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1.
Reprod Biol Endocrinol ; 17(1): 29, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30841911

RESUMO

BACKGROUND: Proteomic studies of follicular fluid (FF) exist for several species, including the horse; however, the seasonal influence on FF proteome has not been explored in livestock. The application of high-throughput proteomics of FF in horse has the potential to identify seasonal variations of proteins involved in follicle and oocyte growth. METHODS: This study (i) profiles the proteomes of equine FF collected from dominant growing follicles during the spring anovulatory season (SAN), and spring (SOV), summer (SUM), and fall (FOV) ovulatory seasons; and (ii) identifies season-dependent regulatory networks and associated key proteins. RESULTS: Regardless of season, a total of 90 proteins were identified in FF, corresponding to 63, 72, 69, and 78 proteins detected in the SAN, SOV, SUM, and FOV seasons, respectively. Fifty-two proteins were common to all seasons, a total of 13 were unique to either season, and 25 were shared between two seasons or more. Protein-to-protein interaction (PPI) analysis indicated the likely critical roles of plasminogen in the SAN season, the prothrombin/plasminogen combination in SUM, and plasminogen/complement C3 in both SOV and FOV seasons. The apolipoprotein A1 appeared crucial in all seasons. The present findings show that FF proteome of SUM differs from other seasons, with FF having high fluidity (low viscosity). CONCLUSIONS: The balance between the FF contents in prothrombin, plasminogen, and coagulation factor XII proteins favoring FF fluidity may be crucial at the peak of the ovulatory season (SUM) and may explain the reported lower incidence of hemorrhagic anovulatory follicles during the SUM season.


Assuntos
Líquido Folicular/metabolismo , Cavalos/metabolismo , Proteínas/metabolismo , Animais , Feminino , Proteínas/química , Proteínas/isolamento & purificação , Proteômica , Reprodução , Estações do Ano
2.
Theriogenology ; 126: 88-94, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30543999

RESUMO

Preservation of cellular integrity and its mechanisms after ovarian tissue cryopreservation (OTC) and in vitro culture (IVC) procedures are crucial aspects for the success of preservation and recovery of female fertility. This study aimed to evaluate the effects of two cryopreservation methods (slow-freezing, SF, and vitrification, VIT) on the equine ovarian tissue after 1, 3, and 7 days of IVC by assessing: (i) preantral follicle morphology and distribution of follicle classes; (ii) protein expression of markers of cell proliferation for EGFR and Ki-67; (iii) markers of apoptosis for Bax and Bcl-2; and (iv) DNA fragmentation. Percentages of normal primordial follicles were similar (P > 0.05) among SF-control, VIT-control, and fresh control groups. After 7 days of culture, VIT-IVC7 had a greater (P < 0.05) total percentage of normal preantral follicles when compared with SF-IVC7, but both had a lower (P < 0.05) percentage than fresh IVC7 group. Prior to and after 7 days of culture, expression of EGFR and Ki-67 were similar (P > 0.05) among fresh, SF, and VIT groups. After 7 days of culture, VIT had higher (P < 0.05) Bax expression than the fresh and SF tissues, but Bcl-2 was similar (P > 0.05) among groups. Prior to IVC, TUNEL signals were similar (P > 0.05) among groups; however, VIT-IVC7 had greater (P < 0.05) TUNEL signals when compared with the fresh IVC7 group. In conclusion, findings demonstrated: (i) similar efficiency between SF and VIT compared with fresh control to preserve morphologically normal follicles; and (ii) similar tissue functionality and cell proliferation capability after equine OTC by either SF and VIT methods following IVC for 7 days. The results herein presented shed light on equine fertility preservation programs using OTC techniques.


Assuntos
Criopreservação/veterinária , Cavalos/fisiologia , Ovário/citologia , Preservação de Tecido/veterinária , Animais , Apoptose , Proliferação de Células , Criopreservação/métodos , Fragmentação do DNA , Feminino , Preservação da Fertilidade/métodos , Preservação da Fertilidade/veterinária , Estresse Fisiológico , Preservação de Tecido/métodos , Vitrificação
3.
Anim Reprod Sci ; 93(3-4): 280-91, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16154300

RESUMO

The objective of this investigation was to examine the effects of 6-methoxy-benzoxazolinone (MBOA), a plant compound that resembles melatonin and alters ovarian function in rodents, in combination with PMSG on superovulatory responses in the cycling ewe. In Experiment I, St. Croix White ewes (n = 44) were synchronized (intra-vaginal progestin sponge) for 14days followed by hCG (750 IU) at 1 day after sponge removal (day 0). Ewes were assigned to one of six treatments administered on day -1: Control (no PMSG or MBOA; n = 7); PMSG (1000 IU i.m.; n = 7); Low MBOA (0.43 mg/kg i.m.; n = 7); High MBOA (1.15 mg/kg i.m.; n = 7); Low MBOA + PMSG (n = 8); High MBOA + PMSG (n = 8). In Experiment II, St. Croix White ewes (n = 24) were synchronized (progestin CIDR) for 14 days followed by hCG on day 1 after CIDR removal (day 0). Ewes were assigned to one of three treatments administered on day -1: Control (n = 8); PMSG (n = 8); Low MBOA+PMSG (n = 8). Laparoscopy was performed on day 9 to assess numbers of corpora lutea (CL) and visible follicles on each ovary. Blood samples were collected on day -13, -1, 0, 1, and days 6 or 7-12 for analysis of serum progesterone (P4) by RIA. Treatment groups receiving PMSG (alone or with MBOA) exhibited greater (P < 0.05) serum concentrations of P4 post-synchrony than Control and MBOA-only groups. Ovulation rate was lower (P < 0.05) for Control and MBOA-only treated ewes than ewes receiving PMSG. Ovulation rate in ewes treated with MBOA alone was similar (P > 0.10) to Controls, and PMSG treatment alone did not differ (P > 0.10) from MBOA + PMSG treatment. Ewes treated with PMSG alone did not differ (P > 0.10) in follicle number from High MBOA + PMSG treated ewes, however, Low MBOA + PMSG treated ewes had greater numbers of follicles at day 9 (P < 0.05) than the PMSG or High MBOA + PMSG groups in Experiment I; although, this was not replicated in Experiment II with numbers of follicles in the Low MBOA + PMSG group being similar (P > 0.10) to PMSG alone. In summary, the addition of MBOA in combination with PMSG as part of a synchronization-superovuation protocol in the ewe did not increase ovulation rate.


Assuntos
Benzoxazóis/administração & dosagem , Gonadotropinas Equinas/administração & dosagem , Ovinos/fisiologia , Superovulação/efeitos dos fármacos , Animais , Gonadotropina Coriônica/administração & dosagem , Corpo Lúteo/anatomia & histologia , Interações Medicamentosas , Estro , Sincronização do Estro , Feminino , Acetato de Fluorogestona/administração & dosagem , Folículo Ovariano/anatomia & histologia , Progesterona/sangue , Fatores de Tempo
4.
Cancer Res ; 57(20): 4447-50, 1997 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-9377549

RESUMO

Elucidation of the molecular mechanisms underlying the development and progression of breast cancer has been hindered by two considerations. First, mammary tumor cells exhibit a considerable degree of morphological and functional heterogeneity. Thus, the conventional strategy of measuring a population response may not provide an accurate reflection of the behavior of the functional unit: an individual cell. Second, important regulatory events are generally separated in time, yet the strategies we use to monitor them are usually static as opposed to dynamic. With these considerations in mind, it would appear that a system for studying this problem should ideally combine the resolving power of single-cell analysis with a dynamic paradigm for making multiple measurements of gene expression from the same, living cell. This report summarizes our efforts at developing, validating, and optimizing such a system for monitoring hormone-driven gene expression in T47-D human breast cancer cells.


Assuntos
Neoplasias da Mama/metabolismo , Estradiol/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Sistemas Computacionais , Feminino , Genes Reporter , Vetores Genéticos , Humanos , Cinética , Luciferases/biossíntese , Vírus do Tumor Mamário do Camundongo , Modelos Biológicos , Fótons , Proteínas Recombinantes/biossíntese , Fatores de Tempo , Transfecção , Células Tumorais Cultivadas
5.
Theriogenology ; 63(4): 1061-9, 2005 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-15710193

RESUMO

Previous reports of adrenal progesterone (P4) contributions during late gestation in cattle, and ACTH-induced P4 responses in the non-pregnant heifer, prompted a retrospective investigation to evaluate the plasma P4 response and the relative ratio of plasma cortisol (CT) to P4 following ACTH administration during mid-gestation in pregnant Brahman heifers. Twenty-three pregnant (139.0 +/- 5.0 days of gestation) Brahman heifers received one of the following treatments: 0 (saline; n = 5), 0.125 (n = 4), 0.25 (n = 5), 0.5 (n = 4), or 1.0 (n = 5)IU of ACTH per kg BW. Blood samples were collected at -15 and -0.5 (time 0), 15, 30, 45, 60, 75, 105, 135, 165, 195, and 255-min post-ACTH challenge. Plasma P4 and CT were quantified by RIA. Pre-ACTH P4 did not differ (P > 0.10) among ACTH treatment groups (pooled, 12.1 +/- 0.6 ng/mL). Among peak P4 values at 15-min post-ACTH infusion, control P4 (9.6 +/- 1.2 ng/mL) tended to be lower (P < 0.07) than 0.5 IU ACTH-treated heifers (13.3 +/- 1.1 ng/mL); and were lower (P < 0.02) than 0.25 and 1.0 IU ACTH-treated heifers (14.7 +/- 1.1 and 22.2 +/- 3.7 ng/mL, respectively). During the primary P4 response period (0 to 75-min post-ACTH), the area under the curve (AUC) was greater (P < 0.05) for 1.0 IU ACTH-treated heifers than all other groups. The CT:P4 ratios were lower (time x treatment, P < 0.01) for control heifers than all ACTH-treated heifers. Among ACTH-treated heifers, CT:P4 ratio response and CT:P4 ratio AUC were similar (P > 0.10) following ACTH challenge. In conclusion, acute increases in ACTH elevated plasma P4, likely of adrenal origin, in mid-gestation pregnant heifers, while the CT:P4 ratio (relative output) remained constant irrespective of ACTH dose (0.125-1.0 IU). Whether ACTH-induced increases in P4 in pregnant animals are of physiological significance (e.g., an accessory role in the maintenance of pregnancy during periods of acute stress) remains to be determined.


Assuntos
Hormônio Adrenocorticotrópico/administração & dosagem , Bovinos/sangue , Progesterona/sangue , Glândulas Suprarrenais/fisiologia , Animais , Feminino , Idade Gestacional , Hidrocortisona/sangue , Gravidez
6.
Theriogenology ; 84(4): 600-7, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26025241

RESUMO

Declines of the southern Rocky Mountain population of boreal toad (Anaxyrus boreas boreas) have led to the establishment of a captive assurance population and reintroduction program, in an attempt to preserve and propagate this geographically isolated population. One of the unique adaptations of this species is its ability to survive in cold environments by undergoing long periods of hibernation. In captivity, hibernation can be avoided altogether, decreasing morbidity caused by compromised immune systems. However, it is not entirely clear how essential hibernation is to reproductive success. In this study, the effects of hibernation versus nonhibernation, and exogenous hormones on oviposition, were examined in boreal toad females in the absence of males. In the summers of 2011 and 2012, 20 females housed at Mississippi State University were treated with a double priming dose of hCG and various ovulatory doses of hCG and LH-releasing hormone analog but denied hibernation. Exogenous hormones, in the absence of hibernation, could not induce oviposition over two breeding seasons (2011-2012). In contrast, during the summer of 2012 and 2013, 17 of 22 females (77%) housed at the Native Aquatic Species Restoration Facility (Alamosa, CO, USA) oviposited after they were treated with two priming doses of hCG (3.7 IU/g each) and a single ovulation dose of hCG (13.5 IU/g) and LH-releasing hormone analog (0.4 µg/g) after hibernation. There was a significant difference in oviposition between females that were hibernated and received hormones (2012, P < 0.05 and 2013, P < 0.01) compared to hibernated control females. In 2013, 12 of 16 remaining Mississippi State University females from the same group used in 2011 and 2012 were hibernated for 1, 3, and 6 months, respectively and then treated with the same hormone regimen administered to females at the Native Aquatic Species Restoration Facility. Together, hibernation and hormone treatments significantly increased oviposition (P < 0.05), with 33% of females ovipositing. These results suggest that (1) hibernation is a key factor influencing oviposition that cannot be exclusively circumvented by exogenous hormones; (2) females do not require the presence of a male to oviposit after hormone treatments; and (3) longer hibernation periods are not beneficial for oviposition. The hormonal induction of oviposition in the absence of males and shorter hibernation periods could have important captive management implications for the boreal toad. Furthermore, the production of viable offspring by IVF where natural mating is limited could become an important tool for genetic management of this boreal toad captive population.


Assuntos
Bufonidae/fisiologia , Gonadotropina Coriônica/farmacologia , Hormônio Liberador de Gonadotropina/farmacologia , Hibernação/fisiologia , Oviposição/efeitos dos fármacos , Animais , Feminino , Oviposição/fisiologia , Fatores de Tempo
7.
Domest Anim Endocrinol ; 12(3): 283-92, 1995 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7587171

RESUMO

The actions of corticotropin-releasing hormone (CRH), vasopressin (VP), the synthetic glucocorticoid dexamethasone (DEX), and mifepristone (RU 486), a glucocorticoid antagonist, on the secretion of adrenocorticotropin (ACTH) by cultured fallow deer corticotrophs were studied in vitro. On Day 5 of primary culture, corticotrophs were challenged for up to 4 hr with medium alone (Control), CRH, VP, DEX, forskolin (FSK), phorbol ester (TPA), cyclic AMP (cAMP), and/or RU 486 at various concentrations and combinations. CRH, VP, FSK and TPA each stimulated (P < 0.01) the secretion of ACTH in dose- and time-related manners. Relative to Control, CRH at 0.001 and 0.1 microM and VP at 0.01 and 1 microM increased (P < 0.01) medium concentration of ACTH by 7.3-, 13.5-, 3.7- and 9.0-fold, respectively. There was a treatment x incubation time interaction (P < 0.01) such that at 30-min posttreatment, CRH-induced ACTH secretion tended (P < 0.10) to be less than that obtained via VP treatment, whereas at 1, 3, and 4 hr posttreatment, medium concentration of ACTH from cells treated with 0.1 microM CRH was greater (P < 0.05) than that in cells treated with 1 microM VP. At equimolar doses of 0.01 and 0.1 microM, CRH was 3.4- and 3.0-fold more potent (treatment x dose, P < 0.05) than VP. Cotreatment with 1 microM DEX reduced (P < 0.001) the stimulatory effects of CRH (0.1 microM), VP (1 microM), FSK (10 microMs), TPA (0.1 microM), and cAMP (0.001 M). However, the coaddition of RU 486 (1 microM) to the CRH plus DEX- and the FSK plus DEX-treated wells partially negated the inhibitory effects of DEX. RU 486 completely negated the inhibitory effects of DEX on the VP-, TPA-, and cAMP-stimulated secretion of ACTH. These data indicate that CRH is a more potent stimulator of ACTH secretion than is VP in primary culture of fallow deer pituitary cells. This study also demonstrates the utility of an in vitro culture system to investigate stress-related hormonal interactions in cervids.


Assuntos
Hormônio Adrenocorticotrópico/metabolismo , Cervos/metabolismo , Adeno-Hipófise/metabolismo , Hormônio Adrenocorticotrópico/análise , Animais , Células Cultivadas , Colforsina/farmacologia , Hormônio Liberador da Corticotropina/farmacologia , AMP Cíclico/farmacologia , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Dexametasona/farmacologia , Relação Dose-Resposta a Droga , Ativação Enzimática , Feminino , Glucocorticoides/farmacologia , Antagonistas de Hormônios/farmacologia , Mifepristona/farmacologia , Adeno-Hipófise/citologia , Proteína Quinase C/fisiologia , Radioimunoensaio , Acetato de Tetradecanoilforbol/farmacologia , Vasopressinas/farmacologia
8.
Domest Anim Endocrinol ; 13(4): 339-49, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8839627

RESUMO

Mifepristone (RU486), bovine corticotropin-releasing hormone (CRH), arginine vasopressin (VP), adrenocorticotropin (ACTH1-24), and protein kinase activators (forskolin, [FSK]; phorbol 12-myristate 13-acetate [PMA]) were used in vitro to investigate their direct effect on adrenocorticosteroidogenesis. Bovine adrenocortical fasciculata/reticularis cells (2 x 10(5) viable cells/well) were cultured for 3 d in medium supplemented with 10% fetal calf serum. After incubation for an additional 24 hr in serum-free medium, cells were treated with serum-free medium alone (Control) or various concentrations of ACTH, CRH, VP, FSK, PMA, RU486, and/or various concentrations for 1, 2, 4, or 24 hr. Medium content of cortisol and progesterone were determined by radioimmunoassays. ACTH, CRH, FSK, and PMA each stimulated (P < 0.05) secretion of cortisol in time- and dose-related manners. Although these agents stimulated (P < 0.05) secretion of progesterone in a dose-related manner, medium content of progesterone declined (P < 0.05) over time. The minimal effective doses of ACTH and CRH required to stimulate (P < 0.05) secretion of cortisol relative to the Control over a 4-hr culture period were 0.01 nM and 3 nM, respectively. Relative to observations at 1 hr posttreatment, 24-hr treatment with ACTH or CRH increased the medium content of cortisol by an additional 19.8- and 48-fold, respectively (whereas content of progesterone declined over that time period). VP-stimulated secretion of cortisol was time- (P < 0.05) but not dose-related. Specifically, by 24-hr posttreatment, the medium content of cortisol was increased (P < 0.05) 4.6-fold relative to the quantity of cortisol secreted by 1-hr postaddition of VP (0.01 to 1 microM). Co-treatment with RU486 (1 microM) decreased (p < 0.05) FSK-, ACTH- and CRH-stimulated secretion of cortisol by 77, 27, and 56%, respectively. Similarly, the stimulatory effects of ACTH and CRH on progesterone secretion were reduced (P < 0.05) by 40 and 22%, respectively, by co-addition of RU486. The inhibitory action of RU486 on production of cortisol was no longer apparent by 24 hr after treatment. These observations indicate that RU486 can act as a steroid agonist and as well as an antagonist. These data characterize time- and dose-related direct actions of ACTH, CRH, and RU486 on adrenocorticosteroidogenesis. This information will assist efforts to clarify complex intra-adrenal interactions of neurohormones, growth factors, and endogenous steroids.


Assuntos
Corticosteroides/biossíntese , Córtex Suprarrenal/efeitos dos fármacos , Bovinos/fisiologia , Hormônio Liberador da Corticotropina/farmacologia , Cosintropina/farmacologia , Mifepristona/farmacologia , Córtex Suprarrenal/metabolismo , Animais , Arginina Vasopressina/farmacologia , Colforsina/farmacologia , Inibidores Enzimáticos/farmacologia , Cinética , Masculino , Progesterona/biossíntese , Inibidores de Proteínas Quinases , Acetato de Tetradecanoilforbol/farmacologia
9.
Theriogenology ; 45(5): 911-22, 1996 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-16727852

RESUMO

Thirty 2 yr old Brangus heifers were randomly assigned to 1 of 3 dietary treatments: Control, 0 g of free gossypol (FG) per head per day (FGHD) from corn and soybean meal (SBM); 5 g of FGHD from cottonseed meal (CSM); and 15 g of FGHD from whole cottonseed (WCS). Blood samples were collected weekly for serum progesterone (P(4)) and later quantified by RIA. Whole blood was collected on Days 1, 28, 42, 56 and 70 for erythrocyte fragility (EF) analysis. Following 65 d on dietary treatments and estrus detection, the heifers received bovine-FSH (bFSH) once daily on Days 10, 11 and 12 postestrus, and PGF(2alpha) on Day 12 postestrus. Fifteen of the thirty heifers were randomly selected, and 12 h following PGF(2alpha), the ovaries were removed and follicular diameters, ovarian weight and stromal weights were recorded. Follicular fluid was analyzed for steroid content by RIA. The remaining fifteen heifers were artificially inseminated. Embryos were recovered non-surgically on Day 7 postestrus and graded, and the recovery efficiencies were calculated. Following embryo collection, both ovaries were removed, the number of CLs was recorded, and CL P(4) content was determined by RIA. By Day 42 of treatment, heifers receiving CSM had elevated (P < 0.04) EF compared with the Controls, and remained elevated above that of Controls throughout the study. At Day 70, the CSM heifers tended to have higher (P < 0.07) EF than the WCS group, which in turn tended to be higher (P < 0.06) than the Controls. The Control and CSM heifers gained weight during the 70 d treatment period, while heifers consuming WCS lost weight (P < 0.05). Ovarian and stromal weights did not differ (P > 0.10) among treatment groups. Heifers receiving CSM had fewer (P < 0.05) follicles > 5 mm than WCS or Control heifers. Follicular fluid weights and steroid content did not differ (P > 0.10) among treatments. Both CL weight and the number of CLs per heifer were similar (P > 0.10) among treatments. Heifers receiving CSM or WCS had a higher (P < 0.003) CL P(4) content per gram of CL tissue than the Controls. Progesterone content per CL was greater in WCS heifers (P < 0.003) than in CSM heifers, while both the CSM and WCS heifers had a higher CL P(4) content than the Control heifers. Weekly and Day 7 postestrus serum concentrations of P(4) were similar (P > 0.10) among treatments. The number of embryos recovered, number of degenerated embryos, embryo grades and recovery efficiencies were not affected (P > 0.10) by dietary treatments. To standardize heifers relative to the number of degenerated embryos, the percentage of degenerated embryos recovered was calculated and tended to be greater (P < 0.06) in heifers consuming CSM than in either the Control or WCS groups. While most ovarian, follicular and embryo characteristics were not affected by dietary free gossypol, these results suggest that differences in the availability of free gossypol and/or dietary components between CSM and WCS may influence weight gain, CL P(4) content and embryo viability.

10.
Theriogenology ; 62(3-4): 652-63, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15226020

RESUMO

The objectives were to determine the efficacy of the HeatWatch (HW) electronic estrus detection system for monitoring behavioral estrus (including duration and intensity) in red deer hinds and to evaluate pregnancy rate to AI after detected estrus. Red deer hinds (Cervus elephus; n = 50) were allocated into two treatment groups: AI following synchronization (CIDR/PMSG) and observed estrus (induced estrus group: IE; n = 25) or AI following the detection of natural estrus (NE; n = 25) without hormonal treatment. Hinds were fitted with two HeatWatch (HW) electronic estrus detection transmitters, one above the tail (bottom) and one between the tuber coxae of the pelvic girdle (top), and visual observations for mounting activity began with the aid of young sterile red deer stags (18 months old) fitted with marking harnesses. Hinds in both groups were inseminated (10-12h after observed estrus) with frozen-thawed red deer semen using a transvaginal/cervical AI approach. Following a 26-day period of AI, hinds were placed with a mature fertile stag for an additional 30-day natural breeding period. Pregnancy diagnosis was performed 57 and 86 days after the start of AI. While the hinds were housed with the young stags, 82% were detected in estrus by visual appraisal of stag crayon marks, but only 32% of these were detected by HW. In contrast, in the hinds housed with the mature stag, 93% detected in estrus by crayon marks were also detected by HW. The top HW transmitter consistently recorded more mounts (P < 0.05) than the bottom transmitter. The pregnancy rate was numerically better in IE versus NE hinds (42% versus 29%, P > 0.10). In summary, there were no differences (P > 0.10) in the intensity (number) or duration of mounts (detected by HW) during estrus in IE versus NE hinds, and HW was most effective in detecting estrus in the presence of a heavier, mature stag versus a younger stag. When used in combination with transvaginal AI, an overall first-service pregnancy rate of 36.6% was achieved with AI of frozen-thawed semen in red deer hinds following detected estrus.


Assuntos
Cervos , Detecção do Estro/métodos , Inseminação Artificial/veterinária , Animais , Cruzamento , Eletrônica , Sincronização do Estro , Feminino , Inseminação Artificial/métodos , Masculino , Gravidez , Taxa de Gravidez , Comportamento Sexual Animal
11.
Theriogenology ; 42(7): 1095-102, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-16727613

RESUMO

The objective of this study was to determine the effectiveness of transrectal ultrasonography and serum progesterone (P(4)), estrone sulfate (E(1)S) and pregnancy-specific protein B (PSPB), without prior knowledge of reproductive status, in detecting pregnancy in elk cows. In addition, body weight and body condition score (BCS) were determined to assess whether body condition affects pregnancy status in elk cows. Twenty-five elk cows were sampled during the early rut (Period 1) and after the rut (Period 2), an interval of 120 d. Age, weight, BCS and blood samples, for P(4), E(1)S and PSPB determinations, were taken at Periods 1 and 2. Ultrasonography was performed at Period 2. The younger elk cows weighed less (P<0.05) than older cows. However, pregnancy status was not affected (P> 0.10) by age or weight of the cow. Elk cows that calved had higher (P<0.02) BCS at Periods 1 and 2 than cows that remained open. Serum P(4) and E(1)S were higher (P<0.0001) in pregnant cows at Period 2 than in open cows. Progesterone was 85.8% accurate in detecting pregnant versus open cows at Period 1, while E(1)S and PSPB were not effective. Elk cows at Period 1 were <20 d pregnant with the exception of 1 cow at 46 d. Ultrasonography was 92% accurate, P(4) was 95% accurate, and E(1)S and PSPB were both 100% accurate in determining pregnant versus open cows at Period 2. Pregnant cows at Period 2 were all > 100 d pregnant. Ultrasonography, serum E(1)S and PSPB all may provide a reliable means for pregnancy diagnosis in elk cows at > 100 d of gestation, while serum P(4) may be effective when multiple samples are compared during or after the rut, or when used in combination with the other diagnostic methods described. Further research is needed to determine the optimum time period after breeding in elk cows for accurate pregnancy detection through hormonal analysis.

12.
Theriogenology ; 49(4): 861-9, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10732094

RESUMO

The objectives of this investigation were to 1) determine serum concentrations of progesterone (P4), estrone sulfate (E1S) and pregnancy-specific protein B (PSPB) from estrus synchronization through mid-gestation in the fallow doe (Dama dama) and 2) characterize the hormonal profiles of does whose embryos or fetuses died in utero. Ten fallow does were synchronized for 14 d with an intravaginal P4-releasing device (CIDR) and were naturally mated after CIDR removal. Blood samples were collected at CIDR insertion, CIDR removal and at intervals through Day 203 post-CIDR removal for analysis of P4, E1S and PSPB by radioimmunoassay (RIA). Ultrasonography was performed on Days 49 and 69 post-CIDR removal. Serum P4 at the time of CIDR insertion was 4.8 +/- 0.6 ng/ml, and at CIDR withdrawal it was 6.2 +/- 0.3 ng/ml. Concentrations of E1S and PSPB were nondetectable at CIDR insertion. Serum E1S was highest at Day 93, and PSPB was first detectable in pregnant does at Days 27 to 30 post-CIDR withdrawal. Ultrasonography on Day 49 revealed that 6 does were pregnant, 2 were not pregnant and 2 others were diagnosed originally as early pregnant. At Day 69, ultrasonography revealed that 6 does (60%) were pregnant and 4 (40%) were not. A comparison of the ultrasonographic and hormonal data indicated that the 2 does diagnosed as early pregnant on Day 49 had conceived but had lost the pregnancy. A third doe which was pregnant on Day 69 lost the fetus later in gestation. Hormonal profiles of does whose embryo or fetus had died were characterized by erratic P4 and E1S profiles, with PSPB becoming undetectable in the 3 does by Days 49, 65 and 80 post-CIDR removal. These data 1) demonstrate the timing for the collection of serum samples for determining early pregnancy in fallow does using 3 hormonal methods and 2) characterize the hormonal profiles of 3 fallow does with embryonic-fetal loss.


Assuntos
Ácido Aspártico Endopeptidases/sangue , Cervos , Estrona/análogos & derivados , Morte Fetal/veterinária , Proteínas da Gravidez/sangue , Testes de Gravidez/veterinária , Progesterona/sangue , Ultrassonografia Pré-Natal/veterinária , Animais , Implantes de Medicamento , Estrona/sangue , Estro , Feminino , Morte Fetal/diagnóstico por imagem , Glicoproteínas/sangue , Gravidez , Testes de Gravidez/métodos , Progesterona/administração & dosagem
13.
Theriogenology ; 46(5): 779-89, 1996 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-16727942

RESUMO

Artificial insemination (AI) was performed on sika hinds (Cervus nippon ) receiving various dosages of pregnant mare serum gonadotropin (PMSG; Year 1: 0, 50 and 100 IU; Year 2: 100 and 150 IU) and using semen collected from elk and 1 2 elk x 1 2 sika stags. The time from synchronization device removal (CIDR vs norgestomet) to estrus was determined through observations of mounting activity. Methods for pregnancy detection, serum progesterone (P4), estrone sulfate (E1S), pregnancy-specific protein B (PSPB) and ultrasonography, following AI (Year 1: AI, Days 28 and 48 after AI; Year 2: AI, Days 42, 53 and 100 after AI) and a 90-d natural breeding season were investigated. From available production data, body weights were compared among sika and 1 4 elk x 3 4 sika hybrids relative to age. Pregnancy rates tended (P < 0.10) to differ relative to PMSG treatment and sire; administration of 0 IU PMSG resulted in fewer hinds becoming pregnant to AI than 50 or 100 IU of PMSG. Hinds receiving 100 IU of PMSG had higher (P < 0.05) pregnancy rates than hinds receiving 150 IU PMSG. Time to standing estrus did not differ (P > 0.10) between the CIDR and norgestomet groups. Pregnancy rates 50 d after a 90-d breeding season were similar (P > 0.10) between ultrasound (70.9%) and PSPB (61.6%). Serum P4 after 90 d in breeding groups and 50 d after stag removal were higher (P < 0.05) for pregnant than open hinds. Pregnancy rates (Year 1) 48 d after AI were similar (P > 0.10) between ultrasound (49.0%) and PSPB (37.3%). Serum P4 28 and 48 d after AI were higher (P < 0.05) for pregnant than open hinds. Serum E1S was higher (P < 0.01) for pregnant than open hinds 48 d after AI. Pregnancy rates (Year 2) 100 d after AI did not differ (P > 0.10) between ultrasound and PSPB (66.7%). Serum P4 was higher (P < 0.03) in pregnant than open hinds at 42, 53 and 100 d after AI. At 100 d after AI, pregnant hinds had higher (P < 0.002) serum E1S than open hinds. At 6 to 8 and 11 to 13 mo of age, 1 4 elk x 3 4 sika males tended (P < 0.08) to be heavier than sika males, while 1 4 elk x 3 4 sika females were heavier (P < 0.05) than sika females at all ages. In summary, this study documents the use of AI and methods for pregnancy detection in sika hinds as well as preliminary information regarding the production of elk-x-sika hybrids.

14.
J Anim Sci ; 74(9): 2253-62, 1996 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8880430

RESUMO

Spring-calving Brahman cows (S) artificially inseminated to Brahman, Angus, or Tuli sires and fall-calving Brahman cows (F) naturally bred to Brahman were allotted randomly to receive 3.74% (LF; n = 9 S and 6 F), 5.20% (MF; n = 8 S and 6 F), or 6.55% dietary fat (HF; n = 8 S). Diets were formulated to contain differing fatty acid concentrations and to be isocaloric and isonitrogenous. Cows were bled and fed twice daily from 2 wk before expected calving date through d 21 after calving. Ultrasonography was performed on d 14 and 21 after calving. From d 21 to 90 after calving a sterile bull equipped with a chin-ball marker was placed with the cows to aid in estrus detection. In both seasons progesterone decreased (P < .01) and estradiol-17 beta increased (P < .01) as parturition approached. Cows receiving MF and HF had increased (P < .01) total numbers of follicles compared to LF cows, and cows receiving MF had larger (P < .01) follicles. During the spring, cows receiving HF and cows bred to Brahman or Tuli sires had longer (P < .01) gestation lengths. Progesterone concentrations before calving were affected (P < .01) by treatment x sire and estradiol-17 beta by a time x treatment interaction (P < .01). Cholesterol after calving was higher (P < .01) in HF cows than in LF or MF cows. In the fall, LF cows had heavier (P < .01) calves than cows receiving MF. Birth weight was also affected (P < .01) by treatment x sex of calf. Progesterone was affected (P < .01) by treatment x sex of calf. Estradiol-17 beta was affected (P < .01) by sex of calf and treatment x sex of calf. Across seasons, by d 90 after calving, 9 of 15 (60%) LF and 11 of 15 (73.3%) MF cows showed estrual behavior. Cows in the spring had increased (P < .01) numbers and larger follicles compared to the fall. In conclusion, dietary fat may influence steroid hormone concentrations before calving, calf birth weight and postpartum follicular populations; furthermore, follicular populations may also be influenced by season.


Assuntos
Bovinos/sangue , Bovinos/fisiologia , Colesterol/sangue , Gorduras na Dieta/farmacologia , Estradiol/sangue , Trabalho de Parto/sangue , Folículo Ovariano/fisiologia , Período Pós-Parto/fisiologia , Taxa de Gravidez , Prenhez/sangue , Progesterona/sangue , Estações do Ano , Triglicerídeos/sangue , Animais , Peso ao Nascer/efeitos dos fármacos , Peso ao Nascer/fisiologia , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Feminino , Trabalho de Parto/fisiologia , Ácido Linoleico , Ácidos Linoleicos/farmacologia , Masculino , Ácido Oleico/farmacologia , Gravidez , Prenhez/fisiologia , Distribuição Aleatória , Caracteres Sexuais
15.
J Anim Sci ; 73(2): 496-507, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7601784

RESUMO

Pregnant Brahman cows (n = 38) and heifers (n = 12) were assigned, 90 d before expected calving dates, to one of three treatment groups: 1) 0 g of free gossypol(FG).animal-1.d-1 (FGHD) from soybean meal (SBM), controls; 2) 2 g of FGHD from SBM and cottonseed meal (CSM), low FG; or 3) 4 g of FGHD from CSM, high FG, to determine the effects of dietary FG on prepartum and postpartum cow performance, calf development, and selected blood variables. Prepartum and postpartum cow BW, 4-h milk production, and calf BW were similar (P > .10) among treatments. Following 84 d of treatment, cows receiving 4 g of FGHD tended (P < .10) to have greater erythrocyte fragility (EF) than cows given 0 or 2 g of FGHD. Mean EF for the 112-d postpartum period were greater (P < .05) in cows given 4 than in those given 0 g of FGHD. Dietary FG consumption by the dam did not affect (P > .10) calf EF. Serum triiodothyronine (T3) and thyroxine (T4) in cows and T4:T3 ratio in calves were similar (P > .10) among treatments. After 84 d of treatment, cows receiving 4 g of FGHD had lower (P < .05) serum concentrations of alpha-tocopherol and beta-carotene than cows given 0 g of FGHD. At parturition, serum alpha-tocopherol and beta-carotene were similar (P > .10) for all cows and calves. On d 7 and 28 after calving, alpha-tocopherol tended to be lower (P < .10) and beta-carotene was lower (P < .05) in calves given 4 than in those given 0 g of FGHD. Calf metacarpal medial cortex tended to be greater (P < .10) in calves from cows given 0 than in those from cows given 2 or 4 g of FGHD, and the lateral cortex (treatment x sex; P < .05) was smaller in male calves from cows given 4 than in those from cows given 0 g of FGHD but was not affected in female calves. By 96 to 105 d after calving, a greater number of (P < .05) cows consuming 4 and 2 g of FGHD experienced luteal activity, and a greater (P < .10) number than of cows receiving 0 g of FGHD had conceived by 112 d after calving. In summary, pre- and postpartum consumption of FG may have impaired some aspects of calf skeletal development and vitamin metabolism, although long-term performance of cows and calves was not affected.


Assuntos
Animais Lactentes/crescimento & desenvolvimento , Bovinos/crescimento & desenvolvimento , Gossipol/farmacologia , Período Pós-Parto/fisiologia , Prenhez/fisiologia , Acetatos/sangue , Animais , Animais Lactentes/sangue , Animais Lactentes/fisiologia , Nitrogênio da Ureia Sanguínea , Desenvolvimento Ósseo/efeitos dos fármacos , Desenvolvimento Ósseo/fisiologia , Carotenoides/sangue , Bovinos/sangue , Bovinos/fisiologia , Óleo de Sementes de Algodão/química , Óleo de Sementes de Algodão/normas , Dieta/veterinária , Deformação Eritrocítica , Feminino , Alimentos Fortificados , Gossipol/análise , Masculino , Gravidez , Distribuição Aleatória , Tiroxina/sangue , Tri-Iodotironina/sangue , Vitamina E/sangue
16.
J Anim Sci ; 77(1): 32-8, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10064025

RESUMO

Fallow does (n = 502) of different ages (mature, 2-yr-old, and yearling) were maintained with bucks for a 60-d breeding season to determine whether previous reproductive performance and changes in BW affect doe pregnancy rates and to compare the effectiveness of ultrasonography and serum pregnancy-specific protein B (PSPB) for the detection of pregnancy in fallow does. Ultrasonography was performed, blood samples collected, and BW recorded at buck removal (d 0) and at 30 and 90 d after buck removal. Lactational status (lactating = WET; nonlactating = DRY) were determined from farm records taken at weaning prior to each breeding season (autumn 1990 through autumn 1994). Ultrasonography and PSPB for determining pregnancy were in agreement 93% of the time. Overall pregnancy rates did not differ (P>.10) relative to age of the doe; the combined pregnancy rate was 92%. We also determined that 82.9% of does conceived early in the breeding season and that the incidence of embryonal-fetal mortality during the first 90 d after buck removal was 2.8%. In general, mature and 2-yr-old DRY does were heavier and had lower pregnancy rates than WET does. The overall weaning rate for all does was 77.9%. Loss in the number of fawns from pregnancy detection to weaning was equivalent to 14.8% for mature does, 24.7% for 2 yr old does, and 42.5% for yearling does. These data indicate that even though pregnancy rates were relatively high, further study is needed to determine the causes associated with subsequent fawn losses, particularly among yearling does. As a production tool, lactational WET/ DRY status testing was found to be an acceptable means for determining the reproductive potential of individual does within the herd. In addition, serum PSPB may be used in place of ultrasonography for pregnancy diagnosis in fallow deer as early as d 30 after buck removal.


Assuntos
Cervos/fisiologia , Prenhez/fisiologia , Fatores Etários , Animais , Ácido Aspártico Endopeptidases/análise , Peso Corporal , Feminino , Gravidez , Proteínas da Gravidez/análise , Testes de Gravidez/veterinária , Radioimunoensaio/veterinária , Reprodução , Ultrassonografia Pré-Natal/veterinária , Desmame
17.
J Anim Sci ; 75(6): 1591-600, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9250522

RESUMO

Brahman cows were used to evaluate dietary fat (3.74% [control] and 5.20% [treated]) effects on blood hormone and lipid concentrations, follicular populations, and in vitro steroidogenesis. Cows were fed and ovaries were monitored by ultrasound from d 1 of the first estrous cycle (EC) until the first follicle of the second EC reached 8 mm, at which time ovaries were harvested. Follicular fluid (FF) was collected from large- and medium-sized follicles and assayed for progesterone (P4), estradiol-17 beta (E2), testosterone, cholesterol, and triglycerides. The corpus luteum was removed, minced, treated with LH, and incubated for 4 h. Granulosa cells harvested from the largest follicle were treated with forskolin, LH, or FSH and incubated for 48 h. Blood was collected during the treatment period and plasma assayed for 13,14-dihydro-15-keto-prostaglandin F(2 alpha) (PGFM), growth hormone (GH), insulin, P4 and E2. Cholesterol and triglycerides were assayed only from blood samples collected every 7 d. Treated cows had greater (P < .01) plasma E2 during the first EC and greater (P < .01) P4 during the second EC than controls. Treated cows had elevated (P < .01) insulin following d 16 of treatment, but GH and triglycerides were similar (P > .10) in both treatment groups. Treated cows tended (P = .10) to have greater PGFM peak concentrations than controls. Plasma cholesterol was elevated (P < .01) in treated cows on d 7 of the first EC. Treated cows tended to have greater (P < .09) follicular populations during the ovulatory and first wave of the first and second EC. Treatment did not affect (P > .10) FF concentrations of P4, E2, testosterone, cholesterol, or triglyceride from either large- or medium-sized follicles. There were no differences (P > .10) in steroid hormones produced in vitro.


Assuntos
Bovinos/sangue , Bovinos/fisiologia , Gorduras na Dieta/farmacologia , Estro/fisiologia , Folículo Ovariano/fisiologia , Animais , Células Cultivadas , Colesterol/análise , Corpo Lúteo/química , Corpo Lúteo/metabolismo , Dinoprosta/análogos & derivados , Dinoprosta/sangue , Estradiol/análise , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/farmacologia , Células da Granulosa/química , Células da Granulosa/citologia , Hormônio do Crescimento/sangue , Insulina/sangue , Lipídeos/análise , Lipídeos/sangue , Hormônio Luteinizante/farmacologia , Folículo Ovariano/química , Ovariectomia/veterinária , Ovário/citologia , Ovário/diagnóstico por imagem , Ovário/efeitos dos fármacos , Progesterona/análise , Progesterona/sangue , Distribuição Aleatória , Reprodução/fisiologia , Testosterona/análise , Triglicerídeos/análise , Ultrassonografia
18.
J Zoo Wildl Med ; 29(3): 295-9, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9809601

RESUMO

The present study compared pregnancy rates of sika deer (Cervus nippon) hinds artificially inseminated with frozen-thawed wapiti (Cervus elephus manitobensis) semen by laparoscopic intrauterine or transvaginal/cervical artificial insemination (AI) techniques. Estrous cycles of 59 sika hinds were synchronized with one-half of a norgestomet ear implant. Fourteen days after implant insertion, norgestomet ear implants were removed and hinds received 50 IU of PG-600 intramuscularly, a combination of 50 IU PMSG and 25 IU hCG. Hinds were then randomly allotted for laparoscopic (n = 25) or transvaginal/cervical (n = 34) AI. AI of the hinds with frozen-thawed wapiti semen (40 x 10(6) spermatozoa) was time-fixed to occur at 55 hr for transvaginal/cervical AI and 65 hr for laparoscopic AI postnorgestomet implant removal. Semen deposition for hinds inseminated by transvaginal/cervical AI occurred as follows: vagina. 8.8% (3/34); os cervix, 67.6% (23/34); intracervical, 20.5% (7/34); and uterus, 2.9% (1/34). On day 42 post-AI, transrectal ultrasonography was performed to determine pregnancy rates. Pregnancy rates were not significantly different (P > 0.10) between laparoscopic (8/25, 32.0%) and transvaginal/cervical AI (9/34, 26.4%), with an overall conception rate of 28.8% (17/59). These results indicate that transvaginal/cervical AI techniques can be as effective as laparoscopic AI under some circumstances. Further refinement of the transvaginal/cervical AI technique to improve pregnancy rates might lead to more widespread use of this technique when laparoscopic AI is not possible.


Assuntos
Cervos/fisiologia , Hibridização Genética , Inseminação Artificial/veterinária , Administração Intravaginal , Animais , Gonadotropina Coriônica , Sincronização do Estro , Feminino , Gonadotropinas Equinas , Inseminação Artificial/métodos , Laparoscopia/veterinária , Masculino , Gravidez , Taxa de Gravidez , Pregnenodionas , Congêneres da Progesterona , Distribuição Aleatória
19.
J Anim Sci ; 92(11): 4949-55, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25253816

RESUMO

Digital infrared thermal imaging (DITI) using a thermal camera has potential to be a useful tool for the production animal industry. Thermography has been used in both humans and a wide range of animal species to measure body temperature as a method to detect injury or inflammation. The objective of these experiments was to compare the temperature of the eye (EYE) or muzzle (MUZ) measured using DITI to vaginal (VT) and rectal temperature (RT) as measures of core body temperature in hair sheep and beef cattle. In Exp.1 EYE, VT and RT were measured in lactating, multiparous hair sheep ewes (St. Croix White, n = 10, and Dorper × St. Croix White, n = 10) in a non-febrile state 5 times over a 48-h period. Data loggers were used to measure VT and a digital veterinary thermometer was used to measure RT. There was a high correlation (P < 0.001) between VT and RT (r = 0.95), EYE and RT (r = 0.76) and EYE and VT (r = 0.77). In Exp. 2 EYE, MUZ, VT and RT were measured in multiparous, lactating ewes (St. Croix White, n = 2, and Barbados Blackbelly, n = 12) at -12, -1, 0, 1, 2, 3, 4, 6, 12, 24, 36, and 48 h after being administered lipopolysaccharide (LPS; n = 7; 0.2 µg/kg BW, i.v.) or saline (n = 7; 0.5 mL, i.v.). Data loggers were used to measure VT and a digital veterinary thermometer was used to measure RT. When data were combined across treatments (LPS and saline) there was a high correlation (P < 0.001) between VT and RT (r = 0.96), EYE and RT (r = 0.82), MUZ and RT (r = 0.72), and EYE and VT (r = 0.93). In Exp. 3 EYE, MUZ, VT and RT were measured in multiparous, non-lactating, pregnant Senepol cattle (n = 44) between 0900 and 1200 h on a single day. A digital veterinary thermometer was used to measure both VT and RT. There was a high correlation (P < 0.001) between VT and RT (r = 0.78), a moderate correlation (P < 0.001) between VT and EYE (r = 0.52), RT and EYE (r = 0.58) and EYE and MUZ (r = 0.48). There was no correlation (P > 0.10) between RT or VT and MUZ. The findings of these three studies indicate that temperature of the eye, measured using DITI, can be used as an indicator of core body temperature in hair sheep and beef cattle as an alternative to using vaginal or rectal temperature.


Assuntos
Temperatura Corporal/fisiologia , Bovinos/fisiologia , Nariz/fisiologia , Fenômenos Fisiológicos Oculares , Reto/fisiologia , Ovinos/fisiologia , Termografia/veterinária , Vagina/fisiologia , Animais , Feminino , Infecções/diagnóstico , Infecções/veterinária , Raios Infravermelhos , Lactação/fisiologia , Sensibilidade e Especificidade , Termografia/métodos , Termômetros/veterinária , Ferimentos e Lesões/diagnóstico , Ferimentos e Lesões/veterinária
20.
J Anim Sci ; 92(7): 3082-7, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24821821

RESUMO

The objective of this study was to estimate the heritability of 3 measures of temperament in Brahman and Brahman-influenced calves (n = 1,209). Individual animal pen scores (PS) were determined by a trained observer who evaluated groups of 5 or 4 calves at a time for willingness to be approached by a human. Exit velocity (EV) was the rate (m/s) at which each calf exited a squeeze chute. Temperament score (TS) was calculated individually as (PS + EV)/2. Temperament was evaluated at 5 different times of record (28 d preweaning, weaning, 28 d postweaning, 56 d postweaning, and yearling). Contemporary groups (n = 34) comprised calves of the same sex born in the same season of the same year. There were an average of 36 calves per contemporary group and group size ranged from 3 to 78 calves. Average weaning age (186 d) ranged from 105 to 304 d. Calves were born from 2002 through 2012. Random effects included additive genetic and the permanent environmental variance. The fixed effects analyzed were age of dam, sex of calf, contemporary group, fraction of Brahman (2 levels: 1 and 0.5), age of calf at record, and weaning age. At weaning, the mean PS was 2.68 ± 0.1, the mean EV was 2.41 ± 0.1, and the mean TS was 2.48 ± 0.1. The PS was affected by fraction of Brahman (P = 0.034) and tended to be affected by age of dam (P = 0.06). The EV was affected by contemporary group (P < 0.001) and tended to be affected by weaning age (P = 0.074). Contemporary group affected TS (P < 0.001). All 3 methods of temperament evaluation were affected by time of record (P < 0.001). The regression coefficients for PS, EV, and TS were 0.0023 ± 0.0014, 0.0022 ± 0.0012, and 0.0015 ± 0.0012 m·s(-1)·d(-1) of age, respectively. Estimates of maternal genetic effects were always 0 and omitted from final models. Estimates of heritability were 0.27 ± 0.1, 0.49 ± 0.1, and 0.43 ± 0.1 for EV, PS, and TS, respectively. Estimates of permanent environmental variances as proportions of phenotypic variance were 0.33 ± 0.1, 0.23 ± 0.1, and 0.33 ± 0.1 for EV, PS, and TS, respectively. There appears to be sufficient additive genetic variance for selective improvement of temperament characteristics in Brahman cattle.


Assuntos
Animais Recém-Nascidos/psicologia , Bovinos/psicologia , Temperamento , Animais , Animais Recém-Nascidos/genética , Bovinos/genética , Feminino , Masculino , Testes Psicológicos , Característica Quantitativa Herdável
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