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The objective of this study was to evaluate the effects of dried distillers grains with solubles (DDGS) on ram lamb feedlot performance, carcass characteristics, serum testosterone concentration, and semen quality. One hundred twenty ram lambs (40.4 ± 9.1 kg; Suffolk × western white face) were used in a completely randomized design to determine the effects of DDGS on feedlot performance and carcass characteristics. Rams were allotted into one of three dietary treatments (n = 4 pens/treatment; 10 rams/pen): 1) 0DDGS: 85% corn and 15% commercial market lamb pellet, 2) 15DDGS: 15% DDGS substituted for corn (DM basis), and 3) 30DDGS: 30% DDGS substituted for corn (DM basis). Rams were weighed on consecutive days at the beginning (d 0 and 1) and end (d 96 and 97 and d 116 and 117) of the trial. Scrotal circumference was measured on all rams on d 84, 96, and 116. Semen and blood samples were collected on a subset of 48 rams (4 rams/pen; 16 rams/treatment; n = 4) to evaluate semen quality. Blood samples were collected every 14 d throughout the study. Semen samples were collected on d 84, 98, and 112. Rams were fed to market weight, shipped to a commercial abattoir, and harvested for carcass data collection. Initial BW, final BW, change in scrotal circumference, days on feed, carcass characteristics, serum testosterone concentrations, and spermatozoa motility score were not different (P ≥ 0.23) due to dietary treatment. However, DMI increased linearly (P0.001) as DDGS increased in the ration, resulting in a linear increase (P = 0.02) in ADG. Additionally, spermatozoa concentration decreased linearly (P = 0.05) as DDGS concentration increased in the ration. Increasing DDGS in the diet did not have a negative impact on ram feedlot performance or carcass characteristics; however, spermatozoa production may have been negatively affected, necessitating the need for additional research on the impact of DDGS on ram development.

Twenty-six of 52 heifers with an average liveweight of 318 kg were dewormed by intraruminal injection of oxfendazole and placed in drylot on 31 January. The other 26 animals served as controls. All heifers were pastured starting on 14 June and the treatment heifers were dewormed in the same manner as at the start of the experiment (31 January) on 1 July and 31 July. The groups started out with similar total worm eggs per gram of fecal sample, but the dewormed heifers had fewer counts each month thereafter. The drylot average daily gain of the treated heifers was higher (P = 0.01) and less variable (P = 0.12) and by 29 May these animals were heavier by 11.7 kg (P = 0.10). The treated animals did not gain as fast on pasture (P = 0.20), but the gain continued to be less variable (P = 0.09). Age at puberty was not different. Number of open heifers in the treated group was 4 vs. 15% for the control group (P = 0.18). Deworming by intraruminal injection resulted in faster feedlot gains, more uniform gains during both drylot and pasture, reduced parasites and no abscess at injection sites. Key words: Anthelmintics, oxfendazole, cattle, heifers

Nutrition has been shown to influence several reproductive functions, including hormone production, oocyte competence and fertilization, and early embryonic development. To determine the effects of maternal diet on in vitro fertilization (IVF) and early embryonic development, ewes (n = 18; 47.0 +/- 1.5 kg of initial BW) were divided into control and underfed (60% of control) nutritional planes for 8 wk before oocyte collection. Pelleted diets containing 2.4 Mcal of ME/kg and 13% CP (DM basis) were fed once daily. During the first 4-wk acclimation phase, control and underfed ewes were fed 1,000 and 600 g/d, respectively. From wk 4 to 8, control (adequate) ewes were fed to maintain BW and offered 720 g/d, whereas underfed ewes received 432 g/d (60% restricted). Synchronization of estrus was performed using progestagen sponges for 14 d. Follicular development was induced by twice daily injections of FSH on d 13 (5 units/injection) and 14 (4 units/injection) of the estrous cycle. Oocytes were collected from all visible follicles on d 15 of the estrous cycle. After IVF, the proportion of developing embryos was evaluated throughout an 8-d culture period. Under-nutrition decreased (P0.006) the rate of cleavage, number of blastocysts per ewe, and rate of blastocyst formation (from 79 to 64%; from 3.3 to 0.8; and from 31 to 8%, respectively). However, the number of visible follicles, total number of oocytes, number of healthy oocytes, percentage of healthy oocytes, number of cleaved oocytes, and morula formation per ewe were similar for control and underfed ewes. These data indicate that undernutrition of donor ewes, resulting in lower BW and BCS, has a negative effect on oocyte quality, which results in lower rates of cleavage and blastocyst formation.

Uterine expression of angiogenic factors (vascular endothelial growth factor [VEGF] and basic fibroblast growth factor [bFGF]) was evaluated in ovariectomized ewes at 0, 2, 4, 8, 24, 48, or 72 h after estradiol (E2) treatment. Endometrial VEGF mRNA increased more than 5-fold from 0 to 4 h, remained elevated at 8 h, and then declined through 72 h after E2 treatment. In contrast, endometrial bFGF mRNA remained constant from 0 to 4 h, increased 2.2-fold from 4 to 8 h, remained elevated at 24 h, and then declined through 72 h. Immunostaining for VEGF was present in myometrial and endometrial microvessels (arterioles, venules, and/or capillaries) and also in myometrial smooth muscle; the pattern of VEGF immunostaining followed that of mRNA expression, being elevated at 4 and 8 h after E2 treatment. Immunostaining for bFGF was present exclusively in uterine glands; the pattern of bFGF immunostaining also followed that of its mRNA, being elevated at 8 and 24 h after E2. On the basis of these observations, we suggest that VEGF and bFGF are probably important factors responsible for the dramatic uterine microvascular response that occurs 8 to 24 h after E2 treatment in ovariectomized ewes.

The time-course of uterine growth, cell proliferation, and microvascular development was evaluated during the first 72 h after implanting estradiol-17beta (E2) into ovariectomized (OVX) ewes. Uterine fresh weight increased 2.3-fold by 24 h and increased further (3.3-fold) by 48 h. The majority (approximately 75%) of this growth response was associated with tissue growth rather than a change in the tissue dry weight:fresh weight ratio. Both uterine cell number (DNA content) and cell size (RNA:DNA ratio) increased from 0 to 24 h (1.8-fold and 1.7-fold, respectively). Cell proliferation also increased dramatically between 8 h and 24 h after E2 implantation. Endometrial microvascular volume density (percentage of tissue volume occupied by microvessels) increased approximately 1.8-fold by 24 h and then remained constant or declined slightly through 72 h. The total endometrial microvascular volume, however, increased approximately 5-fold from 0 to 24 h and increased further by 72 h. Thus, treatment of OVX ewes with E2 caused a dramatic increase in uterine fresh and dry weights by 24 h, due primarily to hyperplasia and hypertrophy, with only a relatively small change in tissue dry weight:fresh weight ratio. This dramatic uterine growth was associated with a profound increase in endometrial microvascular volume.

Cellular interactions mediated by both contact-dependent and contact-independent mechanisms are probably important to maintain luteal function. The objective of the present study was to evaluate the role of cAMP in regulation of contact-dependent gap junctional intercellular communication (GJIC) of bovine luteal cells from several stages of luteal development. In experiment 1, corpora lutea (n = 5) from the mid-luteal phase of the estrous cycle were dissociated with collagenase, and cells were preincubated in a medium with serum. Then the medium was changed to serum-free media containing a cAMP agonist (dbcAMP; 1 mM) or antagonist (Rp-cAMPS; 0, 3, 10, 30, or 100 microM). In experiment 2, corpora lutea from the early (n = 7), mid- (n = 6), and late (n = 6) luteal phases of the estrous cycle were dissociated and preincubated as in experiment 1, and luteal cells were then incubated with no treatment, LH (100 ng/ml), dbcAMP (1 mM), forskolin (1 microM), Rp-cAMPS (100 microM), or LH+Rp-cAMPS. After incubation of luteal cells with treatments for 18-24 h, media were collected for determination of progesterone and cAMP concentrations. Then the rate of GJIC was evaluated for selected cells (small luteal cells in contact with small luteal cells, and large luteal cells in contact with small luteal cells) by using the fluorescence recovery after photo-bleaching technique and laser cytometry. In experiment 1, dbcAMP increased (p0.01) but Rp-cAMPS (p0.05) decreased GJIC between small luteal cells and between large and small luteal cells. In addition, dbcAMP stimulated (p0.01) but Rp-cAMPS did not affect progesterone secretion. In experiment 2, treatments affected (p0.05) GJIC and progesterone production of luteal cells from the mid- and late but not from the early luteal phase of the estrous cycle. GJIC between small luteal cells was increased (p0.01) by LH, dbcAMP, and forskolin. GJIC between large and small luteal cells was increased (p0.05) by dbcAMP and forskolin. Rp-cAMPS decreased (p0.01) GJIC between small luteal cells (mid-luteal phase) and between large and small luteal cells (mid- and late luteal phases). In addition, Rp-cAMPS inhibited (p0.05) the stimulatory effects of LH on GJIC between small luteal cells from the mid- and late luteal phases of the estrous cycle. For luteal cells from the mid- and late luteal phases, progesterone production was increased (p0.05) by LH, dbcAMP, forskolin, and LH+Rp-cAMPS, but was not affected by Rp-cAMPS. Across all stages of the estrous cycle, cyclic AMP accumulation in media was greater (p0.05) in LH- and forskolin-treated cultures than in control cultures and was greater (p0.01) in forskolin-treated than in LH-treated cultures. These data demonstrate that small and large luteal cells communicate with each other and that the rate of GJIC is modulated by LH and cAMP, as has been shown previously for other cell types. Thus, cAMP appears to be involved in the regulation of GJIC within the bovine corpus luteum, which probably is an important mechanism for coordinating luteal cell function.

The purpose of this study was to investigate the potential of near-infrared (near-IR) spectroscopy for non-destructive at-line determination of the amount of polymer coat applied to tablet cores in a Wurster column.The effects of coating composition on the near-IR spectroscopic determination of ethylcellulose (Aquacoat ECD-30) or hydroxypropylmethylcellulose (HPMC)-based (Spectrablend) coating were evaluated, as were the performance of several chemometric techniques.Tablets were coated with up to 30% ethylcellulose or 22% HPMC, and samples were pulled at regular intervals during each coating run. Near-IR reflectance spectra of the intact tablets were then collected. The spectra were preprocessed by multiplicative scatter correction (MSC) or second derivative (D2) calculations, and calibrations developed using either principal components (PCs) or multiple spectral wavelengths. The near-IR method provided predictions of film applied with standard errors of 1.07% w/w or less.Near-IR spectroscopy can be profitably employed in a rapid and non-destructive determination of the amount of polymer film applied to tablets, and offers a simple means to monitor the film coating process.

Weight of placental tissues of cows increased exponentially from Day 100 to Day 250 of gestation, but at much slower relative and absolute rates than fetal weight. In addition, growth rate of fetal placental tissues was less than that of maternal placental tissues. Concentrations of DNA, RNA and protein, however, increased in fetal placental but not in maternal placental tissues. Fetal placental tissues therefore exhibited hyperplasia, which probably contributes to increased functional capacity of the placenta during late gestation. The rate of O2 uptake in vitro was greatest for maternal placental tissues, suggesting that the maternal portion of the placenta accounts for most of the large rate of placental O2 utilization in vivo. Compared with other placental tissues, rate of secretion of macromolecules by intercaruncular endometrium was high, but decreased from Day 100 to 250, suggesting that uterine glandular secretory activity may decrease as gestation advances. Rate of secretion of macromolecules also was high for intercotyledonary tissues and increased with day of gestation, suggesting a role for secretory products of chorioallantois in gravid uterine function.

Samples from corpus haemorrhagicum, mid-cycle corpus luteum (CL) and late-cycle CL were tested for their abilities to stimulate neovascularization of chorioallantoic membranes (CAM) of developing chicks. Responses were graded from 0 to 4 (4 being the greatest response). Luteal tissue implants from each stage of the oestrous cycle stimulated growth of CAM blood vessels, and vascular responses increased with age of CL. Implants from late-cycle CL were typically graded 3 or 4. Luteal tissues from several stages of development were also incubated for 6 h in serum-free medium containing no hormone, LH, PGF-2 alpha or both hormones. Media conditioned by luteal tissues were assayed for progesterone and tested for their ability to stimulate mitogenesis and migration of bovine aortic endothelial cells in vitro. All media conditioned by luteal tissues stimulated mitogenesis and migration of endothelial cells, but media from late-cycle CL exhibited the greatest activity. Luteinizing hormone significantly increased in-vitro secretion of a factor(s) that stimulated migration of endothelial cells. PGF-2 alpha alone had no effect on production of endothelial cell mitogen or migration-stimulating factor(s) from luteal incubations; however, the ability of LH to enhance secretion of the migration-stimulating factor(s) was blocked by PGF-2 alpha. This study demonstrates that angiogenic activity of bovine luteal tissues increases with age of the CL and in-vitro secretion of angiogenic factor is responsive to hormones known to regulate luteal function.

In Study 1, explants of caruncular and intercaruncular endometrium and fetal membrane were collected from ewes (5-6/day) on Days 11-13, 16-18 and 21-23 after mating and Days 10-12 after oestrus, and incubated for 24 h. Explant-conditioned media were evaluated for their effects on endothelial cell proliferation. Both caruncular and intercaruncular endometrium secreted factor(s) which stimulated endothelial cell proliferation, and which appeared to be greater than 100 x 10(3) Mr and heat-labile. In Study 2, conditioned media from explant incubations of caruncular and intercaruncular endometrium, cotyledon and intercotyledonary fetal membrane obtained from ewes (6-7/day) on Days 40, 65, 90, 115 and 140 after mating were evaluated for their effects on endothelial cell proliferation. Caruncular and intercaruncular endometrium and intercotyledonary fetal membrane secreted factor(s) which inhibited endothelial cell proliferation. Media from cotyledonary explants tended to stimulate endothelial cell proliferation on Day 115. Conditioned media from cotyledonary explants obtained from 3 additional ewes at Day 120 of gestation stimulated endothelial cell proliferation, and this activity also appeared to be greater than 100 x 10(3) Mr. Placental angiogenesis in ewes therefore appears to be modulated by both maternal and fetal placental tissues via stimulatory and inhibitory factors.

The objective of the following study was to examine the ability of frequent milking, the physical presence of the calf, and their combination to prevent a postweaning rise in tonic luteinizing hormone (LH) secretion, estrus, and ovulation. Thirty Hereford cows were allowed to suckle their calves ad libitum until 17-21 days post partum and confirmed as anestrus. They were then assigned alternately by order of calving to 1 of 5 treatment groups: (1) Suckled (S) ad libitum; (2) Nonsuckled (NS)--calf removed for 102 h; (3) Nonsuckled--calf present (NSC)--calf remained with cow, but muzzled to prevent suckling for 102 h; (4) Nonsuckled--milked 8 times a day (NSM)--calf removed for 102 h and cow hand-milked for 10 min every 2 h from 0700 to 2100 h; (5) Nonsuckled--calf present--milked 8 times a day (NSMC)--combination of 3 and 4. Luteinizing hormone secretion patterns, estrous activity, and ovulation were monitored throughout the experiment. Prior to treatment (Day 0), mean pulse frequency (pulses/6 h), mean concentrations (ng/ml), and median concentrations (ng/ml) of LH did not differ (p greater than 0.45) between groups, and were 0.7 +/- 0.15, 2.8 +/- 0.14, and 2.6 +/- 0.11, respectively. Marked rises (p less than 0.01--p less than 0.03) in LH pulse frequency were observed in all groups except S between 48 and 54 h after onset of treatment. Mean and median concentrations of LH were lower (p less than 0.02) in S cows than in all other groups at 48-54 h.(ABSTRACT TRUNCATED AT 250 WORDS)

In Exp. 1, maternal (caruncle) and fetal (cotyledon) portions of the placenta as well as uterine endometrium were obtained from cows at mid-gestation and evaluated for angiogenic activity by placing tissue samples on chick chorioallantoic membranes (CAM). Only caruncular tissues exhibited angiogenic activity in the CAM assay. In Exp. 2, lyophilized homogenates of caruncular tissues obtained from cows at mid-gestation were evaluated for angiogenic activity on CAM and for their ability to stimulate mitosis of bovine aortic endothelial cells in vitro. Homogenates of caruncular tissues again were angiogenic on the CAM and also were mitogenic for endothelial cells. In Exp. 3, maternal (caruncle and endometrium) and fetal (cotyledon and fetal membrane) portions of the placenta were obtained from cows at mid-gestation and fine minces (explants) of each were cultured for 24 h. Explant-conditioned media were then tested for angiogenic activity by their abilities to stimulate mitosis and migration of bovine aortic endothelial cells in vitro. Conditioned media from caruncular explants, but not from explants of other tissues, exhibited both mitogenic and migration-stimulating activities. When pools of caruncular explant-conditioned media were fractionated by ultrafiltration, mitogenic activity was not present in fractions of Mr less than 10,000, less than 30,000 and less than 100,000, but was retained in fractions of Mr greater than 10,000, greater than 30,000 and greater than 100,000. Mitogenic activity was not observed in any fractions subjected to heat treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

In conjunction with the tremendous physiological changes that occur in the corpus luteum (CL) during the estrous cycle are equally dynamic intrinsic vascular changes (Bassett, 1943). Since the CL receives one of the greatest rates of blood flow of any organ (Bruce and Moore, 1976; Ford et al., 1982), factors that regulate luteal angiogenic processes may be important determinants of subsequent luteal function.

The current experiment was conducted with beef cows during the first 2 weeks postpartum (PP) to determine the effects of suckling and low-level increases of systemic progesterone on secretory characteristics of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in peripheral plasma. Variables measured included mean gonadotropin concentrations, FSH/LH pulse frequencies, pulse amplitudes and synchrony of coincident release. Suckled (S) cows had lower (P less than 0.01-P less than 0.05) mean concentrations of FSH and LH in plasma, lower (P less than .05) FSH and LH pulse frequencies and a lower (P less than 0.05) pulse synchrony (21.6 vs 72.3% coincident pulses) than nonsuckled (NS) cows on Day 7 PP. Neither FSH nor LH pulse amplitude was affected by suckling. Similar differences existed for mean gonadotropin concentrations, pulse frequencies and pulse synchrony on Day 14 PP between S and NS cows. Implanting cows with progesterone implants on Day 7 PP, which chronically increased plasma progesterone to 0.5-0.6 ng/ml, increased (P less than 0.05) mean plasma FSH and LH concentrations, FSH and LH pulse frequencies and pulse synchrony (87.5 vs. 66.3%) in NS-implanted (NSI) versus NS-nonimplanted (NSNI) cows. Progesterone implants had no beneficial effect in S cows. Thus, three major findings seem pertinent: 1) associated with the suckling-induced depression of episodic gonadotropin release was a marked decline in FSH/LH pulse synchrony; 2) a high degree of FSH/LH pulse synchrony (72-88%) was restored in the absence of suckling when gonadotropin pulse frequency increased to 4-5/6 h; 3) the absence of suckling, followed by the provision of low-level progesterone stimulation for 7 days, appeared to have additive effects on FSH and LH secretion. These results provide evidence that the neuroendocrine block associated with suckling in early PP beef cows is, in addition to being associated with depressed LH release, comprised of characteristic anomalies in FSH secretion, FSH/LH pulse synchrony and failure to respond to a putative hypothalamo-hypophyseal potentiator, progesterone.