at night. Her pregnancy lasts most of a year. If you miss one heat you lose about three weeks. Miss a few in a row and you lose a season.

These notes follow the year of one example cow, from the day she comes into heat to the day her calf is born and she is bred again. She is not a real animal. She stands in for the averages in Thai studies and in the Department of Livestock Development (กรมปศุสัตว์, DLD) manuals linked below. Every number comes from a source you can open yourself. Where my own arithmetic is involved, I say so.

First: which buffalo are we talking about?

There are two kinds of domestic water buffalo. River buffalo have 50 chromosomes and swamp buffalo have 48. The difference comes from two river-buffalo chromosomes that are joined into one in the swamp type, yet the two types can still produce fertile offspring when crossed, although the crossbreds are less fertile (Pineda et al. 2021, Frontiers in Genetics). The same review says that in Southeast Asia swamp buffalo are kept mostly by smallholders for their draft power, and that their main use is moving towards meat and milk as farms mechanise.

Thailand's native buffalo, the kwai plak (กระบือปลัก), is the swamp type. The DLD's own production manual for native buffalo is built around it (DLD Buffalo Research and Development Group, 2567). Murrah, which you may see on dairy buffalo farms, is a river-type breed (Pineda et al. 2021).

The numbers worth remembering

The Thai farm study followed 48 swamp buffalo cows on one intensive farm from 2001 to 2010, with data from 99 calvings. The cows were bred both naturally and by artificial insemination (AI) (Chaikhun et al. 2012). That makes it one herd, not a national average. Even so, the authors note that there are few reports on swamp buffalo reproduction in Thailand, so a herd record like this is worth having.

For comparison, the targets the DLD sets for its own swamp buffalo breeding herds are an age at first calving under 38 months, a calving interval under 450 days and a calving rate of 60% (DLD buffalo manual, 2567).

Note 1. Day 0: she comes into heat, and you might not notice

In the IVIS chapter on estrus detection in buffaloes, Purohit and Rao list the signs: restlessness, bellowing and passing small amounts of urine often. They call standing to be mounted the most reliable sign. In buffalo these signs are often weak, and detection methods that work for cattle tend to work poorly.

The same chapter gives the reasons heats get missed (IVIS):

• Weak signs. Many cows show heat only faintly.
• Silent heat. The cow ovulates without showing any heat behaviour. This is more common after calving and in summer.
• Night-time timing. Sexual activity peaks at night and early in the morning, and heat shows best in the cooler part of the day.
• Heat stress. Hot weather weakens how clearly heat shows.
• Little mounting. Cows rarely mount each other, so one of the best signs in cattle is mostly missing.

QUIET HEAT swamp buffalo                                        
                                                                
                                                                
       ,~~~~~~~~~~~. (\~~/)                ,~^~~~~~~~~~~.       
    ~ /             \ (oo)                /               \ ~   
   ' (               ) \/           (\~~/)                 ) '  
      \_____________/                (oo) \_______________/     
       ||         ||        |  /| | |      ||           ||      
__~~~~~----~~~~~~~----~~~~~_____________________________________
                                                                
                                                                
                                                                
                                  HEAT ~20 h                    
         [····························██··············]         
          ▲                                                     
                    one cycle, about 3 weeks                    

How long should you watch? The chapter says that watching at least 2 to 3 times a day, for 30 minutes each time, can pick up 80 to 90% of buffaloes in heat. It also points out that farmers often look twice a day for less than five minutes (IVIS). With a heat that lasts about 20 hours, two quick glances can easily miss it.

The teaser bull

The bull is the best heat detector on the farm. IVIS describes vasectomised teaser bulls as routine on organised buffalo farms, walked past the cows 2 to 4 times a day, mainly early in the morning and late in the evening. A chin-ball marker leaves paint on the cows he mounts. The chapter rates a vasectomised bull plus close watching as the best method (IVIS). Vasectomy is surgery, so it's a job for a vet.

Why this matters for AI in Thailand: Chaikhun and colleagues list poor heat signs and the difficulty of spotting heat as reasons it is hard to predict ovulation for AI in swamp buffalo (2012). A later study from the same farm, citing the 2012 paper, says difficult heat detection leads to many services per conception (Kanloung et al. 2021, Buffalo Bulletin). In the 2012 herd, cows needed an average of 3.5 ± 2.5 services per conception.

Note 2. Day 0 to 1: timing the mating

In swamp buffalo, ovulation comes about 13.9 hours after the heat signs disappear, and IVIS's advice for AI is to inseminate after the cow stops accepting the bull. The chapter cites conception rates of 40.4% to 60.7% when insemination was done after heat had ended (IVIS). With natural mating the bull does the timing for you. With AI it falls to you and the technician.

If you use the DLD's AI service, its 2566 work manual describes how it works:

• The service is for cattle and buffalo farmers who register with it. It runs from 10 regional AI and biotechnology research centres, with AI staff stationed in livestock areas.
• You can report a cow in heat at the AI unit or by phone from 07:00 to 10:00 and 13:00 to 15:00, or by mobile phone or LINE at any time. The staff then arrange a visit.
• The frozen semen comes from proven sires and is produced by the DLD's certified semen centre. Staff choose semen so that inbreeding in the calf stays at or below 6.25%.
• At the visit, the technician checks the cow. If her heat is clear, she is inseminated. If it's too early or too late, the technician will ask you to watch for her next heat.

So the faster you notice a heat and call, the better your chances.

Note 3. About day 22: does she come back?

If she isn't pregnant, she should come into heat again after about one cycle. For Thai swamp buffalo that's 22.1 ± 2.9 days (IVIS, Table 1). Mark the date and watch closely for a few days on either side. Silent heats are common, though, so "she didn't come back" doesn't prove she is pregnant. That's why the next note matters.

Note 4. Day 60 to 90: the pregnancy check

DLD AI staff confirm pregnancy by rectal palpation 60 to 90 days after insemination (DLD AI manual, 2566). The DLD buffalo manual says palpation works from 60 days of pregnancy. On its own farms the DLD checks twice, one month apart, because the second check is more accurate (DLD buffalo manual). An open cow found at this check can be bred again right away. Without the check you might only find out months later.

Note 5. Month 10.5: calving

In the Thai farm study, gestation averaged 321.4 ± 11.3 days (Chaikhun et al. 2012). That's about 10.5 months (my arithmetic: 321.4 ÷ 30.4 days per month). Here is our example cow's calendar, assuming she is mated on 15 December 2026:

Dates are my arithmetic from the study's mean and standard deviation. Your cow can fall outside the window.

ONE BUFFALO COW, ONE BREEDING CYCLE                         \|/ 
herd averages from a Thai farm study                        -O- 
                                                            /|\ 
                                                                
                                                                
                                                                
                                                                
     ·                                                          
                                                                
     ▼                                                          
     =····················································      
     '  '   '  '  '  '   '  '  '  '   '  '  '  '   '  '  '      
     0      2     4      6     8     10     12    14     16     
    MATING                           CALVING       BRED AGAIN   
             pregnant ~321 days             open ~166 d         
/  |  |  |  |  |  /  |  |   / |  |  |   / /  |  /   /  / |   /  

The pen advice comes from the DLD buffalo manual. Cows 8 to 10 months pregnant should be kept in pens without a wallow, because climbing in and out of mud is risky and a calf born at night can drown in the wallow. They shouldn't be taken to graze far away either (DLD buffalo manual). The same manual lists the signs that calving is near:

• the udder swells and looks tight, with visible veins;
• the area at the base of the tail sinks into a deep groove as the pelvis relaxes;
• the vulva swells;
• thick, cloudy white mucus comes from the vagina.

It also says to call a vet at once if the water bag has broken and the calf still isn't out after 2 hours.

Note 6. After calving: where the time really goes

Here is the most useful sum in this post. In the Thai herd, the calving interval was 486.2 days and gestation was 321.4 days. Subtract one from the other and you get about 165 days, almost exactly the 166.2 days open the study measured. You can't shorten a pregnancy. The days open are the part of the calving interval you can actually change.

The DLD's target of a calving interval under 450 days leaves about 129 days open at that gestation length (my arithmetic: 450 − 321). The DLD returns cows to the breeding herd 1.5 to 2 months after calving (DLD buffalo manual). Its AI staff flag cows not bred more than 60 days after calving, cows with no return to heat more than 90 days after AI, and cows bred more than 3 times without a pregnancy (DLD AI manual).

Season and feed matter too:

• In the Thai herd, most conceptions happened in November and most calvings from August to October. The authors link this to cooler weather and the rainy-season grass that helps cows recover after calving (Chaikhun et al. 2012).
• The DLD manual says conception rates in its breeding herds drop in the dry season, when stored roughage runs short or is poor and minerals are lacking. It advises keeping mineral blocks in the breeding pen at all times. In the hot months from March to May, bulls lose interest in mating, so give them more time in the wallow and longer walks in the morning (DLD buffalo manual).

Note 7. Heifers: the first calving sets the pace

In the 2012 herd, age at first calving was 47.1 ± 8 months. A 2021 study of 98 buffalo on the same farm (2001 to 2013) found that swamp buffalo first calved later than Murrah buffalo: 4.16 ± 0.89 years versus 3.79 ± 0.50 years (least-squares mean ± standard error) (Kanloung et al. 2021).

The DLD's guideline for its herds is to breed heifers first at about 2 years old and 300 kg (the manual's standards table gives 350 kg at 24 months). The manual says weight matters more than age, with 260 kg as the minimum, because heifers that are too small have trouble at calving (DLD buffalo manual). A heifer that conceives at 24 months calves at about 34.5 months (my arithmetic: 24 + 10.5), inside the DLD's under-38-month target. That's another reason a scale, or at least a weighing tape, is worth having.

Natural mating or AI?

Neither choice is wrong. Many farms do both: AI when a heat is clearly seen, and a bull as backup. What matters is that you know which cow was bred, when and how.

What to write down for every cow

The DLD records these for each buffalo in its own herds: ID number, birth date, sire and dam, weights at birth, weaning (240 or 300 days), 400, 600 and 900 days, every mating (date, sire, method) and every pregnancy check (date, result, months pregnant) (DLD buffalo manual). On a small farm, start with these:

1. Every heat you see, even ones you're unsure about: date, time and the signs.
2. Every mating or AI: date, bull or semen, and who did it.
3. Pregnancy check: date and result.
4. Expected calving date: mating date + 321 days, with a window of roughly ±11 days.
5. Actual calving: date, the calf's sex and weight, and any problems.

After a year or two, your notebook can answer the questions in this post for your herd: your own average days open, your own calving interval and your own age at first calving. Those numbers will tell you more than any study.

Sources

• Purohit G.N., Rao T.K.S. (2018). Estrus Detection in Buffaloes, in Bubaline Theriogenology, IVIS
• Chaikhun T., Hengtrakunsin R., De Rensis F., Techakumphu M., Suadsong S. (2012). Reproductive and Dairy Performances of Thai Swamp Buffaloes under Intensive Farm Management. Thai Journal of Veterinary Medicine 42(1): 81–85.
• Kanloung T., Taemchuay D., Hengtrakunsin R., Tavitchasri P. (2021). The reproductive performances of Murrah and swamp buffaloes in Thailand. Buffalo Bulletin 40(3): 495–498.
• Pineda P.S., Flores E.B., Herrera J.R.V., Low W.Y. (2021). Opportunities and challenges for improving the productivity of swamp buffaloes in Southeastern Asia. Frontiers in Genetics 12: 629861.
• Department of Livestock Development, Buffalo Research and Development Group (2567). คู่มือการปฏิบัติงาน การผลิตกระบือ ประจำปีงบประมาณ พ.ศ. 2567 (buffalo production work manual)
• Department of Livestock Development, Bureau of Biotechnology in Livestock Production (2566). คู่มือการปฏิบัติงาน กระบวนการบริการผสมเทียม (AI service work manual)
• Photo: Water Buffalo, Phayao Lake, Heiko S, CC BY 2.0, Wikimedia Commons
• Photo: Buffalo in Nong khai, Thailand, Udom PINTUWONG, CC BY 3.0, Wikimedia Commons
• Photo: Water buffalo, Ang Kep Nam Huai San, Markus G. Klötzer, CC BY-SA 4.0, Wikimedia Commons