Tylosin injectable for the treatment of porcine proliferative enteropathy in experimentally inoculated pigs

ABSTRACT: Porcine proliferative enteropathy (PPE) is one of the most common enteric diseases in growing and finishing pigs. PPE is characterized by reduced growth performance, accompanied or not by diarrhea. PPE is highly prevalent in several countries of the Americas, Europe and Asia, causing high economic losses in swine herds. The most common form of PPE control in pigs is antibiotic therapy. The objective of this study was to evaluate a new product based on tylosin injectable (Eurofarma Laboratórios S.A.) to control PPE in experimentally inoculated animals. Sixty 5-week-old pigs with mean weight of 9.5kg were divided into two experimental groups of 30 animals: medication and control. All pigs were challenged with Lawsonia intracellularis, the etiologic agent of PPE, on day zero. Fecal score, body condition score, and behavior were daily evaluated. Pigs were weighted on days -2, 13 and 21 of the experiment. Pigs in the Medication Group received tylosin injectable 13 days after inoculation, in three doses with a 12-hour interval between them. Pigs in the Control Group received injectable saline solution following the same protocol. In the Control Group, 23pigs presented with diarrhea before day 13. After day 13, the number of diarrheic animals in this group was reduced to 17. In the Medication Group, 26 pigs presented with diarrhea in the initial period, and in the period after medication, only 11 animals had diarrhea. The score of gross intestinal PPE lesions in the Medication Group was lower than that in the Control Group (p=0.031). The Medication Group also showed lower score for Lawsonia intracellularis antigen-labeling by immunohistochemistry compared with that of the Control Group (p=0.032), showing lower level of infection. These results demonstrate that tylosin injectable (Eurofarma Laboratórios S.A.), administrated in three doses (1mL/20kg) every 12 hours, was effective for the control of PPE in experimentally inoculated pigs.

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Some Aspects of Reproductive Performance of Red Sokoto Goat Does Post Synchronization with Prostaglandin F2-Alpha And Progesterone Sponges

Nigerian Veterinary Journal ◽

10.4314/nvj.v40i4.2 ◽

2021 ◽

Vol 40 (4) ◽

pp. 263-277

Author(s):

A.A. Bello ◽

A.A Voh JR ◽

D. Ogwu ◽

L.B. Tekdek

Keyword(s):

Clinical Application ◽

Reproductive Performance ◽

Body Condition Score ◽

Retention Rate ◽

Visual Observation ◽

Control Group ◽

Prostaglandin F2 Alpha ◽

Condition Score ◽

Red Sokoto Goat ◽

And Control

A study on reproduction of 52 Red Sokoto Goat (RSG) does was conducted to evaluate some aspects of their reproductive performance for clinical application and as an update. Does were randomly divided into 18, 18 and 16 as prostaglandin F2-alpha (PGF2α), progesterone sponges (P4S) and control groups respectively. Double injection protocol of PGF2α, 12-days apart, and P4S inserted for 12-days were used to synchronize oestrus, while the control group received no treatment. Thirteen bucks were used, seven as breeders and six as heat detectors. Oestrus detection employed visual observation and apronisation. Standing to be mounted was the cardinal sign of oestrus. Breeding was by hand-mating and at detected oestrus. Results indicated heterosexual and homosexual mounting, thin stringy clear mucous discharge and standing-to-be-mounted as signs of oestrus. Oestrus response rate was 100 %, 94.4 % and 75.0 % for PGF2α, P4S and Control respectively; P4S retention rate was 94%. Effect of synchronization agent on on-set of oestrus was 15.86 + 0.73 h (PGF2α), 15.08 + 0.84 h (P4S) and 17.73 + 0.85 h (Control), while parity on on-set of oestrus was 12.12 + 1.87 h (first), 17.77 + 0.77 h (second) and 18.79 + 1.95 h (third). Effect of synchronization agent on duration of oestrus was 44.76 + 2.13 h, 45.78 + 2.46 h and 42.40 + 2.50 h for PGF2Α P4S and Control respectively, while parity on duration of oestrus was 42.26 + 5.48 h (first), 45.02 + 2.27 h (second) and 45.67 + 5.73 h (third). There were no significant differences (P > 0.05) for oestrus on-set and duration. Overall pregnancy and conception rates were 65.4 % and 72.3 % respectively, kidding rate was 76.5 %, abortion rate was 23.5 % and late embryonic mortality rate was 26.5 %. Mean gestation were 146.29 + 1.59 and 146.63 + 1.64 for single and twin births respectively. Age, parity and body condition score of dam had significant effect on litter size (P < 0.05). It was concluded that some aspects of the reproductive performance of the RSG does studied following oestrus synchronization with PGF2α and P4S had clinical application, good and acceptable. Key Words: Reproductive, Red Sokoto, Does, Prostaglandin F2-alpha and Progesterone.

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10 EFFECT OF ESTRADIOL BENZOATE OR hCG ON DAY 22 AFTER TIMED ARTIFICIAL INSEMINATION ON THE CORPUS LUTEUM SIZE, PROGESTERONE CONCENTRATION, AND PREGNANCY RATE IN RESYNCHRONIZED BEEF HEIFERS

Reproduction Fertility and Development ◽

10.1071/rdv28n2ab10 ◽

2016 ◽

Vol 28 (2) ◽

pp. 134

Author(s):

J. B. S. Borges ◽

H. L. D. Neri ◽

M. R. Almeida ◽

E. P. Silva ◽

A. Bilha

Keyword(s):

Corpus Luteum ◽

Pregnancy Rate ◽

Body Condition ◽

Body Condition Score ◽

Pregnancy Rates ◽

Control Group ◽

Beef Heifers ◽

Pregnancy Diagnosis ◽

Condition Score ◽

And Control

This study aimed to compare the effects of 2 inducers of new follicular wave [oestradiol benzoate (EB) or hCG] administrated at onset of resynchronization protocols initiated 22 days after the first timed AI (TAI) of beef heifers. We evaluated the effect of treatments on corpus luteum (CL) development, serum progesterone (P4) concentrations, and pregnancy rates. A total of 467 grazing Brangus heifers, with 24- to 26-months, 320 ± 10 kg of body weight, and 3.2 ± 0.5 body condition score, were utilised. The resynchronization protocol began 22 days after the first TAI (Day 22). Heifers were randomly allocated into 1 of 3 groups: EB (n = 199), hCG (n = 101), or control untreated (n = 167). The EB- and hCG-treated heifers received an intravaginal P4 device (Procliclar, 0.75 g of P4; Hertape, Brazil) and an IM treatment with 1 mg of EB (Benzoato HC, Hertape) or 1000 IU of hCG (Vetecor 5000, Hertape), respectively. On Day 30, P4 device was removed, and the pregnancy diagnosis was performed. At this time heifers had the CL area (cm2) determined by ultrasound and seric P4 concentration evaluated by chemiluminescence assay. The assay sensitivity was 0.1 ng mL–1, and the intra- and interassay coefficients of variation were 7.9 and 10.6%, respectively. Nonpregnant heifers after the first TAI (EB = 97, hCG = 36) received intramuscularly 150 μg of sodium cloprostenol (Veteglan Luteolítico, Hertape) and 1 mg of oestradiol cypionate (Cipionato HC, Hertape). The second TAI was performed 48 to 52 h after the P4 device removal. On Day 62, heifers were submitted to a second pregnancy diagnosis. No effect of the body condition score (P = 0.28) was observed on the first and second pregnancy per AI. Pregnancy rates after the first TAI were higher (P = 0.03) on hCG-treated heifers (64.4%) than EB (51.3%) or the control group (58.7%). The EB group determined greater (P = 0.04) pregnancy rate after the second TAI (49.5%) than the hCG group (22.2%). The cumulative pregnancy rates were similar (P = 0.46) between groups [EB (72.4%) and hCG (68.3%)]; however, both were greater (P < 0.05) than the control group (58.6%). Heifers treated with hCG (3.42 ± 0.76) presented greater CL area at Day 30 (P < 0.05) than the EB (2.44 ± 0.57) and control (2.61 ± 0.61) groups. The treatment with hCG 22 days after TAI determined greater (12.43 ± 3.48; P < 0.05) serum P4 concentrations on Day 30 than the EB (6.92 ± 3.04) and control (7.29 ± 2.45) groups. Therefore, the use of hCG at the beginning of resynchronization protocol 22 days after the TAI increased pregnancy rate following the first TAI. However, the use of 1 mg of EB determined greater pregnancy rate after the second TAI, and no detrimental effects on CL development, P4 concentration, and on first TAI pre-established pregnancy.

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192 The use of human chorionic gonadotropin seven days after synchronized estrus for the increase of luteal tissue in Morada Nova ewes

Reproduction Fertility and Development ◽

10.1071/rdv31n1ab192 ◽

2019 ◽

Vol 31 (1) ◽

pp. 220

Author(s):

G. B. Vergani ◽

J. T. Trevizan ◽

V. S. A. Pereira ◽

J. F. Fonseca ◽

A. R. Garcia ◽

...

Keyword(s):

Body Condition Score ◽

Physiological Solution ◽

Saline Control ◽

Favourable Effect ◽

Control Group ◽

Corpora Lutea ◽

Control Groups ◽

Luteal Tissue ◽

Condition Score ◽

And Control

The study was performed to evaluate whether the use of hCG 7 days after synchronized oestrus in Morada Nova ewes would increase the number and size of corpora lutea. Multiparous Morada Nova ewes (n=115, mean weight of 36.6kg, body condition score 3.13 on 1 to 5 scale) were used. Oestrus was synchronized by using an intravaginal sponge impregnated with medroxyprogesterone acetate (60mg, Progespon®, Zoetis, Parsippany, NJ, USA) for 6 days and eCG (200IU, IM Novormon®, Zoetis) plus PGF2α analogue (37.5μg, D-cloprostenol, IM, Vetglan®, Hertape Calier, Spain), both administered 24h before the sponge removal. Seven days after the synchronized oestrus, hCG (300IU, IM, Vetecor®, Hertape Calier; n=57) or normal saline (control group, 1mL, IM, 0.9% NaCl, Eurofarma Laboratory SA, Sao Paulo, Brazil; n=58) was injected. B-mode ultrasound examinations of the ovaries were performed using the equipment MyLab Vet 30 Gold (Esoate, Genoa, Italy) on Day 7 (corresponding to the day of hCG or physiological solution administrations), and 6 days later (Day 13). The number of corpora lutea present and the size of luteal tissue (sum of diameter and area) were determined. Data were analysed by ANOVA with Tukey’s post hoc test (mean±s.e.m.) using SAS software (SAS Institute Inc., Cary, NC, USA). On Day 7, the number of corpora lutea was similar (P>0.05) between the hCG and control groups (1.58±0.09v. 1.57±0.08, respectively); however, the number was higher on Day 13 (P<0.05) in the hCG group (2.65±0.13) than in the control group (1.69±0.07). Similarly, there was no difference (P>0.05) between groups in diameter (16.9±0.82v. 16.0±0.71mm) and area (1.61±0.07v. 1.45±0.06cm2) for hCG and control groups, respectively, on Day 7. Differences were observed on Day 13, such that the hCG ewes had luteal tissue of larger (P<0.0001) diameters (27.13±1.25v. 18.44±0.85mm) and area (2.81±0.13v. 1.71±0.08cm2) than ewes of the control group. In conclusion, 300IU of hCG injected 7 days after synchronized oestrus is effective to increase the number of corpora lutea and in the size of luteal tissue. Despite indications of a favourable effect on luteal dynamics, the effects on progesterone production and conception rate need to be examined. This study was supported by CNPq and EMBRAPA (process no. 02.13.06.026.00.02).

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Safety Study on Ketoprofen in Pigs: Evaluating the Effects of Different Dosing and Treatment Scheme on Hematological, Hepatic, and Renal Parameters

Veterinary Sciences ◽

10.3390/vetsci8020030 ◽

2021 ◽

Vol 8 (2) ◽

pp. 30

Author(s):

Luis Emilio Fazzio ◽

Santiago José Raggio ◽

Juan Facundo Romero ◽

Juver Membrebe ◽

Antonio Humberto Hamad Minervino

Keyword(s):

Body Condition Score ◽

Clinical Signs ◽

Study Groups ◽

Control Group ◽

Safety Study ◽

Treatment Groups ◽

Treatment Scheme ◽

Condition Score ◽

Biochemical Evaluation ◽

Different Doses

A safety study on ketoprofen 10% was carried out on pigs using a different dosing and treatment scheme. Forty healthy crossbreed pigs with similar age, weight, and body condition score were distributed into five treatment groups. The pigs were intramuscularly injected once with different doses of ketoprofen: 3 mg/kg (group 1X), 6 mg/kg (group 2X), 9 mg/kg (group 3X). In addition, the 3 mg/kg dosis was administered on three consecutive days (group 1X ext.). Intramuscular injections of saline solution were used in control group (CTL). The pigs were clinically examined throughout the trial and blood samples were taken for hematological and biochemical evaluation on days −4 (before treatment), +3, +7, and +14 (the end of the trial). Any unusual behaviour or clinical signs were reported as potential toxic effects of ketoprofen. Serum measurements showed that none of the ketoprofen doses produced changes in renal or hepatic biochemical parameters, liver enzymes, or total bilirubin. Likewise, hematological assessment indicated no altered parameters or hematocrit percentage in the study groups. These results demonstrate that ketoprofen has no adverse effects in pigs when the doses and scheme evaluated in this study are applied.

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Luteogenesis and Embryo Implantation Are Enhanced by Exogenous hCG in Goats Subjected to an Out-of-Season Fixed-Time Artificial Insemination Protocol

Biology ◽

10.3390/biology10050429 ◽

2021 ◽

Vol 10 (5) ◽

pp. 429

Author(s):

Jorge A. Bustamante-Andrade ◽

César A. Meza-Herrera ◽

Rafael Rodríguez-Martínez ◽

Zurisaday Santos-Jimenez ◽

Oscar Ángel-García ◽

...

Keyword(s):

Corpus Luteum ◽

Artificial Insemination ◽

Body Condition Score ◽

Embryo Implantation ◽

Implantation Rate ◽

Fixed Time ◽

Efficiency Index ◽

Control Group ◽

Condition Score ◽

Interesting Approach

The aim of this study was to evaluate the possible effect of two doses of hCG (100 and 300 IU) applied at two different times (7 and 14 d) after a fixed-time artificial insemination protocol (FTAI) upon some variables involved in the embryonic implantation rate in goats during the natural deep anestrous season (April, 25° north). The experimental units considered crossbred, multiparous, anovulatory goats (n = 69, Alpine, Saanen, Nubian x Criollo), with average body weight (43.6 ± 5.7 kg) and body condition score (1.86 ± 0.28 units) located in northern–semiarid Mexico (25° N, 103° W). Once the goat’s anestrus status was confirmed, goats were subjected to an estrus induction protocol. Upon estrus induction confirmation, goats (n = 61) were subjected to a FTAI procedure. Immediately after the FTAI, the goats were randomly distributed to five experimental groups: (1). G100-7 (n = 13) 100 IU, hCG 7 d post-FTAI, (2). G100-14 (n = 12) 100 IU hCG, 14 d post-FTAI, (3). G300-7 (n = 12) 300 IU, hCG, 7 d post-FTAI, (4). G300-14 (n = 12) 300 IU hCG 14 d post-FTAI, and (5). Control group, CONT (n = 12) 0.5 mL saline, 7 and 14 d post-FTAI. The response variables conception rate (39.36 ± 0.23), fertility rate (27.96%), prolificacy rate (1.1 ± 0.29 kids), ovulation rate (0.74 ± 0.20 corpus luteum) corpus luteum diameter (10.15 ± 0.59 mm), embryo number (1.58 ± 0.20), and embryo implantation rate (48.96%), did not differ between treatments. However, while the variables fecundity rate (67%), embryo efficiency index-1 (33.99 ± 0.20%), and embryo efficiency index-2 (27.94 ± 0.30%) were favored by the G300-14 treatment, the corpus luteum area was favored (p < 0.05) by both G300-7 (113.30 ± 0.19 mm2) and G300-14 (103.04 ± 0.17 mm2). Such reproductive strategy emerges as an interesting approach, not only to enhance the out-of-season reproductive outcomes, but also to boost one of the main rulers defining the global reproductive efficiency of a heard, namely, the embryo implantation efficiency.

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Prevalence and distribution of feet lesions in dairy cows raised in the freestall

Semina Ciências Agrárias ◽

10.5433/1679-0359.2019v40n1p239 ◽

2019 ◽

Vol 40 (1) ◽

pp. 239 ◽

Cited By ~ 1

Author(s):

Rafael Costa Ebling ◽

Amanda Krummenauer ◽

Gustavo Machado ◽

Diego Zeni ◽

Luis Paulo Carazzo ◽

...

Keyword(s):

Dairy Cows ◽

Body Condition Score ◽

The Body ◽

Economic Losses ◽

Productivity Losses ◽

Foot Diseases ◽

Infectious Origin ◽

Condition Score ◽

Foot Lesions ◽

Sole Ulcers

Foot lesions are one of the main causes of productivity losses in the dairy industry. In this study, we aimed to estimate the prevalence of claudication and distribution of hoof lesions by associating them with preventive hoof trimming, as well as list the main causes of involuntary discarding and the main health problems reported in dairy farms. The study included 10 farms distributed in 7 municipalities of Rio Grande do Sul state. The body condition score (BCS) and locomotion score (LS) of the cows were assessed. Hoof examination, lesion classification, and hoof trimming of the animals were performed. Of the 492 animals, 38.4% presented lameness and 36% had foot lesions, 81.4% of which were observed in the pelvic limbs and 19.6% in the thoracic limbs. Of the lesions in the limbs, 47.1% were of infectious origin and 52.9% were noninfectious. The main lesions were sole ulcers (31.6%), digital dermatitis (30.3%), thin soles (12%), and interdigital dermatitis (11.2%). Cows aged 4 to 6 years had a higher number of lesions and a higher LS. Preventive hoof trimming reduced the chances of lameness by 55% as the locomotive system was the main sanitary problem and the first reason for involuntary disposal of the farms. The results show that dairy cows raised in a free stall system have a high prevalence of claudication and foot diseases. These data should be taken into account when altering the livestock management of these animals in order to reduce significant economic losses in the herd.

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Effect of α-tocopherol acetate and zinc supplementation on body condition, energy metabolites and milk production in Karan Fries cows

Indian Journal of Animal Research ◽

10.18805/ijar.8563 ◽

2016 ◽

Vol 50 (1) ◽

Author(s):

Pankaj Kumar Maurya ◽

Anjali Aggarwal ◽

A. K. Singh ◽

B. K. Chaudhari

Keyword(s):

Body Weight ◽

Treatment Group ◽

Milk Production ◽

Body Condition ◽

Body Condition Score ◽

Control Group ◽

Experimental Animals ◽

Tocopherol Acetate ◽

Condition Score ◽

Karan Fries

The study was conducted to investigate the effect of α-tocopherol acetate and zinc on body condition, energy metabolites and milk production in Karan Fries cows. Sixteen pregnant Karan Fries cows were selected two months before expected date of calving. The experimental animals were randomly divided in to two groups namely control group (eight cows) and treatment group (eight cows). Treatment group cows were supplemented with α-tocopherol acetate @ 1000 IU/day/cow and zinc @ 60 ppm/day/cow. Blood samples were collected on the days -60, -45, -30, -15, -7, 0, +7, +15, +30, +45 and +60 with respect to expected date of calving. The body weight and body condition score of all the experimental animals was recorded on the day of blood collection. After calving milk yield of the experimental animals was recorded till 60 days in milk. At parturition, body weight and body condition score differ significantly (P<0.001) in treatment group than control group (448.00 vs. 416.33 Kg and 4.42 vs. 4.17, respectively). The overall mean (±SEM) of plasma glucose was found to be significantly (P<0.001) higher in treatment group as compared to control group (62.39±1.23 vs. 57.44±1.59 mg/dl). The overall mean of non-esterified fatty acids was found to be significantly (P<0.001) lower in treatment group as compared to control group (197.10±3.38 vs. 239.21±3.48 μM/L). The overall mean of milk yield was found significantly (P<0.001) higher in treatment group as compared to control group (20.48±1.16 vs. 16.94±1.38 Kg/day i.e. 20.90%). The results of this study indicated that supplementation of antioxidants like α-tocopherol acetate and zinc have beneficial effects on milk production along with improved body condition and metabolic status of the animals.

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Evaluation of Fermented Oat and Black Soldier Fly Larva as Food Ingredients in Senior Dog Diets

Animals ◽

10.3390/ani11123509 ◽

2021 ◽

Vol 11 (12) ◽

pp. 3509

Author(s):

Kangmin Seo ◽

Hyun-Woo Cho ◽

Julan Chun ◽

Junghwan Jeon ◽

Chanho Kim ◽

...

Keyword(s):

Body Condition Score ◽

Clinical Signs ◽

Skin Condition ◽

Control Group ◽

Black Soldier Fly ◽

Food Ingredients ◽

Treatment Groups ◽

Daily Food ◽

Condition Score ◽

Group A

The aim of this study was to evaluate the suitability of fermented oat (FO) and black soldier fly larva (BSFL) as food ingredients for dogs. A total of 20 spayed female dogs were divided into four treatment groups, with 5 dogs per group. The four treatment groups consisted of a control group, a diet with 10% FO, one with 5% BSFL, and one with 10% FO and 5% BSFL, and each experimental food was fed for 12 weeks. The feeding of FO and/or BSFL did not affect the daily food intake, body weight, body condition score, fecal score, or skin condition of the dogs. In all the experimental groups, no significant differences in serum IgG, IL-10, or TNF-α levels were observed upon the feeding of FO and/or BSFL. Some hematological (white blood cell and basophils) and serum biochemical parameters (phosphorous, globulin, and alkaline phosphatase) showed significant differences with FO and/or BSFL feeding compared to the control group, but they were within the normal reference range. No adverse clinical signs related to these parameters being affected by FO and BSFL were observed. The feeding of BSFL for 12 weeks reduced the serum cholesterol level (p < 0.05) at the end of the experiment. Our findings suggest the suitability of FO and BSFL as food materials for dogs.

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Peri-Conceptional undernutrition in twin bearing ewes: Effect on early fetal growth and birth weight

Ecosistemas y Recursos Agropecuarios ◽

10.19136/era.a4n12.1293 ◽

2017 ◽

Vol 4 (12) ◽

pp. 419

Author(s):

Ricardo Vicente-Pérez ◽

Yolanda Osorio-Marín ◽

María De los Angeles López-Baca ◽

Leonel Avendaño-Reyes ◽

Abelardo Correa-Calderón ◽

...

Keyword(s):

Birth Weight ◽

Body Condition ◽

Fetal Growth ◽

Body Condition Score ◽

Control Group ◽

Maternal Body ◽

Crown Rump Length ◽

Condition Score ◽

Nutritional Restriction ◽

Mating Time

A total of 48 Katahdin x Pelibuey multiparous ewes were used to evaluate the e ect of nutritional restriction (40 %) before (30 d, RT), after (50 d, TR) or both periods (80 d, RR) compared with a control group on maternal body status, early fetal growth and lamb birth weights. Only twin bearing ewes were selected at d 50 of pregnancy for fetal measurements by ultrasonography and record of birth weight. Compared with control ewes, lower (p < 0.05) weight and body condition score had RT and RR ewes at mating time, likewise, TR and RR ewes at d 50 post-conception. There were mainly di erences between fetuses from control and RT ewes, being higher (p < 0.05) the vesicular, abdominal and fetal area, as well as crown-rump length and birth weight for RT fetuses. In conclusion, preconception undernutrition positively altered the early fetal growth and lamb birth weights in hair ewes pregnant with twins.

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Induction of Ovulation in Mangalarga Marchador Mares by hCG or GnRH

Acta Scientiae Veterinariae ◽

10.22456/1679-9216.86667 ◽

2018 ◽

Vol 46 (1) ◽

pp. 6

Author(s):

José Carlos Ferreira-Silva ◽

Pábola Santos Nascimento ◽

Marcelo Tigre Moura ◽

Sarah Romini Lima Basto ◽

Marlon Vasconcelos Azevedo ◽

...

Keyword(s):

Assisted Reproduction ◽

Body Condition Score ◽

High Specificity ◽

Pregnancy Rates ◽

Experimental Conditions ◽

Induction Of Ovulation ◽

Estrus Detection ◽

Condition Score ◽

Inducing Factors ◽

And Control

Background: Induction of ovulation is a key procedure for horse assisted reproduction technologies, such as for artificial insemination (AI) and embryo transfer. The application of hCG remains as the primary ovulation-inducing agent for horse assisted reproduction, but alternatives are in demand to avoid its adverse effects, such as loss of ovulation-inducing efficiency over multiple applications by hCC-antibody production. Despite reports on alternative ovulation-inducing agents, pair-wise comparisons of such agents under similar conditions have been limited. Under such scenario, the work was aimed to determine the efficiency of both hCG and Buserelin at inducing ovulation in Mangalarga Marchador mares raised in the Northeast of Brazil under an AI program.Materials, Methods & Results: Mares were initially selected based on their reproductive performance, the absence of clinical-reproductive alterations and adequate body condition score. Mares in diestrus were randomly distributed in three experimental conditions, received 5 mg of Dinoprost and were monitored daily for estrus detection. After estrus detection, ovaries were monitored by ultrasonography, in 12-h intervals, until the follicle reached 35 mm. At this time-point, ovulation was induced with 0.042 mg of Buserelin endovenously, with 3,000 IU hCG by an intramuscular shot, and control mares received 2 mL of saline solution, also by an intramuscular shot. Both hCG and Buserelin displayed similar efficiencies (P > 0.05) for induction of ovulation and that both agents were effective (P < 0.05) for such purpose, since greater percentages (P < 0.05) of induction on mares treated from those of the control. Moreover, the total number of ovulations in mares treated at the end of the experiment was not different (P > 0.05) from those found in the Control. All ovulations occurred within a 72-h period after treatment. It can be observed that in mares treated with hCG or Buserelin, ovulations occurred both in more mares (P < 0.05) and at earlier time-points than mares from the control. It is also possible to note that pregnancy was not different (P > 0.05) between hCG and Buserelin groups, and that pregnancy of mares treated with ovulation-inducing factors was similar to the control.Discussion: The majority of ovulations in mares occurred within initial 48-h after treatment for both hCG and GnRH, suggesting a similar potential for horse assisted reproduction. Both hCG and Buserelin are two commonly used agents for induction of ovulation in mares. As described here, the majority of ovulations occurred within initial 48-h after treatment, a fact which can be attributed to hCG and GnRH activity, since it can happen in intervals from 36 to 48-h after treatment. Pregnancy rates did not differ among groups. These results are under the working hypothesis that hCG and Buserelin would display similar efficiencies on pregnancy rates. Despite the understanding of hCG activity on induction of ovulation due to its high specificity toward LH receptors and results from a direct effect on diminishing estradiol concentration, increasing LH, and further inducing ovulation within 48-h after treatment. In contrast, Buserelin has a similar functional property but acts upon LH synthesis and its release. In conclusion, ovulation in mares can be induced with both hCG and Buserelin, and both ovulation-inducing agents do not affect pregnancy rates.

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