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At least 1,621 records · Page 90Linked to original sources
PubMed1992

Accelerated lambing using exogenous progesterone and the ram effect.

An experiment was conducted to determine whether controlled internal drug release devices-type G (CIDR-G) could be used in conjunction with the ram effect to advance the breeding season and lambing and thereafter could be reapplied to stimulate breeding of ewes to produce a second lambing in late summer. Finn crossbred and Columbia ewes were treated with CIDR-G from July 6 to 18. Rams, which had been isolated from ewes, were joined with the flock upon CIDR-G removal. All 59 CIDR-G-treated ewes exhibited estrus, and 55 lambed from breeding within a 30-d period after CIDR-G withdrawal. Eighteen of 19 contemporary control ewes (no CIDR-G) were bred, and 16 lambed. Ewes that had lambed from the CIDR-G and control groups were retreated as before, with CIDR_G inserted March 1 and withdrawn March 13, concomitant with sudden exposure to rams. Of 55 CIDR-G-treated sheep, 53 were bred and 45 lambed. All 16 control ewes were bred and lambed. A second experiment was conducted to determine whether treatment with CIDR-G and the ram effect was effective in mid-spring. The CIDR-G were applied for 12 d and removed on May 1 or 6 from Finn crossbred, Columbia, and Polypay ewes. Rams were introduced upon CIDR-G withdrawal. Of 59 CIDR-G-treated ewes, 58 exhibited estrus and 45 lambed. Twenty-three of 30 contemporary control ewes were bred, and 20 lambed.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intravaginal↗
PubMed1998

Expression of the angiogenic factors, basic fibroblast growth factor and vascular endothelial growth factor, in the ovary.

In adult tissues, vascular growth (angiogenesis) occurs normally during tissue repair, such as in the healing of wounds and fractures. Inappropriate vascular growth is associated with various pathological conditions. These conditions include tumor growth, retinopathies, hemangiomas, fibroses, and rheumatoid arthritis in the case of rampant vascular growth and nonhealing wounds and fractures in the case of inadequate vascular growth. The female reproductive organs exhibit dramatic, periodic growth and regression, accompanied by equally dramatic changes in their rates of blood flow. Thus, it is not surprising that they are some of the few adult tissues in which angiogenesis occurs as a normal process. Ovarian follicles and corpora lutea contain and produce angiogenic factors. These angiogenic factors bind heparin and seem to belong to the fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) families of proteins. Based on our studies of the pattern of expression of FGF and its major receptors in bovine, ovine, and porcine corpora lutea, we have suggested that FGF may influence not only luteal cell proliferation but also cell death, thereby regulating cell turnover in the luteal vascular and nonvascular compartments. In addition, we recently have shown that luteal expression of VEGF is greatest during the early luteal phase, coincident with luteal vascularization. Moreover, VEGF is present exclusively in luteal connective tissue and perivascular (arteriolar smooth muscle and capillary pericyte) cells. In fact, the first thecal-derived cells to invade the granulosa-derived regions immediately after ovulation seem to be VEGF-containing pericytes. We have therefore hypothesized that ovarian pericytes play a key role in vascularization of developing follicles and corpora lutea. Further understanding of the specific physiological roles of these factors in follicular and luteal growth, development, and function will ultimately lead to improved methods of regulating fertility.

Angiogenesis Inducing Agents↗
PubMed2002

Weight necessary to change body condition scores in Angus cow.

Weights and body condition scores (BCS) were measured and assessed on Angus females (n = 367) over 14 yr (1981 to 1994) to allow calculation of weight adjustments for different BCS. Data were collected at five time periods: prepartum, postpartum, prebreeding, postbreeding, and midgestation. Individual cows with multiple records were included in the analysis as repeated measures to yield 3,912 total observations. Body condition score was assigned on a scale of 1 = emaciated to 9 = obese. Only BCS 2 through 8 were analyzed, as there were zero recorded observations of BCS 1 or 9. The final model included age and the time period by BCS interaction as fixed effects. Year by animal within age interaction and a residual error term were treated as random effects. Animal was included to correct for repeated measures across time periods and years for individual animals. All these effects were significant (P < 0.0001). Weight adjustments for BCS were calculated for each time period. Cow weight and weight adjustments for BCS were not consistent for each time period. Overall weight adjustments to adjust cows to BCS of 5 were (kg +/- SEM) BCS = 2 (68 +/- 12), BCS = 3 (50 +/- 4), BCS = 4 (21 +/- 1), BCS = 5 (0), BCS = 6(-24 +/- 2), BCS = 7(-51 +/- 3), and BCS = 8 (-73 +/- 7).

Age Factors↗
PubMed2004

High linoleic acid safflower seed supplementation for gestating ewes: effects on ewe performance, lamb survival, and brown fat stores.

Objectives of this study were to determine whether feeding high-linoleic safflower seed to gestating ewes increases cold tolerance and survival in lambs, and whether brown adipose tissue (BAT) stores in lambs are affected by prepartum safflower seed supplementation. In Trial 1, 234 gestating ewes (122 in yr 1 and 112 in yr 2; 75.5 and 81.2 +/- 0.6 kg initial BW for yr 1 and 2, respectively) were allotted randomly to one of two dietary treatments (four pens*treatment(-1)*yr(-1)). Ewes were fed alfalfa-based diets containing (DM basis) either 2.8 (LF) or 5.7% (HF) dietary fat beginning 55 (yr 1) and 42 (yr 2) +/- 1 d prepartum. In Trial 2, 40 Rambouillet cross ewes gestating twins (82.9 +/- 1.7 kg BW) were used in 2 yr (20/yr) and were fed diets containing (DM basis) either 1.9 (LF) or 4.9% (HF) dietary fat beginning 53.4 +/- 1.4 d prepartum. The basal diet was 37.5% each of grass and alfalfa hays and 25% corn silage (DM basis). Cracked safflower seeds (18% CP, 32% fat, 25.6% linoleic acid; DM basis) were used as the supplement in HF, whereas safflower meal and corn were used as the supplement in LF for both trials. At parturition, one lamb from each ewe was selected randomly for slaughter. Perirenal (PR) and pericardial (PC) BAT was excised and weighed, and the carcass was frozen for compositional analysis. In Trial 1, more lambs from HF 0.03; 15.4 vs. 5.8 +/- 2.8%), and dams survived (P = 0.03; 88.4 vs. 78.3 +/- 2.9%), fewer died due to starvation (P = there was a tendency for fewer to die due to pneumonia (P = 0.07; 0.0 vs. 1.7 +/- 0.6%). Ewes fed HF tended to wean more lambs per ewe (P = 0.09; 1.4 vs. 1.2 +/- 0.06) but had similar lamb weight weaned per ewe (P = 0.51; 23.1 +/- 1.22 kg). In Trial 2, prepartum ewe plasma NEFA and glucose concentrations increased with advancing gestation (P < 0.001). Lamb rectal temperature tended (P = 0.08) to be higher in LF lambs and tended (P = 0.06) to increase following parturition. Perirenal BAT weight did not differ among treatments (33.01 +/- 1.66 g; P = 0.28; 0.62 +/- 0.30% BW; P = 0.60). Lambs from LF dams tended (P = 0.08) to have greater PC BAT weight; however, the effect was not significant when expressed as a percentage of BW (0.13 +/- 0.007; P = 0.98). High-linoleic safflower seeds fed during the last 45 d of gestation may be beneficial in improving lamb survivability. Our data do not indicate this response was a result of increased BAT stores. More research is necessary to determine mechanisms that enhance lamb survival when high-linoleic saf-flower seed is fed during gestation.

Adipose Tissue, Brown↗
PubMed1991

Contributions made to chronobiology by studies of fiddler crab rhythms.

One of the classic organisms used in chronobiological research is the fiddler crab (genus Uca), an animal unique in that it displays both circadian and tidal (i.e., circalunidian) rhythms. The pioneering work on this animal helped produce the early evidence for many of the standard properties now recognized for all circadian rhythms: near temperature independence of the period, phase lability and setability, the light and temperature sensitivity rhythms expressed by phase response curves, and the persistence of rhythms in organs isolated from a multicellular animal. Importantly, results arising from studies of this crab--and a few other organisms--resulted in the development of the exogenous timing hypothesis. While philosophically sound, the lack of supporting evidence for this hypothesis has resulted in it being discarded by most chronobiologists; but while still in its prime, it drew great interest, and therefore grant support, to the field in general, stimulated a great deal of research that otherwise might not have been performed, and resulted in the discovery of environmental stimuli previously unsuspected to influence organisms. As could be expected, continuing work with this crab, using modern approaches and statistical techniques, has modified earlier findings and interpretations, has revealed new properties, and has resulted in the creation of new hypotheses. The review and update is a synthesis of 45 years of this work.

Animals↗
PubMed2004

Effect of lameness on ovarian activity in postpartum holstein cows.

A longitudinal study was conducted to examine the relationship between lameness and delayed ovarian cyclicity during the first 60 d postpartum and days to first luteal activity during the first 300 d postpartum in Holstein cows. Two hundred thirty-eight cows from a 600-cow dairy that calved during a 12-mo period were used. Cows were classified into 1 of 6 categories of lameness during the first 35 d postpartum using a locomotion scoring system. Cows were blood-sampled weekly for detection of plasma progesterone concentrations during the first 300 d postpartum. Cows with delayed resumption of ovarian cyclicity were defined as those with progesterone concentrations consistently <1 ng/mL during the first 60 d postpartum. The null hypothesis that risk of delayed cyclicity is the same in cows classified as nonlame, moderately lame, or lame (after adjusting for potential modifying or confounding effects of loss of body condition and other variables related with delayed cyclicity) was tested using logistic regression. Analysis of results of the study reported here support the hypothesis that lameness is associated with delayed ovarian activity in Holstein cows during the early postpartum period. Cows classified as lame had 3.5 times greater odds of delayed cyclicity, compared with cows classified as nonlame. Attributable proportion analysis indicated that delayed ovarian cyclicity in lame cows would be reduced by 71%, if lameness had been prevented.

Animals↗
PubMed2006

Comparison of two strategies for systemic antibiotic treatment of dairy cows with retained fetal membranes: preventive vs. selective treatment.

The objective of this study was to evaluate the efficacy of a blanket systemic preventive treatment (PT) of cows having retained fetal membranes (RFM) with 1 mg/kg of ceftiofur administered the first day after calving regardless of their body temperature. This strategy was compared with a selective treatment (ST) strategy in which only cows having RFM and a rectal temperature > or = 39.5 degrees C within 10 d postpartum received ceftiofur. Cows that retained their fetal membranes for at least 24 h after calving were allocated to 2 groups. Rectal temperature was measured daily for 10 d postpartum. Sixty PT cows having RFM received a daily ceftiofur (1 mg/kg of body weight) treatment, administered subcutaneously during the first 3 d after diagnosis of RFM. If rectal temperature was > or = 39.5 degrees C after 3 daily treatments, cows received ceftiofur for 2 more days. Therapy in 53 ST cows was based on selective administration of ceftiofur to cows having fever during the first 10 d postpartum. Treatment was conducted for 3 to 5 consecutive days as described for PT cows, beginning on the first day of fever. In both groups, manual removal of the placenta was not attempted and antibiotic drugs were not administered into the uterus. For every cow having RFM enrolled in PT or ST, 1 cow without RFM that had calved on the same day was enrolled in a healthy control group (n = 113). All cows received two 25-mg doses of PGF(2alpha): 1 dose between 18 and 24 d and 1 dose between 32 and 38 d postpartum. The PT did not reduce the proportion of cows experiencing fever during 10 d postpartum compared with ST cows (71.7 vs. 69.8%). Results were compared using logistic regression models and survival analyses. The artificial insemination submission rate between 42 and 62 d postpartum was greater in PT (41.2 vs. 20.8 vs. 24.5%), but total conception rate was less in ST and control cows, respectively (25.0 vs. 38.9 vs. 36.2%). In this trial, a preventive systemic antibiotic treatment of all cows having RFM was not superior to a selective antibiotic treatment of cows only in case of fever.

Animals↗
PubMed1982

Self-selection of calcium during the rearing and early laying periods of White Leghorn pullets.

The ability of pullets to selectively consume calcium to meet the requirements of the rearing and early laying period was studied in White Leghorns. In the first of two experiments, 456 pullets were fed either an .89% calcium rearing diet (control) or a .35% calcium diet in combination with a separate source of 38% calcium chick-sized grit (calcium self-selection) from 35 to 126 days of age. Twenty-four pullets from each of these rearing treatments were selected for the second experiment at 112 days of age and were housed in individual laying cages. Rearing treatments were continued until 176 days of age with mash and grit consumption recorded daily for each pullet. From 177 to 225 days of age these pullets were fed a 3.50% calcium diet containing either ground limestone or oyster shell as a calcium source or a .35% calcium diet fed in combination with a separate source of oyster shell. Pullet calcium intake reflected the requirements for growth during the rearing period, calcium storage in the medullary bone 19 days prior to lay, and egg shell formation during the laying period; average calcium intake for these periods was 1.18, 2.08, and greater than 3.50%, respectively. Pullets also demonstrated the ability to compensate for rearing deficiencies by increased calcium consumption when fed oyster shell on an ad lib basis. Calcium consumption was found to be significantly higher on days when an oviposition occurred than when no eggs were laid. Mash consumption during the early laying period also reflected the reproductive status of the hen with the highest consumption on days when both oviposition and ovulation occurred, intermediate consumption when either oviposition or ovulation occurred, and lowest consumption when neither oviposition nor ovulation was detected.

Aging↗
PubMed2005

Association of trypanosomosis risk with dairy cattle production in western Kenya.

Dairy cattle reared in western Kenya are exposed to medium to high levels of trypanosomosis risk. The social background, farm characteristics and dairy cattle productivity of 90 and 30 randomly selected farmers from medium- and high-risk trypanosomosis areas, respectively, were compared. All the 120 farmers were visited between July and August 2002. Data analysis was performed using descriptive statistics and analysis of variance. The results showed that increased trypanosomosis risk represented by an increase in disease prevalence in cattle of 1% to 20% decreased the density of dairy cattle by 53% and increased the calving interval from 14 to 25 months. The increased risk was also associated with a significant increase in cattle mortalities and in a lactation period of 257 to 300 days. It was concluded that removal of the trypanosomosis constraint on dairy production would lead to expansion of dairying since the domestic demand for dairy products is expected to increase.

Analysis of Variance↗
PubMed2000

[Age and experience of puberty in young Tunisian girls].

The puberty is an important period in woman life. We have tried to determine the age of the puberty, the chronology of its events and the real life of this period of preparation to reproductive life of tunisian girl student by an inquiry. The middle age of puberty is 13 years. It depends of sociological, economic and environmental factors. Knowledges about reproductive life are still insufficient for this age group bracket of high risks of non desired pregnancies and sexually transmittable diseases.

Adaptation, Psychological↗
PubMed2000

[Does reduction in multifetal pregnancy increase the risk of poor outcome in twin pregnancy?].

OBJECTIVE: To compare perinatal results for multi-foetal pregnancies where the reduction was performed with pregnancies where the reduction was not performed. SETTING: Sanatorium Pronatal, Na Dlouhé mezi 4/12, 147 00, Praha 4--Hodkovicky. METHODS: We have analyzed results of pregnancies, after delivery, for women with twin pregnancy which originated in our sanatorium, as a result of treatment with assisted reproduction methods, in the period of time from January 1st 1996 to December 31st 1998. In the group being monitored there were 122 twin pregnancies originated as a result of reduction of triple and more-foetal pregnancies. We evaluated the percentage of miscarriages, length of pregnancies, weight of the newborns and the manner of termination of the delivery. These results were compared with our control group consisting of 180 cases of twin pregnancies which were not a result of reduction. RESULTS: Analysis was performed for those mothers only where complete data were available. At a 5% level of statistical significance, it was not proved that both groups differed in average term of pregnancy or average weight of the twins. Average age of the mothers differed at 5% level of significance (average age values were 30.16 for the group with reduction and 31.73 for the group without reduction). Fisher test on 5% significance level did not ascertain any significant difference in the probability of miscarriage between the group with reduction (5.26%) and the group without reduction (12.84%). At 5% level of statistical significance, no significant difference in probability of perinatal death of the foetus or delivery of a stillborn foetus was ascertained. However, it is necessary to point out a low frequency of these phenomena in our group. The percentage of cesarean sections did not differ significantly in both groups (86.24% in the group monitored vs 87.24% in the group of twins without reduction). CONCLUSION: The analysis of both groups proves that reduction of multi-foetal pregnancies does not worsen perinatal results in comparison to pregnancies where reduction was not performed.

Adult↗