Biomedical subjects

H H Meyer

Publications and source records attributed to H H Meyer.

At least 19 recordsLinked to original sources

PubMed1996

Epidermal growth factor and epidermal growth factor receptor in the ovary of the domestic cat (Felis catus).

Identification of epidermal growth factor (EGF) and its distribution in the ovary were examined with an immunohistochemical technique using a polyclonal rabbit antibody against mouse EGF. A combination of HPLC and enzymeimmunoassay was elaborated to quantify EGF in different compartments of the feline ovary. In addition, EGF receptors were localized in ovarian cryostat sections with a new ligand-histochemical technique using biotinylated EGF for labelling. Epidermal growth factor was present in theca interna cells, in specific aggregations of interstitial gland cells located next to tertiary follicles, in smaller, single cells of the ovarian cortex, and in the corpus luteum. The strongest EGF-positive reaction was found in vacuolized cells of the interstitium and in theca interna cells of large tertiary follicles rich in cytoplasm. The strictly cellular localization of the EGF-antibody reaction suggests the synthesis of EGF in these cells. Specific binding sites of EGF were present on granulosa cells of secondary and tertiary follicles and on interstitial gland cells. The EGF-binding capacity of granulosa cells of the cumulus oophorus was greater than that of the mural granulosa cells. Granulosa cells of atretic follicles showed a lower or no affinity for staining. In conclusion, we suggest that EGF plays an important role in ovarian folliculogenesis in cats.

Animals↗

PubMed1995

IGF-I and insulin receptors in bovine skeletal muscle: comparisons of different developmental ages, two different genotypes and various individual muscles.

To investigate the regulation of the IGF-I and the insulin receptor in bovine skeletal muscle, we determined their concentrations and their affinity constants in animals of different age, muscle type and breed. Receptors were solubilized and measured by an enzyme-immunoassay. During ontogenesis the concentration of IGF-I receptors decreased from 1650 /+- 600 fmol/mg protein in 3-5-month old fetuses to 105 /+- 20 fmol/mg protein in 16-month old heifers (p < or = 0.01). The insulin receptor concentrations also decreased with age from 136 /+- 28 fmol/mg protein in 3-5-month old fetuses to 50 /+- 11 fmol/mg protein (p < or = 0.05) in 16-month old heifers. In order to compare different muscle types, seven muscles, which represent large differences in fibre type composition and growth impetus, were selected from 6 month old female Jersey calves and were assayed for IGF-I and insulin receptors. We observed significant differences of the IGF-I as well as the insulin receptor concentrations between distinct muscles. However, no relationship could be established between receptor concentration and fibre type composition or growth impetus. In muscle of two cattle breeds, differing markedly with regard to muscle growth intensity, the Jersey and the German Fleckvieh breed, we observed no divergence in IGF-I nor insulin receptor concentrations. We found no differences in IGF-I and in insulin receptor affinities in any of the adult animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1995

Accumulation of the beta-agonist clenbuterol by pigmented tissues in rat eye and hair of veal calves.

Two independent experiments were carried out to determine whether Clenbuterol is accumulated by pigmented tissues. In the first experiment, unpigmented and pigmented rats were injected two times with 5 micrograms of Clenbuterol subcutaneously and the eyes were analyzed after 63 h of withdrawal by enzyme immunoassay. Only pigmented rat eyes showed a clear accumulation of Clenbuterol (68.1 to 81.5 ng/g), whereas the eyes of unpigmented treated rats demonstrated levels similar to the negative controls (< .27 ng/g). In the second experiment, two Holstein-Friesian calves were fed with .8 microgram of Clenbuterol/kg BW two times a day (therapeutic dose) in milk replacer and black and white hair was collected separately before, during, and after the treatment. The hair was analyzed with an enzyme immunoassay that provided blanks less than 1.0 ng/g and a mean recovery of 67%. This experiment showed an accumulation of Clenbuterol in both sets of hair, but a definitely higher accumulation of Clenbuterol in black (pigmented) hair than in white hair. The black/white quotient amounted to approximately 50 at 1 wk after treatment. Results of these experiments favor the use of the eye as well as the hair for residue analysis but in case of hair, variation of pigmentation in different animals must be considered.

Adrenergic beta-Agonists↗

PubMed1995

Expression of estrogen and androgen receptor in the bovine gastrointestinal tract.

Reproductive and maturational nutritive needs are examples for situations in which alterations in circulating concentrations of sex steroids are associated with changes in gastrointestinal function. In order to investigate whether there is a causal relationship between sex steroids and gastrointestinal function, we aimed to investigate the responsiveness for androgens and for estrogens of the bovine gastrointestinal tract. Using Northern blot analysis, estrogen receptor (ER) mRNA was detected in rumen tissue. Comparing the ER expression in rumen from females of different reproductive stages, we found that no differences related to cycle stage, pregnancy or parturition could be detected. In contrast, the ER expression rates in the uterus of the respective animals showed the same dependency of reproductive stage as demonstrated earlier for the ER protein, indicating that there might be a tissue specific regulation of ER. By in-situ hybridization of rumen tissue sections the expression of ER was localized in the epithelium of the papillae. In the muscular layer no positive signals for ER mRNA were observed. Above rumen, the presence of ER and androgen receptor (AR) mRNA was determined in various intestinal tissues using reverse transcription (RT) and polymerase chain reaction (PCR). Primers were selected from the bovine androgen and estrogen receptor sequence to amplify parts of the sequence coding for the hormone binding part of the respective receptor. The PCR amplifies were subsequently electrophoresed on 1% agarose gels and visualized by ethidium bromide staining. ER mRNA expression was demonstrated in reticulum, omasum, abomasum, duodenum, jejunum, ileum, caecum and colon. AR mRNA expression was not determined in the forestomaches, but was present in all intestinal segments investigated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

An enzyme immunoreceptor assay for the quantitation of insulin-like growth factor-I and insulin receptors in bovine muscle tissue.

To investigate the regulation of insulin-like growth factor-I (IGF-I) and insulin receptor in muscle, a sensitive enzyme immunoreceptor assay (EIRA), which allows for the determination of both affinity and capacity of the receptors, was developed. After solubilization with Triton X-100, receptors were immobilized in microtiter plates using receptor specific monoclonal antibodies that recognize the intracellular beta-domain of the respective receptors (clone 17A3 and clone 29B4). The immobilized receptors were labeled with either biotinylated IGF-I or insulin. The bound hormones were detected with a streptavidin-horseradish peroxidase technique. The assay had a detection limit of 1 fmol receptor/well. The intraassay variation was 9% (n = 22) for the IGF-I receptor concentration and 12% (n = 22) for the insulin receptor. The interassay variation was 5% (n = 4) for the IGF-I receptor and 10% (n = 4) for the insulin receptor. The coefficient of variation of the dissociation constants (Kd) was 26% (n = 7) for the IGF-I receptor and 24% (n = 7) for the insulin receptor. The assay system was used to study the effect of growth hormone treatment upon IGF-I and insulin receptors in bovine skeletal muscle. Three groups of 12 heifers (13 months old) were treated with either 320 or 640 mg recombinant bovine somatotropin (slow release preparation) every fortnight for 3 months. When samples of m. splenius were assayed for IGF-I and insulin receptors, there was no difference between groups for receptor concentration or affinity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Luteal versus placental progesterone: the situation in the cow, pig and bitch.

Placenta and corpus luteum (CL) have acquired different functions for progesterone synthesis and maintenance of pregnancy in the course of placentalia evolution. In the cow and pig, progesterone is produced by the same CL during the entire gestation period with minor or no contribution from the placenta. In the case of an infertile cycle, CL survival is terminated by PGF2 alpha produced by the endometrium. PGF2 alpha secretion is inhibited by the trophoblast in order to guarantee continuous progesterone production. Also in the dog, only the CL synthesizes progesterone and the secretion pattern is similar in pseudopregnant and pregnant animals. The dog CL seems to have an internally programmed life span.

Animals↗

PubMed1994

Predicting total weight of retail-ready lamb cuts from bioelectrical impedance measurements taken at the processing plant.

Data of sixty finished, crossbred lambs were used to develop prediction equations of total weight of retail-ready cuts (SUM). These cuts were the leg, sirloin, loin, rack, shoulder, neck, riblets, shank, and lean trim (85/15). Measurements were taken on live lambs and on both hot and cold carcasses. A four-terminal bioelectrical impedance analyzer (BIA) was used to measure resistance (Rs, ohms) and reactance (Xc, ohms). Distances between detector terminals (L, centimeters) were recorded. Carcass temperatures (T, degrees C) at time of BIA readings were also recorded. The equation predicting SUM from cold carcass measurements (n = 53, R2 = .97) was .093 + .621 x weight-.0219 x Rs + .0248 x Xc + .182 x L-.338 x T. Resistance accounted for variability in SUM over and above weight and L (P = .0016). The above equation was used to rank cold carcasses in descending order of predicted SUM. An analogous ranking was obtained from a prediction equation that used weight only (R2 = .88). These rankings were divided into five categories: top 25%, middle 50%, bottom 25%, top 50%, and bottom 50%. Within-category differences in average fat cover, yield grade, and SUM as a percentage of cold carcass weight of carcasses not placed in the same category by both prediction equations were quantified with independent t-tests. These differences were statistically significant for all categories except middle 50%. This shows that BIA located those lambs that could more efficiently contribute to SUM because a higher portion of their weight was lean.

Abattoirs↗

PubMed1994

Tissue distribution and residues of clenbuterol, salbutamol, and terbutaline in tissues of treated broiler chickens.

To examine the tissue distribution and residues after withdrawal of various beta-agonists (i.e., clenbuterol, salbutamol, and terbutaline) 160 1-d-old broiler chickens were assigned to four groups. During treatment (16 to 35 d), the birds were fed a control diet or a diet containing 1 ppm of clenbuterol, 10 ppm of salbutamol, or 10 ppm of terbutaline. After d 35 all groups received the control diet. Five birds of each group were then slaughtered and tissues were collected on d 0, 1, 2, 3, 7, 14, and 43 following withdrawal of beta-agonists from the feed. Extraction of beta-agonists from the tissues was carried out by a new method using hetero-bifunctional solid phase extraction. The amount of beta-agonists in the extracts was measured by an enzyme immunoassay (EIA). The highest concentrations of beta-agonists were found in feathers: 224 ng of clenbuterol/g, 1,140 ng of salbutamol/g, and 1,159 ng of terbutaline/g. Clenbuterol accumulated above plasma levels in all tissues that were investigated (liver, kidney, stomach, muscle, fat, feather, eye). Salbutamol was most concentrated in feather, eye, liver, and kidney; terbutaline accumulated only in feather, liver, and kidney. Overall, clenbuterol showed the highest accumulation in the tissues analyzed. A withdrawal period of greater than 2 wk was required for residues in edible tissues to decline below detectable levels.

Adipose Tissue↗

PubMed1993

Effects of the beta-adrenergic agonist clenbuterol in cows: lipid metabolism, milk production, pharmacokinetics, and residues.

The effects of the beta-adrenergic agonist clenbuterol on lipid metabolism, milk production, pharmacokinetics, and residues were studied in six lactating Brown Swiss cows. Four of these were treated with the growth-promoting dose of 5 micrograms of clenbuterol/kg of BW, mixed within the concentrate, and administered twice a day for 3 wk. The remaining two cows served as controls. All animals were in their third phase of lactation and were fed diets containing corn silage, hay, and concentrate according to individual milk production level and body weight. Milk and blood samples were collected for analysis following a rigid time schedule. Milk production and milk contents (triglycerides, protein, and lactose) were quantitatively identical in both treated and control animals, whereas significant qualitative changes occurred in the fatty acid composition of milk lipids in clenbuterol-treated animals. Compared with the controls, the relative amount (percentage of total fatty acids) of unsaturated fatty acids, particularly oleic acid (cis-delta 9-octadecaonate, 18:1), increased considerably with a simultaneous decrease of the transition chain length fatty acids (lauric acid [12:0] and myristic acid [14:0]). Plasma glucose and FFA concentrations were elevated. Concentrations of insulin-like growth factor I remained unchanged. We conclude that the physiological effect of clenbuterol is limited to the repartitioning effect in body composition, and that milk production is affected only slightly by clenbuterol. An immediate increase of clenbuterol concentrations in plasma (3.4 +/- 2.0 ng/mL) and milk (10.8 +/- 4.7 ng/mL) could be observed at the commencement of treatment. Clenbuterol concentration peaked after 10 d and remained constant until the end of the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Evidence for the presence of endogenous 19-nortestosterone in the cow peripartum and in the neonatal calf.

Urine samples were collected from five Brown Swiss cows during the 18 days prior to and 11 days after parturition and were analysed for 19-nortestosterone using an enzyme immunoassay. Nortestosterone concentrations ranged from 70 to 130 nmol/l in all samples taken before parturition. The levels declined within two days, and 11 days post partum no nortestosterone was detectable. In urine from newborn calves, maximal nortestosterone concentrations were determined during the first day of life (10.9-120 nmol/l), declining below 7.3 nmol/l until day 3 in most animals and remaining below the detection limit (less than 3.6 nmol/l) after day 8 in all animals. There was no obvious difference between cows carrying a male or a female calf nor between newborn male or female calves. Using the combined methods high performance liquid chromatography/enzyme immunoassay and high performance liquid chromatography/gas chromatography-mass spectrometry, the immunoreactivity in urine was identified to be 19-nortestosterone-17 alpha. Although there is unequivocal evidence for the endogenous production of nortestosterone in pregnant cows, its function for placenta physiology, pregnancy anabolism and parturition remains unclear. However, new threshold levels for residue control of nortestosterone need to be fixed in accordance with the endocrine status of the animals.

Animals↗

PubMed1992

Binding and action of insulin-like growth factors and insulin in bovine luteal tissue during the oestrous cycle.

The effect of insulin-like growth factors (IGFs) and insulin on the release of progesterone and oxytocin from bovine corpus luteum was investigated at early (days 5-7), mid- (days 8-12) and late (days 15-18) luteal phases of the oestrous cycle in an in vitro microdialysis system. The expression of specific receptors was evaluated in bovine corpora lutea of the respective luteal stages. A 30 min infusion of IGF-1, IGF-2 (1.3, 13 and 130 nmol l-1) or insulin (13, 130 and 1300 nmol l-1) caused a stimulation of the release of progesterone (P < 0.05). IGF-1 was most effective in releasing progesterone. Oxytocin release from corpora lutea was stimulated by insulin at all doses tested (13-1300 nmol l-1), whereas the IGFs were only effective at the highest dose (130 nmol l-1) applied. The high doses of IGFs (130 nmol l-1) and insulin (1300 nmol l-1) stimulated the release of progesterone and oxytocin throughout the luteal phase (P < 0.05). For all three peptides, greatest stimulation was seen during the late luteal phase (days 15-18 of the oestrous cycle) with the peak of progesterone release directly related to peptide infusion (P < 0.05). In addition, IGF-1 stimulated total release of progesterone (units in 4 h) after the beginning of the stimulation during this phase (P < 0.05). IGF-1 caused a gradual increase of progesterone even beyond the time of peptide perfusion, whereas IGF-2 and insulin stimulated progesterone release only during the peptide perfusion. Distinct receptors for IGF-1 and IGF-2 were present in corpora lutea membrane preparations at all stages investigated. Specific binding for insulin was also seen in all stages of the cycle without any cycle-dependent changes in the amount of binding. The displacement of labelled insulin by unlabelled IGF-1 and IGF-2 did not show the rank of order that has been described as typical for insulin receptors (i.e. insulin > IGF-1 > IGF-2), but comparable binding affinities were observed for the three unlabelled ligands. Specific binding of IGF-2 was markedly higher than that of IGF-1 or insulin throughout the cycle (1.9- and 4.9-fold higher compared with IGF-1 and insulin, respectively). Receptor specificity did not change during luteal development. Binding affinity and capacity of IGF-1 receptor was constant throughout the oestrous cycle. Specific IGF-2 binding increased and showed a positive co-operativity towards the end of the cycle. Specific binding of insulin was not significantly different in the three luteal stages examined.

Animals↗

PubMed1992

Performance of Polypay, Coopworth, and crossbred ewes: I. Reproduction and lamb production.

Six ewe genotypes, generated by mating Coopworth (C), Polypay (P), and Suffolk (S) rams to Polypay and Coopworth-type (Ct) ewes, were exposed to Hampshire rams for spring lambing from 1986 through 1990. Data from 1,092 exposures and 1,044 resultant lambings were used to analyze reproductive traits and lamb growth rates. Overall conception rate averaged 95% and ranged from 93% for S x Ct ewes to 97% for P x Ct ewes. Mean litter size at birth averaged 1.63 and ranged from 1.45 for C x C ewes to 1.75 for S x P ewes. Ewes from P dams had higher mean litter size (P less than .01) than those from Ct dams (1.73 vs 1.54), but differences between sire breeds were not significant. Incidence of lambing assistance was similar for ewes producing single or multiple lambs. Lamb birth weight influenced the level of assistance rendered to single-bearing but not to multiple-bearing ewes. Lambing assistance was not related to lamb survival, probably because the high surveillance level minimized trauma before assistance was rendered. Incidence of required assistance declined over subsequent parities. Lamb birth weights were affected by ewe genotype and increased with increasing ewe age. Survival of single-born lambs averaged 94% and was not affected by dam genotype. Survival of twins averaged 85%, ranging from 79% for lambs from S x Ct ewes to 89% for lambs from P x P ewes. Suffolk-sired ewes produced the heaviest mean birth and weaning weights for both singles and twins. Coopworth-sired ewes weaned heavier single lambs but lighter twins than P-sired ewes.

Age Factors↗

PubMed1992

Performance of Polypay, Coopworth, and crossbred ewes: II. Survival and cumulative lamb and wool production over 4 years.

Six ewe genotypes, generated by mating Coopworth (C), Polypay (P), and Suffolk (S) rams to P and Coopworth-type (Ct) ewes, were exposed to Hampshire rams for spring lambing from 1987 through 1990. Data from 1,013 exposures and 973 resultant lambings were used to analyze reproductive traits and cumulative ewe productivity over 4 yr. Ewe body and fleece weights were also analyzed. Ewes from S sires weaned the heaviest lambs and ewes from P sires weaned the largest number of lambs, resulting in similar total weight of lamb weaned per ewe mated. Coopworth-sired ewes weaned the least total weight of lamb per ewe mated. Ewes weaning twins produced 54% more total litter weight per ewe than those weaning singles. Annual ewe survival averaged 95%, ranging from 93% for S x P and C x P ewes to 97% for P x Ct and C x Ct ewes. When cumulative number and weight of lamb produced was assessed on the basis of all ewes starting the trial, P-sired ewes were highest, followed in order by daughters of S and C sires. Suffolk-sired ewes (67 kg) were 13% heavier than daughters of P rams and 19% heavier than daughters of C rams. Adjustment of lamb production for ewe metabolic body size resulted in C-sired ewes being more efficient than the heavier S-sired ewes. Coopworth-sired ewes produced 32% more wool than ewes sired by the other two breeds. Differences in wool production between ewes weaning one or two lambs were small.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

[Advice on the x-ray positioning of the upper and the lower leg].

Roentgenographic images of the femur and tibia to demonstrate the bones in two true right-angled projections (anteroposterior, lateral view) can be obtained by using a small hydrostatic level with two levels positioned at right angles against each other. By taping the small plastic device to the skin of the leg under examination, rotation of the limb between the two x-ray exposures can be controlled and adjusted to exactly 90 degrees. Compared to other common positioning procedures (rotation of the leg to approximately 90 degrees by the patient; angulation of the x-ray tube to 90 degrees around the leg) this method yields the highest accuracy of adjustment.

Femur↗

PubMed1992

Use of enzyme immunoassay and reverse-phase high-performance liquid chromatography to detect and confirm identity of dexamethasone in equine blood.

An enzyme immunoassay (EIA) was developed for detection of dexamethasone in equine blood. Dexamethasone 21-hemisuccinate-bovine serum albumin was used for immunization of rabbits, and prednisolone 21-hemisuccinate-horseradish peroxidase was used as enzyme conjugate. The assay had sensitivity in the low-picogram range (detection limit, 0.3 pg/well, 50% inhibition of binding at 4.5 +/- 0.7 pg/well). Apart from cortisol, which was recognized by the antiserum at concentration > 8.5 ng/ml, the dexamethasone antiserum failed to interfere with endogenous steroids, but cross-reacted with triamcinolone, flumethasone, and betamethasone. Thus, the antiserum was used to perform simultaneous screening for these synthetic glucocorticoids and to confirm their identity by combining reverse-phase high-performance liquid chromatography (RP-HPLC) and EIA. The immunoreactivity obtained by direct serum measurements was characterized by means of 2 independent RP-HPLC systems. Serum extracts were submitted to RP-HPLC systems I and II, and the fractions were tested by EIA. Immunoreactive peaks were identified by comparing their retention time with that of the standard glucocorticoids used for calibration. Coinjection of an internal standard (methylprednisolone) in RP-HPLC system II yielded reproducible relative retention times. The effectiveness of the test system was evaluated, using blood from a horse treated with commonly used veterinary preparations of dexamethasone. Administration of the free alcohol of dexamethasone and of dexamethasone 21-trioxaundecanoate, both given IV, was detected, and the identity of each was confirmed for up to 48 hours. Intramuscular administration of dexamethasone 21-isonicotinate was continued for at least 14 days after injection of a therapeutic dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Residue screening for the beta-agonists clenbuterol, salbutamol and cimaterol in urine using enzyme immunoassay and high-performance liquid chromatography.

The antibody for enzyme immunoassay was raised against clenbuterol-diazo-BSA, and salbutamol-carboxymethyl ether-biocytin was used as a label. Procedural blanks from 500 negative urine samples were always less than 0.2 ppb salbutamol or less than 0.02 ppb clenbuterol equivalents, and a residue level of 1 ppb was detected with good reliability. After treatment of veal calves with anabolic dosages, residue levels in urine amounted to 10-200 ppb clenbuterol or salbutamol. beta-Agonists were separated by high-performance liquid chromatography on LiChrospher RP-Select B columns, and acidic methanol-buffer or acetonitrile-buffer mobile phases. Combinations of high-performance liquid chromatography and enzyme immunoassay were used for confirmation.

Adrenergic beta-Agonists↗

PubMed1991

Quantitation of glucocorticoid receptors in bovine skeletal muscle: topographical distribution, sex effect and breed comparisons.

The concentration of the cytosolic glucocorticoid receptor (GR) was determined in skeletal muscles of calves in order to study possible differences in individual muscles from different parts of the body as well as the influence of sex and breed. In male and female Simmental calves the topographical distribution of GR was similar: the lowest concentrations were seen in abdominal muscle, whereas in neck, shoulder and hindleg the GR concentrations were higher; this difference was more pronounced in male than in female calves. In general, female calves had about 2-fold higher GR concentrations than males. The cytosolic cortisol concentrations were differing neither between individual muscles nor between sexes. The cortisol secretion during a 24-h sampling period 1 week prior to slaughter showed no sex difference. GR concentrations in neck muscle of female calves of four different German cattle breeds (Holstein Friesian, Brown Swiss, Simmental and German Gelbvieh) were rather similar; however, when Brown Swiss with the highest GR levels were compared to Holstein Friesian calves with the lowest concentrations, a significant difference was evident (P less than 0.05).

Animals↗

PubMed1991

Effects of genotype and mating weight on ovulation rate, litter size, and uterine efficiency of Coopworth, Polypay, and crossbred ewes.

Six genotypes were produced by mating Coopworth (C), Polypay (P), and Suffolk (S) rams to Coopworth-type and Polypay ewes. In 1989, BW and ovulation rate (OR) were recorded for 188 naturally ovulating 5- and 6-yr-old ewes representing all six genotypes, and litter size (LS) was recorded for 174 ewes (93%) lambing to the ovulation observed by laparoscopy. Overall OR and LS averaged 1.85 and 1.71, respectively. Mean OR and LS did not differ (P greater than .40) among daughters of the various sire breeds; however, daughters of Polypay dams exhibited both higher OR (P less than .05) and LS (P less than .01) than daughters of Coopworth-type ewes. Heterosis estimates for OR and LS were 6 and 7%, respectively. Overall uterine efficiency (UE) of ewes conceiving to twin ovulations was .83. Polypay-derived ewes exhibited higher UE than other genotypes (P less than .05). Premating BW had significant but small effects on both OR and LS. Overall estimates of OR and LS response to a 10% increase in BW were 5 and 3%, respectively. Only Polypay-sired ewes showed a significant relationship between BW and reproductive performance; the estimated responses to a 10% BW increase were 9% for OR and 6% for LS. Variation in BW had no effect on UE of ewes conceiving to twin ovulations (P greater than .50).

Analysis of Variance↗