Effect of GnRH or Estradiol Benzoate on Reproductive  Traits during a Heatsynch Protocol in Dairy Cows

Background: Milk production of cows is closely correlated with its reproductive efficiency. One of the several factors influencing the dairy efficiency is the decline in fertility of the cows/heifers. Use of hormonal protocol are often used to improve the fertility of the recipients. Several programs are available to inseminate dairy cows, with variation in the use of different types of hormones, time of use and range of duration period, as well as the time of AI. The objective of this study was to evaluate the efficiency of follicular wave emergence induction of estradiol benzoate in comparison to GnRH in a Heatsynch protocol and its influence on reproductive parameters.Materials, Methods & Results: In this study were used primiparous and multiparous Holstein cows (n = 325). Animals were divided randomly into two different treatments according with the hormone used to induce follicular wave emergence (D0). The GnRH group (n = 167), was given 25 mg, while in the EB group (n = 158) was used 2 mg. At same day, were inserted, a controlled internal drug-releasing containing 1.9 g of progesterone CIDR®. On day 7, CIDR was removed and cows were given 25 mg luteinizing hormone followed by an injection of 1 mg Inducer Ovulation at day 8. Cows were then observed for signs of estrus for at least two hours (twice daily at 7 am and 6 pm) for three days following CIDR® removal. Cows detected in estrus were inseminated 12 h later the estrus detection. Pregnancy status was determined by ultrasonography at 30 ± 5 d and 60 ± 5 d after AI. A single technician was responsible for the estrus detection and inseminations. A single technician was responsible for the estrus detection and inseminations. Ultrassonographic examinations with ultrasound, transrectal linear probe of 5 MHz, were performed for the diagnosis of pregnancy at 30 and 60 days after artificial insemination. Binomially distributed data, such as, estrous response, conception rate, pregnancy rate and pregnancy losses, were analyzed by Chi-square test. Pregnancy rates at 30-35 days and 60-65 days as well as pregnancy losses were considered in the model for the effect of parity (primiparous vs. multiparous) and the group of estrus behavior during the Heatsynch protocol. Conception rate was similar between GnRH (36.1%, 57/158) and EB (37.7%, 63/167) treatments. Cows showing estrus signs after CIDR removed were 71.9% in GnRH and 62% in EB group (P = 0.05). Embryonic losses were different (P = 0.03) according to groups of cows showing estrus signals or not.Discussion: Our results demonstrate that conception rates are not affected by using either EB or GnRH at the beginning of the Heatsynch protocol. Therefore, the EB can be an alternative choice to GnRH at Heatsynch beginning. Similar results were found by autor in dairy cows, once it was also observed that there is no difference in conception rate in two TAI protocols using either GnRH or EB. In Heatsynch protocols the increase in estrus detection are a key factor to increase fertility in lactating dairy cows. It can be explained once animals in regular estrous cycle have a palpable corpus luteum and circulating progesterone concentration higher than 1 ng/mL which leads than to enhance pregnancy ratios. The use of BE at the time of CIDR insertion in TAI protocols for dairy cattle proved to be an alternative to GnRH considering conception rates. Therefore, the use of BE at the time of CIDR insertion in a Heatsynch protocol in dairy cattle proved to be an alternative to GnRH which can be an important tool to increase the TAI utilization by farmers. Furthermore, in Heatsynch protocol cows showing estrus have pregnancy rates improved and lower pregnancy losses.

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PSIII-9 Differences in Conception Rate across Breeding Protocols in Dairy Cattle

Journal of Animal Science ◽

10.1093/jas/skaa278.428 ◽

2020 ◽

Vol 98 (Supplement_4) ◽

pp. 234-234

Author(s):

Colin Lynch ◽

Gerson Oliveira ◽

Flavio Schenkel ◽

Christine F Baes

Keyword(s):

Dairy Cows ◽

Artificial Insemination ◽

Hormone Treatment ◽

Conception Rate ◽

Activity Monitors ◽

The Past ◽

Wide Range ◽

Estrus Detection ◽

Conception Rates ◽

Commercial Farms

Abstract Fertility performance success on dairy farms starts with estrus detection, especially for artificial insemination programs. Detection of estrus has become more difficult over the years due to a decrease in estrus expression in high-producing dairy cows, with up to 60% of ovulations accompanied by no standing mount. In order to alleviate the pressure of estrus detection, management technologies have been developed, including automated detectors of standing heat, activity monitors, automated in-line systems measuring milk progesterone, and hormonal synchronization protocols (FTAI). To gauge the effectiveness of such technologies, records from 647,940 cows across 1,166 herds over the past ten years (total of 3,466,593 breeding records) from herd management software were analyzed. Across all herds, there were 5,804 breeding protocols, of which 2,046 were unique. Due to the wide range of breeding protocols, records were classified as HORMONES, FTAI, HEAT DETECTION and OTHERS. Breeding protocols were classified as HORMONES if they included any hormone treatment. FTAI was a stricter subset of HORMONES, which included only clear FTAI protocols. Protocols were classified as HEAT DETECTION if they were a clear heat detection protocol, with all remaining protocols classified as OTHERS. These classifications resulted in 3,258 protocols classified as HORMONES, of which 2,002 were FTAI, while a further 1,840 were classified as HEAT DETECTION. The remaining 706 codes were classified as OTHER and removed from this study. These classifications provided an initial overview of breeding methods conception rates, with results indicating significant differences (P < 0.05) between all protocol groups, as outlined in Table 1. Further analysis will be completed to indicate conception rates from the most commonly used breeding protocols across each of the protocol groups within the 1,192 herds. This work will help provide a better understanding of the expected conception rate of various management technologies on commercial farms.

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Influence of early post partum ovulation on the re-establishment of pregnancy in multiparous and primiparous dairy cattle

Reproduction Fertility and Development ◽

10.1071/r98012 ◽

1998 ◽

Vol 10 (2) ◽

pp. 207 ◽

Cited By ~ 59

Author(s):

M. C. A. Smith ◽

J. M. Wallace

Keyword(s):

Dairy Cattle ◽

Dairy Cows ◽

Post Partum ◽

Pregnancy Rates ◽

Conception Rate ◽

Luteal Function ◽

Fertility Treatments ◽

Significant Relationships ◽

Subsequent Fertility ◽

Holstein Friesian

To investigate the influence of early ovulation after calving on subsequent fertility, milk progesterone concentrations were monitored twice weekly in multiparous (n = 87) and primiparous (n = 60) Holstein/Friesian dairy cattle. Luteal activity before 21 days post partum was defined as ‘early’. In multiparous cows, calving-to-conception interval (CCI) was longer, services per cow were more numerous and conception rate to all inseminations was lower with early luteal activity (n = 41, 16·8±0·39 days post partum) than with later luteal activity (n = 46, 37·8±2·09 days post partum); multiparous cows with early luteal activity required more exogenous fertility treatments and were more likely to fail to conceive by 100 days post partum. In contrast, in primiparous cows, no significant relationships were detected between early (n = 32) or later (n = 28) luteal activity and the CCI, number of services per cow or conception rates to all inseminations. However, primiparous cows that ovulated before 21 days post partum had fewer normal progesterone profiles. Early ovulation after calving was associated with reduced pregnancy rates and prolonged CCIs in multiparous but not in primiparous dairy cows. Extra keyword: luteal function.

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19 EFFECTS OF ESTRADIOL OR GnRH ON FOLLICULAR WAVE EMERGENCE AND PREGNANCY RATES FOR A CIDR-BASED TIMED AI PROTOCOL IN REPEAT BREEDER DAIRY COWS

Reproduction Fertility and Development ◽

10.1071/rdv19n1ab19 ◽

2007 ◽

Vol 19 (1) ◽

pp. 128

Author(s):

G. H. Suh ◽

U. H. Kim ◽

T. Y. Hur ◽

S. J. Kang ◽

K. S. Baek ◽

...

Keyword(s):

Dairy Cows ◽

Follicular Development ◽

Economic Loss ◽

Estradiol Benzoate ◽

Pregnancy Rates ◽

Corpora Lutea ◽

Chi Square ◽

Follicular Wave ◽

Array Transducer ◽

Repeat Breeder

Repeat breeding of a high yielding cow causes enormous economic loss to the dairy producers. In this study, we examined the effect of estradiol benzoate (EB) or GnRH on follicular wave emergence and follicular development, and on pregnancy rates for a CIDR-based timed AI (TAI) protocol in repeat breeder dairy cows. Repeat breeder cows received a CIDR device (InterAg, Hamilton, New Zealand), with an injection of 1 mg EB (SY Esrone�; Samyang, Seoul, Korea) plus 50 mg progesterone (P4; SY Ovaron�; Samyang) (EB + P4 group, n = 36) or with an injection of 250 �g Gonadorelin (GnRH, Fertagyl�; Intervet, Boxmeer, The Netherlands) (GnRH group, n = 35) at the beginning of the experiment (Day 0). On Day 7, CIDR devices were removed and all cows received PGF2� (Lutalyse�; Pharmacia & Upjohn, Puurs, Belgium). Thereafter, cows in the EB + P4 group received an injection of 1 mg EB on Day 8, and TAI 30 h later; those in the GnRH group received an injection of 250 �g GnRH on Day 9, and TAI 19 h later. In a subset of cows for both groups (15 cows from each group), the ovaries of the cows were examined by transrectal ultrasonography (Sonoace 600 with 7.5 MHz linear-array transducer; Medison Co., Seoul, Korea) every 24 h from Days 0 to 8, on Day 10, and on Day 13 for the EB + P4 group, and every 24 h from Days 0 to 9, on Day 11, and on Day 14 for the GnRH group, to observe changes in ovarian structures (follicles and corpora lutea). Pregnancy was diagnosed 35 to 60 days after TAI, using both ultrasonography and rectal palpation. Data were analyzed using Fisher's exact, Student's t-, and chi-square tests. Follicular wave emergence occurred within 7 days in 12/15 EB + P4-treated and 13/15 GnRH-treated cows (P > 0.05). The mean diameters of preovulatory follicles were smaller (P < 0.05) in the EB + P4 group (12.1 � 0.1 mm) than in the GnRH group (13.8 � 0.1 mm). However, the proportion of cows with synchronized ovulation and pregnancy rates to TAI did not differ (P > 0.05) between the EB + P4 (11/15 and 19.4%, respectively) and the GnRH (13/15 and 34.3%, respectively) groups. In conclusion, treatment with either EB or GnRH for a CIDR-based TAI protocol in repeat breeder dairy cows results in synchronous follicular wave emergence, follicular development, and ovulation, and thus similar pregnancy rates to TAI.

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23 EFFECTS OF THE NUMBER OF SERVICES FERTILITY IN DAIRY COWS

Reproduction Fertility and Development ◽

10.1071/rdv23n1ab23 ◽

2011 ◽

Vol 23 (1) ◽

pp. 118 ◽

Cited By ~ 1

Author(s):

M. Yamaguchi ◽

M. Tanisawa ◽

H. Koyama ◽

S. Takahashi ◽

O. Dochi

Keyword(s):

Dairy Cows ◽

Conception Rate ◽

Low Fertility ◽

Chi Square ◽

The Third ◽

Total Percentage ◽

Conception Rates ◽

Service Conception ◽

Chi Square Test ◽

Rectal Palpation

In recent years, reproductive performance of dairy cows has been declining worldwide, especially among cows of high genetic merit for milk production. The cause of the low fertility may considerably vary across countries and is probably multifactorial. This problem remains unsolved. Further, the first-service conception rate of dairy cows has remarkably decreased worldwide. The number of services required for conception has increased due to the low fertility in dairy cows. However, there are few reports about the relationship between conception rates and the number of services in the current dairy cows. The objective of this study was to investigate whether the number of services affects the conception rates of dairy cows. Data concerning the conception rates was obtained for 8386 Holstein cows from 40 commercial dairy herds in eastern Hokkaido, Japan, from 2006 to 2009. The diagnosis of pregnancy was confirmed by rectal palpation between 30 and 45 days after insemination. The average interval between calving and the first-service was 87.3 days. The average milk yield was 8500 kg. Number of conducting services was from the first to the seventh service. The conception rate was analysed using chi-square test. The results are presented in Table1. The conception rate from the first to the seventh service was 40.2 to 54.0%. The conception rate at the first service was significantly low (40.2%); however, the conception rates did not significantly differ after the second-service. A similar tendency was observed during each year. Moreover, the total percentage of conceptions from the first to the third service was 83.8%. The average number of services per conception was 2.2. The results of this study indicate that the first service yielded the lowest conception rates. The conception rates after the second service did not significantly differ. Moreover, ∼84% of the dairy cows became pregnant between the first service and the third service. However, this result shows that ∼16% of the dairy cows in the herds were repeat breeding. In order to improve fertility, it is necessary to study the factors that affect the first-service conception rates of dairy cows. Moreover, to improve the conception rate of dairy cows, it is important to elucidate the cause of these problems. Table 1.The number and percentage of dairy cows conceiving at each of the services for consecutive services

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43 COSTS RELATED TO ESTRUS SYNCHRONIZATION AND AI PROTOCOLS IN CROSSBRED HOLSTEIN-ZEBU DAIRY COWS

Reproduction Fertility and Development ◽

10.1071/rdv22n1ab43 ◽

2010 ◽

Vol 22 (1) ◽

pp. 179

Author(s):

L. D. P. Sinedino ◽

B. T. Gerhardt ◽

A. P. Dourado ◽

L. A. G. Nogueira

Keyword(s):

New York ◽

Dairy Cows ◽

Pregnancy Rate ◽

Animal Health ◽

Cost Benefit ◽

Estradiol Benzoate ◽

Estrus Synchronization ◽

Labor Costs ◽

Estrus Detection ◽

The Cost

The objective of this paper was to compare 3 bovine AI protocols, evaluating the cost of each treatment and the pregnancy rates obtained, to demonstrate the importance of routine utilization of estrus synchronization techniques. The experiment was conducted in the Farm School of Cachoeiras de Macacu of the Federal Fluminense University, in the state of Rio de Janeiro, during the period from 2006 to 2007 (August to June). One hundred sixteen crossbred female Holstein-Zebu dairy cows in cycle, with body condition between 2.5 to 4 (on a scale from 1 to 5), were selected and divided randomly in 3 groups (G). Animals in G1 [n = 60; 21 heifers (H), 13 primiparous (P), and 26 multiparous (M)], with palpable corpus luteum, received 25 mg of prostaglandin F2 intravulvar, and AI was done 12 h after estrus detection. For animals in G2 (n = 30; 11 H, 6 P, and 13 M) an intravaginal progesterone device (CIDR®, Pfizer Animal Health, New York, NY, USA) was inserted and 2 mg of estradiol benzoate (EB) was administered i.m. on Day 0. On Day 8 the device was removed and 25 mg of prostaglandin was administered i.m. on Day 9, 2 mg of EB was administered, and 30 h later, timed AI of all animals was performed. For G3 (n = 26; 9 H, 5 P, and 12 M), the protocol used was similar to that for G2, except that on Day 8 400 IU of eCG was administered (in addition to the removal of the device) and on Day 9 the dose of EB was reduced to 1 mg and timed AI was done 27 h later. AI was done with semen from 2 sires with proven fertility, by the same technician. The pregnancy diagnoses were done on Day 45 by palpation per rectum and transrectal ultrasonography. The cost-benefit relation was calculated according to the cost of pharmaceuticals multiplied by the number of animals in each experimental group divided by the number of pregnancies obtained in each one, without considering the manual labor costs in all the groups and considering 3 uses of the CIDR. The statistical analyses were done using chi-square test. The pregnancy rate obtained in G2 (60%, 18/30) was superior to that in G1 (30%, 18/60) (P < 0.05), demonstrating the efficiency of the treatment that utilized progesterone. G3 (53.85%, 14/26) was similar (P > 0.05) to G2, despite the fact that the eCG was added in this group. In reference to cost-benefit, considering only the pharmaceuticals costs and the value for pregnancy obtained in each group, the costs found, respectively, were G1 U$7.02 and U$23.66; G2 U$28.57 and U$47.59; and G3 U$47.96 and U$89.05. The lowest cost in the estrus synchronization was based on the use of prostaglandins alone; the use of progesterone increased the synchronization cost, but also increased the pregnancy rate and eliminated the need for estrus observation. The addition of eCG in cows that are cycling does not necessarily demand a increase in pregnancy rate. Failure in estrus detection, using prostaglandin alone, increased the interval from calving, causing a daily loss in milk production, which justified the investment in protocols of estrus and ovulation synchronization, contributing to increase the reproductive efficiency of a dairy cow herd.

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Effects of GnRH, PGF2α and oxytocin treatments on conception rate at the time of artificial insemination in lactating dairy cows

Czech Journal of Animal Science ◽

10.17221/1283-cjas ◽

2011 ◽

Vol 56 (No. 6) ◽

pp. 279-283 ◽

Cited By ~ 1

Author(s):

A. Gümen ◽

A. Keskin ◽

G. Yilmazbas-Mecitoglu ◽

E. Karakaya ◽

S. Cevik ◽

...

Keyword(s):

Dairy Cows ◽

Artificial Insemination ◽

Reproductive Tract ◽

Female Reproductive Tract ◽

Conception Rate ◽

Beneficial Effects ◽

Lactating Dairy Cows ◽

Conception Rates ◽

Prostaglandin F ◽

And Control

In several studies, hormones such as gonadotropin-releasing hormone (GnRH), prostaglandins and oxytocin were used to increase pregnancy rate by inducing ovulation and improving the sperm transport in the female reproductive tract in lactating dairy cattle. The objective of this study was to compare the effects of GnRH, prostaglandin F2α (PGF2α) and oxytocin treatments at the time of artificial insemination (AI) after spontaneous oestrus on the conception rate (CR) of lactating dairy cows. Oestrus was detected by visual observations by experienced personnel. All cows (n = 430, 308 Holstein-Frisian and 122 Swedish-Red dairy cows) were inseminated based on the am/pm rule by veterinarians of the farm. After AI, cows were alternately assigned to one of the four treatment groups: (1) GnRH (n = 113); (2) PGF2α (n = 106); (3) oxytocin (n = 106) and (4) non-treated control (n = 105). Pregnancy diagnosis was performed 28–34 and 58–64 days post-insemination by transrectal ultrasonography. Conception rates on days 28–34 and 58–64 were not different among GnRH (46.0%; 52/113 and 44.3%; 50/113), PGF2α (37.7%; 40/106 and 35.9%; 38/106) and control (49.5%; 52/105 and 47.6%; 50/105) groups. However, conception rates were lower (P = 0.02) in oxytocin (31.1%; 33/106 and 30.2%; 32/106) than in GnRH and control groups on days 28–34 and 58–64. Other covariant factors, such as milk production, days in milk (DIM), breed, parity, service number did not affect the conception rate. Thus, there were no beneficial effects of treatments with GnRH and PGF2α at the time of AI, and oxytocin had an adverse effect on CR in lactating dairy cows in this study.

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300 Efficacy of the measurements of the vaginal electrical resistance to determine the phase of the estrous cycle in lactating dairy cattle

Journal of Animal Science ◽

10.1093/jas/skz258.282 ◽

2019 ◽

Vol 97 (Supplement_3) ◽

pp. 138-138

Author(s):

Martin G Maquivar ◽

John Swain ◽

Hannah Chiapetta ◽

Tynnetta Stumvoll ◽

Katelin Baker ◽

...

Keyword(s):

Dairy Cattle ◽

Dairy Cows ◽

Estrous Cycle ◽

Electrical Resistance ◽

Luteal Phase ◽

Economic Loss ◽

Estrous Cycles ◽

Follicle Diameter ◽

Estrus Detection ◽

Vaginal Temperature

Abstract Estrus detection in dairy cattle is an important factor that contributes to the reproductive efficiency. Lack and inaccuracy of heat detection are associated with increased days open, calving interval, economic loss and culling due to infertility. Efforts have been made to identify methods to assist in estrus detection. The objective of this study was to examine if vaginal electrical resistance (VER) measured by a commercial probe throughout the estrous cycle in lactating dairy cows aids to determine the onset of estrus. A total of 9 lactating Holstein cows were monitored for 2 – 3 estrous cycles, ultrasonography of the ovary, blood sample for progesterone and VER was assessed every other day during the luteal phase (LUT) and every day during the follicular phase (FOL). A total of 339 VER measurements were collected, 66 during the FOL phase and 273 corresponded to the LUT phase. Mean VER differed (P < 0.001) between FOL (294.5 ± 51.3) and LUT (316.4 ± 46.2), similarly the progesterone concentration was different between the LUT and FOL phases (0.38 ± 0.24 ng/mL vs. 3.41 ± 2.08 ng/mL, respectively) (P < 0.001). No differences were observed between the vaginal temperature of cows in LUT (38.2 ± 0.4 C°) or FOL phase (38.3 ± 0.3 C°). Cervix diameter differed (P < 0.01) between FOL (35.9 ± 3.8 mm) and LUT (34.5 ± 3.4mm), VER has a significant relation (P < 0.001) with the diameter of the Corpus luteum (279.8 + 1.54 x Cervix diameter). Similarly, VER had a significant relationship (P = 0.03) with diameter of the dominant follicle at estrus (355.2 + -3.9 x follicle diameter). These findings suggest that VER changes according to the phase of the estrous cycle, VER decreased during sexual receptivity and increased during the luteal phase. VER may improve the accuracy to diagnose heat in dairy cows.

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180EFFECT OF TIME OF ECG TREATMENT ON PREGNANCY RATES IN BOS INDICUS×BOS TAURUS RECIPIENTS SYNCHRONIZED WITH PROGESTERONE VAGINAL DEVICES AND TRANSFERRED WITHOUT ESTRUS DETECTION

Reproduction Fertility and Development ◽

10.1071/rdv16n1ab180 ◽

2004 ◽

Vol 16 (2) ◽

pp. 212

Author(s):

L.F. Nasser ◽

E.L. Reis ◽

A.M. Oliveira ◽

G.A. Bo ◽

P.S. Baruselli

Keyword(s):

Bos Taurus ◽

Bos Indicus ◽

Fixed Time ◽

Estradiol Benzoate ◽

Pregnancy Rates ◽

Bovine Embryo ◽

Treatment Groups ◽

Estrus Detection ◽

Treatment Interaction

It has been shown recently that treatments with progesterone (P4)-releasing devices combined with estradiol benzoate (EB) plus P4 on Day 0, eCG and PGF on Day 5 and a second application of EB one day after device removal (Day 9) can be used successfully to transfer bovine embryos at a self-appointed time, without the necessity of estrus detection. Although the treatment solved one of the major problems in recipient management, estrus detection, it requires handling the recipients at least five times for treatments and embryo transfer. An experiment was designed to evaluate whether reducing one day of handling, by the administration of eCG and PGF at the time of removal of the P4 device (Day 8), results in comparable pregnancy rates than giving eCG on Day 5. A secondary objective was to determine the effect of injectable P4 at the time of device insertion plus EB treatment. Crossbred Bos taurus×Bos indicus beef heifers (n=301) were randomly assigned to 4 treatment groups in a 2 by 2 factorial design. All Heifers received a P4 device (DIB, Syntex, Argentina) plus 2mg EB i.m. (Syntex) at unknown stages of the estrous cycle (Day 0), with or without 50mg of P4 given i.m. at the same time. Heifers were further subdivided to receive PGF (0.150mg d-cloprostenol, Prolise, Tecnopec, Sao Paulo, Brazil) and 400IU of eCG (Novormon, Syntex) i.m. on Days 5 or 8. In all heifers, DIB devices were removed on Day 8 and 1 mg EB was administered i.m. on Day 9. Day 10 was arbitrarily considered as the day of estrus. On Day 17, heifers were bled for plasma P4 concentrations and examined by ultrasonography to determine the number of CL and their diameter. Heifers that had >1 CL or a single CL with diameter ≥18mm received an in vitro-produced (IVP) embryo by nonsurgical transfer performed by the same veterinarian. Pregnancy rates were determined by ultrasonography 30 days later. The effects of Day of eCG administration (Day 5 or Day 8), P4 of treatment (E2 or E2+P4) and the day-by-P4 treatment interaction on the numbers of CL and plasma P4 were analyzed by ANOVA, and the proportion of recipients selected and pregnant were analyzed using non-parametric tests (NPAR1WAY, SAS). There was no significant effect of P4 treatment or the P4-by-day of eCG interaction in any of the parameters evaluated. However, there was a significant effect of day of eCG administration on plasma P4 concentrations (Day 5=2.4±0.3 v. Day 8=1.7±0.2; P=0.03) and the number of CL (Day 5=1.4±0.1 v. Day 8=1.1±0.0; P=0.02) on Day 17. Furthermore, the proportion of recipients pregnant/treated tended (P=0.1) to be higher in heifers in the Day 5 Group (71/151, 47.0%) than in those in the Day 8 Group (61/150, 40.7%). Although delaying the eCG and PGF administration from Day 5 to Day 8 saves one trip through the chute for treatments, it resulted in lower plasma P4 concentrations and tended to decrease pregnancy rates in bovine embryo recipients synchronized with DIB devices and EB and transferred at a fixed time. Furthermore, the administration of injectable P4 at the time of DIB insertion did not affect pregnancy rates.

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The Effect of Ambient Temperature on Conception and Milk Performance in Breeding Holstein Cows

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun201765051515 ◽

2017 ◽

Vol 65 (5) ◽

pp. 1515-1520 ◽

Cited By ~ 1

Author(s):

Kristýna Klementová ◽

Radek Filipčík ◽

Martin Hošek

Keyword(s):

Ambient Temperature ◽

Dairy Cows ◽

Milk Yield ◽

Winter Season ◽

Conception Rate ◽

Holstein Cows ◽

Experimental Population ◽

Conception Rates ◽

Daily Milk Yield ◽

Daily Milk

The aim of this study was to identify the effect of ambient temperature and season of the year on conception difficulties in Holstein cattle. The experiment was conducted on the School farm in Žabčice. Data were collected from July 2016 to January 2017. Experimental population counted 263 breeding Holstein cows, which were inseminated during the observation period. Results of this study confirmed the effect of temperature and season on conception rates in dairy cows. In winter season, successful conception was recorded in 56.36 % of cows in average ambient temperature 1.48 °C, in summer season the conception rate was only 40.43 % in average daily temperature 18.96 °C. A more detailed analysis revealed the highest conception rates in the dairy cows in January (88.24 %) and February (91.67 %). On the contrary, the worst results were recorded in September (22.73 %) and October (28.57 %). Evaluation of conception rate according to ambient temperature intervals showed best results for the temperatures below 5 °C. A part of the study was also evaluation of an association between daily milk yield and conception rate. This hypothesis cannot be conclusively confirmed, because milk yield was mostly similar in both groups (pregnant and non‑pregnant) on the days of insemination. The effect of lactation order and mean daily milk yield on the conception rate in cows was not confirmed.

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404 SUPEROVULATORY RESPONSE IN BEEF DONORS TREATED DURING THE FIRST FOLLICULAR WAVE OR FOUR DAYS AFTER PROGESTERONE AND ESTRADIOL ADMINISTRATION

Reproduction Fertility and Development ◽

10.1071/rdv22n1ab404 ◽

2010 ◽

Vol 22 (1) ◽

pp. 358 ◽

Cited By ~ 3

Author(s):

D. Carballo Guerrero ◽

A. Tríbulo ◽

R. Tríbulo ◽

H. Tríbulo ◽

G. A. Bó

Keyword(s):

Estrous Cycle ◽

Animal Health ◽

Estradiol Benzoate ◽

Control Group ◽

Wave Groups ◽

Follicular Wave ◽

Estrus Detection ◽

Group 3 ◽

Group 2 ◽

Group 1

Although we have previously shown that ovarian superstimulation during the first follicular wave resulted in a successful response (Carballo Guerrero D et al. 2009 Reprod. Fertil. 21, 242), the current protocol needs to be optimized in order to be used in the field. Therefore, an experiment was designed to simplify this treatment and to compare it with the traditional superstimulation protocol using progesterone and estradiol. Simmental cows (n = 14) were subjected to 3 superstimulation treatments (2 first wave groups and 1 control group) in a crossover design (i.e. all cows received the 3 treatments and all treatments were represented on each collection day). Cows in Group 1 received a progesterone-releasing device (Cue-Mate®, Bioniche Animal Health, Belleville, Ontario, Canada) along with 0.150 mg of D + cloprostenol (PGF; Bioprost-D®, Biotay, Buenos Aires, Argentina) at random stages of the estrous cycle. A second PGF was injected 5 days after Cue-Mate® insertion, followed by GnRH (0.050 mg of lecirelin; Biosin-OV®, Biotay) 36 h later (i.e. 7 days after Cue-Mate® insertion). Based on previous studies, ovulation was expected to occur 30 to 36 h later. Therefore, superstimulation treatments were initiated 36 h after GnRH (Day 0), with a total dose of 400 mg NIH-FSH-P1 of Folltropin®-V (Bioniche Animal Health) in twice-daily decreasing doses over 4 days. Prostaglandin was administered with the last 2 Folltropin®-V injections and Cue-Mate® devices were removed with the last Folltropin®-V injection. Cows received 12.5 mg of porcine LH (Lutropin®-V, Bioniche Animal Health) 24 h after Cue-Mate® removal and were AI 12 and 24 h later. Ova/embryos were collected 7 days after porcine LH and evaluated following IETS recommendations. Cows in Group 2 were treated similarly to those in the Group 1, except they did not receive the second PGF injection 5 days after Cue-Mate® insertion (thus eliminating the need to handle animals on that day). Finally, cows in Group 3 [estradiol benzoate (EB)+P4 control group] received a Cue-Mate® plus 2.5 mg of EB (Bioestradiol®, Biotay) and 50 mg of progesterone (P4; Lab., Rio de Janeiro, Argentina) at random stages of their estrous cycle. Superstimulation treatments were initiated 4 days later (Day 0) following the same protocol used in Group 1. Data were transformed to square root and analyzed by ANOVA. Mean (± SEM) numbers of ova/embryos collected, fertilized ova, and transferable embryos did not differ among groups (12.9 ± 2.0, 9.8 ± 1.7, and 6.6 ± 1.2; 11.5 ± 1.7, 9.3 ± 1.5, and 7.7 ± 1.6; and 14.5 ± 2.8, 9.4 ± 2.3, and 6.8 ± 1.7 for Groups 1, 2, and 3, respectively). In conclusion, data demonstrated that superstimulation during the first follicular wave can be successfully used in groups of randomly cycling donors without the need for estrus detection or estradiol to synchronize follicular wave emergence. The protocol is easy to follow and embryo production is comparable to that of the estradiol and progesterone protocol.

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