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1.
Am J Psychiatry ; 151(2): 216-20, 1994 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8296892

RESUMEN

OBJECTIVE: The authors' goal was to establish, in a large multicenter sample of patients classified according to gender and menopausal status, if the growth hormone (GH) response to clonidine discriminated patients with episodes of major depression from patients with episodes of minor depression. METHOD: The GH response to intravenous clonidine administration (150 micrograms) was compared in 71 male and 140 female patients with major depressive episodes and 47 male and 53 female patients with minor depressive episodes. These patients were diagnosed according to Research Diagnostic Criteria. RESULTS: Differences in the GH response to clonidine between diagnostic groups occurred only between male patients. These results were found in the group as a whole and in each center. The GH responses to clonidine of premenopausal women differed significantly from those of postmenopausal women in each diagnostic group. CONCLUSIONS: These results confirm that gender and menopausal status are of the utmost importance in the interpretation of the clonidine GH test.


Asunto(s)
Clonidina , Trastorno Depresivo/diagnóstico , Hormona del Crecimiento/sangre , Adulto , Biomarcadores/sangre , Clonidina/administración & dosificación , Clonidina/farmacología , Trastorno Depresivo/sangre , Diagnóstico Diferencial , Femenino , Humanos , Inyecciones Intravenosas , Masculino , Menopausia , Persona de Mediana Edad , Factores Sexuales
2.
Anticancer Res ; 11(2): 755-9, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-2064330

RESUMEN

Cytotoxic and mitogenic soluble factors are released into media conditioned by pure or mixed populations of mouse 3T3 fibroblasts and B16 melanoma cells cultivated in vitro. These activities are demonstrated by the use of MTT cell survival test and 3HTDR incorporation. Mitogenic (M.W. greater than 10,000) and cytotoxic factors (M.W. less than 1,000) are present and are generally more active on B16 cells than on fibroblasts. Their release into conditioned media is related to the rate of pigmentation in B16 cells and to the mode of cultivation (monolayers or cell aggregates).


Asunto(s)
Supervivencia Celular , Inhibidores de Crecimiento/aislamiento & purificación , Melanoma Experimental/metabolismo , Mitógenos/aislamiento & purificación , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Medios de Cultivo , Técnicas de Cultivo/métodos , Replicación del ADN , Fibroblastos/citología , Inhibidores de Crecimiento/farmacología , Ratones , Mitógenos/farmacología , Ultrafiltración
3.
Psychiatry Res ; 52(2): 115-23, 1994 May.
Artículo en Inglés | MEDLINE | ID: mdl-7972568

RESUMEN

The current main neurochemical theories of the biological correlates of suicidal behavior involve serotonergic and, to a lesser extent, dopaminergic systems. Few data are available about the possible implication of the noradrenergic function. In the present study, we assessed the growth hormone response to clonidine, a selective alpha 2-adrenergic agonist, in 15 DSM-III-R major depressive inpatients with a history of suicide attempts, compared with 15 age- and gender-matched major depressive inpatients without a history of suicidal behavior. Mean (+/- SD) growth hormone peak responses to clonidine were significantly lower in the group of suicide attempters than in the control group: 2.93 +/- 3.01 ng/ml vs. 8.28 +/- 8.15 ng/ml. Therefore, these results suggest that a blunted growth hormone response to clonidine could be a biological correlate of suicidal behavior.


Asunto(s)
Clonidina , Trastorno Depresivo/psicología , Hormona del Crecimiento/metabolismo , Receptores Adrenérgicos alfa 2/metabolismo , Intento de Suicidio , Adulto , Clonidina/farmacología , Trastorno Depresivo/diagnóstico , Femenino , Humanos , Masculino , Metoxihidroxifenilglicol/líquido cefalorraquídeo , Norepinefrina/metabolismo , Escalas de Valoración Psiquiátrica , Radioinmunoensayo
4.
Eur Psychiatry ; 16(3): 180-5, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11353597

RESUMEN

BACKGROUND: Orthotopic heart transplantation (OHT) is a major surgical intervention inducing distress and anxiety. Psychiatric evaluation of organ transplant candidates is now routinely proposed. This study purposed to assess the psychological evolution in patients having received psychological and/or psychiatric assistance before and during 1-6 postoperative months. METHODS: Twenty-two consecutive transplant candidates were psychically evaluated as part of the preoperative protocol. In the waiting period, 1 and 6 months after OHT, they were asked to fill out the following questionnaires: the General Health Questionnaire, the Spielberger's State-Trait Anxiety Inventory, the Beck Depression Inventory, the Perceived Social Support Scale, the Toronto Alexithymia Scale and the Personal Reaction Inventory. RESULTS: A DSM-IV Axis I diagnosis was found in nine patients (41%); four patients (18%) presented with an Axis II diagnosis. One month after OHT, scores of depression, anxiety and general health significantly improved, while scores of social support, alexithymia and social desirability did not differ. In the sixth postoperative month, all psychological scores remained stable. CONCLUSIONS: A high prevalence of preoperative psychopathology was reported in 22 candidates who received OHT. Surgical intervention obviously improved the quality of life after cardiac transplantation. If the impact of psychological and/or psychiatric aid remains difficult to appraise, these results emphasize the positive impact of surgery on psychological status and the appropriateness of the psychosomatician's social support intervention on patients facing the transplant process.


Asunto(s)
Síntomas Afectivos/diagnóstico , Síntomas Afectivos/etiología , Trastornos de Ansiedad/diagnóstico , Trastornos de Ansiedad/etiología , Trastorno Depresivo Mayor/diagnóstico , Trastorno Depresivo Mayor/etiología , Trasplante de Corazón/psicología , Adaptación Psicológica , Adulto , Síntomas Afectivos/epidemiología , Anciano , Trastornos de Ansiedad/epidemiología , Trastorno Depresivo Mayor/epidemiología , Femenino , Estado de Salud , Humanos , Masculino , Persona de Mediana Edad , Cuidados Posoperatorios , Cuidados Preoperatorios , Prevalencia , Escalas de Valoración Psiquiátrica , Calidad de Vida , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Deseabilidad Social , Apoyo Social , Encuestas y Cuestionarios
5.
Rev Med Liege ; 55(11): 1003-10, 2000 Nov.
Artículo en Francés | MEDLINE | ID: mdl-11195702

RESUMEN

It seems that SSRI (moreover than being antidepressant) may reduce alcohol consumption by decreasing desire, craving and liking for alcohol. The 5-HT reuptake inhibitors may be helpful for the treatment of alcoholism by reducing relapse frequency and severity. Moreover, if depression or anxiety is present, it should be effective to give them immediately because of the frequent association between these pathologies and alcoholism.


Asunto(s)
Alcoholismo/tratamiento farmacológico , Inhibidores Selectivos de la Recaptación de Serotonina/uso terapéutico , Alcoholismo/complicaciones , Alcoholismo/psicología , Ansiedad/complicaciones , Depresión/complicaciones , Humanos , Factores de Riesgo , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Resultado del Tratamiento
7.
Can J Comp Med ; 42(1): 128-31, 1978 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-647452

RESUMEN

Blood serum tocopherol was determined in 44 calves born in the spring from cows that had been fed either timothy grass silage or timothy hay produced in Norther Ontario. On all sampling dates (at birth and at eight, 21, 35 and 60 days of age), calves from the silage group had higher average tocopherol levels than those from the hay group. Studies on serum tocopherol distribution in cows and their calves obtained 60 days after birth from the silage group showed that alpha-tocopherol averaged 85% and beta + gamma-tocopherols 12%. Only trace quantities of delta-tocopherol were detected in the serum of cows but none in those of calves.


Asunto(s)
Alimentación Animal , Bovinos/sangre , Vitamina E/sangre , Animales , Femenino , Masculino , Poaceae , Estaciones del Año , Ensilaje
8.
Ann Rech Vet ; 7(2): 185-94, 1976.
Artículo en Francés | MEDLINE | ID: mdl-1035840

RESUMEN

Two experiments to study nutritional muscular dystrophy (N.M.D.) in calves were conducted in northern Ontario, where the disease is prevalent. In the first experiment, ninety Shorthorn cows were used. They were divided into three groups and fed the following forages during the winter of 1972-1973. Group I - Silage. Group II. - Heated-air-dried hay. Group III. - Field-dried hay. Chemical analysis of the forage during storage showed that the silage had a higher tocopherol content than the other two forages. This higher content had a direct effect on plasma tocopherol concentrations in the cows, since tocopherol levels were found to be higher in the group fed silage than in the other two groups. The highest mortality rate-eight dead calves-was in the group fed heated-air-dried hay; one calf died in each of the other two groups. Hence, it is evident that the severity of N.M.D. symptoms in calves is directly linked with the quantity of selenium or vitamin E ingested. The substances act synergistically to protect against the disease. In a second experiment, a herd of forty-seven Shorthorn cows, some of which had calves with N.N.D. and some of which had healthy offspring, were studied to measure the activity of serum creatine phosphokinase. The dams were found to have the same C.P.K., whether or not their calves suffered from N.M.D.


Asunto(s)
Alimentación Animal/análisis , Enfermedades de los Bovinos/epidemiología , Distrofia Muscular Animal/epidemiología , Vitamina E/análisis , Animales , Aspartato Aminotransferasas/sangre , Bovinos , Creatina Quinasa/sangre , Femenino , Selenio/análisis , Ensilaje/análisis , Vitamina E/sangre
9.
Acta Psychiatr Belg ; 95(4-5): 210-33, 1995.
Artículo en Francés | MEDLINE | ID: mdl-8525861

RESUMEN

The current main neurochemical theories of the biological correlates of suicidal behavior principally involve the serotonergic system. Few data are available about the possible role of the catecholaminergic (noradrenergic and dopaminergic) function. In the present study, in a first part, we assessed the growth hormone (GH) response to clonidine, a selective alpha 2-adrenergic agonist, and to apomorphine, a dopaminergic agonist, in 22 DSM-III-R major depressive male inpatients with a history of suicide attempts compared to 22 age-matched major depressive inpatients without history of suicidal behavior. Hormonal responses to clonidine and apomorphine were also compared with 4.00 PM postdexamethasone cortisol levels. The two groups differed significantly in the GH peak response after apomorphine: 6.27 +/- 3.18 ng/ml in suicide attempters vs 17.40 +/- 14.87 ng/ml in nonattempters (F = 11.78, p = 0.001). There was no statistically significant difference between the two groups for GH peak responses after clonidine. Moreover, mean postdexamethasone cortisol levels did not exhibit any significant difference between suicide attempters and nonattempters. Violent and nonviolent attempters did not differ on any of the biological measures. In a second part, P300 and contingent negative variation (CNV) were recorded in 20 depressive inpatients subgrouped into suicide attempters (n = 10) and nonattempters (n = 10). The results showed a significant reduction of both P300 and CNV amplitudes in patients who attempted suicide compared to patients without history of suicide attempts. Moreover, a significant correlation was found between the Suicidal Risk scale and CNV amplitude. In conclusion, these results suggest that a dopaminergic hypoactivity as assessed by a blunted GH response to apomorphine and by a reduction of both P300 and CNV amplitudes, could be considered as a biological correlate of suicidal behavior. In contrast, noradrenergic disturbances, particularly at the level of alpha 2-adrenergic receptors, seem to play a more minor role. Moreover, DST nonsuppression cannot be considered as a biological marker of suicidal behavior.


Asunto(s)
Trastorno Depresivo/sangre , Hormona del Crecimiento/sangre , Intento de Suicidio , Adolescente , Agonistas alfa-Adrenérgicos/farmacología , Adulto , Apomorfina/farmacología , Clonidina/farmacología , Variación Contingente Negativa , Trastorno Depresivo/psicología , Dexametasona , Agonistas de Dopamina/farmacología , Potenciales Relacionados con Evento P300 , Humanos , Hidrocortisona/sangre , Masculino , Intento de Suicidio/psicología
10.
J Dairy Sci ; 76(5): 1365-74, 1993 May.
Artículo en Inglés | MEDLINE | ID: mdl-8505427

RESUMEN

Thirty-two Holstein cows (8 primiparous) were assigned to negative control or to one of three treatments to assess three forage harvesting and conservation techniques. Forage was harvested as low moisture silage by either a cylinder-type forage harvester, a self-loading forage harvester, or a round baler. Treatment diets were fed from wk 4 to 15 of lactation and consisted of silages harvested by the respective methods supplemented with concentrate at 1.1% of BW. Unsupplemented silage harvested by a cylinder-type forage harvester was used as a control. Daily DMI was higher for cows fed supplemented heap silage cut with either a cylinder-type forage harvester (23.7 kg) or a self-loading forage harvester (22.6 kg) than for cows fed the control (20.0 kg) or supplemented round bale silage (20.1 kg). Milk yield was highest for cows fed supplemented heap silage cut with a cylinder-type forage harvester (26.6 kg/d) and lower for those fed supplemented heap silage cut with a self-loading forage harvester (22.7 kg/d) or the control (20.8 kg/d). Milk composition and digestibilities of DM, N, ADF, and energy were similar among treatments. Postfeeding NEFA concentration decreased more for control cows than for those fed supplemented silage, which was related to greater BW loss. The high milk yield for cows fed supplemented heap silage cut with a cylinder-type forage harvester could be related to a high DMI and low BW gain.


Asunto(s)
Bovinos/fisiología , Lactancia/fisiología , Ensilaje , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Bovinos/sangre , Digestión , Metabolismo Energético , Ácidos Grasos no Esterificados/sangre , Femenino , Leche/química , Nitrógeno/metabolismo
11.
Anxiety ; 1(5): 237-41, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-9160581

RESUMEN

Six commercial divers were investigated for anxiety responses during a 29-day, open-sea world record dive at 500 meters of depth. Three of six (50%) divers developed anxiety. The authors emphasize the importance of research on personality traits as possible predictors for the development of anxiety during deep dives of exceptional depth and duration of confinement.


Asunto(s)
Ansiedad/psicología , Buceo/psicología , Enfermedades Profesionales/psicología , Adulto , Ansiedad/diagnóstico , Síndrome Neurológico de Alta Presión/diagnóstico , Síndrome Neurológico de Alta Presión/psicología , Humanos , Masculino , Personal Militar/psicología , Enfermedades Profesionales/diagnóstico , Determinación de la Personalidad
12.
Acta Psychiatr Belg ; 93 Spec No: 343-58, 1993.
Artículo en Francés | MEDLINE | ID: mdl-7916521

RESUMEN

Disturbances in dopaminergic neurotransmission seem to play an important role in biochemical mechanisms involved in depressive disorders. The study of the growth hormone (GH) response to apomorphine, a dopaminergic agonist, provides an indirect index of dopaminergic neurotransmission at the postsynaptic level. In the present study, we assessed the role of the dopaminergic system in some psychopathological dimensions in depression: personality dimensions, suicidal behavior, psychomotor disturbances and dichotomy unipolar/bipolar. Our studies included major depressed inpatients matched for gender, age and, in the case of women, menopausal status. Our results show that dopaminergic disturbances are related to social introversion and anxiety according to dopaminergic hypothesis of schizophrenic disorders and dopaminergic hyperactivity hypothesis of anxiety disorders. A blunted GH response to apomorphine could be considered as a biological marker of suicidal behavior. Moreover motor retardation appeared to be in relationship with dopaminergic disturbances. Finally, the dopaminergic system did not appear to play a significant role in the dichotomy unipolar/bipolar. The results show the interest of the apomorphine test in the assessment of the relationship between biochemical disturbances and clinical correlates.


Asunto(s)
Trastorno Depresivo/metabolismo , Dopaminérgicos/metabolismo , Adulto , Apomorfina , Trastorno Bipolar/metabolismo , Trastorno Depresivo/psicología , Femenino , Hormona del Crecimiento/metabolismo , Humanos , MMPI , Masculino , Persona de Mediana Edad , Desempeño Psicomotor , Serotonina/metabolismo , Suicidio/psicología , Transmisión Sináptica
13.
J Dairy Sci ; 77(8): 2400-14, 1994 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-7962862

RESUMEN

Additive and nonadditive genetic effects on lifetime yields of milk and milk components and lifetime profitability were estimated from 5070 cattle in a Holstein pureline, an Ayrshire-based pureline, and 10 crossbred groups of these purelines. Lifetime yields of milk, fat, protein, and lactose and lifetime milk value and annualized discounted net returns were analyzed. Lifetime yields, lifetime milk value, and annualized discounted net returns of the Holstein x Ayrshire-based line F1 and an F1 x (F1 x F1) cross were not significantly different from those for the Holstein pureline. Net reproductive rate for F1 females was 9% greater than that of contemporary Holsteins. The Holstein pureline was superior to the Ayrshire-based pureline for direct additive genetic merit for all traits. Heterosis for the lifetime traits ranged from 16.6% for lifetime milk yield to 20.6% for annualized discounted net returns. Cytoplasmic maternal effect on annualized discounted net return was significant and favored the Ayrshire-based line. Potential economic benefit may derive from development of a crossbred cow that is superior to Holsteins. Maximum exploitation of additive and nonadditive genetic effects on lifetime yields and profitability appears to favor a rotational crossbreeding system with two breeds.


Asunto(s)
Bovinos/genética , Industria Lechera/economía , Animales , Cruzamiento/métodos , Cruzamiento/estadística & datos numéricos , Cruzamientos Genéticos , Femenino , Lactancia/genética , Lactosa/metabolismo , Metabolismo de los Lípidos , Masculino , Leche/metabolismo , Proteínas de la Leche/metabolismo
14.
J Dairy Sci ; 69(3): 760-8, 1986 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-3711408

RESUMEN

A total of 253 heifers bred at first estrus after 350 d of age (350-d breeding age group) and 249 contemporary heifers bred at first estrus after 462 d of age (462-d breeding age group) were used to study the effects of age at first breeding on productive and reproductive performances of first lactation heifers. Heifers of both breeding age groups were subject to similar feeding and management practices. The average age at first calving was 698 d for the 350-d breeding group and 796 d for the 462-d breeding group. Although not statistically significant, heifers of the 462-d breeding group tended to have a higher conception rate at first service (47 vs. 38%) and fewer days between first service and conception (39 vs. 44 d) than those of the 350-d breeding age group. Breeding heifers as early as 350 d of age has no adverse effects on calving ease or retained placenta but does result in calves 1.2 kg lighter at birth. Heifers of the 350-d breeding group had lower milk, protein, and fat yields at both 168 and 308 d of first lactation than those of the 462-d breeding group. A 1-d reduction in age at first calving decreased 308-d milk yield by 2.01 kg for the 350-d breeding group as compared with 4.74 kg for the 462-d breeding group.


Asunto(s)
Bovinos/fisiología , Preñez , Factores de Edad , Animales , Peso Corporal , Femenino , Lactancia , Embarazo
15.
Transpl Int ; 14(6): 391-5, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11793036

RESUMEN

Orthotopic heart transplantation (OHT) is a major surgical intervention inducing distress and anxiety. Psychological problems after OHT have been described in many studies. Little is known, however, about the relationship between the psychological state of the patient and time after surgery. The present study involved 41 consecutive OHT patients that underwent transplantation from January 1991 to December 1992, with a retrospective review of pretransplant psychiatric evaluations to define a Diagnostic and Statistical Manual of Mental Disorders, 3rd edn., revised (DSM III-R) Axis I diagnosis. Patients completed the Beck Depression Inventory (BDI-13), Spielberger's State Trait-Anxiety Inventory (STAI-Y), and the General Health Questionnaire (GHQ-28) between 1 and 41 months after transplantation. For comparison, 29 presumably healthy volunteers were given the same questionnaires. The study confirms the occurrence of abnormal psychological scores in the OHT group as compared to the reference population. Psychological scores, however, do not appear to be related to the time they were recorded after surgery.


Asunto(s)
Ansiedad/etiología , Depresión/etiología , Trasplante de Corazón/psicología , Adulto , Anciano , Anciano de 80 o más Años , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad
16.
Pharmacopsychiatry ; 28 Suppl 2: 91-2, 1995 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8614706

RESUMEN

The prevailing neurochemical theory about biological correlates of suicidal behavior focuses on the serotonergic system. In this study, we assessed the cortisol, ACTH, GH, prolactin and temperature responses to flesinoxan, a5-HT1A agonist, in 30 DSM-III-R major depressed inpatients subgrouped into suicide attempters (n = 15) and nonattempters (n = 15). The patients were assessed after a drug-free period of at least 3 weeks. A subsample of 16 patients completed the Buss-Durkee Hostility Inventory as a measure of impulsive aggressive behavior. Mean delta cortisol responses to flesinoxan were significantly lower in the group of depressed patients with a history of suicide attempts than in the group without history of suicidal behavior: for the delta cortisol values 14.5 +/- 16.3 micrograms/l vs 101 +/- 94 micrograms/l (F = 8.9, df = 5.25, p = 0.006). There was also a very significant difference between suicide attempters and nonattempters for the temperature (delta T degrees) responses to flesinoxan: 0.20 +/- 0.24 degrees C vs. 0.60 +/- 0.24 degrees C (F = 18.1, df = 5.25, p = 0.0003). Hormonal and temperature responses to flesinoxan were not correlated with BDHI irritability or assault subscale scores. The results of the present study support the implication of the serotonergic system, particularly 5-HT1A receptors, in the control of self-directed aggressive behavior. Moreover, in depressed patients, serotonergic abnormalities do not appear to be related to aggressive behavior.


Asunto(s)
Trastorno Depresivo/diagnóstico , Trastorno Depresivo/psicología , Piperazinas , Receptores de Serotonina/efectos de los fármacos , Agonistas de Receptores de Serotonina , Intento de Suicidio/psicología , Adulto , Temperatura Corporal/efectos de los fármacos , Estudios Cruzados , Método Doble Ciego , Hormonas/sangre , Humanos , Masculino , Escalas de Valoración Psiquiátrica
17.
J Dairy Sci ; 70(11): 2385-93, 1987 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-3693641

RESUMEN

Data from 1341 Holstein heifers of 71 sires were used to study heritabilities of and genetic and phenotypic correlations among milk production traits (308-d milk, front and rear half yields), body measurements (heart girth, withers height, body length, and rump length), udder measurements (front teat length and diameter, rear teat length and diameter, teat distance and udder height), and age at first calving. Genetic and phenotypic parameters were estimated by the multitrait restricted maximum likelihood method. Multitrait estimates of heritability ranged from .37 to .47 for first lactation yield traits, from .19 to .51 for body measurements, and from .08 to .41 for udder measurements. Age at first calving averaged 22.3 mo with a heritability estimate of .11. Milk production traits were all positively correlated with body measurements, suggesting that high producing heifers would be taller, larger, and longer than low producing heifers. Multitrait estimates of genetic and phenotypic correlations between udder height and yield traits were all negative, suggesting that high producing heifers tend to have lower udders. Of four body measurements studied, rump length showed the greatest genetic correlations with yield traits. Among six udder measurements, udder height exhibited the highest degree of associations with yield traits. Thus, rump length and udder height merit greater attention for prediction of lactational performance.


Asunto(s)
Constitución Corporal , Bovinos/fisiología , Lactancia/fisiología , Glándulas Mamarias Animales/anatomía & histología , Animales , Femenino , Modelos Biológicos , Fenotipo , Embarazo
18.
J Dairy Sci ; 70(10): 2105-11, 1987 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-3680728

RESUMEN

Weekly milk yields of 1022 Holstein heifers from 61 sires were used to derive coefficients of the lactation curves using modified gamma and inverse polynomial functions. The natural logarithm of a modified gamma function was ln(yn) = ln (a) + b ln (n) + cn + u sin (x) + v cos (x), where a, b, c, u, and v are coefficients to be estimated; n is the day of lactation; and x is the day of year. Estimates of a, b, and c were combined to define persistency [-(b + 1) ln c], week of peak yield (b/c), and peak yield [a(b/c)be-b]. The inverse polynomial function was n/yn = A0 + A1n + A2n2, where A0, A1, and A2 are coefficients to be estimated. Variance and covariance components for the coefficients of the lactation curve were estimated by the multitrait restricted maximum likelihood method using canonical transformation. Heritability estimates were ln (a) .11, b .07, c .04 u .01, v .04, A0 .28, A1 .26, A2 .21, persistency .21, week of peak .18, peak yield .23, and 308-d milk yield .41. Genetic correlations indicated that selection for faster rate of increase to peak production would result in higher 308-d milk production, higher peak yield, and greater persistency.


Asunto(s)
Bovinos/genética , Lactancia/fisiología , Algoritmos , Animales , Femenino , Fenotipo , Embarazo
19.
J Dairy Sci ; 67(10): 2420-8, 1984 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-6501653

RESUMEN

Data of 2779 purebred and crossbred heifers collected from five research stations of Agriculture Canada were used to study additive and nonadditive genetic effects on ages at first heat and at first breeding and conception rate at first service. Of these heifers, 2378 heifers had information on ages at first conception and at first freshening, days from first service to conception, and gestation length. The model included station, year of birth, sire, breed additive, maternal, and heterosis effects where sire effects were treated as random. Station differences were a significant source of variation for all reproductive traits. Year of birth had significant effects on four of seven reproductive traits. Breed additive effects for all genetic groups were not significant except for Finnish Ayrshire and American Holstein. No significant maternal effects were detected. Of 21 combinations of heterosis effects, six combinations showed significance. Partial regression coefficients ranged from negative to positive, suggesting that breed additive, maternal, and heterosis effects could increase or decrease for each percent increase of genetic contribution, depending upon the trait, breed group, and type of inheritance.


Asunto(s)
Bovinos/genética , Reproducción , Animales , Bovinos/fisiología , Cruzamientos Genéticos , Ambiente , Femenino , Vigor Híbrido , Modelos Biológicos
20.
J Dairy Sci ; 70(1): 29-39, 1987 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-3571624

RESUMEN

A total of 890 heifers was used to study the effects of four milk protein loci (alpha S1-casein, beta-casein, kappa-casein, and beta-lactoglobulin) on heifer growth and reproduction. The additive effects of gene substitutions at the four milk protein loci were significant only in 4 of 56 cases for all traits studied. Dominance effects at alpha S1-casein, beta-casein, and kappa-casein loci were not significant for any traits except beta-casein locus on body weight at first calving. Heifers with AB type of beta-lactoglobulin showed greater body weights and measurements and gestation length than the AA or BB type, indicating an overdominance effect. Heifers with AB type of beta-lactoglobulin were significantly younger at first conception and at first freshening and had fewer number of days from first service to conception than the AA or BB type, indicating underdominance effect. Thus, beta-lactoglobulin locus shows overdominance, underdominance, or no dominance, depending upon the traits considered. The four milk protein loci contributed more dominance variance than additive variance to total phenotypic variance. This might account for the existence of milk protein polymorphism in the cattle population. The combined genotypes of the four milk protein loci showed significant effects on 2 of 14 traits studied.


Asunto(s)
Bovinos/fisiología , Proteínas de la Leche/genética , Preñez/fisiología , Animales , Peso Corporal , Caseínas/genética , Bovinos/crecimiento & desarrollo , Femenino , Genotipo , Lactoglobulinas/genética , Embarazo
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