J. H. Bruschi

Autoclaved, previously used intravaginal progesterone devices induces estrus and ovulation in anestrous Toggenburg goats

Intravaginal progesterone devices are used worldwide for estrus induction in goats. Reused devices are able to induce estrus; however, this can be a health risk within a flock. The objective was to compare new and previously used (and autoclaved) progesterone-releasing intravaginal devices for induction of estrus and ovulation in seasonally anestrous Toggenburg goats. Anestrous goats (n=42) received new intravaginal devices containing 0.3g progesterone (CONTROL), or similar devices previously used for either 6 (USED6) or 12d (USED12) and subsequently autoclaved. All goats received 5mg dinoprost at device insertion and 200 IU eCG 5d later, and all devices were removed after 6d. After device removal, estrus was monitored and females displaying signs of estrus were mated by fertile bucks. Transrectal ovarian ultrasonography was performed after device removal until detection of ovulation. Blood samples were collected for determination of plasma progesterone concentration at different times. There was no difference (P>0.05) among groups CONTROL, USED6 or USED12 for: estrus response (87, 100 or 100%, respectively); duration of estrus (32.3±2.3, 25.2±3.4 or 27.3±4.1h); ovulation rate (100, 88 or 100%); number of ovulations (1.5±0.2, 1.9±0.3 or 1.7±0.3); and pregnancy rate (60, 58 or 67%). Plasma progesterone (P4) concentrations were greater (P<0.05) in CONTROL than in USED6-treated and USED12-treated goats (7.2±1.2, 4.7±0.7 and 4.3±0.6 ng/mL, respectively) at 6h after device insertion; these differences were maintained until 4d after device insertion (3.4±0.4, 2.3±0.2, and 2.5±0.2 ng/mL). Overall, plasma progesterone concentrations were greater (P<0.05) in nulliparous than in lactating goats (3.1±0.8 compared to 2.4±0.6 ng/mL, respectively). In conclusion, autoclaved, previously used intravaginal progesterone-releasing devices resulted in significant lesser plasma progesterone concentrations than new devices, but were similarly effective in inducing estrus and ovulation in anestrous goats.

Correlations among semen quality traits and scrotal circumference of sires of the Gyr breed.

Data related with semen characteristics such as volume (VOL), gross motility (TURB), motility (MOT), vigor (VIG), concentration (CONC), major defects (DMA) and minor defects (DME) from 807 semen output (CS) of 105 sires of the Gyr breed selected for milk production, and their measurements of scrotal circumference (CE) were used to study factors that affect these traits and the correlations among them. Uni and bivariate animal models that included the fixed effects of AI company, year and season of CS or CE measurement, age at CS or CE measurement, and random animal (bull) effect were used to evaluate the effects of these source of variation and the correlation between those traits. AI company and sire had a significant effect on all traits. Age affected only CE, TURB and NEMOV (= VOL x CONC x MOT). Repetabilities estimated by univariate model ranged from 0.23 for CONC to 0.70 for TURB. In general, phenotypic correlations, estimated by bivariate model were in a favorable direction. Pearson correlation between CE and all other traits ranged from -0.19 to 0.35. The recorded correlations, in general in a favorable direction, suggested that CE could be used as an elimination trait of sire to be pre-selected as a semen donor.

Indução de estro em cabras da raça Toggenburg com dois diferentes dispositivos intravaginais

Twelve Toggenburg breed nuliparous female goats were randomly assigned to two treatments intended to induce estrus. On day zero, animals on T1 (n=6) were treated with an intravaginal sponge impregnated with 60mg of medroxyprogesterone acetate plus 50µg of PGF analogue. The T1 goats received eCG (250IU) on day 4, and on day 5 the sponge was removed. The T2 goats (n=6) received CIDR-G® as intravaginal sponge plus 50mg of PGF analogue. All goats expressed behavioral estrus, and the pregnancy rates were 83.3 (5/6) and 33.3% (2/6) for T1 and T2, respectively. The interval from withdrawal of the device to onset of estrus did not differ between treatments (P>0.05). Ovulatory traits also were not affected by treatments. The interval between CIDR-G® removal and ovulation for T1 and T2 goats were similar (P>0.05). Both sponge and CIDR-G were equally efficient in inducing the estrus behavior in goats.

Parâmetros reprodutivos de cabras Toggenburg inseminadas com sêmen resfriado, após diluição em meio à base de gema de ovo

The conception rate, the prostaglandin response, the estrus duration, the reproductive class, and the mucous of goats inseminated with semen diluted in egg yolk extender and cooled at 5oC, for 12 or 24 hours were evaluated. Sixty-two female goats and two sexually mature Toggenburg bucks were used. The females received two doses of 22.5µg of prostaglandine F2α, at 10-day intervals. After the first injection, the estrus was monitored three times a day (6:00, 12:00, and 18:00h), with a buck teaser. Only one insemination was used. The percentages of animals that showed estrus after the first and the second injection of PGF2α were 85.5% and 88.7%, respectively. The average intervals from first and second PGF2α injection to estrus were 41.04±20.32 and 45.67±9.28h, and the estrus durations for both injections were 40.02±15.96 and 32.24±12.09h, in this order. The interval from the PGF2α injection to the beginning of the estrus was longer (P 0.05) the conception rate. The mucous observed at the insemination time influenced (P<0.05) the fertility of inseminated goats, with the striated aspect associated to higher fertility.

Dinâmica folicular em cabras da raça Toggenburg em lactação tratadas ou não com somatotropina bovina recombinante

The effect of the r-bST injection was evaluated on the goats estrous cycles. Twenty-four Toggenburg does were used in two treatments: T1 (n=12) treated with r-bST; and T2 (n=12) treated with saline solution (control). After the first r-bST injection, the estrous cycles were checked between two estrus. The estrous cycle length and interovulatory period of the goats did not differ between treatments (P>0.05). Estrous cycles with two, three and four waves of follicular growth were observed. The number of waves during the estrous cycle were not affected by the r-bST treatment (P>0.05). The number of 3mm follicles was different between T1 and T2 (P 0.05) between treatments. The r-bST did not affect the ovarian response during the estrous cycle. The r-bST not affected the follicular dynamic of Toggenburg lactating does, but increased the number of emerging follicles ≥3mm during the estrous cycle.

Taxa de concepção de cabras inseminadas com sêmen caprino resfriado a 5ºC, por 12 ou 24 horas, em meio diluidor à base de gema de ovo

The fertilizing capacity of goat semen cooled in egg yolk diluent at 5oC, for 12 or 24 hours was evaluated. Sixty-two Toggenburg does and two sexually mature Toggenburg bucks were used in a fatorial treatment combination (two bucks and two storage periods). The semen was diluted in 2.5% Tris-frutose-egg yolk; envased in 0.25mL plastic straws, with 150x106 mobile spermatozoa; and cooled at 5oC for 12 or 24 hours. The females received two doses of 22.5µg of prostaglandine F2α, at each 10-day intervals in order to synchronize the estrous. From the first PGF2α injection, estrous occurrence was monitored three times per day. Only one insemination was used, using the cervix fixation method, 12 hours after the estrous onset. The means of motility and strength, 12 (TI) and 24 hours (TII) after semen cooling at 5oC, were 66.14±0.11% and 62.50±0.05%, and 3.46±0.61 and 3.27±0.50, respectively. Neither the sire nor the period of semen influenced (P>0.05) the conception rate of the does, which was 49.1%.

Sincronização de estro com CIDR reutilizado em cabras lactantes da raça Toggenburg tratadas com somatotropina bovina recombinante (r-bST)

The response of goats treated with r-bST in the estrous synchronization protocol was evaluated. Twenty-six Toggenburg females were divided in two treatments: T1 (n=13) treated with four injections of 250mg r-bST, at 14 days intervals, and T2 (n=13) treated with saline solution (control). The intravaginal device previously used by five days was inserted (day 0) one week after the last injection of r-bST and PGF2a (22.5µg) was injected in the animals of both treatments. The device was removed on day 6. All the females in estrus were bred by fertile bucks. The percentage of animals in estrus and the pregnancy rate were: 76.9 and 70, and 84.6 and 72.7% for goats in T1 and T2, respectively. The estrous cycle length; the interval from treatment to the onset of estrus; the ovulation number; and the intervals from the onset of estrus to ovulation, end of estrus to ovulation, and from device removal to ovulation were not affected by r-bST injection. The r-bST did not affect the diameter of the ovulatory follicles (P>0.05). Progesterone concentration showed similar values (P>0.05) among the goats of T1 and T2 during the treatment with device. The r-bST administration did not affect estrous synchronization.

Milk fatty acids profile of Holstein cows grazing tropical forages supplemented with two concentrate levels.

ABSTRACT Milk fatty acids profile was evaluated using12 Holstein cows producing 15 kg/day of milk with 4.0% of fat. The animals were assigned to four treatments in a 2 x 2 factorial arrangement (two tropical grasses -Brachiaria brizanthacv. Xaraes and Panicum maximum cv. Tanzania, supplemented with two concentrate levels - 3 and 6 kg/cow/day) in a completely randomized block design. There was no effect of forage and concentrate level (P>0.05) on concentrations of rumenic, vaccenic, (C18: 1 trans-11) and oleic acids in milk fat (mean values of 1.01 1.79, and 22.55 g/100 g of total fatty acids, respectively). The ,concentrations of lauric (C12:0), myristic (C14:0), and palmitic (C16:0) acids were also unaffected by treatments (mean values of 2.63, 9.77, and 27.44g/100g of total fatty acids, respectively). Overall, the results illustrate the potential of tropical grasses in producing milk containing a more desirable fatty acids profile in terms of human health. Keywords: dairy cow, conjugated linoleic acid, Brachiaria brizantha, Panicum maximum

Estimativas de parâmetros de cruzamentos para peso de fêmeas Holandês/Gir

Monthly weights (18.089) of 412 females on a demonstration farm in the Zona da Mata, Minas Gerais State, were used to develop a model to describe the liveweight of cows, heifers and calves. The data were analyzed using Proc Mixed of the SAS package, separately for the following categories: a) cows, b) heifers older than 12 mo., c) heifers 70-d to 12 mo-old and d) female calves up to 70 d. For each of these, the regression equations of weight on age (mo) were, respectively, Y i = 267.730 24.319 q + 81.025 z + 1.152 x 0.007 x2 + 3.908 qx + 0.958 zx 0.017 qx2; Y i = -230.446 + 205.033 q + 76.206 z + 27.304 x 0.278 x2 11.806 qx + 0.166 qx2; Y i = -58.167 + 99.107 q + 47.627 z + 16.730 x + 0.093 x2 4.928 qx and Y i = 17.286 + 20.343 q + 11.023 z + 0.680 x + 4.117 x2 + 3.663 qx, where q is the proportion of Holstein genes and z the breed heterozygocity. The average weight maintained by cows during their herd life was estimated by integration of the predicted weight (v) between the ages at first calving and at disposal. Heterosis had important effect on this weight.

Taxa de gestação em cabras Alpinas e Saanen tratadas com hCG no terceiro dia após o estro

The experimental objective was to evaluate the effect of human chorionic gonadotropin (hCG) administration on pregnancy rate and gestation length and on serum concentration of progesterone (P4) in Alpine (83) and Saanen (60) dairy goats induced by artificial photoperiod to enter the breeding season. Animals were randomly allocated to two treatments following estrus: in treatment 1 (T1) goats received 1ml saline solution and in treatment 2 (T2) animals received 250IU of hCG in 1ml saline intramuscularly during the third day after estrus. Pregnancy rates detected by ultrasound technology 35 days after mating did not differ significantly between treatments (P>0.05). They equaled 80.4 and 70.3% for Alpine goats and 72.7 and 81.5% for Saanen goats in T1 and T2, respectively. Overall pregnancy rates were 77.2% and 75.0% for the controls and treated animals, respectively. Gestation length was not affected by the hCG treatment. Blood samples were collected from 5 Alpine does from each treatment the day of estrus (day 0) and on days 3, 8, 15, 21, 42 and 60 after estrus, for determination of progesterone concentration in plasma. Means were 5.84 and 5.76ng/ml for the control and treated does, respectively, and were not affected by treatment (P>0.05), although concentrations did differ among collection days (P<0.05). The administration of hCG the third day after estrus did not affect pregnancy rate or P4 concentration and had no beneficial effect on reproduction in the does.