Estradiol Priming Potentiates the Kisspeptin-Induced Release of LH in Ovariectomized Cows

The present study examined whether priming with estradiol benzoate (EB) for 12 h increased both the peak and duration of LH release in response to kisspeptin (KISS1, KP) in cows. In a Latin square design, ovariectomized Nelore cows (n = 8) received: Control, i.m. 4 mL of 0.9% saline; KP, i.m. 4 mg murine KISS1-10; EBKP, i.m. 4 mg KISS1-10 + i.m. 2 mg EB simultaneously; EB12KP, i.m. 4 mg KISS1-10 + i.m. 2 mg EB 12 h before KISS1-10. Concentrations of LH were determined in blood samples obtained at time 0 (treatment), 20, 40, 60, 90, 120, 150, 180, 210 and 270 min. Concentrations of LH were analyzed by Proc GLIMMIX for repeated measures. In case of significance, the adjusted Tukey test was used to test for differences among treatments. GraphPad 8.0 PRISM® was used to determine the area under the LH-response curve (AUC) after injection of KISS1-10. Plasma LH remained relatively constant throughout sampling after treatment with saline. The peak in LH after injection of KISS1-10 occurred at 20 min in Groups KP and EBKP and at 40 min in Group EB12KP. The peak LH response (∆LH, ng/mL) was greater (p < 0.01) in Group EB12KP (5.6 ± 0.9) than in Groups KP (2.4 ± 0.9) and EBKP (3.5 ± 0.9), which did not differ. AUC (LH ng/mL*min) was greater (p = 0.02) in Group EB12KP (439 ± 73) than in Groups KP (176 ± 73) and EBKP (241 ± 73), with the latter two groups not differing. The findings indicated that 12 h priming with EB increased both the peak and duration of the LH response to treatment with KISS1. The incorporation of EB priming and KISS1 could improve the efficiency of estrus synchronization with fixed-time AI in cows. This would have an important practical application in assisted breeding in beef and dairy cattle.

Download Full-text

215SUCCESSFUL OUT-OF-BREEDING SEASON ESTRUS SYNCHRONIZATION FOLLOWED BY FIXED TIME INSEMINATION IN WATERBUFFALO (BUBALUS BUBALIS)

Reproduction Fertility and Development ◽

10.1071/rdv16n1ab215 ◽

2004 ◽

Vol 16 (2) ◽

pp. 229 ◽

Cited By ~ 1

Author(s):

R.M. Züge ◽

U. Rodacki ◽

A.T. Grandi ◽

J.M.J. Aerts ◽

P.E.J. Bols

Keyword(s):

Breeding Season ◽

Buenos Aires ◽

Fixed Time ◽

Estradiol Benzoate ◽

Sao Paulo ◽

Reproductive Efficiency ◽

São Paulo ◽

Estrus Synchronization ◽

The Impact ◽

Synchronization Protocol

The most important barrier to the increase of buffalo productivity is an overall poor reproductive efficiency, characterized by late sexual maturity, seasonal anestrus and long periods of postpartum ovarian inactivity resulting in extended calving intervals and poor expression of estrus behavior (Singh J et al., 2000, Anim. Reprod. Sci. 60–61, 593–604). Buffaloes are seasonal breeders with the highest reproductive activities during winter (short day lengths) and a high frequency of anestrus during the summer months (Singh G et al. 1985, Ind. J. Anim. Res. 19, 57–60). Recent research demonstrated that a combination of progesterone, estradiol benzoate and equine chorionic gonadotropin (eCG) was effective for estrus induction and synchronization in buffalo heifers under Mediterranean conditions (Barile et al. 2001, Livestock Prod. Sci. 68, 283–287). The aim of the present study was to investigate the impact of an estrus synchronization protocol on reproductive efficiency of water buffalo during out of the normal breeding season. A total of six heifers (21 to 23 months of age) and three cows (5, 6 and 18 years of age) were enrolled in an estrus synchronization protocol lasting for 12 days. All animals were kept under tropical conditions in the coastal part of Paraná (Antonina), about 450km south of São Paulo. The experiment was performed in December, 2002, during the Brazilian summer season, when reproductive efficiency of buffaloes is greatly reduced. On the first day of the protocol (Day 0), animals were implanted with an intravaginal device containing 1g of progesterone (DIB, Syntex SA, Buenos Aires, Argentina) and injected with 10mg estradiol benzoate (Estrogin, Famavet, São Paulo, Brazil). On Day 9, the DIB implant was removed and the animals received 150μg (i.m.) of cloprostenol (Prolise, Syntex SA, Buenos Aires, Argentina) and 2500 IU of eCG (Novormon, Syntex SA, Buenos Aires, Argentina). On Day 11, all animals received 1500 IU of hCG (Vetecor, Lab. Calier, Spain). Artificial insemination (AI) was performed on Day 12 using frozen-thawed semen from a bull of proven fertility. Only one AI was performed per heifer/cow. Pregnancies were determined by ultrasound examination at 53 days following AI and confirmed by rectal palpation at 90 days post AI. The use of this estrus synchronization protocol, followed by fixed-time insemination, resulted in four pregnant heifers (66%) and three pregnant cows (100%). Our results demonstrate that buffalo reproduction can be successful during out-of-breeding season when adequate hormonal treatment is used. Additional experiments should be done to validate the protocol.

Download Full-text

Effect of recombinant bovine somatotropin on pregnancy rates of Nellore cows resynchronized with the use of new DIB and third use, and inseminated at fixed-time

JOURNAL OF ADVANCES IN AGRICULTURE ◽

10.24297/jaa.v4i1.4304 ◽

2015 ◽

Vol 4 (1) ◽

pp. 356-362

Author(s):

Josemara Silva Santos ◽

Tania Cavalcante ◽

Francisca Elda Ferreira Dias ◽

Domenica Palomaris Mariano de Souza ◽

Alencariano J.S. Falcão ◽

...

Keyword(s):

Artificial Insemination ◽

Linear Models ◽

Plasma Concentrations ◽

Fixed Time ◽

Estradiol Benzoate ◽

Pregnancy Rates ◽

Recombinant Bovine Somatotropin ◽

Equine Chorionic Gonadotropin ◽

Rectal Palpation ◽

Intravaginal Device

The objective of the experiment was to evaluate the effects of recombinant bovine somatropin (rbST), and the reuse of the progesterone (P4) releasing devices in resynchronization, on the pregnancy rates of Nellore cows submitted to fixed-time artificial insemination. A group of 123 multiparae Nellore cows, was submitted to a resynchronization protocol: on day 0 a Bovine Intravaginal Device (DIB® ) with 1,0g of P4 was implanted, associated with intramuscular administration of 2,0mg of estradiol benzoate (IM); on day 8 DIB was removed; and 1,0mg of estradiol cypionate, 0,15mg of prostaglandin F2? and 300 UI of equine chorionic gonadotropin were administered; on day 10, fixed-time artificial insemination was conducted (FTAI). The cows were randomized into G1 (n=12) – without rbST / with used Bovine Intravaginal Device, G2 (n=50) – without rbST / with new DIB, G3 (n=11) - with rbST / with used DIB and G4 (n=50) – with rbST/ with new DIB. rbST was introduced on the eighth day of the protocol. Sixty days after TAI, pregnancy diagnoses were conducted, via rectal palpation. Blood samples were taken on day 0, 8 and 10 of the protocol, in order to assess P4 plasma concentrations. Pregnancy rates were statistically evaluated through Generalized Linear Models Theory and their significance was tested with Analysis of Deviance. Pregnancy rates were 58%, 40%, 81% and 48% for G1, G2, G3 and G4, respectively, with significant statistical difference for G3. Plasma concentrations of P4 were not statistically different among groups, or collections. In view of the results obtained, we concluded that the administration of rbST in association with P4 DIB, used for the third time, improves pregnancy rates. Estrus resynchronization and re-insemination positively impacted pregnancy rates.

Download Full-text

The intra-articular administration of triamcinolone hexacetonide in the treatment of osteoarthritis. Its effects in a naturally occurring canine osteoarthritis model

PLoS ONE ◽

10.1371/journal.pone.0245553 ◽

2021 ◽

Vol 16 (1) ◽

pp. e0245553

Author(s):

João C. Alves ◽

Ana Santos ◽

Patrícia Jorge ◽

Catarina Lavrador ◽

L. Miguel Carreira

Keyword(s):

Weight Distribution ◽

Repeated Measures ◽

Weight Bearing ◽

Interleukin 1 ◽

Response To Treatment ◽

Control Group ◽

Radiographic Findings ◽

Triamcinolone Hexacetonide ◽

Paired Samples ◽

Kaplan Meier

Objective To evaluate the effect of an intra-articular (IA) administration of triamcinolone hexacetonide, compared with saline. Patients and methods Forty (N = 40) hip joints were randomly assigned to a treatment group (THG, n = 20, receiving IA triamcinolone hexacetonide) and a control group (CG, n = 20, receiving IA saline). On treatment day (T0), and at 8, 15, 30, 90 and 180 days post-treatment, weight distribution, joint range of motion, thigh girth, digital thermography, radiographic signs, synovial fluid interleukin-1 and C-reactive protein levels were evaluated. Data from four Clinical Metrology Instruments was also gathered. Results were compared Repeated Measures ANOVA, with a Huynh-Feldt correction, Paired Samples T-Test or Wilcoxon Signed Ranks Test. A Kaplan-Meier test was performed to compare both groups, with p<0.05. Results Joints were graded as mild (65%), moderate (20%) and severe (15%). Patients of both sexes, with a mean age of 6.5±2.4 years and bodyweight of 26.7±5.2kg, were included. No differences were found between groups at T0. Comparing THG to CG, weight distribution showed significant improvements in THG from 8 (p = 0.05) up to 90 days (p = 0.01). THG showed lower values during thermographic evaluation in the Lt view (p<0.01). Pain and function scores also improved from 30 to 180 days. Increasing body weight, age, and presence of caudolateral curvilinear osteophyte corresponded to worse response to treatment. Results of the Kaplan Meier test showed significant differences between groups, with THG performing better considering several evaluations and scores. Conclusion THG recorded significant improvements in weight-bearing and in with the considered CMIs, particularly pain scores. Lower thermographic values were registered in THG up to the last evaluation day. Age, sex, and radiographic findings did significantly influenced response to treatment.

Download Full-text

Effects of reproductive tract development and hormonal treatment on estrous synchronization in heifers

Emirates Journal of Food and Agriculture ◽

10.9755/ejfa.2020.v32.i3.2061 ◽

2020 ◽

pp. 198

Author(s):

Jorge Alonso Peralta-Torres ◽

Jesús Ricardo Aké-López ◽

Carlos Luna-Palomera ◽

José Candelario Segura-Correa ◽

Oswaldo Margarito Torres-Chablé ◽

...

Keyword(s):

Pregnancy Rate ◽

Reproductive Tract ◽

Bos Indicus ◽

Hormonal Treatment ◽

Hormone Treatment ◽

Fixed Time ◽

Estradiol Benzoate ◽

Visual Observation ◽

Estrous Synchronization ◽

Tropical Conditions

Evaluation of the reproductive tract development (RTD) is a criterion rarely used when heifers are included in estrous synchronization programs. The objective of the present study was to determine the effect of RTD (mature and immature) and hormonal treatment (EC and EB) on estrous expression rate and pregnancy rate in Bos indicus heifers under tropical conditions. RTD was evaluated with an ultrasound and classified as mature (n=99) or immature (n=101). Heifers received an intravaginal device (DIB®; day 0), 2 mg of estradiol benzoate (EB) and 250 µg of cloprostenol (PGF2α). The DIB was removed on day 7 post insertion, and 250 µg of PGF2α was applied and heifers were divided into two groups: One group of heifers received 0.5 mg of estradiol cypionate (EC group), and on day 8, a second group of heifers received 1 mg of estradiol benzoate (EB group). Estrus was detected by visual observation, and all heifers were inseminated at a fixed-time (FTAI). Fifteen days after insemination, bulls were introduced to the treatment groups. Data were analyzed using general modeling and binary logistic regression procedures. The percentage of estrus was similar for both mature and immature heifers (P>0.05), however, the heifers treated with EB had 17% animals in estrus, than the heifers that received EC (P <0.05). The pregnancy rate after FTAI (74.8%) and total pregnancy (FTAI + natural mating = 91.9%) was greater for the group of heifers with a mature reproductive tract (P<0.05). The hormone treatment had not effect (P>0.05) on the pregnancy rate. In conclusion, the heifers with mature reproductive tracts had the highest pregnancy rate after artificial insemination and total pregnancy. Hormonal treatment did not influence the pregnancy rate.

Download Full-text

Pairs of Latin Squares to Counterbalance Sequential Effects and Pairing of Conditions and Stimuli

Proceedings of the Human Factors Society Annual Meeting ◽

10.1177/154193128903301812 ◽

1989 ◽

Vol 33 (18) ◽

pp. 1223-1227 ◽

Cited By ~ 10

Author(s):

James R. Lewis

Keyword(s):

Human Factors ◽

Repeated Measures ◽

Random Sequence ◽

Latin Square ◽

Latin Squares ◽

Sequential Effects ◽

Long Run ◽

Within Subjects ◽

Human Factors Research

This paper discusses methods with which one can simultaneously counterbalance immediate sequential effects and pairing of conditions and stimuli in a within-subjects design using pairs of Latin squares. Within-subjects (repeated measures) experiments are common in human factors research. The designer of such an experiment must develop a scheme to ensure that the conditions and stimuli are not confounded, or randomly order stimuli and conditions. While randomization ensures balance in the long run, it is possible that a specific random sequence may not be acceptable. An alternative to randomization is to use Latin squares. The usual Latin square design ensures that each condition appears an equal number of times in each column of the square. Latin squares have been described which have the effect of counterbalancing immediate sequential effects. The objective of this work was to extend these earlier efforts by developing procedures for designing pairs of Latin squares which ensure complete counterbalancing of immediate sequential effects for both conditions and stimuli, and also ensure that conditions and stimuli are paired in the squares an equal number of times.

Download Full-text

COMPARISON OF LONG-TERM PROGESTERONE-BASED PROTOCOL ON REPRODUCTIVE PERFORMANCE OF PREPUBERTAL AND PUBERTAL BEEF HEIFERS.

Archives of Veterinary Science ◽

10.5380/avs.v19i1.32805 ◽

2014 ◽

Vol 19 (1) ◽

Cited By ~ 1

Author(s):

Emanoel Faleiros Silveira ◽

Luiz Ernandes Kozicki ◽

Marcio Saporski Segui ◽

Romildo Romualdo Weiss ◽

Ivo Walter Santos ◽

...

Keyword(s):

Ultrasound Examination ◽

Prostaglandin F2α ◽

Estradiol Benzoate ◽

Pregnancy Rates ◽

Estrus Synchronization ◽

Device Removal ◽

Timed Artificial Insemination ◽

Red Angus ◽

Natural Service

The aim of this study was to investigate estrus synchronization in prepubertal and pubertal heifers (crossbred ½ Nelore x Red Angus - commercial herd) submitted to a long-term progesterone-based protocol for timed artificial insemination (TAI), as well as overall pregnancy rates. Four hundred forty-seven heifers underwent ultrasound examination of the ovaries and were assigned to one of 3 groups: (1) prepubertal heifers (PPNS; n = 114) with ovarian follicles <8 mm in diameter and no corpus luteum (CL) that were submitted to natural service (NS) by bulls for 10 days; (2) prepubertal heifers (PPTAI; n = 124) with follicles <8 mm in diameter and no CL that underwent estrus synchronization with injection of 4.0 mg estradiol benzoate (EB) and insertion of a controlled-release intravaginal progesterone (P4) device containing 0.558 g P4 on d 0, followed by P4 device removal and injection of 150 mg prostaglandin F2α and 0.6 mg estradiol cypionate (ECP) on d 8, and TAI on d 10; and (3) pubertal heifers (PTAI; n = 209) with follicles >8 mm in diameter and/or a CL that underwent the same protocol as PPTAI heifers. Overall pregnancy rate was determined by transrectal ultrasonography on d 45 after NS or TAI. Data were analyzed using the FREQ procedure of SAS (SAS Inst. Inc., Cary, NC). Pregnancy rates were as follows: 20.1% in PPNS, 37.0% in PPTAI, and 48.5% in PTAI (P < 0.05). In conclusion, TAI after estrus synchronization with a hormonal protocol using EB and ECP in prepubertal and pubertal heifers resulted in higher pregnancy rates than prepubertal heifers exposed to natural service, and exposure of prepubertal heifers to a long-term progesterone-based protocol effectively synchronized estrus.

Download Full-text

PSXI-21 Effects of different levels and protein sources on ruminal fermentation of feedlot Nellore steers fed high-concentrate diets

Journal of Animal Science ◽

10.1093/jas/skz258.803 ◽

2019 ◽

Vol 97 (Supplement_3) ◽

pp. 405-405

Author(s):

Vinícius C De Souza ◽

Juliana Messana ◽

Erick Batista ◽

Paulo Henrique Colovate ◽

Maria Júlia Ganga ◽

...

Keyword(s):

Protein Level ◽

Repeated Measures ◽

Volatile Fatty Acids ◽

Rumen Fluid ◽

Latin Square ◽

Ruminal Fermentation ◽

Protein Sources ◽

Nitrogen Levels ◽

Protein Levels ◽

Different Levels

Abstract The goal of this study was to evaluate the effects of different levels (10 and 13% crude protein) and protein source on ruminal fermentation of feedlot Nellore steers fed high-concentrate diets. The protein sources tested were urea, dried distillers grains (DDG) and corn gluten meal. The DDG and gluten were used as RUP sources. We used 6 cannulated Nellore steers, rumen, duodenum, and ileum arranged in 6×6 Latin square designed in factorial (2 nitrogen levels and 3 protein sources) balanced for residues. The pH was measured immediately after rumen fluid sampling at 0, 2, 4, 6, 8 and 10h after feeding. The NH3-N concentrations were determined with micro-Kjeldahl apparatus. The concentration of volatile fatty acids (VFA) was assessed by gas chromatography. Data were evaluated using the MIXED procedure of SAS, with repeated measures over time. There was no interaction between sampling time and treatments for NH3-N and pH (P > 0.05). Animals fed diets containing Urea had a higher concentration of NH3-N (20.6 mg/dL) than animals supplemented with Gluten (16.2 mg/dL) or DDG (12.7 mg / dL). There was an increase in the NH3-N concentration (P = 0.049) with the increase of the protein level 10 to 13% CP with 14.7 and 18.3 mg/dL, respectively. The ruminal pH was affected by the dietary protein level (P = 0.016), in which animals fed a level of 10% CP had a higher pH (6.80) compared to the level of 13% CP (6.43). Total and individual VFA concentration was not affected by protein levels and sources (P > 0.05). The reduction of N level and the use of RUP did not adversely affect the ruminal fermentation. Although significant differences were observed for pH, they were small and adequate for microbial protein synthesis in the rumen.

Download Full-text

The microdynamics of social regulation: Comparing the navigation of disagreements in text-based online and face-to-face discussions

Group Processes & Intergroup Relations ◽

10.1177/1368430220935989 ◽

2020 ◽

Vol 23 (6) ◽

pp. 902-917 ◽

Cited By ~ 1

Author(s):

Carla A. Roos ◽

Tom Postmes ◽

Namkje Koudenburg

Keyword(s):

Social Relationships ◽

Repeated Measures ◽

Latin Square ◽

Online Discussions ◽

Social Regulation ◽

Interpersonal Interaction ◽

Message Content ◽

Face To Face ◽

Differences Of Opinion ◽

The Face

This study explores how people navigate the field of tension between expressing disagreement and maintaining social relationships in text-based online as compared to face-to-face discussions. In face-to-face discussions, differences of opinion are socially regulated by introducing ambiguity in message content coupled with instant responding on a relational level. We hypothesized that online messages are less ambiguous and less responsive, both of which may hinder social regulation. Thirty-six groups of three unacquainted students discussed politically controversial statements via chat, video-chat (nonanonymous), and face-to-face, in a multilevel repeated measures Graeco-Latin square design. Content coding revealed that online discussions were relatively clear and unresponsive. This related to participants experiencing reduced conversational flow, less shared cognition, and less solidarity online. These results suggest that ambiguity and responsiveness enable people to maintain social relationships in the face of disagreement. This emphasizes the key role that subtle microdynamics in interpersonal interaction play in social regulation.

Download Full-text

184PREGNANCY RATES AFTER ESTRUS SYNCHRONIZATION TREATMENT WITH NEW AND REUSED CIDR-B DEVICES

Reproduction Fertility and Development ◽

10.1071/rdv16n1ab184 ◽

2004 ◽

Vol 16 (2) ◽

pp. 214 ◽

Cited By ~ 1

Author(s):

C.W. Solorzano ◽

J.H. Mendoza ◽

J. Oden ◽

S. Romo

Keyword(s):

New Zealand ◽

Ethylene Glycol ◽

Prostaglandin F2α ◽

Estradiol Benzoate ◽

Direct Transfer ◽

Estrus Synchronization ◽

Experimental Conditions ◽

Statistical Comparison ◽

Rectal Palpation ◽

To Receive

It is not well known whether used CIDR devices containing progesterone (P4) combined with estradiol benzoate (EB) and prostaglandin F2α (PGF) can provide acceptable estrus synchronization rates (ESR) and pregnancy rates (PR) in ET or AI programs. Three experiments were designed to study the effect of new and used CIDR-B, with different P4, EB and PGF treatments on ESR and PR in a reproductive program in beef cattle in a tropical climate. Experiment 1 was a control to evaluate ESR and PR in lactating recipient females. All cows (n=284) were treated with a new 1.9-g CIDR (CIDR-B, InterAg, New Zealand), combined with 2mg EB and 50mg P4 on Day 0. CIDR devices were removed on Day 8 and all cows received 0.25mg cloprostenol at that time. Estrus was expected to occur 24h later. Seven days after estrus, all cows showing heat were examined by rectal palpation and those with a CL 15mm in diameter or larger were selected to receive a frozen/thawed embryo (1.5M ethylene glycol=EG) by nonsurgical direct transfer (DT). PR were determined by rectal palpation 60d after estrus. Ninety percent of the cows displayed signs of estrus (256/284) and 40% of those that received a frozen embryo were pregnant (96/239). Experiment 2 was designed to evaluate ESR and PR in dry recipient cows treated with a used CIDR-B (first reuse). All cows (n=274) were treated with a reused 1.9-g CIDR combined with 2mg EB and 50mg P4 on Day 0. CIDR devices were removed on Day 8 and all cows received 0.25mg cloprostenol at that time. Estrus was expected to occur 24h later. Seven days after estrus, all cows that showed estrus were rectally evaluated and those with a CL 15mm in diameter or larger received a frozen/thawed embryo (1.5M EG) by DT. A total of 93% of the treated cows showed signs of estrus (254/274) and 51% of those that received an embryo were pregnant (110/217). Experiment 3 was designed to evaluate ESR and PR in virgin heifers, treated with a used CIDR (second reuse). All heifers (n=414) were treated with a reused 1.9-g CIDR combined with 1mg EB on Day 0. CIDR devices were removed on Day 8 and all heifers were expected to show estrus 24h later. Approximately 12h after estrus, all heifers that showed signs of estrus were inseminated, using frozen/thawed semen from a single bull. Of the treated females, 78% showed signs of estrus (323/414) and 69% of the inseminated were pregnant (223/323). These results suggest that in a CIDR that was used in two previous occasions, there is still a remaining amount of P4 that allows estrus synchronization in heifers. Furthermore, the reutilization of CIDR-B devices can contribute to reduce the costs related to ET or AI programs in cattle. However, the diverse existing conditions among the 3 experimental groups in this study make a statistical comparison impossible. Therefore, further studies are needed, under controlled experimental conditions, to confirm the results obtained.

Download Full-text

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.

Download Full-text