Pre-synchronization of ovulation timing and delayed fixed-time artificial insemination increases pregnancy rates when sex-sorted semen is used for insemination of heifers.

This study was conducted to determine effects of pre-synchronization of ovulation timing among heifers and delayed fixed-time artificial insemination (TAI) with sex-sorted semen on proportion of heifers pregnant after TAI (PR/AI). Heifers were assigned to one of eight treatments: 1 and 2), 7-d CO-Synch + CIDR treatment regimen with administration of gonadotropin-releasing hormone and a CIDR insert on Day 0, prostaglandin F2α (PGF) at CIDR removal on Day 7, and TAI occurring 54 h later with conventionally processed (CTRL54-CNV) or sex-sorted semen (CTRL54-SEX); 3 and 4), same as CTRL54 but TAI delayed to 72 h with conventionally processed (CTRL72-CNV) or sex-sorted semen (CTRL72-SEX); 5 and 6), same as CTRL54 but additional administration of PGF on Day -7 and TAI with conventionally processed (PRE54-CNV) or sex-sorted semen (PRE54-SEX); 7 and 8), same as PRE54 treatments but TAI delayed to 72 h with conventionally processed (PRE72-CNV) or sex-sorted semen (PRE72-SEX). Proportion of heifers pregnant after TAI was greater (P ≤  0.02) with conventionally processed semen compared with sex-sorted semen, yet PR/AI did not differ (P =  0.14) between heifers in PRE72-CNV and PRE72-SEX groups. There were greater PR/AI in the PRE72-SEX (P =  0.03) than CTRL54-SEX group (46.1 % and 36.9 %) and there was no difference (P =  0.31) in PR/AI between CTRL54-CNV and PRE72-SEX groups (50.4 % and 46.1 %). In conclusion, pre-synchronization of ovulation timing among heifers combined with delayed TAI resulted in increased PR/AI with sex-sorted semen compared with the 7-d CO-Synch+CIDR treatment regimen.

Effect of castration method and analgesia on inflammation, behavior, growth performance, and carcass traits in feedlot cattle.

Our objective was to determine the effect of castration timing, method, and use of the analgesic meloxicam (MEL) on inflammation, behavior, performance, and carcass traits in feedlot cattle. This study was a randomized complete block design conducted over a 3-yr period. In total, 194 crossbred beef calves from a single ranch origin were randomized at birth to receive one of five treatments arranged as a 2 × 2 + 1 factorial: 1) bulls castrated within 48 h of birth (CON), 2) bulls surgically castrated on day 0 without MEL (SUR), 3) bulls surgically castrated on day 0 with MEL (SUR + MEL), 4) bulls band castrated on d 0 without MEL (BAN), and 5) bulls band castrated on day 0 with MEL (BAN + MEL). Upon feedlot arrival (day -11; average 287 ± 2.03 d of age), animals were blocked by initial BW (224 ± 4.5 kg) and assigned randomly to treatment pens in three consecutive years (n = 2 pens per treatment in each year). Oral MEL was administered at 1 mg/kg BW concurrent with applicable castration treatment on day 0. Data were analyzed using the MIXED and GLIMMIX procedures of SAS with pen (year) serving as experimental unit. From days 0 to 7, ADG was reduced (P = 0.01) for surgical (-0.42) compared to band (0.43 kg/d) castration. Conversely, ADG was increased for surgical (1.74) vs. band (1.46 kg/d) castration from days 14 to 32. There was also an overall (day 0 to final) improvement in ADG for MEL (P = 0.02), but no effect of castration method was observed (P = 0.81). The CON group had the greatest (P = 0.05) marbling score. Backfat thickness was increased (P = 0.01) for MEL. A treatment × day interaction (P = 0.04) existed for serum haptoglobin, with SUR having the greatest (P < 0.01) concentration on days 1 and 4. Meloxicam administered in the surgically castrated treatment reduced (P = 0.01) serum haptoglobin concentration on day 1. Relative to baseline, standing duration for surgical castration was increased 113 min (P < 0.01), while banding caused 6.7 more lying bouts (P < 0.01) immediately following castration on day 0. Step count was greatest for BAN, intermediate for CON, and least for surgical (P < 0.01). Results suggest that MEL mitigated the more pronounced inflammation observed for surgical castration, whereas behavior was differentially altered for castration method indicative of a divergent pain response. Castration, regardless of method, transiently reduced ADG, but MEL administration improved overall ADG for both methods.

Feeding distillers' grains, soybean hulls, or a mixture of both to cows as a forage replacement: Effects on intake, digestibility, and ruminal fermentation characteristics.

Coproduct feedstuffs offer a unique and potentially profitable avenue for cattle feeding strategies. However, research is lacking in the evaluation of varying coproducts on ruminal fermentation and digestive characteristics when included as the major component of the diet of cows. Our objective was to determine the effect of coproduct feedstuffs as a forage replacement on digestive and fermentative characteristics of cows. Eight ruminally fistulated cows (672 ± 32.0 kg initial BW and approximately 9 yr of age) were stratified by BW and randomly allocated to 1 of 4 diets (2 cows∙diet∙period) in a 2-period study: soybean hulls (SH), distillers' dried grains with solubles (DG), an isoenergetic mixture of soybean hulls and distillers' dried grains with solubles (MX), or ad libitum hay plus 0.9 kg/d of an isoenergetic mixture of soybean hulls and distillers' dried grains with solubles (HY). Diets were formulated to meet the ME requirements of a similar, companion study. Coproduct amounts were increased over a 14-d period. This was followed by a 14-d adaptation to diet and facilities and 5 d of total fecal collections. On the final day of fecal collections, rumen fluid was sampled immediately prior to feeding and 2, 4, 6, 8, 10 and 12 h after feeding for measurement of rumen VFA and ammonia concentrations. Intake of DM and OM was not different ( ≥ 0.28) among treatments, but digestibilities of DM, OM, NDF, and ADF were improved ( < 0.05) by coproduct feeding and by MX vs. the mean of SH and DG. Ruminal DM and OM fill were greater ( < 0.05) for cows offered HY than for cows offered the coproduct diets, greater for cows offered SH than for cows offered DG, and for the mean of SH and DG vs. MX. Ruminal retention time was greater ( < 0.05) for HY vs. the coproduct diets and for SH vs. DG. Apparent N absorption tended ( < 0.10) to be greater for cows offered the coproduct diets than for cows offered HY and greater for cows offered DG than for cows offered SH. Total VFA averaged across sampling times were greatest ( < 0.05) for cows offered SH, and ruminal ammonia N was greatest ( < 0.05) for cows offered either DG or MX at all sampling times. Based on these data, coproduct feedstuffs may be fed to meet the energy requirement of cows without negative effects on digestion or ruminal fermentation.

Technical note: Digital quantification of eye pigmentation of cattle with white faces.

Cancer of the eye in cattle with white faces occurs less frequently in cattle with pigmented eyelids. Corneoscleral pigmentation is related to eyelid pigmentation and occurrence of lesions that may precede cancer. Objectives of this study were to assess 1) variation in the proportion of eyelid and corneoscleral pigmentation in Hereford, Bos taurus, and Bos indicus crossbreds and 2) the occurrence of lesions with the presence of pigmentation in those areas. Hereford and Bos indicus crosses (Brahman or Nellore with Angus and Hereford and straightbred Brafords) and Bos taurus crosses (Angus-Hereford) were included in the study (n = 1,083). Eyelid pigmentation proportions were estimated by pixel quantification and were evaluated as total proportions and for upper and lower eyelids distinctly for each eye. Fixed effects included breed type, age categories, and sex of the animal. Lesion presence (1) or absence (0) was obtained by visual appraisal of image and was assumed to be binomially distributed. Eyelid pigmentation proportions (overall, upper, and lower eyelids) for Hereford ranged from 0.65 ± 0.03 to 0.68 ± 0.03 and were significantly lower than Bos indicus (range from 0.93 ± 0.02 to 0.95 ± 0.02) or Bos taurus (ranged from 0.88 ± 0.02 to 0.92 ± 0.02) crosses. Corneoscleral pigmentation in Hereford cows (0.17 ± 0.06) did not differ (P = 0.91) from Hereford calves and yearlings (0.16 ± 0.07). Bos indicus and Bos taurus crossbred cows had larger corneoscleral pigmentation (0.38 ± 0.05 and 0.48 ± 0.04 for left eyes and 0.37 ± 0.05 and 0.53 ± 0.04 for right eyes, respectively) than all calves (P < 0.001), and their corneoscleral pigmentations were greater than that of Hereford cows (P < 0.003). Bos indicus and Bos taurus cows had greater proportions of left eye corneoscleral pigmentation (0.38 ± 0.05 and 0.48 ± 0.04, respectively) than Hereford cows (0.17 ± 0.06) and all young animal breed types (P < 0.05). Right eye proportions differed for all cow groups (P < 0.05; 0.53 ± 0.04, 0.37 ± 0.05, and 0.17 ± 0.06). Among calves and yearlings, Hereford had a lower right eye corneoscleral pigmentation proportion (0.16 ± 0.07) than Bos taurus (P = 0.02). The lesion proportion for Hereford (0.08 ± 0.03) was significantly greater than that of either Bos indicus (0.01 ± 0.005) or Bos taurus (0.01 ± 0.003). Crossbreeding with Bos taurus or Bos indicus animals appears to increase eye pigmentation, which may help reduce the occurrence of cancer in eyes of cattle with white faces.

Effect of growth implant regimen on health, performance, and immunity of high-risk, newly received stocker cattle.

Growth implant efficacy may be affected when administered to nutritionally stressed calves, whereas the procedure may alter health or the humoral immune response to respiratory vaccination. The study objective was to determine the effect of different administration times (d 0, 14, or 28) of a growth implant containing 200 mg progesterone and 20 mg estradiol benzoate on health, performance, and metabolic and immunologic variables in high-risk, newly received beef calves used in a 120-d receiving/grazing stocker system. Crossbred bull and steer calves ( = 203) were weighed (initial BW = 203 ± 2.7 kg), stratified by castrate status on arrival, and randomly assigned to experimental treatments consisting of 1) negative control (no growth implant administered), 2) growth implant administered on d 0, 3) growth implant administered on d 14, and 4) growth implant administered on d 28. There were no differences ( ≥ 0.16) in BW or ADG during the 42-d receiving period. However, ADG during the subsequent grazing period and overall was greater ( ≤ 0.01) for implanted calves versus the negative control. Growth implant timing did not affect the rate of clinical bovine respiratory disease morbidity ( = 0.52; 94% morbidity overall) or bovine viral diarrhea virus type 1a antibody titer concentration ( = 0.61). Indicative of an overall negative energy balance on arrival, NEFA decreased sharply subsequent to d 0 (day effect, < 0.001), but was not affected ( = 0.47) by the timing of growth implantation. Blood urea N concentrations increased transiently (day effect, < 0.001); however, no treatment effect was observed ( = 0.72). Therefore, under conditions of this study, the timing of growth implant administration did not affect growth implant efficacy, health, or metabolic or immunologic variables in newly received, high-risk beef stocker calves. Overall, our observations suggest that there is not a clear benefit to delaying growth implantation and that a growth implant does not affect health or vaccine response in newly received beef calves.

Effect of surgical castration with or without oral meloxicam on the acute inflammatory response in yearling beef bulls.

Pain management and welfare are increasingly prevalent concerns within animal agriculture. Analgesics may alleviate pain and inflammation associated with castration of beef cattle. This study was conducted to elucidate the effects of surgical castration on the acute inflammatory response and immunomodulation and whether concurrent oral administration of meloxicam (1 mg/kg BW) would alter these responses. On d -1, crossbred bull calves ( = 30; initial BW = 227.4 ± 10.3 kg) were fitted with indwelling jugular catheters and rectal temperature (RT) recording devices, placed into individual stanchions, and randomly assigned to 1 of 3 treatments. Treatment application occurred at h 0 and consisted of 1) intact bull calves treated with sham castration (CON), 2) bulls surgically castrated without meloxicam administration (CAS), and 3) bulls surgically castrated with oral meloxicam (1 mg/kg BW) administration (MEL). Blood samples were collected at 0.5-h intervals from h -2 to 4, 1.0-h intervals from h 4 to 8, and 12-h intervals from h 12 to 72. Serum was analyzed for cortisol and haptoglobin (Hp) concentrations using ELISA. Whole blood was analyzed for complete blood counts at -2, 0, 2, 4, 6, 8, 12, 24, 36, 48, 60, and 72 h, and RT was recorded in 5-min intervals. Postcastration RT was greatest for MEL (39.04), intermediate for CAS (38.99), and least for CON (38.93°C; ≤ 0.01). Serum cortisol was increased ( < 0.001) for CAS (12.3) and MEL (11.3) compared with CON (6.7 ng/mL) during the postcastration period. At 0.5 and 1.5 h, cortisol concentration was greater in CAS and MEL than CON, whereas at 2 and 2.5 h, cortisol concentration was greatest for CAS, intermediate for MEL, and least for CON (treatment × time, < 0.001). Total white blood cell ( ≤ 0.04), lymphocyte ( ≤ 0.02), and monocyte ( ≤ 0.002) counts were greatest for CAS, intermediate for MEL, and least for CON. Administration of MEL reduced ( ≤ 0.002) eosinophil counts during the postcastration period when compared with CON and CAS. The change in serum Hp, relative to baseline values, was reduced for MEL at 36 ( < 0.01) and 60 h ( ≤ 0.03), and the overall Hp concentration was least for MEL ( < 0.001). Oral administration of meloxicam at the time of castration reduced the acute inflammatory response in castrates, as evidenced by a reduction in Hp and certain leukocyte concentrations; it also caused a delayed increase in RT. Further research is needed to determine if this reduced acute inflammatory response would equate to improved health and/or performance after castration.

Effect of castration timing and oral meloxicam administration on growth performance, inflammation, behavior, and carcass quality of beef calves.

Beef bull calves (n = 62) were assigned randomly, within sire breed, to 1 of 4 treatments at birth. Treatments were 1) surgical castration near birth, 2) surgical castration near birth with oral administration of meloxicam (1 mg/kg BW), 3) surgical castration at weaning (WNG), or 4) surgical castration at weaning with oral administration of meloxicam (1 mg/kg BW; WMX). A subset of calves (n = 7/treatment group) were selected randomly near birth for blood collection, behavioral analyses, and rectal temperature (RT) records for a 7-d postcastration period on d 0 (birth), 1, 3, and 7, and on d 214 (weaning), 214 + 6 h, 215, 217, 221, and 228. Calf standing and lying activity were monitored from the same subsets by recording x- and y-axis positions of an accelerometer attached to the right metatarsus for 7 d postcastration. Calf BW was recorded throughout the entire production cycle, and carcass data were collected at slaughter. For statistical analyses, bulls left intact at birth were considered a positive control (BUL) for observations that occurred before their treatment application at weaning; likewise, bulls castrated at birth were considered a negative control (STR) during postweaning observations. No difference (P > 0.88) occurred in ADG between treatments throughout the preweaning period (d 0 to 214); however, 56-d postweaning ADG was greatest ( P= 0.02) in STR, intermediate in WMX, and least in WNG. At weaning, haptoglobin (Hp) was greater (P ≤ 0.005) for WNG and WMX compared to STR on d 214+6 h, 215, and 217, and Hp was greater (P = 0.05) in WNG compared to WMX on d 217. Neutrophils increased (P < 0.001) and red blood cells decreased (P ≤ 0.03) for WNG and WMX on d 214+6 h and 217, respectively. Postweaning behavior observations indicated that STR calves spent the least proportion of time standing (P = 0.002) when compared to WNG and WMX. Furthermore, WMX calves exhibited a greater proportion of time spent standing (P = 0.03) compared to WNG. Grazing and finishing phase ADG and carcass measurements did not differ (P ≥ 0.24) across treatments. In this study, surgical castration at weaning, but not near birth, altered the acute phase response, behavior, and growth performance. Oral meloxicam reduced serum Hp and improved ADG briefly when administered to calves castrated at weaning. Oral administration of meloxicam may be efficacious for mitigating some of the stress and inflammation associated with castration of weaning-age bull calves.

Supplemental trace minerals (zinc, copper, and manganese) as sulfates, organic amino acid complexes, or hydroxy trace-mineral sources for shipping-stressed calves.

Crossbred calves (n = 350; average BW 240 ± 1 kg) were obtained from regional livestock auctions. Within each set (block, n = 4), calves were stratified by BW and arrival sex into 1 of 8, 0.42-ha pens (10 to 12 calves per pen). Pens were assigned randomly to 1 of 3 treatments consisting of supplemental Zn (360 mg/d), Mn (200 mg/d), and Cu (125 mg/d) from inorganic (zinc sulfate, manganese sulfate, and copper sulfate; n = 2 pens per block), organic (zinc amino acid complex, manganese amino acid complex, and copper amino acid complex; Availa-4, Zinpro Corp., Eden Prairie, MN; n = 3 pens per block), and hydroxy (IntelliBond Z, IntelliBond C, and IntelliBond M; Micronutrients, Indianapolis, IN; n = 3 pens per block) sources. During the 42- to 45-d backgrounding period calves had ad libitum access to bermudagrass hay and were fed corn and dried distillers grain-based supplements that served as carrier for the treatments. After removal of data for chronic (n = 6) and deceased (n = 1) calves, trace-mineral source had no effect on final or intermediate BW (P = 0.86) or ADG (P ≥ 0.24). With all data included in the analysis, dietary treatments had no effect on the number treated once (P = 0.93), twice (P = 0.71), or 3 times (P = 0.53) for bovine respiratory disease or on the number of calves classified as chronic (P = 0.55). Based on these results, trace-mineral source had no effect on total BW gain, ADG, or morbidity during the receiving phase in shipping-stressed cattle.

Weaning management of newly received beef calves with or without continuous exposure to a persistently infected bovine viral diarrhea virus pen mate: effects on rectal temperature and serum proinflammatory cytokine and haptoglobin concentrations.

Exposure to animals persistently infected (PI) with bovine viral diarrhea virus (BVDV) results in immunomodulation in cohorts. It is hypothesized that the extent of modulation differs for low-risk, preconditioned (PC) vs. high-risk, auction market (AM) beef cattle. Our objective was to compare immune responses of PC or AM calves in the presence (PI) or absence (CON) of a PI-BVDV pen mate. Crossbred PC steers (n = 27) from a single ranch origin were weaned, dewormed, vaccinated against respiratory and clostridial pathogens, tested for PI-BVDV, and kept on the ranch for 61 d. Subsequently, PC steers were transported to a receiving unit (RU), weighed, stratified by d -1 BW, and assigned randomly to treatment (PCPI or PCCON) with no additional processing. Simultaneously, crossbred AM calves (n = 27) were assembled from regional auction markets and transported to the RU. The AM calves were weighed, stratified by gender and d -1 BW, processed under the same regimen used for PC steers at their origin ranch, except bull calves were castrated, then assigned randomly to treatment (AMPI or AMCON). Treatment pens were arranged spatially so that PI did not have fence line contact with CON. Blood samples were collected on d 0, 1, 3, 7, and 14 to determine serum concentrations of haptoglobin (Hp), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), IL-4, and IL-6. Rectal temperature (RT) was recorded concurrent with blood sampling. In AM calves, RT and Hp increased (management effect; P < 0.001) sharply on d 1; however, exposure to a PI-BVDV pen mate did not affect either variable (P ≥ 0.79) during the 14-d evaluation period. Serum concentrations of TNF-α tended to increase (P = 0.09) for the PI cohort. A treatment × day interaction (P ≤ 0.05) was observed for IFN-γ on d 7 and 14 and IL-6 on d 14; these indices were greatest for AMPI. Results indicate weaning management and PI-BVDV exposure alter the immune status of newly received beef cattle. These main effects may be additive because proinflammatory cytokine concentrations were greatest for AMPI. Therefore, results further indicate that potential health or growth consequences in cohorts exposed to a PI-BVDV pen mate are impacted by previous management and health history.

Weaning management of newly received beef calves with or without continuous exposure to a persistently infected bovine viral diarrhea virus pen mate: effects on health, performance, bovine viral diarrhea virus titers, and peripheral blood leukocytes.

Exposure to animals persistently infected (PI) with bovine viral diarrhea virus (BVDV) results in immunomodulation of cohorts that may have health and growth consequences; however, effects may differ in low-risk, preconditioned (PC) vs. high-risk, auction market (AM) beef cattle. Our objective was to compare health and performance of PC or AM management systems with (PI) or without (CON) presence of a PI-BVDV pen mate using a 2 × 2 factorial arrangement. Four shipment blocks of crossbred PC steers (n = 236) from 3 ranch-origins were weaned, dewormed, vaccinated, tested for PI-BVDV, and kept on the ranch for ≥42 d. Subsequently, PC steers were transported to a stocker receiving unit (RU), weighed (251 ± 2 kg), blood sampled, stratified by d -1 BW, and assigned randomly to treatment (PCPI or PCCON) with no additional processing. Simultaneously, 4 blocks of crossbred AM calves (n = 292) were assembled from regional auction markets and transported to the RU ± 36 h from PC arrival. The AM calves were weighed (245 ± 1.3 kg), stratified by gender and d -1 BW, processed under the same regimen used for PC steers at their origin ranch except bull calves were castrated, and then assigned randomly to treatment (AMPI or AMCON). Treatment pens (0.45 ha) were arranged spatially such that PI did not have fence-line or water source contact with CON. Calves were fed identically and followed the same antibiotic treatment protocol. Daily BW gain for the entire 42-d receiving trial was greater (P < 0.001) for PC (1.2 kg) compared with AM (0.85 kg). There was an exposure effect (P = 0.002) on ADG from d 28 to 42; CON gained 1.12 kg vs. 0.90 kg BW for PI cohort. Morbidity was markedly greater (P < 0.001) in AM (70%) vs. PC (7%), resulting in (P < 0.001) an antibiotic treatment cost of $20.52 and $2.48/animal, respectively. Treatment with a third antibiotic occurred more often (P = 0.04) for PI cohort, and the percentage of chronically ill cattle was greatest (P = 0.06) for AMPI. Upon arrival, BVDV type 1a, 1b, and 2a titers were greater for PC (treatment × day, P < 0.001), and the percentage seropositive to BVDV type 1a on d 0 was 100% for PC vs. 23% in AM. Platelets increased transiently (P < 0.001) with greater platelets observed in AM (P < 0.001). Results indicate that PC calves gain faster and require fewer antibiotic treatments during the receiving period. Exposure to PI reduced BW gain from d 28 to 42, increased the number of calves treated thrice, and increased chronically ill cattle for AM.

Effects of on-arrival versus delayed clostridial or modified live respiratory vaccinations on health, performance, bovine viral diarrhea virus type I titers, and stress and immune measures of newly received beef calves.

Stress, commonly associated with weaning, marketing, and shipment of feeder cattle, can compromise immune function, and vaccine administration during immunosuppression may reduce vaccine efficacy and calf growth. Four treatments were compared in a 2 x 2 factorial arrangement to evaluate the effect of on-arrival (d 0) vs. delayed (d 14) administration of clostridial (CLOS) and respiratory (RESP) vaccines on health, performance, bovine viral diarrhea virus (BVDV) antibody titers, and physiological immune measurements of high-risk, newly received calves. Crossbred bull and steer calves (n = 263) were weighed (239 +/- 1.2 kg), stratified by sex, and randomly assigned to vaccination treatment: 1) arrival CLOS, arrival RESP (ACAR); 2) arrival CLOS, delayed RESP (ACDR); 3) delayed CLOS, arrival RESP (DCAR); and 4) delayed CLOS, delayed RESP (DCDR). Body weight and blood samples were collected on d 0, 14, 28, 42, and 56. Average daily gain did not differ (P > or = 0.34), averaging 0.98, 0.93, 0.95, and 0.91 kg/d for ACAR, ACDR, DCAR, and DCDR, respectively, for the entire 56-d trial. Vaccination timing did not affect morbidity (P > or = 0.23); however, there tended to be a CLOS timing effect (P = 0.07) and RESP timing effect (P = 0.09) on days to initial bovine respiratory disease (BRD) treatment. Average days to initial BRD treatment were less for ACAR (6 +/- 0.8 d) compared with DCDR (8 +/- 0.8 d; P = 0.01). Greater white blood cell counts were observed for DCDR than ACDR (P = 0.01), with ACAR and DCAR being intermediate. Serum cortisol concentrations were greater on d 0 than d 14 (P < 0.01) or d 28 (P = 0.01) but no treatment x day interaction (P = 0.21) was observed. Timing of RESP administration affected (P = 0.001) serum BVDV type I titers, with greater (P < 0.01) levels in calves receiving RESP vaccine on arrival. Delaying CLOS or RESP vaccination did not affect BW gain or morbidity in high risk, newly received stocker calves. Calves administered RESP vaccine on d 0 developed antibody titers to BVDV type I earlier than delayed RESP treatments. Total white blood cell count was greatest when RESP and CLOS vaccination were delayed (DCDR).

Effectiveness evaluation of several cattle anthelmintics via the fecal egg count reduction test.

Utilizing groups of cograzed, naturally infected beef-type heifers, three fecal egg count reduction tests were conducted in the later months of 2007 at the University of Arkansas. Each test was 28 days in length consisting of individual animal fecal nematode egg counts and coprocultures. Both original and generic ivermectin injectable formulations were used in two of the tests at 0.2 mg/kg BW, with FECR percentages never exceeding 90% in either test. Oral fenbendazole was evaluated at 5 and 10 mg/kg BW, with FECR%'s exceeding 90% on all occasions, but with a precipitous drop when recently treated animals were treated at the lower dose. Evaluated in one test, injectable moxidectin given at 0.2 mg/kg BW resulted in egg count reductions of 96-92% (days 7 to 28). Also evaluated in one test, albendazole delivered orally at 10 mg/kg BW was 98% and 97% effective at 17 and 28 days post-treatment. For all tests, coprocultures conducted post-treatment contained only Cooperia spp. larvae (benzimidazole use), relatively unmodified percentages of Cooperia spp. and Haemonchus spp. larvae (ivermectin use), and primarily Cooperia spp. larvae with a small percentage of Haemonchus spp. larvae (moxidectin use).

Molecular structure and chromosomal mapping of the human homolog of the agouti gene.

The agouti (a) locus in mouse chromosome 2 normally regulates coat color pigmentation. The mouse agouti gene was recently cloned and shown to encode a distinctive 131-amino acid protein with a consensus signal peptide. Here we describe the cloning of the human homolog of the mouse agouti gene using an interspecies DNA-hybridization approach. Sequence analysis revealed that the coding region of the human agouti gene is 85% identical to the mouse gene and has the potential to encode a protein of 132 amino acids with a consensus signal peptide. Chromosomal assignment using somatic-cell-hybrid mapping panels and fluorescence in situ hybridization demonstrated that the human agouti gene maps to chromosome band 20q11.2. This result revealed that the human agouti gene is closely linked to several traits, including a locus called MODY (for maturity onset diabetes of the young) and another region that is associated with the development of myeloid leukemia. Initial expression studies with RNA from several adult human tissues showed that the human agouti gene is expressed in adipose tissue and testis.

Dexamethasone-induced hyperglycemia in obese Avy/a (viable yellow) female mice entails preferential induction of a hepatic estrogen sulfotransferase.

Sex steroid sulfotransferases (ST) sulfurylate and thus inactivate estrogens or androgens, producing an androgenized or estrogenized state in the liver. The expression of diabetes in a number of animal models is sexually dimorphic and has been associated with steroidal states. Although the viable yellow (Avy) mutation produces an insulin-resistant obesity syndrome in mice of both sexes, only males develop chronic hyperglycemia. Hyperglycemia was rapidly induced in Avy/a females by dexamethasone (dex). This treatment completely suppressed both endogenous plasma corticosterone and hepatic corticosterone-binding globulin (CBG) mRNA within 24 h. Hyperglycemia in dex-implanted Avy/a females was accompanied by aberrant shifts in hepatic androgen/estrogen balance. This was effected by induction of estrogen sulfotransferase (EST) mRNA together with a > 10-fold increase in enzymatic activity. Similar dex-induced increases in androgen ST or phenol ST were not observed. Prior implantation of estrogen prevented development of hyperglycemia. The time-dependent spontaneous reversal of dex-induced hyperglycemia correlated with re-expression of CBG mRNA transcripts and reduced levels of EST transcripts and enzyme activity. Although dex-induced hyperglycemia was limited to Avy/a females, dex elicited hyperinsulinemia in lean a/a control mice of both sexes and exacerbated constitutive hyperinsulinemia in Avy/a males and females. In summary, dex-induced hyperglycemia in Avy/a females was associated with increased catabolism of hepatic estrogens mediated by induction of EST.

High dose intravenous, but not low dose subcutaneous, insulin-like growth factor-I therapy induces sustained insulin sensitivity in severely resistant type I diabetes mellitus.

We have previously demonstrated weekly iv insulin-like growth factor-I (IGF-I; 500 micrograms/kg) bolus therapy to be effective in inducing sustained insulin sensitivity in a patient with type I diabetes mellitus and massive insulin resistance. The present study was undertaken to determine the efficacy of daily sc IGF-I in the treatment of two severely insulin-resistant type I diabetic patients (requiring in excess of 3500 U insulin/day) compared to weekly iv IGF-I therapy. Prolonged insulin sensitivity was achieved in both patients after weekly 500 micrograms/kg iv bolus infusions of IGF-I, with sc insulin requirements falling to approximately 1 U/kg.day. Smaller iv doses (250 micrograms/kg) of IGF-I were ineffective in acutely lowering serum glucose or inducing sustained insulin sensitivity. However, even this smaller IGF-I dose resulted in acute symptomatic hypophosphatemia, which could be prevented by coadministration of potassium phosphate. With sc administered IGF-I (up to 10 mg twice daily), insulin appeared to control patient glucose concentrations, but severe insulin resistance returned within 72 h of discontinuing IGF-I therapy. IGF-I dosing was decreased to the lowest concentration that maintained euglycemia (7.5 mg in the morning and 2.5 mg in the evening). However, severe arthropathy in both patients and neurological symptoms including multiple cranial nerve palsies in one patient were associated with chronic therapy. We conclude that both iv and sc administered IGF-I can precipitate acute symptomatic hypophosphatemia. Chronic low dose sc therapy may be associated with severe neuropathy and arthropathy, and does not induce the sustained insulin sensitivity associated with high dose intermittent bolus IGF-I therapy.

Ciglitazone prevents and reverses dexamethasone-induced hyperglycemia in female viable yellow mice.

Hypercorticism has been observed in numerous obese and diabetic animal models. Adrenalectomy reduces adiposity, hyperglycemia, hyperinsulinemia, and insulin resistance in these animals. The effects of adrenalectomy can be reversed by glucocorticoid replacement. Male and female viable yellow mice share all phenotypic expressions caused by the viable yellow mutation except that males are hyperglycemic and most females are either normoglycemic or only mildly hyperglycemic. The mechanisms that protect female viable yellow mice from hyperglycemia are not known. Implantation of dexamethasone pellets induced hyperglycemia in female viable yellow mice but had no effect on blood glucose of male viable yellow mice and male and female normal mice. The duration of dexamethasone-induced hyperglycemia correlated to the time endogenous plasma corticosterone levels were suppressed. Plasma insulin levels rose in normal mice but only transiently in viable yellow mice. Ciglitazone prevented and reversed dexamethasone-induced hyperglycemia in female viable yellow mice. Since female viable yellow mice, similar to male viable yellow mice, are obese, hyperinsulinemic and insulin resistant, and since dexamethasone is known to cause insulin resistance, these data suggest that dexamethasone increased insulin resistance to a degree that the protective mechanism was overwhelmed and hyperglycemia was induced. Ciglitazone, a compound known to improve insulin sensitivity, may prevent and reverse dexamethasone-induced hyperglycemia by ameliorating the additional insulin resistance caused by dexamethasone. On a molecular level, since dexamethasone suppresses glucose transport, an insulin-sensitive process in many tissues, whereas ciglitazone and other thiazolidinediones facilitate glucose transport, it is possible that ciglitazone prevents and reverses dexamethasone-induced hyperglycemia by regulating the glucose transport systems in insulin-sensitive tissues.

Reliability and interrelations among serum sex hormones in postmenopausal women.

Serum sex hormones may be related to the risk of several diseases in postmenopausal women including osteoporosis, heart disease, and breast and endometrial cancer. For assessment of the relation of sex hormones to disease, the measurements should be reliable, valid, and practical. In this paper, the authors evaluated the short-term (4-week) and long-term (2-year) reliability of serum sex hormones and interrelations among serum sex hormones in white postmenopausal women recruited in Pittsburgh, Pennsylvania, 1981-1986. For comparison, the authors simultaneously evaluated the short- and long-term reliability of other commonly measured risk factors, i.e., lipids, lipoproteins, and blood pressure. Serum concentrations of estrone, estradiol, testosterone, and androstenedione were measured by extraction, column chromatography, and radioimmunoassay. Reliability was estimated by calculating the intraclass correlation coefficients (R) and their 95% confidence interval. About 50% of the estradiol levels were below the sensitivity of the assay and, therefore, these results should be interpreted with some caution. The intraclass correlation coefficient for testosterone was 0.92 (95% confidence interval 1.0-0.82), suggesting that a single measure may be reliable in characterizing women for epidemiologic research. Over 4 weeks, estrone could be measured more reliably (R = 0.72) than over 2 years (R = 0.56), but the variability over the long term was similar to that observed for other biologic variables, suggesting that, in situations where the relation between estrone and disease is fairly substantial, a single measure may be used. For estradiol and androstenedione, the intraclass correlations were small, indicating poor reproducibility and the need for more measurements. Estrone concentrations were 11 pg/ml or 46% higher in women with measurable estradiol. Estrone was also positively related to androstenedione concentrations (r = 0.33, p less than 0.001). Concentrations of estradiol are extremely low in postmenopausal women, and accordingly, there is a greater possibility of laboratory error. Since the data suggest that estrone levels can be more reliably measured and are, in fact, related to estradiol levels, it is possible that estrone levels may be used to indicate the total estrogen status of postmenopausal women.

The relation of endogenous sex steroid hormone concentrations to serum lipid and lipoprotein levels in postmenopausal women.

The relation of concentrations of endogenous estrogens and androgens to lipid and lipoprotein levels was examined in 176 white, postmenopausal women (mean age, 58 years) with an average of 9 years since the onset of menopause. All of the women were participants in a clinical trial of the effect of walking on postmenopausal bone loss. In that trial, women were randomized into either a walking group or a control group and were followed for 3 years. There were no differences in the serum hormones or lipids by randomized group, and hence, results from this study are presented for both groups combined. None of the women were on estrogen replacement therapy. Data were available from year 1 (1982-1983) of the trial for the estrogens, lipids, and lipoproteins. Information on androgens was available for 143 of these women. Hormone levels were determined by highly specific methods involving extraction, column chromatography, and radioimmunoassay. About 50% of the women had estradiol levels at or below the sensitivity level (2.5 pg/ml) of the assay; therefore, estradiol levels were viewed as dichotomous (measurable/not measurable), and the estradiol results should be interpreted with caution. There was little relation of the androgens to the lipid values. Univariate analyses suggested a direct relation between total cholesterol, low density lipoprotein cholesterol, and triglyceride levels with estradiol. An inverse relation was suggested between serum estrone and estradiol and total high density lipoprotein (HDL) cholesterol and HDL2 cholesterol, although none of these associations were statistically significant. Multiple regression analyses revealed that the primary determinant of the HDL cholesterol and triglyceride levels was the degree of obesity as estimated by the body mass index (weight (kg)/height (m)2). Addition of estrone or estradiol to the models did not contribute to the prediction of lipid levels. These results do not support the hypothesis of there being a relation between endogenous sex hormone levels and lipid levels in postmenopausal women. The results suggest that sex hormones cannot explain the sex difference in lipid levels and may not contribute to the rise in coronary heart disease that occurs in women around menopause.

The epidemiology of serum sex hormones in postmenopausal women.

Serum sex hormones may be related to the risk of several diseases in postmenopausal women. In the current report, the authors examined the epidemiology of serum sex hormones in 176 healthy, white postmenopausal women (mean age 58 years) recruited from the metropolitan Pittsburgh, Pennsylvania, area. The data were collected during 1982-1983; none of the women were on estrogen replacement therapy. Serum concentrations of estrone, estradiol, testosterone, and androstenedione were measured by a combination of extraction, column chromatography, and radioimmunoassay. Neither age nor time since menopause was a significant predictor of sex hormones. The degree of obesity was a major determinant of estrone and estradiol. The estrone levels of obese women were about 40% higher than the levels of nonobese women. There was a weak relation between obesity and the androgens. Cigarette smokers had significantly higher levels of androstenedione than nonsmokers, with little difference in serum estrogens between smokers and nonsmokers. Both estrone and estradiol levels tended to decline with increasing alcohol consumption. Physical activity was an independent predictor of serum estrone. More active women had lower levels of estrone. There was a positive relation of muscle strength with estrogen levels. The data suggest interesting relations between environmental and lifestyle factors and serum sex hormones. These environmental and lifestyle factors are potentially modifiable and, hence, if associations between sex hormones and disease exist, modification of these factors could affect disease risks.