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1.
Eur Psychiatry ; 16(3): 180-5, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11353597

ABSTRACT

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.


Subject(s)
Affective Symptoms/diagnosis , Affective Symptoms/etiology , Anxiety Disorders/diagnosis , Anxiety Disorders/etiology , Depressive Disorder, Major/diagnosis , Depressive Disorder, Major/etiology , Heart Transplantation/psychology , Adaptation, Psychological , Adult , Affective Symptoms/epidemiology , Aged , Anxiety Disorders/epidemiology , Depressive Disorder, Major/epidemiology , Female , Health Status , Humans , Male , Middle Aged , Postoperative Care , Preoperative Care , Prevalence , Psychiatric Status Rating Scales , Quality of Life , Retrospective Studies , Severity of Illness Index , Social Desirability , Social Support , Surveys and Questionnaires
2.
Transpl Int ; 14(6): 391-5, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11793036

ABSTRACT

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.


Subject(s)
Anxiety/etiology , Depression/etiology , Heart Transplantation/psychology , Adult , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Humans , Male , Middle Aged
3.
Rev Med Liege ; 55(11): 1003-10, 2000 Nov.
Article in French | MEDLINE | ID: mdl-11195702

ABSTRACT

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.


Subject(s)
Alcoholism/drug therapy , Selective Serotonin Reuptake Inhibitors/therapeutic use , Alcoholism/complications , Alcoholism/psychology , Anxiety/complications , Depression/complications , Humans , Risk Factors , Selective Serotonin Reuptake Inhibitors/pharmacology , Treatment Outcome
4.
Pharmacopsychiatry ; 28 Suppl 2: 91-2, 1995 Oct.
Article in English | MEDLINE | ID: mdl-8614706

ABSTRACT

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.


Subject(s)
Depressive Disorder/diagnosis , Depressive Disorder/psychology , Piperazines , Receptors, Serotonin/drug effects , Serotonin Receptor Agonists , Suicide, Attempted/psychology , Adult , Body Temperature/drug effects , Cross-Over Studies , Double-Blind Method , Hormones/blood , Humans , Male , Psychiatric Status Rating Scales
5.
Acta Psychiatr Belg ; 95(4-5): 210-33, 1995.
Article in French | MEDLINE | ID: mdl-8525861

ABSTRACT

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.


Subject(s)
Depressive Disorder/blood , Growth Hormone/blood , Suicide, Attempted , Adolescent , Adrenergic alpha-Agonists/pharmacology , Adult , Apomorphine/pharmacology , Clonidine/pharmacology , Contingent Negative Variation , Depressive Disorder/psychology , Dexamethasone , Dopamine Agonists/pharmacology , Event-Related Potentials, P300 , Humans , Hydrocortisone/blood , Male , Suicide, Attempted/psychology
6.
J Dairy Sci ; 77(8): 2400-14, 1994 Aug.
Article in English | MEDLINE | ID: mdl-7962862

ABSTRACT

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.


Subject(s)
Cattle/genetics , Dairying/economics , Animals , Breeding/methods , Breeding/statistics & numerical data , Crosses, Genetic , Female , Lactation/genetics , Lactose/metabolism , Lipid Metabolism , Male , Milk/metabolism , Milk Proteins/metabolism
7.
Psychiatry Res ; 52(2): 115-23, 1994 May.
Article in English | MEDLINE | ID: mdl-7972568

ABSTRACT

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.


Subject(s)
Clonidine , Depressive Disorder/psychology , Growth Hormone/metabolism , Receptors, Adrenergic, alpha-2/metabolism , Suicide, Attempted , Adult , Clonidine/pharmacology , Depressive Disorder/diagnosis , Female , Humans , Male , Methoxyhydroxyphenylglycol/cerebrospinal fluid , Norepinephrine/metabolism , Psychiatric Status Rating Scales , Radioimmunoassay
8.
Am J Psychiatry ; 151(2): 216-20, 1994 Feb.
Article in English | MEDLINE | ID: mdl-8296892

ABSTRACT

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.


Subject(s)
Clonidine , Depressive Disorder/diagnosis , Growth Hormone/blood , Adult , Biomarkers/blood , Clonidine/administration & dosage , Clonidine/pharmacology , Depressive Disorder/blood , Diagnosis, Differential , Female , Humans , Injections, Intravenous , Male , Menopause , Middle Aged , Sex Factors
10.
Anxiety ; 1(5): 237-41, 1994.
Article in English | MEDLINE | ID: mdl-9160581

ABSTRACT

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.


Subject(s)
Anxiety/psychology , Diving/psychology , Occupational Diseases/psychology , Adult , Anxiety/diagnosis , High Pressure Neurological Syndrome/diagnosis , High Pressure Neurological Syndrome/psychology , Humans , Male , Military Personnel/psychology , Occupational Diseases/diagnosis , Personality Assessment
11.
J Dairy Sci ; 76(5): 1365-74, 1993 May.
Article in English | MEDLINE | ID: mdl-8505427

ABSTRACT

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.


Subject(s)
Cattle/physiology , Lactation/physiology , Silage , Animal Nutritional Physiological Phenomena , Animals , Cattle/blood , Digestion , Energy Metabolism , Fatty Acids, Nonesterified/blood , Female , Milk/chemistry , Nitrogen/metabolism
12.
Acta Psychiatr Belg ; 93 Spec No: 343-58, 1993.
Article in French | MEDLINE | ID: mdl-7916521

ABSTRACT

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.


Subject(s)
Depressive Disorder/metabolism , Dopamine Agents/metabolism , Adult , Apomorphine , Bipolar Disorder/metabolism , Depressive Disorder/psychology , Female , Growth Hormone/metabolism , Humans , MMPI , Male , Middle Aged , Psychomotor Performance , Serotonin/metabolism , Suicide/psychology , Synaptic Transmission
13.
J Dairy Sci ; 75(5): 1273-80, 1992 May.
Article in English | MEDLINE | ID: mdl-1597582

ABSTRACT

Early part records for milk yield and feed consumption of 2230 first lactation purebred and crossbred dairy cows were analyzed to evaluate various measures of feed efficiency. Corrected milk yield was estimated by adjusting the second 8 wk of milk yield for differences in weight of TDN consumed during wk 9 to 16, percentage of TDN derived from concentrate, and BW.75. Corrected milk yield is an estimate assuming that cows are the same size and consume the same amount of feed. Hence, it represents an expression of feed efficiency. Net feed efficiency, gross efficiency, corrected milk yield, and wk 9 to 16 milk were analyzed simultaneously. Coefficient of determination for net efficiency (.51) and gross efficiency (.72) were lower than that of milk (.82), whereas corrected milk yield had a coefficient of determination similar to that of milk. Hence, the use of ratios to define feed efficiency was less accurate than using corrected milk yield. Effects of genetic groups, stations, season of freshening, year of freshening, and heterosis were similar for gross efficiency and corrected milk yield, but different from those for milk. Therefore, corrected milk yield performed the same function as feed efficiency with higher accuracy.


Subject(s)
Cattle/physiology , Eating , Lactation , Milk/metabolism , Animals , Breeding , Cattle/genetics , Female , Genotype , Hybrid Vigor , Lactation/genetics , Least-Squares Analysis
15.
Anticancer Res ; 11(2): 755-9, 1991.
Article in English | MEDLINE | ID: mdl-2064330

ABSTRACT

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).


Subject(s)
Cell Survival , Growth Inhibitors/isolation & purification , Melanoma, Experimental/metabolism , Mitogens/isolation & purification , Animals , Cell Line , Cell Survival/drug effects , Culture Media , Culture Techniques/methods , DNA Replication , Fibroblasts/cytology , Growth Inhibitors/pharmacology , Mice , Mitogens/pharmacology , Ultrafiltration
16.
J Dairy Sci ; 72(11): 3085-90, 1989 Nov.
Article in English | MEDLINE | ID: mdl-2625498

ABSTRACT

Data from 889 cows at five research stations of Agriculture Canada were used to study the effects of alpha s1-casein, beta-casein, kappa-casein, and beta-lactoglobulin loci on herdlife and total yield over fixed parities (one, two, and three parity) and to a fixed age (36, 48, and 61 mo). Actual yields of all cows were utilized to compute total milk regardless of lactational length. The model consisted of station, breed, year of birth, season of birth, and milk protein types with age at first calving as a covariate. Of the four milk protein types studied, only the kappa-casein locus had significant effects on fixed parity and fixed age total milk and herdlife. Cows with BB kappa-casein type outproduced those with AB or AA kappa-casein types in three parity total milk by 963 and 1657 kg, respectively. Considering total milk accumulated up to 61 mo of age in life, cows with BB kappa-casein type outperformed their counterparts with AB or AA kappa-casein types by 1050 and 1923 kg, respectively. Complete replacement of A by B allele at kappa-casein locus would result in an increase of 1657 kg in three parity total milk and an increase of 1923 kg in 61-mo total milk. The moderate gene frequency of kappa-casein B allele in the current dairy population can be increased to improve lifetime total milk to the benefit of the dairy industry.


Subject(s)
Caseins/genetics , Cattle/physiology , Lactation/genetics , Lactoglobulins/genetics , Alleles , Analysis of Variance , Animals , Breeding , Caseins/analysis , Cattle/genetics , Female , Lactoglobulins/analysis , Least-Squares Analysis , Milk/analysis , Parity , Pregnancy
17.
J Dairy Sci ; 71(4): 1011-24, 1988 Apr.
Article in English | MEDLINE | ID: mdl-3392297

ABSTRACT

The proportional hazards model with censoring was used to assess the effects of breeding value, disease, calving, size, and udder and lactation traits on length of herdlife of 3881 heifers in five herds. Data were recorded over 10 yr from three lines: a Holstein line, an Ayrshire-based line, and a crossbred line. Influences on survival were assessed from data collected at birth, 34, 50, and 82 wk, first freshening, and at 112 and 308 d postpartum. Median estimated herdlife (age at 50% culling) was 3.9 yr for animals alive at first freshening and increased to 4.3 yr for those that completed a first lactation (308 d postpartum). Herds differed greatly in the pattern of culling after freshening. Crossbred females had 21 wk longer median estimated herdlife than the mean of the purelines at 308 d postpartum. Individual milk yield was positively associated with longevity and had the greatest impact on length of herdlife. Abortion and fertility measured as days to last insemination were negatively associated with length of herdlife. Large heifers tended to have increased longevity. High feed intake postpartum was associated with reduced length of herdlife. Objective measures of conformation, which included measurements of the udder, were not important in determining herdlife.


Subject(s)
Cattle/physiology , Crosses, Genetic , Longevity , Models, Biological , Animals , Female
18.
J Dairy Sci ; 71(4): 1000-10, 1988 Apr.
Article in English | MEDLINE | ID: mdl-3392296

ABSTRACT

Data on 3957 heifers from the Holstein H line, Ayrshire-based A line, and C line (crossbreds between H and A lines) were used. Growth, feed consumption, and feed efficiency from 26 to 34 wk were examined. The full model included the fixed effects of herd, year of birth, season of birth, and additive, maternal, and heterotic genetic effects with 26-wk weight as a covariate. Heterotic and maternal effects were not significant. Adjusted for the 26-wk weight covariate, H line heifers gained 3 kg more than A line heifers with C line heifers intermediate. Adjusted for 26 and 34-wk weight covariates, H line heifers ate 2 kg less TDN than A line heifers and, hence, were more efficient. Correlations among traits were estimated using the residual variance-covariance matrix from the full model. Body weight at 34 wk was correlated with 26-wk weight (r = .88) but essentially independent of rate of gain (r = .02). It was correlated with feed consumed (r = .51) and negatively associated with gain/feed consumed (r = -.25). Gain was correlated (r = .84) with gain/feed consumed but mildly so (r = .28) with feed consumed. Feed consumption was negatively correlated (r = -.25) with gain/feed consumed when the 26-wk weight covariate was included but became much larger (r = -.95) when both 26 and 34 wk weight covariates were included. Although genetic differences in feed consumption and feed efficiency of growing heifers exist, these are small and closely associated with weights and weight gains.


Subject(s)
Animal Nutritional Physiological Phenomena , Body Weight , Cattle/growth & development , Crosses, Genetic , Animals , Female
19.
J Dairy Sci ; 70(11): 2385-93, 1987 Nov.
Article in English | MEDLINE | ID: mdl-3693641

ABSTRACT

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.


Subject(s)
Body Constitution , Cattle/physiology , Lactation/physiology , Mammary Glands, Animal/anatomy & histology , Animals , Female , Models, Biological , Phenotype , Pregnancy
20.
J Dairy Sci ; 70(10): 2105-11, 1987 Oct.
Article in English | MEDLINE | ID: mdl-3680728

ABSTRACT

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.


Subject(s)
Cattle/genetics , Lactation/physiology , Algorithms , Animals , Female , Phenotype , Pregnancy
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