Estrous Control and Synchrony in Cattle
| Regimen | Drug Name (Established Name, also called ... | Application Number and Manufacturer | Sequential Use with Another Drug |
| Gonadorelin-Prostaglandin | Factrel® Injection (gonadorelin injectio ... | NADA a 139-237 Zoetis Inc. | Lutalyse® Injection or Lutalyse® HighCon ... |
| Gonadorelin-Prostaglandin | Fertagyl® (gonadorelin) | ANADA b 200-134 Intervet, Inc. | Estrumate® |
| Gonadorelin-Prostaglandin | GONAbreed® (gonadorelin acetate) | ANADA 200-541 Parnell Technologies Pty. ... | cloprostenol sodium |
| Gonadorelin-Prostaglandin | CYSTORELIN® (gonadorelin) | NADA 098-379 Merial, Inc. | cloprostenol sodium |
What happens during metestrus in cows?
During metestrus, the site of where the follicle ruptured becomes a corpus luteum (CL) that secretes progesterone (the calming hormone) to inhibit estrus and, if the cow is pregnant, maintains pregnancy. Some cows may have a bloody vaginal discharge during metestrus indicating they were in heat a day or two earlier.
What is estrus in cows?
Estrus is considered the beginning, or “Day 0,” of the estrous cycle. Besides causing the heifer or cow to show signs of estrus, the high level of estrogen produced by the dominant ovarian follicle also triggers the hypothalamus—a section of the brain—to release a surge of gonadotropin releasing hormone (GnRH) right before ovulation.
What drugs are used for estrous control in cattle?
Some FDA-approved animal drugs are available for use in estrous control and synchrony regimens for cattle (see Table 1). These regimens use three classes of drugs: Drugs in the gonadorelin class act similar to gonadotropin releasing hormone (GnRH) naturally released from the hypothalamus during the estrous cycle.
Why is it important to understand estrous cycles in cattle?
This understanding is also critical when using a drug regimen to control and synchronize estrous cycles in cattle. A heifer has her first estrus, or heat, at puberty. The age at puberty is influenced by genetics, nutrition, and body weight. Heifers fed an appropriate diet will generally reach puberty between 9 and 15 months of age.
What happens Metestrus?
Estrus is followed by a 3 to 4 day period referred to as metestrus. During this period the corpus luteum develops under the influence of LH and starts to produce increasing amounts of progesterone. The period between metestrus and the beginning of the regression of the corpus luteum is referred to as diestrus.
What is the Metestrus stage?
The metestrus phase of the estrous cycle follows as the CL grows, fills the ruptured follicle cavity of the CH, and increases its synthesis of progesterone.
What is Metestrus in estrous cycle?
Proestrus is the preparatory stage for an animal coming into heat, metestrus which is a brief period characterized with decline of corpus luteum functions in the absence of conception when the activities of reproductive organs gradually subside, diestrus which is a period of short rest during the breeding season, and ...
How long is cow Metestrus?
Estrous CycleParameterRiver buffaloCattleAge at puberty (months)15–3610–24Estrous cycleLength (days)18–2214–29Estrus (h)12–3017–247 more rows
What are the 4 stages of estrus?
The estrous cycle has four phases, namely proestrus, estrus, metestrus and diestrus and lasts for 4 to 5 days [4] (Table 1).
What does Dioestrus mean?
a period of sexual inactivity/ (daɪˈiːstrəs) / noun. a period of sexual inactivity between periods of oestrus in animals that have several oestrous cycles in one breeding season.
What is Diestrus and anestrus?
Anestrus is the time between diestrus and the next proestrus. This stage will last for about 4 months, though certain breeds can be much longer. The vulva is no longer swollen, there is no vaginal discharge. The body uses this time to allow the uterus to prepare for the next possible pregnancy.
What is Polyestrus?
Definition of polyestrous : having more than one period of estrus in a year.
What does FSH do in cattle?
FSH is secreted during and shortly after estrus and causes a new wave of ovarian follicles to develop. A surge of LH causes the dominant ovarian follicle to rupture approximately 24 to 32 hours later, thus releasing the egg. This is ovulation and marks the transition from the follicular phase to the luteal phase.
At what age can a heifer become pregnant?
12 to 14 monthsA: Breeding should occur when the heifer reaches puberty. Puberty is a function of breed, age, and weight. Most heifers will reach puberty and be bred by 12 to 14 months of age and will be between 55% and 65% of their mature weight when they first begin to exhibit estrous cycles.
What drugs are given to cows?
Since the 1950s, the Food and Drug Administration (FDA) has approved a number of steroid hormone drugs for use in beef cattle and sheep, including natural estrogen, progesterone, testosterone, and their synthetic versions.
What causes a cow to rupture?
High estrogen from the ovary causes an LH surge or spike that causes the ovarian follicle to rupture and release the egg. During metestrus, the site of where the follicle ruptured becomes a corpus luteum (CL) that secretes progesterone (the calming hormone) to inhibit estrus and, if the cow is pregnant, maintains pregnancy.
How long does the proestrus last?
Proestrus lasts for one to three days immediately before the cow comes into estrus or heat. Metestrus is the three to four days after estrus, and diestrus is the 12 to 15 days in the middle of the cycle. During proestrus, the pituitary gland of the brain secretes the follicle stimulating hormone (FSH) that causes the ovary to develop follicles.
What hormone is released during proestrus?
During proestrus, the pituitary gland of the brain secretes the follicle stimulating hormone (FSH) that causes the ovary to develop follicles. Several follicles develop in what is termed follicular waves, but only one dominant follicle and egg mature for ovulation (rupture of the follicle and release of the egg).
How long is the estrous cycle?
What is the basic estrous cycle of the cow? The basic estrous cycle of the cow averages 21 days in duration (a range of 18 to 24 days) and extends from one period of heat (estrus) to the next. There are four parts to the estrous cycle. Proestrus lasts for one to three days immediately before the cow comes into estrus or heat.
Why does the uterus get bigger during the estrous cycle?
Estrogen causes estrus (“heat”) and contractions of the uterus to aid in transport of sperm. The pituitary gland of the brain secretes lutenizing hormone (LH) usually in a pulsatile rhythm during the estrous cycle.
What is the Estrus cycle of rats?
Estrus cycle of rats became irregular with prolonged estrus and metestrus phases, and reduced diestrus and proestrus phases after the oral administration of petroleum ether, benzene, chloroform, and alcohol extracts of the seeds of Momordica charantia (Cucurbitaceae) at a dose level of 25 mg/100 g body weight. The results showed reduced ovarian weight, number of developing follicles, Graffian follicles, and corpora lutea and an increased number of atretic follicles in histological sections of the ovary. However, the benzene extract of M. charantia seeds was more effective in causing these changes as compared to other extracts [25].
How long is the estrous cycle?
In rodents, there are four phases in the estrous cycle, and the average cycle length is 4–5 days. In metestrus (day 1), progesterone and estradiol circulate at relatively low levels. The following day (day 2), diestrus ensues, and early on in this postovulation phase, progesterone increases sharply and then drops quickly by the end of day (Butcher et al., 1974 ). At ∼1200 h on day 3, proestrus is initiated by a significant surge in estradiol levels. This marked increase in estradiol causes a rapid peak of LH and FSH between 1600 and 1800 h as well as an increased progesterone secretion. Finally, in estrus, ovulation occurs and all hormones return to baseline, save for a temporary peak in estradiol in the evening of estrus on day 4 ( Butcher et al., 1974 ).
When do mice ovulate?
Ovulation in mice usually occurs during the dark period about 2–3 h after the onset of estrus (though there may be cycles without ovulation). Rats tend to ovulate during the metestrus period (Sharp and Vilano, 2013 )] about 8–11 h after the onset of estrus and usually between midnight and 2 am ( Peluso, 1992 ). Ova remain viable about 10–12 h after ovulation ( Fox and Laird, 1970 ). Rats and mice both have fertile post-partum estrus.
How often does a cow have estrus?
Estrus Detection In Cattle. Estrus in cattle is commonly referred to as heat. It occurs every 18 to 24 days in sexually mature, open (nonpregnant) female cattle when they are receptive to mounting activity by bulls or other cows or heifers, according to Dr. Jane A. Parish, Associate Extension/ Research Professor, Animal and Dairy Sciences; Dr.
Why is it important to observe cattle for heat?
More frequent observation of cattle for heat improves detection accuracy and increases the likelihood of recogn izing the optimal time for breeding cattle, particularly in cattle in which heat is less intense or shorter in duration.
How long does it take for a heifer to reach puberty?
Heifers have reached puberty if they have resumed normal estrus function (cycling) after calving (typically 40 days or more postcalving), are free of reproductive disorders or reproductive tract infections, and are open. A heat detection rate of 80 to 85 per cent should be attainable.
How do you know if a cow is in heat?
The surest sign of heat is when a cow or heifer allows other cattle to mount her while she remains standing. This is called standing heat. Cattle may be willing to mount others but may not stand to be mounted when outside of standing heat. This usually indicates she is either coming into or going out of standing heat.
When do cows show heat?
Standing heat can occur any time in a 24-hour period. However, the most likely time for a cow or heifer to show heat signs is at night. The season of the year can influence this, with more cows showing heat at night in hot weather and more showing heat during the day in cold weather.
How often should you check cattle in heat?
Space heat detection observation times evenly over 24 hours. Each observation period must be sufficiently long, usually at least 30 minutes, to be effective.
What is a teaser animal?
Teaser animals include several types of gomer bulls, which are surgically altered to prevent successful insemination. Select gomer bulls that will not become excessively large. Acceptable disposition and freedom from disease are also important in gomer bulls.
How long does it take for a cow to control its estrus?
Females that have previously calved normally need to be at least 40–45 days postpartum . The suckling effect of the calf has a potential negative effect on estrus synchronization in beef ...
What is MGA in heifers?
Melengestrol acetate (MGA) is a steroidal progestogen used as a feed additive to accelerate weight gain and suppress estrus in heifers. MGA is used at a dosage of 0.5 mg/head/day for 14 days for estrus synchronization. In the US, this product is only approved for use in heifers. Fertility after this treatment is low, and females should not be bred.
What is the minimum body condition score for a cow?
It is recommended that heifers have reached at least 60% of the expected mature weight for the breed. The minimum body condition score for a satisfactory hormonal control of estrus in beef cattle is 5 (scale 1–9) and for dairy cattle 2.5 (scale 1–5). In cows, ovulation may be synchronized with a progestogen and estrogen combination treatment ...
Is there a protocol for estrus synchronization?
Currently, there are multiple protocols of estrus synchronization and ovulation for beef and dairy ca ttle. When selecting a protocol, factors such as category of female (heifers versus cows), lactation, postpartum, suckling effect, estrus detection or not, movement of animals (stress), type of semen (sexed versus conventional), facilities, ...
What is the corpus luteum?
the corpus luteum. Literally means “yellow body” and is responsible for progesterone production within the ovary. is present for a similar period of time regardless of whether the bitch is pregnant or not and, as such, Progesterone. a steroid hormone secreted by the corpus luteum of the ovary that maintains pregnancy and promotes the development ...
Which hormone stimulates changes in the female reproductive organs during the oestrous cycle?
a steroid hormone produced primarily by the ovaries that stimulates changes in the female reproductive organs during the oestrous cycle and promotes the development of secondary sexual characteristics. production and the start of pro-oestrous.
What hormone is released when a bitch is not pregnant?
If the bitch is not pregnant, Prolactin. a hormone released from the anterior lobe of the pituitary gland that stimulates the secretion of progesterone by the corpus luteum and initiates and maintains lactation. levels will decline after this point. In the pregnant bitch, after parturition. give birth.
What is tetanus in cattle?
Tetanus in cattle is characterized clinically by hyperesthesia, tetany, and convulsions. The causal agent of the disease is widely present in soil and animal feces. The spores of the organism are capable of persisting in the soil for many years. The disease is associated with disbudding, shearing, calving, naval infection, ear tagging, etc.
What causes a cow to be stiff?
Tetanus is a less common disease in cattle, but it causes substantial economic loss in a cattle farm if outbreaks occur. The disease is caused by the neurotoxin produced by bacteria Clostridium tetani and causes stiffness of muscles, especially in mastication muscle. The name of the disease also “Lockjaw.” All age groups of cattle are vulnerable to this disease but stressed animals are more vulnerable.
How long does it take for tetanus to show up in animals?
The disease is highly fatal, and many animals died before showing any clinical signs. The incubation period of the disease usually 10-14 days. Initially, the animal shows muscle stiffness accomplished by muscle tremors. Lockjaw and unable to masticate by mouth.
What condition does spore growth occur in?
The spore grows only in the anaerobic condition that is in tissues without any process of oxidation-reduction. The deep cuts and contamination usually make the condition of the cuts by deposition of the small amount of soil and foreign bodies or by punctured wound caused by rusted nils leading to necrosis of the tissues.
Is tetanus a sporadic disease?
Though tetanus is a sporadic disease in cattle, there is a considerable risk of disease in your herd . The risk factors should be managed well. It would be best if you gave TT before any operation, castration, docking, dehorning, disbudding, shearing, and management of any wound.
Can you give a calf a TT?
Vaccination is done by Tetanus Toxoid (TT) that is inexpensive. In an immediate case, ATS is given to treat the animal. In the case of castration, you can give both TT and ATS to the calf to treat and prevent further development of antibodies.
Heat Signs and Detection Methods
- Several methods of heat detection can be implemented. Some involve using heat detection aids. Several different methods can be combined to improve heat detection rates and accuracy. These include visual observation, heat mount detectors, tailhead markers (paint, chalk, crayon, paste), chin-ball markers, detector animals, and electronic heat detection devices.
Management Considerations
- Good management is important for a successful heat detection program. Animals must have clearly readable, unique identification. An adequate area and equipment for heat detection must be available. This may include binoculars or the ability to approach cattle very closely. Nighttime observations may require artificial lighting, such as security lights, flashlights, or lanterns. Recor…
Summary
- The effectiveness of detecting heat in cattle varies, depending on method used. Consider the cost, labor, and management system associated with each method in deciding on the best approach to heat detection. The purpose of heat detection also determines the level of heat detection accuracy needed. For more information on cattle reproduction or related topics, contact an offic…
HeatWatch 11
- Application Place small, digital radio transmitter in a piece of polyester material (patch) and glue onto tailhead of cow or heifer. Detection method Every time there is a mount, data is sent from that transmitter to a small radio receiver (base station) in the proximity of the heat detection area. Data generated on every mount include the female c...