Several factors affecting reproduction rate

1 Environmental factors

2. Feeding management

3. Genetic factors

4. Disease factors

5. Reproduction techniques

 

 

 

 

Environmental factors

 

Dairy cows have the lowest conception rate and the highest abortion rate in the hot summer, especially those who are pregnant for more than 5 months. Sudden changes in geographical environment or climatic conditions can affect the reproductive function of dairy cows and cause temporary oestrus infertility. Even in the same area, different changes in climate from year to year can reduce the reproductive capacity of cows.

In winter, pay attention to ice water and frozen feed, especially the cattle house insulation measures should be done well.

 

feeding management

 

1. Nutrition

Malnutrition or high nutritional level will have different effects on the estrus, conception rate, embryo quality, reproductive system function and endocrine balance of dairy cows. Cows are given standard 50% feed for limited feeding at young age, body maturity is inhibited, initial stage will be delayed, the growth of cows will be affected under poor feeding conditions for a long time, and the reproductive system will appear such as small uterus, small ovary and long-term non-estrus. On the other hand, the high proportion of concentrate in the dairy cow's diet will lead to material metabolism disorders and lower milk fat rate. When the proportion of concentrate exceeds 50%, acetic acid fermentation in the rumen of dairy cows is inhibited, protein andMineralsmetabolic disorders,Decreased reproduction rate; Vitamin A, E deficiency,Lack of trace elements, cows can be long-term non-estrus or estrus irregular, non-ovulation, difficult implantation of fertilized eggs, early embryonic death, etc;Crude fiber deficiency, in addition to can lead to metabolic diseases, but also can cause the afterbirth and obstetric diseases.

Rocky Lick Brick

Red RockyLick brick significant effect

1: Improve animal health and reduce morbidity (e. g., increase pregnancy rate in the initial stage, mastitis, hoof disease, retention of the placenta, etc.);

2: increase water intake, increase appetite, increase weight and milk production;

3: enhance fertility and fetal health;

4: improve the quality of fur, improve food digestion, improve feed utilization;

 

Phosphorus-rich RockyLick brick significant effect

1: Solve the problem of maternal reproduction (for example, long interbirth time, repeated mating infertility, frequent abortion)

2: extend the peak period of lactation; improve milk production.

3: Extend the life of the mother; (an 8,000-litre cow loses 60kg of minerals in its milk)

4: Improve the comprehensive health index of dairy cows and reduce the incidence of dairy cows (e. g. mastitis, hoof disease).

5: Cow pica disappears (gnawing wood, licking hair, licking urine, gnawing plastic) and the fur is smooth.

6: to promote food digestion, improve feed utilization, saving concentrate.

 

2. Tune cattle

The transfer of cattle between regions and regions makes the cows not adapt to the new environment, resulting in great stress for the cows. Secondly, the cows rub and collide with each other during the transfer of cattle, which is easy to lead to abortion. If the ground is slippery, it is easy to lead to fall, abortion, foot lying, etc.

3. Postpartum care

Improper postpartum care, poor hygiene in the delivery room, easy to suffer from obstetric diseases, delayed estrus after delivery, inadequate disinfection and hygiene during delivery, and more artificial midwifery are easy to cause vulvar strain, placenta retention, etc.

4. Rational use of drugs

Irrational use of drugs on pregnant cattle caused abortion, stillbirth, etc., reduce the reproduction rate; newborn calves improper care, resulting in a decline in the survival rate of calves.

 

genetic factors

 

1. Effect of gene screening on reproductive performance of dairy cows

In the past 30 years, genetic screening has increased the milk production of dairy cows. From 1985 to 2003, the milk production of dairy cows in the United States, the Netherlands, New Zealand and Ireland increased by 193kg, 131kg, 35kg and 46kg per year respectively. Although the dairy farming model, genetic screening standards, climate and environment are inconsistent in these countries, they all report a substantial decline in the reproductive performance of dairy cows; therefore, in recent years, the screening of dairy cows abroad has been tilted from the standard that focuses solely on production performance to the standard that can improve health and reproductive performance. It is very important to correctly understand the interaction between the feeding environment and genotypes of dairy cows and establish a reasonable feeding management mode for improving the milk yield and reproductive performance of dairy cows. High milk yield does not mean the decline of reproductive performance. There are cases where the reproductive performance of cattle is still higher than that of low-yield cattle when the annual average milk yield is more than 10000kg, this shows that the high reproductive performance of dairy cows may be largely affected by the nutritional level and breeding management. However, the negative effects of high milk yield on various physiological paths of dairy cows cannot be ignored, and the disorder of these physiological paths will reduce the possibility of pregnant cows, so it is necessary to provide a series of solutions for high-yield cattle in feeding and management.

2. Avoid close relatives

The intersection of close relatives will lead to the production of heterosexual twin calves. Although there are external reproductive organs, most of them are underdeveloped internal reproductive organs after adulthood. Some have no cervix, some have no uterus and ovary, single uterine horn, and even have no reproductive ability. Such cows have great influence on the whole reproduction and pasture.

 

Disease factors

 

1. Diseases of the uterus

Within a few days after delivery, 80-100% of cows will have bacterial contamination in the uterine cavity, which is closely related to inflammation of the endometrium and purulent discharge of vaginal mucus. Most cows can successfully remove bacterial contamination within 21 days after delivery, but at least 20% of cows cannot avoid bacterial contamination and develop endometritis. Among them, the infection rate of endometritis in cows with twins, stillbirths, dystocia and stillbirths will be higher. Studies have shown that endometritis can increase the number of empty pregnant days of cows by 15 days and reduce the relative pregnancy rate of cows within 150 days after delivery by 31%. Even if the clinical endometritis of dairy cows is successfully treated, the pregnancy rate of these cows is still about 20% lower than that of those not affected by endometritis, and 3% of the sick cows will be eliminated because they cannot conceive. In addition, after the sperm into the uterus, bacterial toxins, white blood cell phagocytosis and other inflammatory factors will cause sperm death or decreased motility, so that the number of sperm into the fallopian tube decreased. Endometritis cow uterine gland secretion function will also appear obstacles, supply early blastocyst growth lack of nutrients, thus affecting the development of the embryo.

2. Foot and foot disease

Claudication leads to an increase in the number of inseminations, a decrease in the conception rate of the first artificial insemination, a 2.63-fold increase in the rate of ovarian cysts in cows with claudication within 30 days after delivery, and the conception rate is only half that of cows without claudication within 150 days. When dairy cows appear hoof leaf inflammation caused by acidosis, the release of histamine and endotoxin in dairy cows increases, which will affect the hormone secretion state of the hypothalamus-pituitary gonadal axis, and promote the secretion of LH to be damaged. The decrease of feed intake of lameness cows will produce negative energy balance, resulting in the decrease of estrogen and progesterone concentration, the cow will appear quiet estrus, the quality of eggs will decrease, the early embryo will die, and the embryo will develop slowly. Limb disease will also reduce the activity of dairy cows, increasing the difficulty of identification of dairy estrus.

3, mastitis

The immune function of lactating cows is more likely to decline and lead to the occurrence of diseases, especially the pathogenic bacteria are easy to enter the nipple of dairy cows to cause mastitis. The incidence of mastitis within 30 days after delivery was about 23%. The genetic correlation between mastitis and milk yield ranged from 0.5 to 0.68, and the incidence of mastitis in high-yielding dairy cows was higher. Within 28 days after delivery, the estrus behavior of cows with clinical mastitis is delayed, and cows with clinical mastitis require 0.5 more insemination per pregnancy than healthy cows, and the empty pregnancy period is extended by 60 days. In addition, cows that developed clinical mastitis during artificial insemination and pregnancy had a 2.8-fold higher rate of embryo loss than cows without mastitis symptoms. The occurrence of mastitis within 50 days of pregnancy results in an increased abortion rate in cows. The mechanism of the effect of mastitis on the reproductive performance of dairy cows is mainly reflected in that the increase of various cytokine levels during mastitis will reduce the concentration of circulating luteinizing hormone and affect estrus and ovulation, and inflammatory factors such as interferon and interleukin will reduce the proliferation of endometrial cells and interfere with oocyte maturation and embryonic development.

4. Other diseases that affect the rate of reproduction

Reproduction above ovarian dysfunction, ovarian quiescence, ovarian atrophy, follicular cyst, corpus luteum cyst, multiple follicles, and so on.

Infectious diseases: Brucellosis, bovine leptospirosis, trichomoniasis and other infectious diseases can cause pregnant cows to miscarry or produce weak fetuses and stillbirths.

Veterinary clinical disease, ketosis, metabolic disease, etc

 

 

reproduction technique

 

1. The accuracy of estrus identification

2. Basic operation is not skilled

3. Infusion technology is not in place, not skilled

4. Collation of breeding data

5. Accuracy of Tire Test

Countermeasures to Improve the Reproduction Rate of Dairy Cows

Breeding equipment

 

 

1. postpartum check:

Birth canal inflammation: mucus cannot be seen, it is basically full of pus, the uterus is softer than that, and the uterine horn also feels not hard.

Uterine fibroids, uterine sclerosis: both hands feel the whole uterus or uterine horn hard like stone, occupy the uterine area is relatively large, can determine uterine sclerosis or fibroids.

Ovarian cyst: ovarian cyst can be divided into follicular cyst and corpus luteum cyst, follicular cyst is the whole ovarian area is relatively large, bare hands feel like a water balloon,

Treatment: LH5, HCG1 box, GNRH1 and HCG1 box can be selected after pressing. Corpus luteum cyst: it feels like a meat ball. it is relatively large and cannot be broken. Treatment: PG3-5 branch,

Ovarian quiescence: free hand feeling two ovaries are relatively small, feeling and soybean grain size, obviously nothing on the ovary, treatment: HCG1 box, progesterone 1 box, GNRH2, LH5, pregnant horse serum 1 can be.

2. the role of pre-contemporaneous programming

The first PG14d after delivery --- the second PG14d (28d after delivery) --- the third PG14d(40d)--- the 12d GNRH (52d)--- the 7d PG(59d)--- the 2d GNRH(61)--- the 8-12h is the next day (62d) breeding

The purpose of the first injection of PG is to discharge impurities in the uterus. The purpose of the second injection of PG is to regulate ovarian function and the development of follicular waves, and whether uterine secretions are normal during estrus is to be examined during labor. The third injection of PG is very important. In order to pave the way for the same period, follicular development is to regulate the normal development state. The purpose of the fourth injection of PG is to expel the first follicular wave in the ovary and make the dominant corpus luteum mature, the fifth injection of PG causes the degeneration of the dominant corpus luteum, thus causing the production of the dominant follicle. The sixth injection of GNRH aims to promote the maturation of the dominant follicle, which is discharged during the validity period and finally bred.

3. Basic operations of reproduction

Water temperature: 36-37 ℃,

Thaw: Do not exceed the frosting line

Thawing time: 35-45 seconds,

Mating time: no more than 5 minutes

bucket time: 5 seconds,

Inseminal operation: vulva wipe, gentle action to avoid damage to the uterine wall

Frozen semen effects: avoid contact with water, sunlight, blood, and heat preservation to avoid heat

Fetal examination operation: the action should not be too large, especially B- ultrasound, with high accuracy, and learn to distinguish the difference between intrauterine mucus and fetus.

Estrus identification: combined with cow climbing action, vulva changes, back friction changes to determine estrus, bare-handed rectal examination of follicular softness, fluctuation, thickness

Data entry: accurate understanding of each link above the data, entry and subsequent date changes should be reasonable.

Postpartum care: do a good job in disinfection and aseptic awareness, combined with Medajia, PG, PE treatment, the detection rate must be high, timely treatment.

Metritis: Cattle with metritis should be recorded when checking the shed, and treated as early as possible. Drug resistance should be reasonably avoided. Drugs can be changed for treatment. Ovarian diseases can be treated with other treatment schemes if single treatment fails.

4. selection and matching

1. The application of frozen semen of fine breed bulls as artificial insemination, so that the excellent genetic quality obtained, improve the production performance and economic benefits of the descendants, is the means of long cycle and the highest rate of return in dairy technology.

2. The descendants of the parent cows of different pedigree have different degrees of effect and rate of return, and there are also negative effects. Therefore, when selecting the same excellent bull semen, we must also pay attention to its combined effect, that is, we must pay attention to the selection and matching, in order to get a good selection effect.

3. When selecting and matching the first best bull, factors such as conception rate and semen antagonism should also be taken into account. A second best bull should be selected for standby at the same time. If neither of them is available, only the third choice.

5. Strengthen the Feeding Management of Dairy Cows

1. Avoid slipping when adjusting cattle. Sawdust can be paved in the passage of adjusting cattle to prevent slipping and abortion caused by crowding. In winter, the cowshed should be ventilated in time, but it should be cold-proof. Ventilation is to discharge a large amount of ammonia from the cowshed. Timely replacement of water, summer heat, heatstroke prevention and cooling is the most important, stress is relatively large, abortion cattle are more, and the sharp decline in yield affects benefits.

2. Create suitable environmental conditions for growth and reproduction of dairy cows. The allocation of diet should be reasonable and all kinds of nutrition should be balanced. Actively prevent and control infertility of dairy cows and improve fecundity. According to different types, adopt comprehensive prevention and control measures to combine prevention and treatment. Attention should be paid to the selection and elimination of congenital and physiological infertility. The reproductive function of old cattle is reduced, pregnancy is not high, and milk production is not high, it should also be eliminated and updated in time. For sick cattle suffering from infectious diseases, the epidemic prevention and quarantine regulations of infectious diseases should be strictly implemented. For difficult-to-pregnant cattle and aborted cattle caused by suspected infectious diseases, the spread of infectious diseases (foot-and-mouth disease) should be reduced.