José Camisão de Souza

Effects of two estradiol esters (benzoate and cypionate) on the induction of synchronized ovulations in Bos indicus cows submitted to a timed artificial insemination protocol

The effects of estradiol benzoate (EB) and estradiol cypionate (EC) on induction of ovulation after a synchronized LH surge and on fertility of Bos indicus females submitted to timed AI (TAI) were evaluated. In Experiment 1, ovariectomized Nelore heifers were used to evaluate the effect of EB (n = 5) and EC (n = 5) on the circulating LH profile. The LH surge timing (19.6 and 50.5 h; P = 0.001), magnitude (20.5 and 9.4 ng/mL; P = 0.005), duration (8.6 and 16.5 h; P = 0.001), and area under the LH curve (158.6 and 339.4 ng/mL; P = 0.01) differed between the EB and EC treatments, respectively. In Experiment 2 (follicular responses; n = 60) and 3 (pregnancy per AI; P/AI; n = 953) suckled Bos indicus beef cows submitted to an estradiol/progesterone-based synchronization protocol were assigned to receive one of two treatments to induce synchronized ovulation: 1 mg of EB im 24 h after progesterone (P4) device removal or 1 mg of EC im at P4 device removal. There was no difference (P > 0.05) between EB and EC treatments on follicular responses (maximum diameter of the ovulatory follicle, 13.1 vs. 13.9 mm; interval from progesterone device removal to ovulation, 70.2 vs. 68.5 h; and ovulation rate, 77.8 vs. 82.8%, respectively). In addition, P/AI was similar (P < 0.22) between the cows treated with EB (57.5%; 277/482) and EC (61.8%; 291/471). In conclusion, despite pharmacologic differences, both esters of estradiol administered either at P4 device removal (EC) or 24 h later (EB) were effective in inducing an LH surge which resulted in synchronized ovulations and similar P/AI in suckled Bos indicus beef cows submitted to TAI.

Sensibilidade dos espermatozoides de dourado (Salminus brasiliensis) a diferentes soluções crioprotetoras

The sensitivity of dourado (Salminus brasiliensis) spermatozoa to different cryoprotectant solutions was evaluated in three experiments. In experiment 1, semen was diluted, 1:10, in 12 solutions (four extenders x three cryoprotectants - dimethylsulphoxide (DMSO), methyglycol, or glycerol). Half of each sample was refrigerated for one hour while the other half was cryopreserved. Sperm motility was immediately assessed after dilution and after refrigeration in all samples, and after thawing in those cryopreserved in DMSO. In experiment 2, semen was diluted, 1:5, in five solutions containing DMSO, refrigerated, cryopreserved, and analyzed as in experiment 1. In experiment 3, semen was diluted, 1:5, in five solutions containing DMSO, cryopreserved and evaluated for motility and fertility. When semen was diluted 1:10, motility higher than 58% was observed in all samples refrigerated in DMSO and in NaCl-tris-methylglycol. Low motility was observed in samples refrigerated in the other combinations of methylglycol (5-32%) or glycerol (0-8%) and in those cryopreserved (16-20%). All samples diluted 1:5 yielded motility of 65-72% after refrigeration, and 45-66% after thawing (experiments 2 and 3). The hatching rates produced with cryopreserved semen, however, were lower (17-23%) compared to fresh semen (60%).

Effect of concentrate: voluminous ratio on the performance of Santa Inês lambs

O experimento foi conduzido no Setor de Ovinocultura da Universidade Federal de Lavras, com o objetivo de avaliar os efeitos das diferentes relacoes concentrado:volumoso sobre o desempenho de cordeiros Santa Ines apos o desmame. Foram utilizados 40 cordeiros, machos nao castrados, que foram alimentados com quatro dietas: dieta A (100% concentrado), dieta B (75:25 concentrado:volumoso), dieta C (50:50 concentrado:volumoso) e dieta D (25:75 concentrado:volumoso). As dietas experimentais foram iso-proteicas, diferenciando apenas em seus niveis de concentrado:volumoso e foram balanceadas para atender as exigencias nutricionais segundo as recomendacoes do Agricultural Research Council (1980). O periodo experimental nao teve duracao pre-fixada, pois correspondeu ao periodo necessario para que o ultimo cordeiro atingisse o peso vivo de 35 Kg. Os consumos de materia seca (CMS), consumos de proteina bruta (CPB), consumos de fibra em detergente neutro (CFDN) e consumos de fibra em detergente acido (CFDA), foram afetados pelas diferentes relacoes de concentrado:volumoso, sendo que, os animais alimentados com dietas com maior inclusao de concentrado apresentaram os melhores resultados para as variaveis relativas ao desenvolvimento. Os cordeiros alimentados com a dieta com maior inclusao de volumoso nao apresentaram ganho de peso, pelo contrario, apresentaram perda de peso, sendo que nenhum animal chegou ao peso de abate e a mortalidade foi extremamente alta (80%).

Influência do manejo de mamada sobre o retorno ao estro em ovelhas no pós-parto

Conduziu-se este estudo, com o objetivo de avaliar o retorno ao estro pos-parto de ovelhas submetidas a diferentes manejos de mamada. Foram utilizados 56 ovelhas Santa Ines e Bergamacia, 71 cordeiros e 3 rufioes. Os manejos de mamada (MM) foram: 1: continua; 2: duas mamadas diarias; 3: mamada durante a noite. O periodo experimental foi dos 15 dias pos-parto ate o desmame aos 60 dias. Ate os 15, dias de idade os cordeiros permaneceram com suas maes em periodo integral. No MM 1, as ovelhas permaneceram com seus cordeiros em uma baia, em periodo integral. No MM 2, as ovelhas passaram a noite em uma baia e o dia em pastagem, momento em que nao possuiam contato fisico e visual com as crias. Seus cordeiros permaneceram em outra baia em periodo integral, para onde as ovelhas eram encaminhadas no momento da amamentacao. No MM 3, as ovelhas passaram o dia em pastagem e a noite com seus cordeiros em uma baia, na qual os cordeiros permaneceram em periodo integral. Todas as ovelhas e todos os cordeiros receberam alimentacao nas baias. Para identificacao das ovelhas em estro foram utilizados rufioes, os quais permaneceram com elas em periodo integral. Os dados foram submetidos a analise de variância (PROC GLM, Sas®), e as medias comparadas por contrastes. O MM 2 possibilitou retorno ao estro pos-parto precoce quando comparado ao MM 3 e ao MM 1. Houve pouca ou nenhuma influencia do anestro lactacional, pois 80% das ovelhas apresentaram estro durante a amamentacao.

Effect of flushing with sources of protein with different degratability on ovulation in Santa Inês ewes

This study aimed at evaluating plasma concentration of urea nitrogen, the number of ovulations and the diameter of ovulatory follicle of Santa Ines ewes submitted to flushing with sources of protein with different ruminal degradabilities. Forty-four estrus-synchronized ewes were fed isoprotein diets composed of soybean meal (n = 24) or corn gluten meal and cottonseed meal (n = 20) for 28 days before ovulation. Animals were distributed in a block design in which the blocks were formed by three score ranges of body condition score. Body weight and body condition score gains, body weight and body condition score on the 28th experimental day, urea nitrogen plasma concentration, number of ovulations and diameter of the ovulatory follicle did not differ among ewes submitted to flushing with soybean meal or with corn gluten and cottonseed meal. Ewes under soybean meal flushing showed higher urea nitrogen plasma concentration on days seven and 14 and lower concentration on the 28th day when compared to those fed corn gluten and cottonseed meal (day vs. diet interaction). The supply of one diet with lower content of ruminal degradable protein does not reduce urea nitrogen plasma concentration neither alters the number of ovulations and diameter of ovulatory follicle.

Characterization of cattle slaughtered at the public abattoir in Lavras-MG

The objective was to characterize cattle slaughtered from the region of Lavras - MG. In the public abattoir 720 bovines were identified and slaughtered from September 20th through November 20th of 2004. Variables such as: genetic origin, live weight, body condition, age, and sex were studied. At arrival, animals were weighed and classified according to their genetic origin. Before slaughter, their body condition (BC) was determined on a 1 - 9 scale. Reproductive status was observed during scratch and evisceration: castrated male, MC; intact male, MI; pregnant female, FG; and Non-pregnant female, FNG. Age was determined by the count of the permanent incisive teeth (p.i.t.). Most animals slaughtered during the survey were male, with predominance of the Girolando genetic group. Overall mean slaughter weight was 438.5 ± 115.97 Kg (n=720). Females (FG and FNG) were older (>48 months old) as compared to male animals, FNG had lower body condition scores (3, 4 and 5). Male (MC and MI), had good body condition scores. Most of slaughtered cattle in Lavras were characterized as non-specialized for beef production.

Use of sex-sorted and unsorted frozen/thawed sperm and in vitro fertilization events in bovine oocytes derived from ultrasound-guided aspiration

The objective was to investigate the effects of sex-sorting on early fertilization events in ovum pick up (OPU) derived oocytes fertilized in vitro with frozen-thawed sperm at different co-incubation lengths. Eighty-four OPU sessions were carried out in 18 cyclic, dry and non-stimulated Holstein Friesian and German black pied cows. Ovum pick up oocytes were matured in vitro for 24 hours and fertilized with frozen-thawed sex sorted or unsorted sperm from the same ejaculate. Fertilization was achieved by two experimental protocols: 1) short gamete co-incubation length: 4, 8 and 12 hours; and 2) long gamete co-incubation length: 18 and 24 hours. After in vitro fertilization, ova were fixed and stained to identify early fertilization events. Sperm penetration, monospermy, pronuclear formation and syngamy did not differ, whether sexed or unsexed sperm was used. Overall, the findings demonstrate similar fertilizing potential between sex-sorted and unsorted sperm.

Gordura corporal e eficiência reprodutiva em éguas doadoras de embrião Mangalarga Marchador

Foi comparado o julgamento do escore de condicao corporal (ECC) com a espessura de gordura subcutânea (EGS) e sua relacao com a eficiencia reprodutiva de eguas Mangalarga Marchador doadoras de embriao. O experimento foi conduzido com 56 eguas doadoras entre os meses de agosto/08 e abril/09. O ECC foi maior em eguas mais velhas e aumentou com os dias de permanencia no experimento. Houve correlacao positiva entre peso e tempo de experimento. O peso nao foi associado a idade, porem aumentou ao longo do experimento. A EGS na regiao da cauda e entre a 12a e 13a costelas aumentou com a idade e diminuiu com os dias de permanencia no experimento. Houve correlacao positiva entre EGS e ECC para a cauda e costela. O diâmetro do foliculo dominante aumentou ao longo do ciclo estral, e foi menor em eguas com ECC abaixo de 6,5. O diâmetro folicular nao foi influenciado pela idade. O diâmetro medio do foliculo ovulatorio foi 38,43 ± 3,09 mm. A recuperacao embrionaria nao foi afetada pela idade ou ECC, mas foi menor (41%) emeguas que ovularam foliculos menores que 40 mm quando comparados as que ovularam foliculos maiores que 40 mm (59%). A idade da doadora nao foi associada a taxa de gestacao dos embrioes nas receptoras. A gordura corporal afetou a eficiencia reprodutiva das eguas, alem disso, a ultrassonografia parece ser essencial para a avaliacao precisa e correta do escore de condicao corporal.

Efeito de diferentes dosagens de vitamina A injetável na produção e qualidade de embriões bovinos da raça Nelore

Conduziu-se este trabalho com o objetivo de avaliar o efeito de quatro diferentes doses de vitamina A (0 - (n=14), 500.000 (n=15), 1.000.000 (n=17) e 1.500.000 (n=16) (UI) (na forma de palmitato de retinol) na producao e qualidade de embrioes coletados de vacas doadoras da raca nelore (n=64). O experimento foi realizado na Central de Transferencia de Embrioes Cauembryo no municipio de Funilândia - MG. As vacas foram superovuladas no 10o (n=18), 11o (n=10), 12o (n=26) ou 13o (n=10) dia apos a data do cio com 20 ml de Folltropin® (Vetrepharm, Belleville, Canada) ou 10 ml Pluset® (I.F. Serono, Roma, Italia) distribuidos em dosagens decrescentes durante quatro dias, em duas aplicacoes diarias (intercaladas de doze horas). Os tratamentos com vitamina A foram iniciados juntamente com a primeira dose de FSH. A luteolise foi induzida no quarto dia do tratamento de FSH com uma aplicacao de 0,75 mg de cloprostenol sodico (Ciosin®, Coopers do Brasil, Sao Paulo, Brasil) e as doadoras observadas em cio foram inseminadas as 12 e 24 horas apos o seu inicio, usando semen de diferentes touros. As analises estatisticas foram feitas utilizando o procedimento GENMOD do SAS (SAS INSTITUTE, 1995). O numero de embrioes viaveis aumentou significativamente (P 0,05) entre as doadoras suplementadas (9,5, 8,3 e 10,5, respectivamente para 500.000, 1.000.000 e 1.500.000 UI de vitamina A) e nao-suplementadas (8,2). Por meio desses dados, verifica-se que a suplementacao de vitamina A injetavel antes da coleta melhora a qualidade dos embrioes coletados, sem interferir na quantidade de estruturas produzidas.

Anti-Müllerian Hormone (AMH), antral follicle count (AFC), external morphometrics and fertility in Tabapuã cows

The intense selection of characteristics related to animal performance may affect the reproductive efficiency of beef cows negatively. Selection for fertility along with production traits is, therefore, readily justifiable. The objective of the present study was to evaluate possible relationships among AFC, serum AMH concentrations and external morphometrics with reproductive efficiency in Tabapuã (a Brazilian Bos indicus beef breed) females. Antral follicle counts and external morphometrics were measured in nulliparous (n = 162), primiparous (n = 80) and multiparous (n = 351) cows, from four farms. Age at first parturition (AFP), parturition interval (PI), maternal ability (MA), precocity, rusticity and survival (PRS) and overall reproductive efficiency (RE) were evaluated according to the Brazilian Association of Zebu Breeders (ABCZ) data bank indexes. A single blood sample per animal was collected at random stages of the reproductive cycle from a subset of animals (nulliparous = 84, primiparous and multiparous = 136) to determine serum AMH concentrations. The AFC classes were defined as lesser (<28), intermediate (28-50) and greater (>50). Correlations between all variables and the effects of parity and AFC on reproductive traits, AMH and external genitalia size were analyzed by the PROCORR and by the PROCGENMOD procedures of SAS® (SAS, Cary, NC, USA), respectively. Antral follicle count did not differ (P = 0.71) among nulliparous (38.6 ± 23.96) primiparous (47.54 ± 26.16) and multiparous (41.08 ± 25) cows and was negatively correlated with pregnancy interval (PI), such that, as PI decreased (r = -0.28; P < 0.005), AFC increased. Vulva width was not affected (P = 0.08) by parity and was larger (P < 0.05) for females in the greater AFC class (8.81 ± 0.12 cm) compared with the intermediate (8.42 ± 0.11 cm) and lesser (8.38 ± 0.13 cm) classes. As vulva width increased, parturition interval decreased (r = -0.15; P < 0.005) and overall reproductive efficiency increased (r = 0.17, p < 0.005). Thoracic depth was associated with greater AFCs (r = 0.10; P < 0.001). Anti-Müllerian hormone concentrations were greater (P < 0.05) for animals in the greater AFC class (1.15 ± 0.09 ng/mL) compared with the lesser (0.44 ± 0.02 ng/mL) and intermediate (0.73 ± 0.05 ng/mL) classes. Vulva width, AFC, external morphometrics and AMH concentrations were moderately associated, considering the low heritability of fertility traits, and should be studied further to be considered in the selection for fertility in Bos indicus cattle.