Heat Detection In Cattle And Buffalo: An Overview
Estrus detection is the key in the success of effective breeding program. Good estrus detection is an essential part of good fertility. Several factors like climate, temperature, photoperiod and nutrition affects the length of estrous cycle and the degree of heat expression. Poor nutrition, minerals, and vitamin A deficiency in the feed prevent maturation of graffian follicles. Climatic factors affect the bovine reproduction particularly in tropical and subtropical areas (Singh et al. 2000). Efficient and profitable reproductive performance requires careful heat detection and proper timing of artificial insemination. Failure to detect estrus is a major factor contributing to low fertility and results in economic loss, extended calving intervals and additional semen expense. Estrus is the period during reproductive cycle when female animals become sexually accessible. It is indicated by the cow standing to be mounted by a bull or other cows. Estrus symptoms during in buffaloes are much less obvious than those in cattle. In cattle and buffaloes most of domestic animals, ovulation takes place about 10-12 hrs after end of estrus (Noakes et al. 2001). Standing heat typically lasts for about 12-18 hours, but some cows may stand as short as four hours or as long as 24 hours. Estrous cycle refers to whole sequence of hormonal and reproductive changes that take place from one heat period to the next. Average length of the estrous cycle is 21 days, but may vary with 17- 24 days. Improving reproductive efficiency, shortening of calving interval and increasing conception rate are the significance of estrus detection.
Proper heat detection to achieve appropriate timing of insemination is the biggest restriction in attaining high conception rate in dairy herd. Heat detection is the key in the success of an effective breeding program. This was achieved by close observation, timed AI and sound record keeping. There is no substitute for good management. Accurate estrus detection is a key to efficient reproduction and to high milk production (Roelofs et al., 2010). The term estrus was used for the first time by Heape. It comes from the Greek word “Oistros” meaning a gadfly, member of the Family Oestridae, who’s buzzing during summer, caused cows to become hyperactive, usually showing frenzied behavior similarly to that exhibited by females at estrus (Sanders and Bancroft, 1982). In female cow the estrus behaviour comprised of attractiveness, proceptivity and receptivity. Three distinct patterns are observed during estrus includes male like mounting, rise in spontaneous activity and mating responses. The female stands immobile for mounting on her, indicates that she is definitely in heat (Negussie et al., 2002). Buffaloes are seasonally polyestrous with an average cycle length of 21 day (range 18-24), and an average duration of estrus of 18 hours (5- 36) (Drost, 2007). Buffaloes are shy or poor breeder. The estrus behaviour is shown during September to January with peak during October to November (Suthar and Dhami, 2010). The nutrition was one of the most important factors for conception in animals. Cattle in poor condition or negative energy balance generally have poor reproductive performance. Deficiency of vitamin and minerals (Vitamin A, E & Selenium) could be the cause of deterioration in sign and symptoms of estrus (Zobel et al., 2012). Ruminal temperature has daily variation; therefore, RuT were compared for time periods before, during, and after estrus that included the same daily hours the day before and the day after estrus. Ruminal temperature was greater (P < 0.001) during the first 8 h after cows were first observed in estrus (38.98) compared with RuT on the same daily hours the 2 previous days (38.45) (Cooper-Prado et al., 2011). Acidity, pH, density, dry matter, fat and lactose levels, were determined from the obtained milk samples in evening milking. In this study, milk yield of cows in estrus was determined as 4.8 kg while post estrus production elevated to 5.8 kg (P<0.01) (Akdag et al., 2010). The cervical mucus is > collected from cow suspected of heat; it is smeared on slide and dried naturally in air. If fern pattern appears in slide in microscope indicates animal in estrus. This pattern appears 84 hours before estrus and starts declining before ovulation (Mangal, 2009). Heat detection aids are very important tools for efficient reproductive management if used in combination with expert eye. Cows with detector (KaMaR) plus CHALK marking on tail were more efficient than detector alone. Visual observation with tail paint is 98 % efficient as compared to heat watch alone i.e. 91 %. Electronic heat mount detector also known as heat watch system is a radio-telemetric system that senses the mounting activity. The data recoded is transmitted to a receiver then recorded by computer for subsequent retrieval (Taras and Spahr, 2001).
Estrus Signs in Cattle:
Primary signs
- Standing to be mounted is the most accurate sign of estrus · Standing heat: Most sexually intensive period of the estrous cycle · Average duration of standing heat is 15 to 18 hours, but may vary from 8 to 30 hours · An estrous cow usually stands to be mounted 20 to 55 times during her estrous period · Each mount lasts three to seven seconds.
Secondary signs:
- Mounting other cows: Cattle that exhibit this behavior may be in heat or approaching heat. Mounting activity is performed much less frequently by cows in midcycle. Although mounting cannot be used as a true primary sign of heat. Cows exhibiting such behavior should be watched closely for standing behavior.
· Mucus discharge: As a result of elevated estrogen levels, mucus is produced in the cervix. Long viscous, clear elastic strands of mucus generally hang from the vulva. Mucus may be smeared on tail, thighs, flanks, or perineal region ·
Swelling and reddening of vulva: During heat the vulva swells and the interior becomes moist and red. Generally these symptoms appear before heat and remain for a short period after heat. This is not the precise indicators of estrus.
· Bellowing and Restlessness ·
Rubbed tail head hair and dirty flanks: As a result of being ridden, the hair on the tail head and rump is fluffed-up, rubbed, or matted, and the skin may be exposed. Legs and flanks may be smeared with mud or manure.
· Chin resting and back rubbing: Prior to mounting, cows often rest or rub their chin on the rump or back of the cow to be mounted. This sign is considered as test for receptivity to being mounted. Both cows should be observed closely for mounting and standing behavior ·
Sniffing the genitalia: Occur much more frequently with cows in proestrus and estrus · Head raising and lip curling: This activity follows sniffing of the genitalia and occurs more frequently if the cow being investigated is in heat and urinates.
· Decreased feed intake and milk yield:
· Metestrous bleeding: Some cows and most heifers have a bloody mucus discharge one to three days after estrus. High estrogen levels during estrus cause blood to leak from vessels near the surface of the uterus.
Estrus Signs in Buffaloes:
Buffaloes are shy or poor breeder. They are seasonally poly estrous. Behavioral sign in buffaloes are less obvious than those in cattle therefore less than one third of buffaloes in heat might be detected by homosexual behavior. Unlike cattle obvious and raged sign in buffaloes are not pronounced. Hetero sexual behavior, particularly standing to be mounted by a bull, is most reliable sign of estrus in buffaloes, whereas homosexual behavior observed only occasionally. Signs such as swelling of vulva, clear transparent mucus discharge, spontaneous milk letdown, bellowing, restlessness, frequent urination and raised tail vary in intensity from animal to animal, and in relation to standing estrus. Generally in buffaloes, estrus commences towards late evening and the peak sexual activity occurs during hours of darkness. Biostimulation favors behavior sign of estrus clearly.
Methods of Estrus Detection:
- Physical Methods 2. Biological Methods 3. Chemical Methods 4. Miscellaneous Methods
1. Physical Methods a) Visual and Personal Observations b) Sound Record Keeping c) Heat Expectancy chart d) Vaginal Probes e) Pedometer f) Tail Paints g) Chin ball Marker h) Gomer bull i) Close Circuit Television Camera (CCTV Camera) j) Radio Frequency Communication System or Heat Watch System k) Trans Rectal Ultrasonography l) Use of colored paints, dyes,oils and grease on the brisket m) Vaginal pH n) Vaginal Smear
1.a) Visual and Personal Observations: This is the commonly used method of heat detection. It involves trained personnel’s recognizing and recording the signs of heat in animals. Observable signs of heat include; mounting or attempting to mount other cattle, standing to be mounted by other cattle, smelling and trailing other females, bellowing, depressed appetite, nervous and excitable behavior, mud on hindquarters and sides of cattle, roughed up tail hair, vulva swelling and reddening, clear vaginal mucous discharge, mucous smeared on rump etc.
b) Heat Expectancy Chart: This method allows heat to be recorded and the time of next heat to be predicted so that cow can be viewed more closely at the time of the next expected heat.
c) Vaginal Probes: During estrus, electrical resistance decreases and conductivity of the vaginal tissues and discharges increases.
d) Pedometer: Cows in heat are more mobile and walk two to four times as compared to nonestrous animals. Activity meters used at the neck or a leg of cow and may be read by receiver and pass on to computer for retrieval. ALT (Activity, Lying time and Temperature) pedometer is a real time watch used for measuring time interval for activity rise.
e) Tail Paints: Tail painting is commonly used in combination with visual observation. Fluorescent paint may be used in night for heat detection with artificial provision of electric lamp.
f) Chin ball Marker: Device placed under the chin of the bull, causes paint to be smeared on back of the cow if mounting takes place.
g) Gomer bull: Bulls are altered, so that they cannot make sexual contact with female. If the bull mounts, it shows that the female must be in heat.
h) Close Circuit Television Camera (CCTV Camera): This system is unique for round the clock observation and data recording of herd. This is applicable in intensive system of housing i.e. close housing.
i) Electronic heat mount detector: Also known as heat watchsystem. It is a radiotelemetric system that senses the mounting activity. A similar instrument the mount count is pressure sensitive estrous detector pasted at sacral area of cow.
j) Ultrasonography: By using trans-rectal probes we can measure the size of mature follicle and can predict the estrus. Ultrasonography is used to detect ovulation time with respect to different sign of heat (Layek et al. 2011).
k) Vaginal pH: pH is good indicator of animal in estrus. pH falls from 7.0 to 6.72 one day before estrus which further fall to a level of 6.45 immediately before ovulation.
l) Vaginal Smear: Smear also shows increase in cornified acidophil cells during estrous period.
m) Fern pattern of cervical mucus discharge: Cervical mucus is collected from cow suspected of heat. It is smeared on slide and dried naturally in air. If fern pattern appears in slide in microscope indicates animal in estrus. This pattern appears 84 hours before estrus and starts declining before ovulation. If fern pattern show more branching, it shows appropriate time for insemination. Viscosity of mucus decreases at the time of estrus i.e. it become very thin liquid.
2. Biological Methods: a) Trained Dogs b) Use of Teaser Bulls: · Vasectomized Bull · Androgenized Steers · Surgically Diverted Penis
Chemically Treated Bulls · Penile Blocked · Cystic Cows
3. Chemical Methods: · Radioimmunoassay (RIA) used for PROGESTERONE estimation in milk · Kit method for PROGESTERONE determination · Kit method for 17â-estradiol determination
4. Miscellaneous Methods: · Temperature Change Measurement: Little increase in temperature in heat is observed.
Change in parlor behavior: Cow in estrus may be less regular in parlor behavior like, entry habits, restless in milking, kicking during teat cup fitting, drop in milk yield.
Bio-stimulation: Presence of male in the vicinity of the females improves the expression of estrus to be detected. This is commonly used as curative measure for silent heat problems especially in buffaloes.
Milk yield fluctuation: Sudden drop in milk on estrus followed by recovery at next milking is good indication of estrus. Such drop in milk is due to concentration of estradiol in blood. · Endometrial Biopsy: It shows rise in phosphate activity around estrus. Cervical mucus glucose content. Glucose test is more positive on day of estrus than on the other day. · Uterine tone: Maximum tone in uterine horn remains on day of estrus.
Estrus synchronization: One of the important methods for easy detection of heat and timed A.I.Synchronizationis a process by which group of animal are managed in such a way that they will come in heat on same day. Different protocols are used like; ovsynch, pre synch, co-synch, select synch, double synch and heat synch (Mohan et al. 2009) in both cattle and buffaloes. ·
Infra red spectroscopy and magnetic resonance spectra: Carried out to detect estrus related change (inflammatory reaction) in vaginal, vulva and vestibule.
Bovinose: Pheromone based sensor system. Detection of sex pheromones that are secreted by cow exclusively in estrus. Pheromones are released by dung of cow in estrus. Pheromones are volatile fatty acids i.e Acetic Acid and Propionic acid ·
Laparoscopic technique: Used for study genital organs in general and ovary in particular. This technique is not economical to be used by farmers in field condition.
Flehmen phenomenon in buffaloes: The flehmen response, also called the flehmen position, flehmen reaction, flehming, or flehmening, is a behaviour whereby an animal curls back its upper lips exposing its front teeth, inhales with the nostrils usually closed and then often holds this position for several seconds.
PROTOCOL FOR SUCCESSFUL HEAT DETECTION (Du Ponte, 2007):
1. Tracking of individual animal throughout their life using permanent numbering system. 2. A sound record keeping system should be supplemented with frequent information updates. 3. Standard operating procedure (SOP) should be established. Punctual staff should be selected for the heat detection program and recording information like animal identification, time of onset of heat with respect to different sign and estimating ovulation time. 4. Morning hours are crucial for heat detection as heat detection rate were higher during morning hours (Dransfield et al., 1998). Cow in heat is the first cow to rise in morning in herd. 5. Any interruption to cattle such as feeding or milking should be avoided during monitoring. 6. Special surveillance required for detecting animal grouping activity i.e., SAG. Cattle approaching heat usually congregate together. 7. Duration of heat may change with respect floor surface, as activity rises 3- 15 times greater on soil surface than on concrete. There is sudden drop in mounting activity on slippery surface. 8. Heat detection aids should be used wisely and efficiently. Heat detector should be used only as a supplement to visual observation rather replacement 9. The herd may synchronize with hormones or its combination to increase the probability of detecting estrus at appropriate time. 10. To catch every in heat a balance programme should be formulated keeping in view that animal return to estrus 18-24 days later. 11. Hoof problems and sore feet should be treated immediately as lame cattle will not mount or permit to ride on, which decreases the chances of detecting animal in heat. 12. Standard protocol should be followed and all activities are documented.
HEAT DETECTION EFFICIENCY AND ACCURACY:
Efficiency and accuracy of heat detection is increased by noticing animal in heat, before elapse of 50 days of parturition. Factors which affect the expression of estrus should be thoroughly monitored. Herd is critically monitored using heat expectancy chart. Number and percentage of breedable heat should be observed carefully. Efficiency of detection is expressed as percentage of possible estrus period that are observed in a given period of time. The accuracy of detection is the percentage of estrous period observed that is true estrus. Inadequate heat detection is one of the major factor limiting reproductive performances in factor limiting reproductive performances in herds; therefore it is an area of farm activity where increased effort or investment is likely to be profitable. Cattle come into estrus at all times of the day, moreover she may not be very active in hot weather and remain in heat for only a short period of time (roughly 12-18 hours), making it difficult to observe. Allowing animal to interact in small group (three to five) with two to three visual observations per day will increase the chances of catching cycling animals. The use of synchronization and heat-detection aids can greatly shorten the time spent in heat detection but will not benefit a non-cycling herd. The management interventions are required to maintain the herd cyclic. For this high grade nutrition should be provided, and also need exceptional cow comfort including hoof health, body condition and non slippery surface.
CONCLUSION
Proper heat detection to achieve timing of insemination is the main constraint biggest restriction in attaining high conception rate indairy herd. Inadequate heat detection is one of the factor limiting reproductive performances thus reduces the fertility status of herd. Cattle come into estrus at all times of the day, and remain in heat for only around 12-18 hours), making it hard to observe. The standing to be mounted is the best sign of estrus. Ovulation time can be estimated by standing heat. The use of synchronization and heat-detection aids can shorten the time spent in heat detection. The management interventions like good quality nutrition, good housing etc. plays a significant role in maintaining the herd cyclic. Estrus detection significantly affect the reproductive status of the herd, therefore it is utmost important to critically observe the animals to lessen the incidence of unobserved estrus.
Heat detection techniques in cattle and buffalo
Heat detection techniques in cattle and buffalo
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