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Abstract The objective of this work was to investigate whether puberty and parturition alter the antral follicle count (AFC) in female Nelore (Bos indicus) beef cattle. Two experiments were carried out to compare AFC between the prepubertal and pubertal periods and between the prepubertal and postpartum periods. AFC and follicle concentrations did not differ between the prepubertal and pubertal periods. However, the ovarian area increased after puberty. In addition, AFC and the ovarian area were greater in the postpartum than in the prepubertal period. Therefore, AFC is not affected by the puberty of Nelore heifers, but increases significantly when the prepubertal heifers become cows.

This study aimed to determine the effect of antral follicle count (AFC), and pubertal status on the fertility of beef heifers. In this study, 230 Nelore heifers, 20±2 months of age, were subjected to an estradiol progesterone-based timed artificial insemination (TAI) program. On Day 0 of the TAI protocol, the heifers were examined by transrectal ultrasound to record videos of the ovaries. Later, in the darkroom of the laboratory of images, the videos were analyzed for AFC (≥ 3 mm) of each ovary. Females who failed the first TAI were resynchronized with the same hormonal protocol. The pregnancy status was evaluated by ultrasonography 30 days after each FTAI. The general mean of the AFC was 22.0 follicles. Thus, the heifers were divided into 2 groups according to AFC: Low AFC (˂ 22 follicles, n = 114), and High AFC (≥ 22 follicles, n = 116). No differences (P > 0.05) in the pregnancy per AI (P/AI) were observed between the Low and High AFC groups, and between pubertal and prepubertal categories. The P/AI was not different between heifers that displayed or did not estrus (P = 0.2). However, considering the estrus response of each AFC group, High AFC heifers that displayed estrus had greater P/AI (P = 0.01) than High AFC heifers that did not display estrus. In summary, AFC and pubertal status did not affect the fertility of Nelore heifers. In contrast, the P/AI of heifers that did not display estrus was lower than heifers observed in estrus only in the High AFC group.

We evaluated the effects of nulliparous, primiparous, and multiparous conditions on the estrus and pregnancy rates in females that did not show estrus but were treated with gonadotropin-releasing hormone (GnRH) at the time of timed artificial insemination (TAI). Nelore females (n = 531) were allocated according to the following categories: nulliparous (n = 144), primiparous (n = 132), and multiparous (n = 255). The animals received a conventional TAI protocol, and estrus expression was identified by the absence of paint in the sacrococcygeal region on the day of TAI. Females that did not show estrus were treated with 10 µg of GnRH together with insemination. The rates of estrus and pregnancy were analyzed using a logistic regression model (P < 0.05). The estrus expression was lower (P = 0.006) in the primiparous (61.36%) group than in the nulliparous (76.39%) and multiparous (75.69%) groups. Similar pregnancy rates were observed in females that showed estrus (nulliparous 84.54%, primiparous 86.42%, and multiparous 80.31%; P = 0.39) and in females that did not show estrus and received GnRH (nulliparous 41.18%, primiparous 56.86%, and multiparous 58.06%; P = 0.24). The total pregnancy rates were also similar (P = 0.98) among the categories (nulliparous 74.3%, primiparous 75.0%, and multiparous 74.9%). The primiparous females had a lower rate of estrus, and the pregnancy rates were similar among the categories that received GnRH.

The objective of this study was to evaluate the efficiency and cost of two distinct hormonal protocols for induction of puberty in Bos indicus heifers in the western Amazon region. Nelore prepubertal heifers (n = 127) aged 20 to 24 months (21 ± 0.3 months) and weighing 300 to 340 kg (318 ± 7 kg) were submitted to two distinct protocols for induction of cyclicity. Females were previously submitted to two ovarian ultrasound examinations (12-day interval) to verify the absence of the corpus luteum (CL). Then, the heifers were divided into two experimental groups: G-CIDR/EC (n = 54) and G-P4/EC (n = 73). The G-CIDR/EC group utilized a CIDR® for 12 days and on the day of its withdrawal, 0.6 mg of estradiol cypionate (IM) was administered. The G-P4/EC group received 150 mg of injectable progesterone (IM) and one injection of 0.6 mg EC 12 days after the progesterone injection. Twelve days after the end of the hormonal protocols, the heifers were submitted to another ultrasound evaluation for identification of cyclicity (ovulatory follicle or CL). These females were then submitted to a conventional protocol of synchronization of ovulation for timed artificial insemination (TAI). Only heifers responsive to puberty induction (G-CIDR/EC (n=30) and G-P4/EC (n=51)) were included in the TAI protocol. After seven days of insemination, both groups were exposed to natural breeding. In addition, an economic analysis was performed to evaluate cyclicity induction, the TAI protocol, and pregnancy in both groups. The G-CIDR/EC group showed 81.48% (44/54) of females responsive to induction of cyclicity (presence of CL) while the G-P4/EC group obtained 86.3% (63/73; p=0.463). Regarding the conception rate to TAI and to bull (natural breeding), the G-CIDR/EC group displayed 43.33% (13/30) and 33.33% (10/30), respectively, and the G-P4/EC group exhibited 54.9% (28/51) and 39.22% (20/51), respectively. The overall pregnancy rate (TAI+Bull) was 76.67% (23/30) in the G-CIDR/EC group compared to 94.12% (48/51; P=0.023) in the G-P4/EC group. The cost of the hormonal protocol to cyclicity induction resulted in an economy of 42.8% for injectable P4 compared to the intravaginal P4 group. In addition, the final cost of cyclic induction associated with TAI was 34% lower in the G-P4/EC group compared to the G-CIDR/EC group. We concluded that both cycling induction protocols were efficient in Bos indicus heifers from the western Amazon. However, injectable P4 provided a higher conception rate and lower pregnancy cost at the end of the reproductive season.

The aim of this study was to evaluate the dynamics of the scrotal temperature, sperm quality and testicular blood flow by using infrared thermography and Doppler ultrasonography in bulls submitted to scrotal insulation. Braford bulls (n = 8) at 18 months of age, were assigned into the following groups: insulated for 72 h (G 72; n = 2), 96 h (G 96, n = 2), 120 h (G 120, n = 2), and control animals (CON; n = 2) that remained without insulation. Infrared thermography and Doppler ultrasonography parameters were measured at four different time points: immediately after the scrotal insulation (M0), within 10 min (M10), 30 min (M30) and 60 min (M60) after scrotal insulation. The sperm quality was evaluated weekly (S1/S12). The data were analyzed by ANOVA, t-test (paired) and Pearson's correlation with a significance level of 5%. None of the observed variables were different between the insulated groups (P > 0.05). Insulated animals showed higher scrotal temperature in M0 compared to that in the M10, M30 and M60 periods (P < 0.05). There was no difference in the pulsatility and resistive indexes after scrotal insulation. However, blood flow velocity was higher in M10 compared to that in the M0, M30 and M60 periods (P < 0.05). The sperm quality was higher (P < 0.05) in all twelve collections from the control group compared with the insulated groups. Scrotal insulation resulted in changes in the sperm quality, scrotal temperature and testicular blood flow velocity.

O objetivo deste estudo foi avaliar a reutilização de um dispositivo intravaginal de progesterona (P4) durante o diestro de vacas Nelore receptoras de embriões, a fim de melhorar a taxa de concepção, acelerar a ressincronização do ciclo estral de animais não prenhes e reduzir a quantidade de resíduos gerados por biotécnicas na produção animal. Foram realizados dois experimentos com 268 vacas Nelore multíparas. No experimento 1, todos os animais foram submetidos a um procedimento de transferência de embriões em tempo fixo (TETF), mas no momento da transferência embrionária foram estabelecidos dois grupos de tratamento: T1 - o tratamento controle (N = 132) e T2 - animais recebendo um dispositivo de segundo uso CIDR® por 12 dias (N = 136). O experimento 2 foi realizado em vacas que permaneceram vazias após o experimento 1 usando dois grupos: G1 - um grupo controle (N = 69) e vacas ressincronizadas (G2) que receberam um dispositivo P4 por 12 dias para a TETF (N = 74) No experimento 1, não foi observado efeito significativo do tratamento P4 na taxa de concepção (T1 = 37,9%, T2 = 39,7%; P = 0,50) e diâmetro do corpo lúteo (CL) (T1 = 17,5 ± 3,4 mm, T2 = 18,1 ± 3,4 mm; P = 0,61). No experimento 2, nenhum efeito significativo do tratamento foi observado na taxa de concepção (G1 = 22,2%, G2 = 35,7%; P = 0,24), taxa de utilização de receptoras (G1 = 75,4%, G2 = 70,3%; P = 0,86), e diâmetro do CL (G1 = 17,4 ± 3 mm, G2 = 18,1 ± 3,2 mm; P = 0,27). No entanto, o tratamento P4 (para ressincronização) aumentou significativamente a taxa de concepção (G1 = 22,2%, G2 = 35,7%; P = 0,04), semelhante ao de um protocolo TETF convencional realizado com dispositivo de primeiro uso (38,8%). Concluímos que dispositivos P4 intravaginais reutilizáveis podem ajudar a acelerar protocolos TETF, sugerindo um método de aplicação alternativo; além disso, este protocolo pode ajudar a reduzir a produção de resíduos nas biotécnicas de reprodução assistida.

This study evaluated the pregnancy rate in Nelore cows (Bos indicus) that were subjected to fixed-time artificial insemination (FTAI) using different protocols consisting of injectable progesterone (P4) or an intravaginal device (impregnated with P4). Multiparous cows 72-84 months in age, 30-45 days postpartum, were selected on the basis of the absence of a corpus luteum (CL) and follicles < 8 mm after transrectal palpation and ultrasound examinations. On a random day of the estrus cycle (D0), the selected animals (n = 135) were randomly assigned to one of three experimental groups (n = 45 each). Group I (injectable P4/FTAI 36 hours) received 250 mg of injectable P4 and 2 mg EB on D0; on D7, they received 500 µg of cloprostenol; on D8, 300 IU of eCG and 1 mg of EB were administered; and finally, FTAI was performed 36 hours after the application of EB. Group II (injectable P4/FTAI 48 hours) received the same protocol as Group I, except that the FTAI was performed 48 hours after ovulation induction. The animals of Group III (Control/CIDR) received a conventional protocol for FTAI using an intravaginal device (D0: P4 and 2 mg EB; D8: device removal, 500 µg cloprostenol, 300 IU eCG, 1 mg EB; and FTAI performed 48 hours after removal of the device). The results showed that cows synchronized with the conventional protocol for FTAI (Control/CIDR) had a higher pregnancy rate (60 %, 27/45) than those synchronized with an injectable P4/FTAI 36 hours (33.33 %; 15/45, P = 0.010). However, the group receiving injectable P4 group/FTAI 48 hours had a similar pregnancy rate (48.9 %; 22/45; P = 0.290) when compared to both the group receiving the conventional protocol and that receiving injectable P4/FTAI 36 hours (P = 0.134). Although the injectable P4 may affect pregnancy rate with the FTAI performed in 36 hours, we found similar pregnancy rates from cows inseminated 48 hours after induction ovulation, considering injectable or intravaginal P4. Therefore, we suggest that injectable P4 represents an alternative source of progesterone for synchronization of cattle for FTAI.

Most fixed-time artificial insemination (FTAI) protocols utilize progesterone (P4) as a hormonal source to achieve synchronization of estrus in cattle. The use of an injectable P4 source to control estrus would be an interesting pharmacological strategy owing to the practicality of parenteral application. However, the effects of injectable P4 on estrus cycle control in cattle remain poorly studied. In particular, no existing studies have investigated the effect of injectable P4 on the fertility of cows subjected to FTAI. The aim of this study was to evaluate the pregnancy rate of lactating and non-lactating Nelore cows subjected to FTAI with injectable P4. Of the 422 non-lactating cows in this study, 162 (38.3%) became pregnant by 60 days post-FTAI. In the lactating group (n = 516), 166 (32.1%) were pregnant by 60 days after treatment with injectable P4. The proportions of lactating and non-lactating cows becoming pregnant were compared using the chi-square test, adopting a significance level of P < 0.05. It was found that the pregnancy rate of the cows subjected to FTAI with injectable P4 was influenced by lactation status. Lactating cows had lower reproductive performance, possibly because of their higher nutritional requirements. However, the use of injectable P4 shows promising results and may prove to be a useful strategy in large-scale livestock production.

The objective of this study was to compare the number of follicles, oocytes and the recovery rate in sheep submitted to the one-shot protocol with or without ovarian priming with estradiol benzoate (EB). Pluriparous non-lactating sheep (n=33) with an average age of five years (range 4-6) and a body condition score of 3.0±0.3 were divided into three groups. The one-shot group (n=10) was treated with a subcutaneous implant containing 1.5 mg of norgestomet from D0 to D10. The animals in this group were administered 0.04 mg of D-cloprostenol, 200 IU of follicle stimulating hormone (FSH) and 300 IU of equine chorionic gonadotropin (eCG) on D8. Animals in the EB group (n=11) received the same treatment as one-shot plus the administration of 0.6 mg of EB on D0. In the untreated group (n=12), the animals received no hormone stimulation. The collection of the oocytes was performed by laparotomy 36 h after the administration of gonadotropins (D10). Oocytes were searched and classified based on morphology. An increase was observed (p

This study evaluated the follicular dynamics and the pregnancy rates of Nelore cows with or without a CL synchronized with FTAI employing injectable progesterone (P4). Multiparous cows (n=44), 45-65 days postpartum were allocated into a 2x2 factorial. Eleven cows with and 11 without a CL received a conventional protocol of FTAI (D0/1 g P4 + 2 mg EB; D8/500 ?g cloprostenol, 300 IU eCG and 24 h later 1 mg EB; D10/FTAI). Other 11 cows with and 11 without a CL received 350 mg of injectable P4 (300 mg sc and 50 mg im) and 2 mg of EB im on D0. On D6, 500 ?g of cloprostenol and 300 IU of eCG were administered im. After 24 h, 1 mg of EB was administered im and FTAI was performed on D8. The results were analyzed by ANOVA and Tukey or by Chi-square test (p?0.05). The presence of follicles ? 5mm on D4, follicular growth rate and CL diameter were similar between groups (50-55%, 1.1-1.2mm/ day and 16.1-17.6mm; respectively). The diameter of the dominant follicle (DF) at FTAI and ovulatory follicle (OF) were similar between groups with CL (10.5±1.8 and 11.4±1.3mm, respectively) and without CL (10.8±2.3 and 11.1±2.2mm, respectively) but device was higher than injectable (11.7±2.0 and 11.8±1.7 vs. 9.7±1.7 and 10.6±2.0mm, respectively). The ovulation and pregnancy rate were similar between groups with CL (59% and 36%, respectively) and without CL (77% and 27%, respectively) but device was higher than injectable (91% and 45% vs. 45.5% and 18%; respectively). The ciclicity did not affect the follicular dynamics and pregnancy rate. The device showed higher diameter of the DF at FTAI, OF and ovulation and pregnancy rates. However, the injectable P4 produced similar percentages of follicles ? 5 mm on D4, follicular growth rate and CL diameter, raising the possibility of further investigation.

This study aims to evaluate ovarian follicular dynamics of Nelore cows subjected to fixed-time artificial insemination (FTAI) with injectable progesterone (P4) or intravaginal device. In the device group, 20 cows received an intravaginal device with 1 g P4 and administration of 2 mg estradiol benzoate (EB) intramuscularly (im) on D0. The device was removed on D8, followed by administration of 500 ?g cloprostenol, 300 IU equine chorionic gonadotropin (eCG) and 1 mg estradiol cypionate (EC), im. The cows were inseminated 48h later. In the injectable group, 350 mg P4 (300 mg subcutaneously and 50 mg im) and 2 mg EB im were administered on D0 to 16 cows. On D6, 500 ?g cloprostenol, 300 IU eCG and 1 mg EC were administered im. The FTAI was performed 48h later. Sixty-five percent of cows from the device group (13/20) and 75% from the injectable group (12/16) showed follicles ? 5 mm on D4 (p>0.05). The average rate of follicular growth was 0.92±0.25 mm/day for the device group and 1.06±0.45 mm/day for the injectable group (p>0.05). The average diameter of the dominant follicle (DF) at FTAI was 11.4±1.4 mm for the device group and 10.8±1.8 mm for the injectable group (p>0.05). In the device group, ovulatory follicles (OF) had an average diameter of 12.1±1.4 mm, and in the injectable group 12.3±1.6 mm (p>0.05). Ninety percent of the device group (18/20) and 37.5% of the injectable group (6/16) demonstrated ovulation (p

The diaphragmatic hernia is a rare cause of colic in equine and may be congenital or acquired. The intestine is commonly involved in cases of diaphragmatic hernia, and clinical signs are related to the intestinal segment involved and the extension, obstruction may occur from a simple process to a strangulating. Often, clinical signs are characterized by acute abdominal whit severe pain, dyspnea and tachypnea. The diagnosis of diaphragmatic hernia can be difficult, and in most cases only is established during surgery or at necropsy. This paper reports a diaphragmatic hernia case in a quarter horse stallion, with 14 years of age showing acute abdominal signs. The clinical examination showed tachycardia, tachypnea and absence of intestinal motility. Turbidity, increase of leukocytes and protein was observed in the analysis of peritoneal fluid. Exploratory laparotomy was performed, but due to the presence of hemorrhagic mesentery, intestinal ischemia, and irreducible incarceration of the jejunum in epiploic foramen, euthanasia was decided. Furthermore, at necropsy, was observed a diaphragmatic hernia with presence of the small intestine in the thorax.

The ruminal degradability of different byproducts was evaluated by the in situ technique. The feeds were incubated in the rumen of three crossbred E x Z steers averaging 300 kg for 72, 48, 24, 18, 12, 6, 3 e 0 hours. The potentially degradable fraction and effective degradability of DM and CP for the sunflower crushed were, respectively, 40.2 and 26.2% and 50.97 and 38.65%. The crushed soybean presented soluble fraction of 36.6 and 20.7%, for DM and CP, with an effective degradability of 72.5 and 69.9%, and the crushed grape, of 21.61 and 19.84% for DM and CP, with degradation rate of 4.2 and 7.67%/h, that resulted in effective degradabilities of 54.36 and 50.03 for DM and CP, respectively. For the protein, the cookie residue showed high soluble fraction (53.87%), the soybean hulls, high potentially degradable fraction (77.55%), and the wheat hulls, soluble fraction (63.23%).Avaliou-se a degradabilidade ruminal de diferentes alimentos alternativos, utilizando-se a técnica in situ, em três novilhos mestiços ExZ, com peso médio de 300 kg. Os alimentos foram incubados por 72, 48, 24, 18, 12, 6, 3 e 0 horas. A fração potencialmente degradável e a degradabilidade efetiva da MS e PB para a torta de girassol foram, respectivamente, de 40,2 e 26,2% e 50,97 e 38,65%. A torta de soja apresentou fração solúvel de 36,6 e 20,7%, para MS e PB, com degradabilidade de 72,5 e 69,9%, e o bagaço de uva, de 21,61 e 19,84% para MS e PB, com taxa de degradação de 4,2 e 7,67%/h, o que acarretou degradabilidades de 54,36 e 50,03 para MS e PB, respectivamente. Para a proteína, o resíduo de bolacharia apresentou alta fração solúvel (53,87%); a casca de soja, alta fração potencialmente degradável (77,55) e a casca de trigo, fração solúvel (63,23%).