Timed-artificial insemination protocols for Bos indicus beef heifers: Evaluation of protocol length and variations in prostaglandin F2α treatments.

The aim was to compare reproductive outcomes of Nelore heifers submitted to timed AI (TAI) protocols, with 7 or 9 d of permanence of the intravaginal progesterone (P4) device and different times of prostaglandin F2α (PGF) administration, for first (n = 935) and second (n = 530) services. On Day -24, heifers without corpus luteum (CL) underwent a protocol for induction of ovulation. On Day 0, heifers received a P4 device (0.5 g) and 1.5 mg estradiol (E2) benzoate. In order for the TAI to be carried out on the same day, these treatments were performed 2 d later on the heifers treated with the 7-d protocol. Additionally, heifers received 0.5 mg PGF at different times, resulting in four experimental groups: 9dP4-PGFd9 (n = 365); 9dP4-PGFd7 (n = 369); 9dP4-PGFd0&9 (n = 364); 7dP4-PGFd0&7 (n = 367). These nomenclatures indicate for how many d the P4 device was kept and the specific day on which PGF was given. At P4 removal, all heifers received 0.5 mg E2 cypionate and 200 IU eCG, and TAI was performed 2 d later. Effects were considered significant when P ≤ 0.05 (superscript letters a,b) whereas a tendency was assumed when 0.05 < P ≤ 0.10. Groups 9dP4-PGFd0&9 and 7dP4-PGFd0&7 had lower percentage of heifers with CL at P4 removal. The diameter (mm) of the dominant follicle (DF) was affected by treatment at P4 removal (9dP4-PGFd9: 11.3 ± 0.3b; 9dP4-PGFd7: 11.8 ± 0.2ab; 9dP4-PGFd0&9: 12.6 ± 0.2a; 7dP4-PGFd0&7: 10.8 ± 0.2c) and at TAI (9dP4-PGFd9: 12.7 ± 0.3ab; 9dP4-PGFd7: 13.2 ± 0.2a; 9dP4-PGFd0&9: 13.4 ± 0.2a; 7dP4-PGFd0&7: 12.4 ± 0.3b). Expression of estrus (%) was affected by treatment (9dP4-PGFd9: 89.6a; 9dP4-PGFd7: 93.5a; 9dP4-PGFd0&9: 88.2ab; 7dP4-PGFd0&7: 85.6b). There were no differences among treatments for P/AI on Day 40 (30-35 d post AI), final P/AI (between Day 70 and parturition) and pregnancy loss (between Day 40 and final P/AI). When the permanence of the P4 device was compared, regardless of PGF treatments, 9-d protocols resulted in greater DF diameter at P4 removal and at TAI, and greater expression of estrus (90.4 vs. 85.6%) than the 7-d protocol. Despite that, the 7-d protocol resulted in greater P/AI on Day 40 (55.3 vs. 49.1%). In addition, there was an interaction between protocol duration and body weight, in which heavier heifers (≥ 307 kg) had greater P/AI when treated with the 7-d protocol, in comparison to 9-d. In conclusion, longer TAI protocols (9 d of P4 device duration) resulted in greater DF diameter and expression of estrus. However, the shorter TAI protocol (7 d of P4 device duration) produced greater P/AI on Day 40, particularly in heavier heifers. Within 9-d protocols, the additional dose of PGF on Day 0 or the anticipation of the PGF to Day 7 did not influence fertility.

Comparison of gonadotropin-releasing hormone and estradiol benzoate plus gonadotropin-releasing hormone to initiate a progesterone-based timed artificial insemination resynchronization protocol in lactating dairy cows.

The present study compared 2 strategies to initiate a progesterone (P4)-based timed artificial insemination (TAI) protocol for lactating dairy cows: only GnRH or estradiol benzoate (EB) plus GnRH (EB+GnRH). Lactating Holstein cows (n = 487; 184 primiparous and 303 multiparous) from 2 commercial dairy herds were used for their second or greater services postpartum. Each week, cows that were nonpregnant at the pregnancy diagnosis 32 d after a previous AI were randomly assigned to 1 of 2 experimental groups that differed only in the strategy to initiate (d 0) the TAI protocol. On d 0, every cow received a 2.0-g P4 implant; in the EB+GnRH group, cows were treated with 2.0 mg i.m. of EB and 16.8 µg i.m. of the GnRH analog buserelin acetate, whereas in the GnRH group, cows received only 16.8 µg i.m. of GnRH. On d 7 after the initial treatment, 0.530 mg i.m. of cloprostenol sodium (PGF) was administered in all cows, followed by a second dose on d 8, concomitant with 1.0 mg i.m. of estradiol cypionate and P4 implant withdrawal. The TAI was performed on d 10 (48 h after P4 device withdrawal) in both experimental groups. Only conventional Holstein semen was used throughout the study. The percentage of cows with corpus luteum (CL) on d 0 (73%) and overall ovulation rate after d 0 (54%) did not differ between groups. The CL regression between d 0 and the first PGF treatment was greater in the EB+GnRH group than the GnRH group (42% vs. 31%). Consequently, the proportion of cows with CL at PGF was greater when only GnRH was used on d 0 compared with EB+GnRH (86% vs. 82%), and the mean number of CL at PGF was greater (1.23 vs. 1.11). The expression of estrus near TAI was greater in GnRH group (84% vs. 77%), and cows showing estrus had greater (44% vs. 10%) pregnancy per AI (P/AI) on d 32 for both treatments. We found no effect of the presence of CL on d 0 or at PGF, nor of ovulation after d 0 or CL regression between d 0 and d 7 on fertility. However, fertility was critically impaired when cows did not have CL at both times, d 0 and at PGF treatment. We did not observe any interaction between treatment and other variables, and the P/AI was similar in cows receiving EB+GnRH or only GnRH on d 0 (37.8% vs. 36.6%). In summary, although there was no detectable difference in P/AI between treatments, this study demonstrated potential negative physiological outcomes caused by EB treatment on d 0 (greater incidence of luteolysis after d 0 and fewer cows with CL at PGF treatment). Overall, we found no benefit of adding EB at the initiation of a P4-based TAI protocol on fertility compared with using GnRH alone, despite differences in ovarian dynamics and expression of estrus.

Effect of progesterone from corpus luteum, intravaginal implant, or both on luteinizing hormone release, ovulatory response, and subsequent luteal development after gonadotropin-releasing hormone treatment in cows.

This study aimed to determine the effect of circulating progesterone (P4) concentrations produced by a corpus luteum (CL) or released by an intravaginal P4 implant (IPI) on GnRH-induced LH release, ovulatory response, and subsequent CL development, after treatment with 100 µg of gonadorelin acetate (GnRH challenge). Nonlactating multiparous Holstein cows were synchronized and GnRH was used to induce ovulation (d -7). Over 4 replicates, cows that ovulated (n = 87) were randomly assigned to a 2 × 2 factorial arrangement (presence or absence of CL and insertion or not of an IPI at GnRH challenge), creating 4 groups: CL_IPI, CL_NoIPI, NoCL_IPI, and NoCL_NoIPI. On d -1.5, NoCL_IPI and NoCL_NoIPI received 2 doses of 0.53 mg of cloprostenol sodium (PGF2α), 24 h apart to regress CL. On d 0, cows were treated with 100 µg of GnRH and, simultaneously, cows from IPI groups received a 2-g IPI maintained for the next 14 d. Diameter of dominant follicle, ovulatory response, and subsequent CL volume were assessed by ultrasonography on d -1.5, 0, 2, 7, and 14. Blood samples were collected on d -1.5, 0, 1, 2, 3, 5, 7, and 14 for analysis of circulating P4 and at 0, 1, 2, 4, and 6 h after GnRH challenge for analysis of circulating LH. In a subset of cows (n = 34), the development of the new CL was evaluated daily, from d 5 to 14. The presence of CL at the time of GnRH challenge affected the LH peak and ovulatory response (CL: 5.3 ng/mL and 58.1%; NoCL: 13.2 ng/mL and 95.5%, respectively). However, despite producing a rapid increase in circulating P4, IPI insertion did not affect LH concentration or ovulation. Regardless of group, ovulatory response was positively correlated with LH peak and negatively correlated with circulating P4 on d 0. Moreover, new CL development and function were negatively affected by the presence of CL and by the IPI insertion. In summary, circulating P4 produced by a CL exerted a suppressive effect on GnRH-induced LH release and subsequent ovulation of a 7-d-old dominant follicle, whereas the IPI insertion at the time of GnRH had no effect on LH concentration or ovulation. Finally, elevated circulating P4, either from CL or exogenously released by the IPI, compromised the development and function of the new CL, inducing short cycles in cows without CL at the time of GnRH treatment.

What are the factors associated with pregnancy loss after timed-artificial insemination in Bos indicus cattle?

Pregnancy loss (PL) has important impacts on the profitability of livestock production systems, although it is not widely reported, particularly in Bos indicus cattle. The present study retrospectively evaluated PL after timed-artificial insemination (TAI) in Bos indicus (Nelore) beef cows corresponding to several factors, such as parity, body condition score (BCS), presence of corpus luteum (CL) at the beginning of TAI protocols, expression of estrus, and hormonal manipulations during the TAI protocol. Data from two experiments performed during three breeding seasons (BS) were reanalyzed. Both experiments evaluated adding GnRH treatment at TAI in a 7-d estradiol (E2) plus progesterone (P4)-based protocol, with intravaginal P4 implant removal on Day 7 combined with treatment with 0.5 or 1.0 mg E2 cypionate and 300 IU eCG, and TAI on Day 9. In addition, during BS 2 and 3 (Exp 2), cows were randomized to receive or not a PGF treatment on Day 0 (beginning of the TAI protocol). In all BS, presence of CL and BCS were evaluated at the beginning of TAI protocols, follicle size and expression of estrus were evaluated at TAI. The PL was assessed between the first pregnancy diagnosis (∼35d) and parturition. There were no effects of hormonal manipulations within TAI protocols of different BS on PL. There was no interaction between GnRH treatment at TAI and the other variables within BS, and there was no main effect of GnRH treatment on PL (without = 10.1% [102/1007] vs. with = 10.4% [114/1100]). The addition of PGF on Day 0 had no effect on PL (11.5% [102/886] vs. 10.5% [89/850]), as well as EC dose to induce final ovulation (10.8% [89/827] vs. 11.2% [102/909] for 0.5 and 1.0 mg, respectively). Primiparous had greater PL than multiparous cows (14.0% [77/550] vs. 8.9% [139/1557]), and cows not expressing estrus near TAI had greater PL than those expressing estrus (13.5% [57/422] vs. 9.7% [156/1617]). There was no interaction between follicle size at TAI and GnRH treatment on PL. However, probability of PL decreased linearly as follicle size at TAI increased. There were no effects of service number (first TAI or resynchronization), BCS, or presence of CL on D0 on PL. In addition, PL was not affected by sire within any of the BS. In conclusion, some factors that are known to impact pregnancy per AI also influenced PL, such as parity and expression of estrus, although, other aspects such as BCS, number of services, and presence of CL on D0 did not affect PL. Moreover, commonly implemented treatments to increase fertility (e.g., PGF on Day 0 and increasing EC dose to 1.0 mg) did not affect PL. Finally, the GnRH treatment at TAI had no effect on PL and did not interact with any of the variables, an important result, since GnRH at TAI also increases fertility in Bos indicus beef cows.

Hormonal combinations aiming to improve reproductive outcomes of Bos indicus cows submitted to estradiol/progesterone-based timed AI protocols.

The aim was to study reproductive outcomes of Nelore (Bos indicus) cows submitted to a 7-d estradiol (E2)/progesterone (P4)-based timed artificial insemination (TAI) protocol, receiving various combinations of doses and hormones. Primiparous (n = 962) and multiparous (n = 1935) cows were submitted to synchronization (n = 2012) and resynchronization (n = 885 non-pregnant cows at pregnancy diagnosis 30 d after TAI) protocols, following a 2 × 2 × 2 factorial arrangement of eight treatments. At the initiation of the TAI protocol (Day -9), all cows received a 1.0 g intravaginal P4 insert, 2.0 mg E2 benzoate and received (PGF1) or not (PGF0) 0.5 mg cloprostenol sodium (PGF). On Day -2, the P4 insert was removed, all cows received 0.5 mg PGF, 300 IU equine chorionic gonadotropin (eCG) and 0.5 (EC0.5) or 1.0 mg estradiol cypionate (EC1.0). On Day 0, cows were treated (G1) with 8.4 µg buserelin acetate (GnRH) or not (G0), concurrently with TAI. The eight treatments were generated: 1) PGF0-EC0.5-G0 (n = 364), 2) PGF0-EC0.5-G1 (n = 363), 3) PGF1-EC0.5-G0 (n = 363), 4) PGF1-EC0.5-G1 (n = 360), 5) PGF0-EC-1.0-G0 (n = 360), 6) PGF0-EC1.0-G1 (n = 363), 7) PGF1-EC1.0-G0 (n = 361), and 8) PGF1-EC1.0-G1 (n = 363). Pregnancy per AI (P/AI) was greater at first AI compared with resynchronization (58.9 [n = 2012] vs. 54.9% [n = 885]). Presence of CL on Day -9 resulted in more cows expressing estrus (81.3 [n = 680] vs. 67.1% [n = 2033]) and greater P/AI (66.0 [n = 692] vs. 54.9% [n = 2106]). There was no difference in P/AI between cows that received or not PGF on Day -9 (58.7 [n = 1447] vs. 56.6% [n = 1450]). In contrast, PGF tended to increase P/AI of cows with CL on Day -9 (with PGF = 69.1 [n = 375] vs. without PGF = 62.5% [n = 317]). Cows that received 1.0 mg EC expressed more estrus than those treated with 0.5 mg (73.8 [n = 1414] vs. 67.9% [n = 1398]) and had greater P/AI (60.2 [n = 1447] vs. 55.1% [n = 1450]). P/AI was greater in cows treated with GnRH at TAI (59.8 [n = 1449] vs. 55.5% [n = 1448]), particularly in cows that did not show estrus (52.7 [n = 393] vs. 38.1% [n = 420]). Moreover, GnRH on Day 0 increased P/AI in cows with BCS < 3.0 (57.1 [n = 723] vs. 48.6% [n = 698]), in primiparous (50.1 [n = 465] vs. 41.9% [n = 497]) and in cows that received 0.5 mg EC (58.9 [n = 723] vs. 51.3% [n = 727]). In conclusion, 1.0 mg of EC on Day -2 and GnRH at TAI improved P/AI, but the combination of a higher dose of EC and GnRH treatment at AI did not enhance this effect. Furthermore, GnRH improved P/AI especially in Bos indicus cows with lower expression of estrus, such as primiparous, thinner cows, and cows treated with 0.5 mg of EC.

Interactions of circulating estradiol and progesterone on changes in endometrial area and pituitary responsiveness to GnRH†.

Changes in circulating progesterone (P4) and estradiol (E2) during proestrus produce dynamic changes in endometrial function and pituitary release of gonadotropins. Independent and combined effects of P4 and E2 on endometrium and pituitary were evaluated. In a preliminary study, an exogenous hormone model of proestrus was created by removal of corpus luteum and follicles ≥5 mm followed by gradual removal of intravaginal P4 implants during 18 h and treatment with increasing doses of estradiol benzoate during 48 h to mimic proestrus using high E2 (n = 9) or low E2 (n = 9). Decreased P4, increased E2, and increased endometrial area (EA) simulated proestrus in high-E2 cows and this was used subsequently. The main experiment used a 2 × 2 factorial design with: high E2 and low P4 (n = 11); high E2 and high P4 (n = 11); low E2 and high P4 (n = 11); low E2 and low P4 (n = 10). At 48 h, gonadotropin-releasing hormone (GnRH)-induced luteinizing hormone (LH) and follicle stimulating hormone (FSH) release was determined. Variables were analyzed using PROCMIXED of Statistical Analysis System. The EA increased dramatically during 48 h only in high-E2 and low-P4 cows. For FSH, high-E2 cows had greater area under the curve (AUC) and FSH peak after GnRH than low E2, with mild negative effects of high P4. For LH, concentration at peak and AUC were 2-fold greater in high E2 compared to low-E2 groups, with low P4 also 2-fold greater than high-P4 groups. Thus, maximal changes in uterus and pituitary during proestrus depend on both low P4 and high E2, but different physiologic responses are regulated differently by E2 and P4. Changes in endometrium depend on low P4 and high E2, whereas GnRH-induced FSH secretion primarily depends on high E2, and GnRH-induced LH secretion is independently increased by high E2 or reduced by high P4.

Association of increased morbidity with the occurrence of hyperglycemia in the immediate postoperative period after elective pediatric neurosurgery.

OBJECTIVE The acute elevation of blood glucose in perioperative pediatric patients subjected to cardiac surgery and in victims of head trauma is associated with higher rates of postoperative complications. Data on the occurrence of hyperglycemia and its association with unfavorable outcomes among patients who have undergone elective neurosurgery are scarce in the literature. This study aimed to determine whether the occurrence of hyperglycemia during the perioperative period of elective neurosurgery for the resection of tumors of the CNS in children is associated with increased morbidity. METHODS This retrospective cohort analysis included 105 children up to 12 years of age who underwent elective neurosurgery for resection of supratentorial and infratentorial CNS tumors between January 2005 and December 2010 at the São Rafael Hospital, a tertiary care medical center in Salvador, Brazil. Demographic data and intraoperative and postoperative information were collected from the medical records. Differences in blood glucose levels during the perioperative period were evaluated with nonparametric tests. RESULTS The patients who developed postoperative complications exhibited higher blood glucose levels on admission to the intensive care unit (ICU) (162.0 ± 35.8 mg/dl vs 146.3 ± 43.3 mg/dl; p = 0.016) and peak blood glucose levels on postoperative Day 1 (171.9 ± 30.2 mg/dl vs 156.1 ± 43.2 mg/dl; p = 0.008). Multivariate analysis showed that peak blood glucose levels on postoperative Day 1 were independently associated with a higher odds ratio for postoperative complication (OR 1.05). The occurrence of hyperglycemia (>150 mg/dl) upon admission to the ICU was associated with longer ICU (p = 0.003) and hospital (p = 0.001) stays. CONCLUSIONS The occurrence of hyperglycemia during the postoperative period after elective pediatric neurosurgery for the resection of CNS tumors was associated with longer hospital and ICU stays. Postoperative complications were associated with higher blood glucose levels upon admission to the ICU and higher peak blood glucose on the first postoperative day.

Condiçöes de trabalho e saúde de professores da rede particular de ensino Salvador, Ba / Working contitions and health of teachers from private schools of Salvador, Bahia

Foi realizado um estudo epidemiológico transversal com o objetivo de identificar possíveis associaçöes entre condiçöes de trabalho e saúde de professores da rede particular de ensino. Para a coleta de informaçöes foi utilizado um questionário padronizado, respondido pelo próprio professor. Foram estudadas 58 escolas e 573 professores. As características mais freqüentes referidas por professores sobre suas condiçöes de trabalho foram: esforço físico elevado, exposiçäo ao pó de giz, fiscalizaçäo contínua do desempenho e ritmo acelerado de trabalho. As queixas de doenças mais freqüentes foram: dor na garganta, dor nas pernas, dor nas costas, rouquidäo e cansaço mental. As características do trabalho associadas estatisticamente às queixas de doença foram, em ordem decrescente: salas inadequadas, trabalho repetitivo, exposiçäo ao pó de giz, ambiente de trabalho estressante, ritmo acelerado de trabalho, desempenho das atividades sem materiais e equipamentos adequados e posiçäo de trabalho incômoda.