Plasma fatty acids, prostaglandin F2alpha metabolite, and reproductive response in postpartum heifers fed rumen bypass fat.

An experiment was conducted to determine whether feeding rumen-protected fatty acids (FA) to postpartum heifers would increase plasma concentrations of linoleic acid and PGF2, metabolite (PGFM), shorten the interval from calving to first increase in plasma concentrations of progesterone (P4), and increase pregnancy rate relative to controls. Hereford x Angus heifers (346 kg) were assigned randomly to treatments containing either lipid or barley supplemented diets for the first 30 d postpartum. Lipid was .23 kg.heifer(-1).d(-1) of calcium salts of FA (CSFA; n = 20), and an isocaloric amount of barley served as the control (n = 19). Supplements, with .23 kg of barley as a vehicle, and a basal diet of meadow and alfalfa hays were pen fed to heifers (5/pen). Heifers were bled on alternate days (d1 to 30) and twice weekly (d 30 to 2 wk after first estrus) for RIA of plasma PGFM and P4, respectively. Weight percentage of major FA in plasma on d1 and 7 was determined with gas chromatography. First behavioral estrus was detected by use of intact bulls and confirmed by an increase in plasma P4. On d 7, but not d 1, plasma from heifers fed CSFA had altered proportions of major FA (P < .01), including an increase in linoleic acid compared with those of controls (29.1 vs 25.6% of total FA; SE = .75; P < .01). Analysis of variance of contrast variables revealed an effect of treatment on direction of change in PGFM from d 3 to 5 (P < .01). By d 7 and on d 9, plasma concentrations of PGFM were greater in heifers fed CSFA than in controls (P = .02 and P = .06, respectively). There was no difference in plasma concentration of PGFM between treatments on d 1, 3, 5, 11, 13, and 15 postpartum (P = .80, .17, .52, .82, .46, and .77, respectively). Days to first estrus with ovulation, pregnancy rate, and calving interval were not affected by treatments (P = .58, .52, and .24, respectively). Although supplemental lipid fed to primiparous beef heifers increased plasma levels of linoleic acid and production of PGFM in the early postpartum period, it did not improve the fertility of these heifers in the subsequent breeding season.

Prostaglandin f(2alpha) concentrations, fatty acid profiles, and fertility in lipid-infused postpartum beef heifers.

Effects of lipid infusion into postpartum (PP) beef heifers on plasma concentrations of linoleic acid and prostaglandin (PG) F(2alpha) metabolite (PGFM), days to first estrus, and subsequent pregnancy rate were examined. Treatments (n = 5 per group) of 1 L intralipid (20% soybean oil; IL), 1 L 50% dextrose (DEXT; isocaloric to IL), 0.5 L intralipid (0.5 IL), and 1 L physiological saline (SAL) were infused i.v. over 4 h on each of Days 7 through 11 PP. Capacity of the uterus to produce PG was evaluated after i.v. injection of 150 IU of oxytocin (OT) to IL- and DEXT-treated heifers Day 12 PP. Change in plasma concentrations of PGFM from 0 to 4 h was greater for IL-treated heifers than for heifers given other treatments on Day 7 (P = 0.04) and on Day 11 (P = 0.01), but not on Day 9 (P>0.10). Plasma linoleic acid on Day 11 and OT-induced release of PGFM on Day 12 were greater in IL-treated heifers compared with DEXT-treated heifers (P<0.06 and P = 0.01, respectively). There were no significant differences among treatments for mean days to first estrus or pregnancy rate. Infusion of lipid increased systemic concentrations of linoleic acid and increased the capacity of PP heifers to produce uterine PGF(2alpha) as indicated by plasma PGFM concentration after OT injection.

Gender, social status, and emotional reliance.

Past research has suggested the potential importance of considering emotional reliance, a dimension of interpersonal dependence, when addressing social and developmental risk factors for depression. Based on a probability sample of 1,393 adults aged 18-55 residing in Toronto, Canada, this paper addresses gender differences in emotional reliance and the relevance of emotional reliance in explaining the gender-depression association. We also explore link-ages between emotional reliance and status factors. Findings indicate that emotional reliance is significantly related to depression and that women report greater reliance than men, independent of social status factors like marital and parental status, education, income, and occupational prestige. Moreover, the positive association between emotional reliance and depression is greater for women. Several social status factors modify the relationship between gender and emotional reliance. Both education and occupational prestige reduce reliance, and are particularly beneficial in this regard for women. Marriage, on the other hand, increases emotional reliance, especially for men. We offer interpretations of this pattern of findings.

Age, disability, and the sense of mastery.

Are there age differences in the sense of mastery, independent of physical disability? Do age and disability have joint effects on mastery? We propose that both age and disability have independent and synergistic effects on the sense of mastery or control. We analyze data from a large community sample of disabled individuals and a comparison of nondisabled respondents. Our study finds that, indeed, disabled and older respondents report lower levels of mastery. Moreover, the influence of disability on mastery is conditioned by age--and the interaction differs across age groups. In addition, our findings suggest that disabled individuals are disadvantaged in the status variables traditionally associated with greater control. When we adjust for these status variables, we reduce the strength of a quadratic age by disability interaction term considerably. The patterns we find in mastery among those individuals in their middle-years suggest to us that disabled and nondisabled individuals may live out their lives with differential opportunities for attainment and that this inequality has implications for their sense of mastery. Our findings reveal complex nonlinear and synergistic associations among age, disability, and the sense of mastery and raise provocative questions for future research.

Sources and determinants of social support for caregivers of persons with AIDS.

This study examines the determinants of social support among a sample of 642 caregivers of persons with AIDS living in San Francisco and Los Angeles. Respondents include both traditional family caregivers (mothers, spouses, other relatives) and non-traditional caregivers (friends, homosexual partners). Multiple regression analyses are conducted to assess the independent effects of six sets of variables on emotional and instrumental support: social-structural factors (age, education, employment status), caregiver's relationship to the person with AIDS, situational variables (caregiver's HIV status, patient's functional disability, interpersonal conflict), social network factors (contact with family, contact with friends, community integration), personal resources (mastery, caregiving competence), and use of formal community services (patient-directed services, caregiver-directed services). A number of factors and conditions appear to be relevant for caregiver support. For example, results indicate that network factors, including frequency of contact, conflict, and community integration, are importantly related to caregivers' perceptions of emotional support. There is also a trend suggesting lower emotional support among traditional family caregivers, relative to nonfamily caregivers, within gender categories. With respect to instrumental assistance with caregiving, factors that place greater demands and time constraints on caregivers, such as being employed and caring for an AIDS patient with greater functional limitations, appear to increase the level of informal instrumental support the caregiver receives. Partners and spouses, however, receive significantly lower instrumental assistance, independent of other factors. Implications of the findings are discussed.

Informal caregiving to persons with AIDS in the United States: caregiver burden among central cities residents eighteen to forty-nine years old.

Characteristics and caregiving experiences of friends and family members caring for people with AIDS (PWAs) were examined. Based on a probability sample of informal AIDS caregivers ages 18-49 living in central cities of the United States (n = 260), analyses were conducted to (a) identify the sociodemographic characteristics of young central city caregivers; and (b) examine the effects of caregiver characteristics (relationship to PWA, gender, race/ethnicity, income, sexual orientation, HIV status, perceived susceptibility), and level of objective caregiving demands, on subjective caregiver burden. Results indicate that the largest group of caregivers in this age category are male friends of the PWA--a group not typically found among caregivers to persons with other types of illnesses. In general, gay or bisexual caregivers, caregivers who have traditional family ties to the PWA, men relative to women, and lower income caregivers, report the greatest burden. While level of caregiving demands represents the most influential predictor of caregiver burden, white and male caregivers experience greater burden, independent of level of involvement and other caregiver characteristics. Receiving instrumental support with caregiving buffers the impact of high objective demands on subjective burden.

Determinants of perceived family support and conflict: life-course variations among the physically disabled.

This study assesses variations in the levels and determinants of family support and family conflict in three age groups of non-institutionalized physically disabled individuals (18-49; 50-64; 65+). Analyses are based on a representative sample of 730 physically disabled adults from ten countries of southwestern Ontario, Canada. Results indicate life-course related differences in the levels of both family support and family conflict, with the oldest group perceiving the greatest support and the least conflict from family members. While level of disability was not significantly related to perceived family support, findings indicate that individuals with greater functional limitations experience less frequent negative or conflictive interactions with family. A number of additional socio-demographic and psycho-social factors were also associated with perceived family support and conflict. However, the determinants of support and conflict were not equivalent and varied considerably by age group. In general, the results of this study support the notion that support and conflict represent independent dimensions of experience. Moreover, the factors that influence family support and conflict appear to change across the life course.

The prevalence of informal caregiving to persons with AIDS in the United States: caregiver characteristics and their implications.

Based on U.S. national (N = 2673) and central cities (N = 8263) probability samples, this paper: (1) presents estimates of the proportion of the United States population that has provided informal care to persons with AIDS; (2) identifies socio-demographic characteristics of 'typical' AIDS caregivers in the U.S.; and (3) discusses social, economic and health-related implications of informal caregiving to persons with AIDS. Results indicate that 5.0% of all adults age 18-75 living within central cities and 3.2% of the entire adult U.S. population have provided care to a friend, relative or lover with AIDS. Although caregivers are distributed throughout different age and ethnic groups, the majority of caregivers are younger (< 40 years) and white. Males, gay and bisexual men in particular are over-represented among central cities caregivers. Data on the types of caregiving tasks performed show that 64.4% of all caregivers within central cities perform domestic types of caregiving tasks, while 27.7% are involved in personal care of AIDS patients. Caregivers are more likely than non-caregivers to have been tested for HIV, and among the tested, caregivers are more likely to have tested positive. While informal caregiving reduces costs to the formal medical sector, costs to the caregivers themselves should be considered. Physical and emotional stress, as well as reduced opportunity for social and economic development, represent potential outcomes of caregiving. Socio-demographic characteristics of AIDS caregivers, such as their typically young age, suggest that these caregivers may be at particular risk for detrimental consequences.

Gonadotropin-releasing hormone-induced secretion of luteinizing hormone in postpartum beef heifers maintained on two planes of nutrition before and after breeding.

An experiment was conducted to examine the effect of pre- and postbreeding nutrition on GnRH-induced LH release in beef heifers on d 3 and 14 of the subsequent postpartum period. Treatment groups consisted of heifers fed high (H; n = 12) and low (L; n = 12) planes of nutrition for 204 d before breeding. Each group was further subdivided to receive either high or low planes of nutrition after breeding in a 2 x 2 factorial arrangement of treatments (H-H, H-L, L-H, and L-L). On d 3 and 14 postpartum, heifers were injected with 100 micrograms of GnRH (i.v.), and blood was collected via jugular venipuncture at 15-min intervals for 2.5 h and at 30-min intervals for an additional 2.5 h for LH analysis. Heifers fed a high level of nutrition throughout gestation (H-H and L-H) had a greater (P < .05) mean cumulative serum concentration of LH (ng LH.mL-1.min) in response to GnRH on d 3 than did those fed a lower level of nutrition. On d 14, mean cumulative serum concentration of LH in the H-H group was greater (P < .05) than that of the other three groups. These data indicate that postbreeding nutritional status significantly influenced pituitary responsiveness to GnRH on d 3 and that response to GnRH on d 14 was greatly enhanced by maintaining heifers on a high plane of nutrition both before and after breeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Determinants of social support among gay men: the context of AIDS.

In this study, the determinants of social support are examined among a probability sample of gay men residing in San Francisco. Using two waves of data (collected in 1985 and 1987), cross-sectional and longitudinal analyses focused on the effects of five sets of factors (demographic, community integration/network, AIDS-related loss, individual, and health) on satisfaction with three types of support (emotional, informational, and practical). Personal acceptance of one's gay identity and talking to family members about AIDS showed the strongest positive associations with concurrent measures of support and changes in support satisfaction over the two-year period. Conversely, depression and number of HIV symptoms were negatively associated with cross-sectional support and support changes. Family knowledge of respondents' homosexuality interacted with HIV symptoms, such that knowledge was negatively associated with support among those experiencing greater numbers of HIV symptoms. Findings suggest that those most in need of support may be the least satisfied with the support they receive. Family appear to have the potential to be particularly helpful or especially harmful to gay men trying to cope with the AIDS crisis.

Coping with death anxiety: help-seeking and social support among gay men with various HIV diagnoses.

UNLABELLED: OBJECTIVE, DESIGN AND PARTICIPANTS: We examined sources of help-seeking related to worries or concerns about death and dying and the effects of social support on death anxiety in a longitudinal sample of gay men (n = 52). RESULTS: Friends and primary sexual partners were the most frequent sources sought in dealing with death concerns for all groups of respondents (HIV-negative, HIV-positive asymptomatic, and HIV-positive symptomatic). Men experiencing HIV symptoms were more likely than HIV-negative and asymptomatic men to use formal sources of support (medical, psychological). Although HIV-positive symptomatic men did not differ from HIV-negative men in terms of help-seeking from family sources, they were significantly more likely to seek the help of family members than HIV-positive asymptomatic men. All three HIV groups showed significantly different mean levels of death anxiety, with HIV-negative men reporting the lowest level and HIV-positive symptomatic men the highest. Among HIV-negative men, only mental health sources of support (psychologists and clergy) were significantly related to death anxiety, measured 1 year later (beta = -0.35). These sources of support were also associated with death anxiety among HIV-positive asymptomatic men, but in the opposite direction (beta = 0.26). Contrary to expectations, men experiencing HIV symptoms benefited most from family support (beta = -0.31), although peer (beta = -0.19) and medical (beta = -0.28) support sources were also prominent. CONCLUSIONS: Thus, while earlier research found peers to be the most common and effective source of support among gay men, this study suggests that obtaining support from family may become particularly important as one approaches death. The effectiveness of social support in reducing death anxiety appears to vary over the course of the disease from asymptomatic to symptomatic. HIV-symptomatic men obtain support from a wide range of helpers, including medical and peer supports and family.

Nutritional and managerial considerations for range beef cattle production.

A number of nutritional and managerial schemes have been presented to help optimize range livestock production. Forage quality, animal requirements, and the animals' ability to meet their requirements from the forage is presented. After determining the nutritional value of the forages and animal requirements, prescription supplementation produces very efficient additional gains. Management alternatives to compensate for poor quality forage on range in late summer and early fall, such as selling market animals, moving to better feed, chemical curing of forages, time of calving, time of weaning, and using the range as a feedlot are discussed. Winter feeding programs using native flood meadow hay as a base were also presented for both growing animals and mature cows. Included were discussions on using rake-bunched hay, an ionophore, and feeding strategies for wintering cows. Material presented illustrates a philosophy of range nutrition with methods and procedures that are adaptable to grazing systems in all parts of the world. It should be noted, however, some data need to be extrapolated to fit local conditions.

Gonadotropin releasing hormone-induced secretion of luteinizing hormone during the milk-ejection reflex in the postpartum beef cow.

A study was conducted to determine the effect of the milk-ejection reflex on exogenous gonadotropin releasing hormone (GnRH)-induced release of luteinizing hormone (LH) after short-term calf removal. Twenty-four postpartum multiparous beef cows were assigned randomly to groups arranged in a 2(3) factorial arrangement. Factors consisted of two levels of suckling [suckled (S) or nonsuckled (NS)], treatment with GnRH [saline (C) or 200 micrograms GnRH] and days postpartum (d 1 and 14). Dams were isolated from their calves for 4 h on d 1 and 14 postpartum. At the end of 4 h dams were reunited with their calves in S + C and S + GnRH groups, while dams of calves in NS + C and NS + GnRH groups remained separated an additional 2 h. Cows were injected iv with saline or GnRH following the 4-h isolation period, 5 min after calves had begun suckling or nuzzling the udder. Sera from jugular blood samples collected 15 min prior to the end of the 4-h isolation period, immediately prior to injection (0 h) and at 15 min intervals thereafter for 120 min were analyzed for LH. Serum concentrations of LH in control cows did not differ due to suckling or stage of the postpartum period and averaged 2.3 +/- .1 ng/ml. Pituitary response to GnRH was determined by computing the rate of LH release. Rate of LH release (ng LH.ml-1.min-1) in response to GnRH on d 14 was greater (P less than .001) than on d 1 in both suckled and nonsuckled groups (S + GnRH, 37.1 +/- 3.9 vs 18.3 +/- 5.0; NS + GnRH, 34.7 +/- 5.9 vs 14.5 +/- 1.1). However, GnRH-induced release of LH did not differ between suckled and nonsuckled cows on either d 1 or 14 postpartum. These data indicate that response of the bovine pituitary to GnRH during the postpartum period is not influenced by the act of suckling but is enhanced with time after parturition.

The efficacy of an estradiol-silicone rubber removable implant in suckling, growing and finishing steers.

Sixty steer calves, 42 Simmental x Hereford and 18 Hereford, averaging 59 days of age and 78 kg, were assigned to six estradiol-17 beta implant treatments. Implants were cut from cylindrical formed tubes containing a mix of 80% nonpolymerized silicone and 20% microcrystalline estradiol-17 beta by weight and cut into lengths that provided 0, 8.5, 15.6, 30.7, 30.9 and 46.7 micrograms estradiol- 17 beta/day over a 499-day trial period. Two types, a coated and solid implant, were tested at the 31-microgram level; all others were coated with a solid placebo used for the 0-microgram or control treatment. Animal performance was recorded through the suckling, growing and finishing phases of production, and carcass data were collected. Cumulative gains over the 499 days were greater (P less than .05) for the steers given 30.9- and 46.7-micrograms levels than for those given 0-, 8.5- and 15.6-microgram levels, with respective daily gains being .97 and .97 vs .90, .90 and .89 kg; steers given the implant delivering 30.7 micrograms daily tended to gain more (P less than .10) than the controls: .95 vs. 90 kilograms. These values represent a 6% increase in gain over the control with the 30.7-kg coated implant and an 8% increase with the 30.9-microgram solid and 46.7-microgram coated implants. Implants did not improve feed efficiency during a 65-day feedlot period. Neither the amount of estradiol-17 beta nor the type of implant significantly influenced any carcass parameters except maturity. As the dose rate increased, the degree of carcass maturity increased. Type of implant did not affect gain during any period or any of the carcass measures. Results of this study indicate that a single implant of estradiol-17 beta delivering approximately 30.7 micrograms/day will improve weight gains over a long period of time and increase carcass maturity grade of steers.

Effect of various levels of monensin on efficiency and production of beef cows.

Ninety-six gravid cows were allotted to three replications of four treatments. Monensin treatments consisted of 0, 50, 200 and 300 mg per head per day. The basic feed was meadow hay with .45 kg of barley per head per day. Feed was adjusted periodically to maintain equal weight gain between treatments. Initial cow weights for the control, 50-, 200- and 300-mg treatments were 455, 447, 456 and 457 kg, respectively. Daily prepartum cow gains were .34, .38, .38 and .37 kg (P greater than .05) for the control, 50-, 200- and 300-mg levels, respectively. Treatments were terminated about 30 days after calving. Over the entire treatment period, including 30 days postpartum, daily losses for the cows were .12, .05, .10 and .17 kg (P greater than .05) for the control, 50-, 200- and 300-mg levels, respectively. Hay consumption was 92, 88 and 90% of the controls for the 50-, 200- and 300-mg groups. Adjusted weaning weights for the calves were 124, 134, 129 and 133 (P greater than .05) for the control, 50-, 200- and 300-mg groups, respectively, with calves being weaned at 139 days of age. Control cows came into estrus an average of 44 days postpartum as compared to 44, 41 and 45 days for the cows given 50-, 200- and 300-mg treatments, with no differences in conception rates. Concentration of rumen acetic and butyric acid production was reduced and propionic increased with the 200- and 300-mg levels. Monensin feeding improved efficiency and reduced hay requirements without reducing production or reproductive performance.