Giovanni Ribeiro de Carvalho

Características da dinâmica folicular e regressão luteal de vacas das raças Gir e Nelore após tratamento com cloprostenol sódico

ABSTRACT - The follicular dynamics and luteal regression were studied in 12 Gir and seven Nelore cows, treated with analogprostaglandin F 2 α, between day 10 and 12 of the estrous cycle. The synchronization rate was higher than 92% for the two breeds, andthe ovulation of second dominant follicle occurred in 72.7% of Gir and all Nelore cows. Ovulatory follicle diameter for Nelore was lower(11.0 ± 0.9 mm) than Gir cows (13.0 ± 1.7 mm). The average intervals from treatment to estrus, treatment to ovulation time and fromthe beginning of the estrus to ovulation were 88.7 and 91.6h, 119 and 113h, 26.5 and 24.3h for Nelore and Gir cows, respectivel y.Key Words: bovine, corpus luteum, estrus synchronization, luteolitic, zebu 1 Parte da tese de Doutorado do primeiro autor, parcialmente financiada pela FAPEMIG. 2 Med.Vet. autonomo – DsC – Rua Cap. Neves , 408. CEP: 37.170-000 B. Esperanca – MG. Bolsista do CNPq. E.mail: amborges@hotmail. com 3 Professor do Departamento de Zootecnia da UFV – Av. PH Holfs, s/n

Avaliação do comportamento sexual em touros Nelore: comparação entre os testes da libido em curral e do comportamento sexual a campo

The objectives of this study were to determine the efficiency of the libido test in corral compared to the test performed at field and to relate them to the gestation rate observed in a breeding season of 120 days. Thirteen Nelore bulls able to reproduce were submitted to the libido test in corral for 3 hours and evaluated by scores every five minutes. Nine of them were submitted to evaluation at field using a bull:cow proportion equal to 1:33. The gestation was diagnosed every 21 days through ultrasonographic evaluation. During the test in corral, the classification scores increased as the testing time increased, but no bull accomplished complete service in the first 10 minutes of the test. A very good bull obtained 84.80% for pregnancy rate, but other questionable bulls obtained 86.67 and 96.55% at the end of the breeding season. Correlations estimates among physical and morphologic characteristics of the semen were close to zero or null. The main physiologic indicators of the bull sexual behavior were: smelling or licking the female body, smelling or licking the vulva, followed or not by the Flehmen reflex. The results suggested 30 minutes of observation as the most efficient time to evaluate the libido test in corral. The libido test at field during daytime was not effective probably because of the sexual behavior of some bulls at night.

Efeito do acondicionamento térmico ambiental sobre o desempenho reprodutivo da fêmea suína

The objetive of this experiment was to evaluate a system of thermal artificial condition for gestation sow housing, at Ponte Nova-MG. A total of 95 Cambourough 22® sows from the second parturition were assigned to two treatments. Forty-six sows of treatment one were submitted, during the first 35 days of gestation, to a system of controlled thermal artificial condition (fans and aspersion) which were automatically turned on according to the air temperature (VFN). In treatment two, during the same period 49 sows of the same variety as the first ones were submitted to any artificial thermal condition (SVFN). From 35 days on of gestation to the parturition, all the animals received the same management. The average room temperature for treatments VFN and SVFN were 22.6°C and 23.4°C, respectively. During the hottest hours of the day, this system was efficient to reduce the temperature by 2°C. In spite of such difference, the system could not reduce the room temperature to an adequate level to these animals (18-21oC). For this reason the animals showed high breathing frequency in both treatments, but this was capable to maintain the body temperature of the sows. There were no differences on the evaluated parameters of reprodutive efficiency and progesterone levels. That is why the ventilation and nebulization systems during the autumn is not justified since the temperatures at this time of the year is not high enough to take the animals to a stress condition which could directly affect their reproductive performance.

Resposta superovulatória de novilhas mestiças holandês-zebu tratadas com somatotropina bovina recombinante (rbST)

The objective of the experiment was to study the effect of pretreatment with 500 mg of sometribove (rbST) on superovulatory response, on number and embryos quality of twenty six crossbred holstein-zebu heifers, allocated into two treatments: T1 ¾ treated with rbST (n=13) and T2 - control (n=13). Thirteen superovulations were done between september and december of 1997 (period 1), and thirteen superovulations between the end of december 1997 and february of 1998 (period 2). For each period seven animals were injected with 500 mg SC sustained-release formulated rbST (T1) on day 3 of estrous cycle, while six animals (T2) did not receive any medication. The animals were superovulated with FSH on day 10, and the embryo collection were performed on day 7 or 8 after the artificial insemination (A.I.). Pretreatment of heifers with rbST did not increase the superovulatory response, total number of structures recover, viable and non viable embryos and ova per collection. The average of total number of structures recovered, viable and non viable embryos and ova per collection were: 15.3 ± 9.5 and 17.4 ± 10.9; 8.5 ± 8.3 and 11.5 ± 10.0; 4.6 ± 4.7 and 3.4 ± 1.3; 2.2 ± 2.8 and 2.8 ± 4.0, respectively, for T1 and T2. The morulae and initial blastocists were recovered in greater percentage on day 7 or 8 after A.I.

Efeitos do local de deposição do sêmen e do intervalo inseminação/ ovulação sobre a fertilidade de éguas inseminadas com sêmen fresco diluído

The effect of the interval from artificial insemination to ovulation on mare fertility rates was studied, taking account the semen deposition site. The intervals were 48 hours and 24 hours prior to ovulation, 48 hours and 72 hours between the two last inseminations. The inseminations in the tip of the uterine horn (GII) were carried out by the deep intravaginal technique using 1/5 of the inseminating dose used in the uterine body (15mL-GI). The mares were teased daily and inseminated on Mondays, Wednesdays and Fridays, starting with a follicle from 3.0 to 3.5 cm of diameter, using fresh semen diluted in skim milk glucose extender. Only one stallion of 20 year-old and well-known fertility was utilized. There was no difference in the conception rates/cycles between the inseminations carried out in the uterine body (42.86%) and in the tip of the uterine horn (45.95%) utilizing average concentrations of 489 and 102 million mobile spermatozoa, respectively. No differences were observed between experimental groups for the same artificial/ovulation interval, but when the conception rates were between intervals in the same semen deposition place, lower conception rates were associated to inseminations carried out before ovulation. However, artificial insemination carried out before and after ovulation, regardless of the artificial insemination/ovulation intervals, resulted in better conception rates. The spermatic concentrations/inseminating dose can be significantly reduced, without damaging fertility, when the semen is placed close to the tubaric papille. However, inseminations are needed before and after ovulation to obtain better fertility rates when using low viability semen in the mare genital tract, in order to establish an adequate sperm reservoir at the time of ovulation.

Perfil de progesterona e intervalo ao estro de receptoras bovinas sincronizadas com doses reduzidas de cloprostenol

The objective of this research was to compare the effects of different doses of application of sodic cloprostenol (doses equivalent to 50% the conventional), in the intramuscular (IM) and intra-vulvosubmucosal (IVSM) vias on the synchronization rates, interval of application to estrus and decrease of seric progesterone concentrations. One hundred and ninety-nine females, 103 with of previus report estrous and 96 without report of previus estores evaluated by rectal palpation to verify the presence of corpus luteum, were randomly divided into three treatments: 1 - 68 animals (38 with report of previous estrus) received 1 mL of cloprostenol through IVSM; 2 - 66 animals (33 with report of previous estrus) received 1 mL through IM; 3 - 65 animals (32 with report of previous estrus) received 2 mL through IM. It was considered the animals that showed estrus up to 96 hours after cloprostenol application. The seric progesterone concentrations (P4) were analyzed by RIA at 0 and 48 hours after the application of luteolitic drug. No effects of treatments on synchronization rates (72.1, 53.0, and 64.6%, respectively), interval from application to estrus (69.3 ± 15.2, 67.9 ± 16.7, and 68.3 ± 16.9 hours, respectively) and P4 percentage concentration decrease (79; 68 and 83%, respectively) were observed. However, when data of animals from treatments of days 11 to 16 were grouped and compared to those of treatments of days 7 to 10, the synchronization rates differed (76.1% vs 55.5%). Sodic cloprostenol doses that was reduced by 50%, in IM or IVSM vias, showed effect similar to the conventional dose. Animals during days 11 to 16 respond better to a synchronization with cloprostenol than those during days 7 to 10 of diestrus.

Uréia para vacas leiteiras no pós-parto: teor plasmático de uréia e pH uterino

The objective of this work was to evaluate the effects of increasing levels of urea in the diets in postpartum crossbred dairy cows on plasma level of N-urea (NUP) and uterine pH in the estrus and luteal phase. Sixteen crossbred cows (Holstein-zebu) with body condition score at parturition between 3.5 and 4.0 (1 to 5 scale) were assigned in four treatments with diets made up with corn silage and concentrate in the proportion of 60:40 as: T1=0.0; T2=0.7; T3=1.4; and T4=2.1% of urea in the dry matter. The uterine pH was measured four hours after the diet intake, during the estrus and luteal phase from the second or third estrous cycle postpartum period in dairy cows. Simultaneously, blood samples were collected for determination of the level of plasma urea. The dry matter intake from 70 to 110 days of lactation reduced from 0.7% of urea. The levels of plasma N-urea were not affected in the samples collected during the estrus (19.59 mg/dL). The uterine pH during estrus (6.66) and luteal phase (6.97) were not affected by the different levels of urea.

Efeito do número de inseminações artificiais por ciclo sobre a fertilidade de éguas inseminadas com sêmen eqüino diluído, resfriado a 20ºC e transportado

One hundred and twenty estrus cycles of 105 Mangalarga Marchador breed mares were analyzed to study the effect of number of inseminations per cycle on the fertility of mares inseminated with cooled semen. The mares were randomly allocated in the following group: T1 - one AI/cycle; T2 - two AI/cycle; T3 - tree or more AI/cycle. The cycles were controlled by rectal palpation and teasing. The insemination were made at each 48 hours, from a 30-35 mm follicle diameter until ovulation, with diluted, cooled (20oC) and transported equine semen. The conception rates in the first cycle were, respectively, to T1, T2 and T3, 47.83% (11/23), 70.00% (21/30), and 45.16% (14/31) (P>0,05), and after five cycles were 51.43% (18/35), 48.89% (22/45) and 47.50% (19/40) (P>0,05). The number of AI/cycle had no effect fertility in mares.

Fertilidade de éguas inseminadas no corpo ou no ápice do corno uterino com diferentes concentrações espermáticas

Seventy-two estral cycles of 37 mares, aging from four to 20-year-old, were randomly distributed in two experimental groups (GI and GII). The aim of the study was to evaluate the effect of the semen deposition placed in the female genital system on the fertility. The inseminations in uterine horn tip (GII) were carried out by deep intravaginal way, using the pipette of insemination IVI pippette (75cm), containing 1/5 (3mL) of the inseminant dose of that utilized in uterine body or horn (15mL-GI). The mares were daily teased and inseminated on Mondays, Wednesdays, and Fridays, starting from a follicle from 3.0 to 3.5cm diameter, with fresh semen diluted in skim milk glucose extender. Only one 20 year-old stallion with wellknown fertility was utilized. The conception rates/cycles for inseminations carried out in the uterine body (42,9%-15/35) and in the uterine horn tip (45,9%-17/37) utilizing average concentrations of 489 and 102 million of mobile spermatozoa, respectively, did not present difference (P>0.05).