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ABSTRACT: Clinical endometritis (CE) and subclinical endometritis (SCE) are diseases that affect dairy cows during the puerperium, causing negative effects on the animals' milk production and fertility. The objective of this study was to assess the main bacteria related to cases of CE and SCE from uterine samples of dairy cows in Brazilian herds. Selective and differential media were used for isolation of aerobic and anaerobic bacteria and further MALDI-TOF mass spectrometry (MS) identification. A total of 279 lactating dairy cows with 28 to 33 d in milk from 6 commercial farms were evaluated. Initially, cows were classified in 3 groups: cytologic healthy cows (n = 161), cows with CE (n = 83), and cows with SCE (n = 35). Healthy animals presented 97 species, followed by the CE group with 53 identified species, and SCE cows presented only 21 bacterial species. We found a significantly higher isolation rate of Trueperella pyogenes in CE (26.5%) cows compared with healthy and SCE cows. Some anaerobic species were exclusively isolated from the CE group, even though they presented lower frequency. Interestingly, 18.1% of samples from CE cows and 40% of SCE cows were negative to bacterial isolation. Despite the use of culture-dependent methods instead of molecular methods, the present study enabled the identification of a complex community of 127 different species from 48 genera, composed of aerobic and anaerobic bacterial species among the 3 different animal groups. The method of sample collection, culture, and identification by MALDI-TOF MS were essential for the success of the analyses.

ABSTRACT The objective of this study was to compare the reproductive efficiency of dairy buffaloes undergoing fixed-time artificial insemination (FTAI) protocols based on progesterone/estrogen (P4/E2) and eCG during unfavorable breeding season using cooled (CS) and frozen semen (FS). A total of 446 buffaloes (> 40 days postpartum) were randomly distributed into four blocks (years): B1-2014 (n = 143), B2-2015 (n = 34), B3-2016 (n = 90), and B4-2017 (n = 179). Each block was subdivided into two (AI with CS and FS using the same ejaculate of each bull). Thus, the block subdivision was as follows: B1 (CS = 71 and FS = 72); B2 (CS = 18 and FS = 16); B3 (CS = 47 and FS = 43); and B4 (CS = 90 and FS = 89). The ejaculates of eight Murrah bulls collected using an artificial vagina were divided into two aliquots: one aliquot was diluted in Botu-Bov® commercial extender and cooled (BB-CS), and the other was diluted in the same extender and frozen (BB-FS). BB-CS aliquots were cooled at 5 °C/24 h using a refrigerator. BB-FS group aliquots were also cooled, and after equilibrating at 5 °C for 4 h, were placed in a 21-L Styrofoam box, 5 cm above the surface of liquid nitrogen. In the afternoon (A) on D0 (2:00 p.m.) the animals received EB 2.0 mg IM (Estrogin®) and an ear implant (CRESTAR® 3.0 mg P4). At D9 (A), the implant was removed, and the animals received eCG 400 IU IM (Folligon® 5000) + Cloprostenol PGF2α 0.530 mg IM (Sincrocio®). At D10 (A), the animals received EB 1.0 mg IM (Estrogin®), and at D12 (8:00 a.m.), AI was performed. At D42, pregnancy was diagnosed via ultrasonography. Total CRs were 48.2% CS and 34.6% FS for years 2014 to 2017, with a significant difference of 13.7% (P

The aim of this review is to compare the performance of different reproductive programs using natural service, estrus synchronization treatment before natural service (timed natural breeding (TNB)), artificial insemination (AI) following estrus detection and timed artificial insemination (TAI) in beef herds. It is well known that after parturition the beef cow undergoes a period of anestrous, when they do not exhibit estrus, eliminating the opportunity to become pregnant in the early postpartum by natural mating or by AI after detection of estrus. Hormonal stimulation is already a consistent and well-proven strategy used to overcome postpartum anestrus in beef herds. Basically, hormones that normally are produced during the estrous cycle of the cow can be administered in physiological doses to induce cyclicity and to precisely synchronize follicular growth, estrus and ovulation. Furthermore, two options of mating may be used after hormonal stimulation: natural service (i.e. utilization of bull service after synchronization, referred to as TNB) and TAI. These strategies improve the reproductive efficiency of the herds compared with natural service without estrus induction or synchronization. After the first synchronized service, the most common strategy adopted to get non-pregnant cows pregnant soon is the introduction of clean-up bulls until the end of the breeding season. However, methods to resynchronize non-pregnant cows after the first service are already well established and offer a potential tool to reduce the time for subsequent inseminations. Thus, the use of these technologies enable to eliminate the use of bulls by using resynchronization programs (i.e. two, three or four sequential TAI procedures). The dissemination of efficient reproductive procedures, such as TNB, TAI and Resynch programs, either isolated or in combination, enables the production of a greater quantity (obtaining increased pregnancy rates early in the breeding season) and quality (maximization of the use of AI with superior genetic sires) of beef calves. These technologies can contribute to improve the production efficiency, and consequently, improve livestock profitability.

The main objective of the implementation of artificial insemination (AI) in cattle is to produce a sustained genetic progress in the herd. Although AI is an old reproductive biotechnology, its widespread implementation is very recent and is mainly because of the use of protocols that allows AI without oestrus detection, commonly called fixed-time artificial insemination (FTAI). The development of FTAI protocols also allowed the application of AI in larger, extensively managed herds and especially in suckled cows instead of restricting the breeding programmes to the heifers. Fixed-time AI treatments are widely used in South America, with about 3 000 000 cows inseminated in the last season in Argentina and about 8 000 000 in Brazil. The objective of this review is to present and describe the various treatments available and some of the factors that may affect pregnancy rates in beef cattle.

The relationship between variations of weight and BCS was evaluated using growing buffalo heifers, fed diets with different energy level. 12 Murrah bred heifers (age: 790 days, LW: 400 kg), raised in Saint Paul (Brazil) were equally divided in group H and L fed diets with 5.8 UFL/day and 3.6 UFL/day, respectively. At the end of treatment, groups showed significant differences in weight and values of BCS. In this trial each point of BCS, in Murrah heifers, seems to be equivalent to an increase and/or a loss of about 50 kg of live weight. During this trial the mean value of daily weight gain (DWG) was significantly higher in group H (310 g. vs 0 g.; P

The objective of this study was to induce an accessory corpus luteum (CL) in buffaloes fixed time artificially inseminated. Two hundred and forty buffaloes received the treatment sequence GnRH/PGF2α/GnRH after which were inseminated artificially. Six days after the insemination, the animals were divided in two groups (G1 = Control and G2 = GnRH) and received 0 μg or 25 μg of GnRH to induce an accessory CL. After twenty four days (D40), pregnancy diagnosis was performed by ultrasonography and 79 buffalo (G1, n = 39; G2, n = 40) were randomly selected to verify the ovary status by ultrasound. Fifty three pregnant buffaloes (G1, n = 32; G2, n = 21) were followed to verify the birth rate. Data were analyzed by Chi-square test. The conception rate, the accessory CL rate and the birth rate were higher in G2 than in G1 (P

The objectives of the present work were to determine follicle deviation assessed by ultrasonography and profile of plasmatic gonadotrophins, and ovulatory capacity in buffalo species, since these information are not available in the literature. The knowledge of follicular development and gonadotrophins profile during deviation and the follicular response to an exogenous ovulation inducer can be useful tools for follicular manipulation of estrous cycle.

The objective of present study was to evaluate the effect of OPU interval and the effect of bST treatment on embryo production in buffalo. Sixteen females were assigned in 4 groups, in a 2x2 experimental design, with main effects of bST (0 or 500mg) and interval of OPU session (every 7 or 14 days), as follows: G-CONT7: OPU once a week; G-CONT14: OPU each 14 days; G-bST7: OPU once a week + 500mg of bST and G-bST14: OPU each 14 days + 500mg of bST. Animals of G-CONT7 and G-bST7 were submitted to 8 OPU sessions, and those of G-CONT14 and G-bST14 to 4 OPU sessions. Overall, OPU once a week (without bST) reduced the number of aspirated follicles, and the total and viable oocytes. Despite of this, OPU every 14 days + bST increased the number of degenerated oocytes, and reduced the number of blastocysts produced on days 6 and 7.

The objective of this study was to evaluate the effects of the season and number of calving on average milk production and persistence of lactation. Fifty hundred and ninety one lactation of buffaloes, milked once a day and bred on pasture conditions were analyzed. The animals were allocated according season (off breeding season = Goff and breeding season = Gon) and number of calving (first = FC, second = SC and more than two calving = MC). Data was analyzed by ANOVA. Average milk production was higher on Gon than Goff, and the persistence of lactation was short on Gon than Goff. FC showed lower average milk production than SC and MC that did not differing about. The persistence of lactation was similar among FC, SC and MC. The results showed that on pasture condition, calving on off breeding season results in lower average milk production but in higher persistence of lactation. It is possible that, buffaloes during the off breeding season had higher disposability of pasture that guarantee higher persistence of lactation and buffaloes on breeding season calved with better corporal condition that guarantee higher average milk production. The lower average milk production of first calving buffaloes was according to the expected.

The efficiency of different doses of rBST in a MOET protocol was verified in buffaloes. The animals received an intravaginal progesterone device (DIB) plus 2.0 mg of estradiol benzoate (Ric-BE, i.m.) and 0 mg, 250 mg or 500 mg of rBST. Ovarian follicular growth was stimulated by treatment with 200 mg of FSH in decreasing amount (12/12hs). Buffaloes received injections of PGF2α on D6 and on D7. The DIB was removed on D7. On D8, 24 hours after DIB removal, ovulation was induced with GnRH. The follicular emergence and the response to FSH treatment were evaluated by ultrasound on D4 and D8. The artificial insemination (AI) was performed 12 and 24 hours after the GnRH administration. The embryonic structures were collected 5.5 days after the first AI. Data were analyzed by ANOVA. No statistical differences were found between groups. The results indicated that rBST, associated to a MOET protocol at the different dosages used, does not to improve the efficiency of the technique in buffalo.

The objective of this study was to evaluate the effect of intravaginal progesterone device (P4; first or second use) of different ovulatory inductors on ovulation and conception rates in buffaloes during the off breeding season. Two hundred and forty two buffaloes were allocated in four groups and received P4 device of first or second use plus estradiol benzoate on Day 0 (D0). The P4 device was removed and a dose of PGF2α and eCG was administered on D9. On D11, buffaloes received hCG or GnRH and 16hs after the animals were inseminated. The ultrasound examination was performed on D0 to verify the ovarian status, from D9 to D14 to establish the moment of ovulation and on D40 for pregnancy diagnosis. Data were analyzed by ANOVA and Chi-square test. There was no effect of interaction. The ovulation and conception rate were similar for P4 device of first and second use, for hCG and GnRH. Results indicate that the use of P4 device for two times and the use of GnRH instead of hCG provide satisfactory ovulation and conception rate in buffalo during the off breeding season and might reduce the cost of the protocol for artificial insemination.

The aim of this experiment was to evaluate membrane integrity, vitality, and mitochondrial cytochemical activity, in frozen semen samples of buffalo bulls and compare those functions with the routine semen evaluation and field fertility. Twenty one frozen semen batches from 2 buffalo bulls were used for AI. For the semen evaluation, after thawing, an aliquot was evaluated for motility and vigor. An aliquot of each batch was used to evaluate the cytochemical activity using the 3-3’ diamino benzidine. Samples were scored in four classes according to the degree of midpiece staining, being class I showing midpiece totally stained, indicating full mitochondrial activity, and class IV showing no staining of the midpiece, indicating no mitochondrial activity. Two other aliquots were used for the hypo-osmotic swelling test (HOST) and the eosin nigrosin staining (VIT), to evaluate membrane integrity and vitality, respectively. Correlations were found between pregnancy rate and vitality and class II and III of the DAB staining (r=0.53, r=-0.39, and r=-0.38, respectively; p=0.05). No correlation was found for pregnancy rate and motility or vigor. Results indicate that functional tests may be an alternative to better predict the fertility of buffalo frozen semen samples.

In order to verify the causes of the low embryo recovery rate in superovulated buffaloes, the effect of species and of estradiol-17β (E2) treatment were evaluated on oocyte transport across the oviduct in Murrah and Nelore. The females were synchronised with progesterone plus estradiol benzoate followed by an injection of PGF2α and eCG. The ovulation was induced with GnRH and 48hs after the animals were slaughtered and the oviducts removed. The oviducts were washed with HBSS and oocytes of both species were inserted into infundibulum portion. The oviducts were put in a dish with HBSS with or without E2 and incubated for 24 h. The oviduct were then flushed with DPBS, in order to recover and count the oocytes. Data were analyzed by ANOVA. There was no effect of interaction. The total number of oocytes and the recovery rate were higher for Nelore than Murrah (P

The relationships between feed intake, growth and reproduction are of great interest in breed species in order to optimize the different steps of farm management. In the last years leptin has been proved to be involved in the regulation of the energy balance of human and several mammalian and avian species (Ingvartsen and Boisclair, 2001).