Effects of organic or inorganic cobalt, copper, manganese, and zinc supplementation to late-gestating beef cows on productive and physiological responses of the offspring.

Eighty-four multiparous, nonlactating, pregnant Angus × Hereford cows were ranked by pregnancy type (56 AI and 28 natural service), BW, and BCS and allocated to 21 drylot pens at the end of their second trimester of gestation (d 0). Pens were assigned to receive forage-based diets containing 1) sulfate sources of Cu, Co, Mn, and Zn (INR); 2) an organic complexed source of Cu, Mn, Co, and Zn (AAC; Availa 4; Zinpro Corporation, Eden Prairie, MN); or 3) no supplemental Cu, Co, Mn, and Zn (CON). Diets were offered from d 0 until calving and formulated to meet requirements for energy, protein, macrominerals, Se, I, and vitamins. The INR and AAC diets provided the same daily amount of Cu, Co, Mn, and Zn. Cow BW and BCS were recorded and liver samples were collected on d -10 and 2 wk (d 75) before the calving season. Within 3 h after calving, calf BW was recorded, liver samples were collected, and the expelled placenta was retrieved ( = 47 placentas). Calves were weaned on d 283 of the experiment, preconditioned for 45 d (d 283 to 328), transferred to a growing lot on d 328, and moved to a finishing lot on d 440 where they remained until slaughter. Liver Co, Cu, and Zn concentrations on d 75 were greater ( ≤ 0.05) for INR and AAC cows compared with CON cows, whereas INR cows had reduced ( = 0.04) liver Co but greater ( = 0.03) liver Cu compared with AAC cows. In placental cotyledons, Co concentrations were greater ( ≤ 0.05) in AAC and INR cows compared with CON cows, whereas Cu concentrations were increased ( = 0.05) only in AAC cows compared with CON cows. Calves from INR and AAC cows had greater ( < 0.01) liver Co concentrations at birth compared with calves from CON cows. Liver Cu and Zn concentrations at birth were greater ( ≤ 0.05) in calves from AAC cows compared with cohorts from CON cows. Weaning BW was greater ( ≤ 0.05) in calves from AAC cows compared with cohorts from CON cows, and this difference was maintained until slaughter. In the growing lot, calves from AAC cows had reduced ( < 0.01) incidence of bovine respiratory disease compared with CON and INR cohorts. Collectively, these results suggest that feeding the AAC diet to late-gestating beef cows stimulated programming effects on postnatal offspring growth and health compared with the CON diet. Therefore, supplementing late-gestating beef cows with an organic complexed source of Co, Cu, Zn, and Mn instead of no supplementation appears to optimize offspring productivity in beef production systems.

Late gestation supplementation of beef cows differing in body condition score: effects on cow and calf performance.

A 2-yr study utilizing 120 mature, crossbred (Angus × Herford) cows/year, evaluated the influence of cow BCS and dried distillers grains with solubles (DDGS) supplementation during late gestation on cow performance and productivity of subsequent offspring. Treatments were arranged as a 2×2 factorial in a randomized complete block design with 2 BCS and with or without DDGS supplementation. Cows were nutritionally managed to enter the last trimester of gestation with a BCS of approximately 4 (LBCS) or 6 (HBCS) and were thereafter managed in a single herd (initial BCS were 4.4 and 5.7 for LBCS and HBCS treatments, respectively). During the last trimester, 12.7 kg/cow of low quality meadow hay (6.4% CP; DM basis) was provided each day. Supplemented cows were gathered and sorted into pens (12 pens; 5 cows/pen; 6 pens/BCS) every Monday, Wednesday, and Friday, and received the equivalent of 0.9 kg/cow daily of DDGS (31% CP; DM basis; supplement was consumed within 30 min on each supplementation day). Calf birth weight was greater for HBCS compared to LBCS (P=0.001) and for supplemented compared to nonsupplemented cows (P=0.04). Cow weight at weaning was greater for HBCS compared with LBCS (P<0.001); however, no differences were noted because of supplementation (P=0.16). Weaning weight was greater for the offspring of supplemented compared to nonsupplemented cows (P=0.02). There were no differences in postweaning calf performance (growing lot and feedlot) or carcass characteristics (P>0.05) due to treatments. Nevertheless, HBCS cows had approximately 10% more live calves at birth and at weaning (P≤0.01) compared to LBCS cows. Consequently, the total weaned calf weight per cow was 26 kg greater for HBCS compared with LBCS (P=0.004). Pregnancy rate was greater (P=0.05) for HBCS than LBCS cows (92% vs. 79%, respectively) but not affected by supplementation (P=0.94). This research demonstrates the potential consequences of not maintaining cows in adequate BCS at calving. Also, though it appears that supplementation of beef cows with DDGS during late gestation has a positive effect on weaning weight, there was no apparent developmental programming effect on feedlot performance and carcass characteristics of calves.

Effects of temperament and acclimation to handling on feedlot performance of Bos taurus feeder cattle originated from a rangeland-based cow-calf system.

Two experiments evaluated the effects of temperament and acclimation to handling on performance of Angus × Hereford feeder cattle reared in extensive rangeland systems until weaning. In Exp. 1, 200 calves (n = 97 for yr 1; n = 103 for yr 2) were evaluated for temperament at weaning (average age ± SE = 152 ± 1 d) by chute score and exit velocity. Chute score was assessed on a 5-point scale according to behavior during chute restraining. Exit score was calculated by dividing exit velocity into quintiles and assigning calves a score from 1 (slowest) to 5 (fastest). A temperament score was calculated for each calf by averaging chute and exit scores. Calf temperament was classified according to temperament score as adequate (≤3) or excitable (>3). After weaning, calves were assigned to a 40-d preconditioning followed by growing (139 d) and finishing (117 d) phases until slaughter. Weaning BW was decreased (P = 0.04) in excitable calves compared with adequate calves. No differences were detected (P ≥ 0.21) for ADG during preconditioning, growing, and finishing phases; hence, excitable calves tended (P = 0.09) to have decreased HCW compared with adequate calves. In Exp. 2, 60 steers (initial age ± SE = 198 ± 2 d) were weighed and evaluated for temperament score 35 d after weaning (d -29). On d -28, steers were ranked by these variables and assigned to receive an acclimation treatment or not (control). Acclimated steers were processed through a handling facility twice weekly for 4 wk (d -28 to -1) whereas control steers remained undisturbed on pasture. On d 0, all steers were transported for 24 h and returned to the research facility (d 1). On arrival, steers were ranked by BW within treatment and randomly assigned to 20 feedlot pens for a 28-d feedlot receiving period. Acclimated steers had decreased temperament score and plasma cortisol compared with controls on d 0 (P = 0.02). During feedlot receiving, acclimated steers had decreased ADG (P < 0.01) and G:F (P = 0.03) and tended to have decreased DMI (P = 0.07) compared with controls. Acclimated steers had greater plasma haptoglobin on d 4 (P = 0.04) and greater ceruloplasmin from d 0 to 10 (P ≤ 0.04) and tended to have greater cortisol on d 1 (P = 0.08) than controls. In conclusion, temperament affects productivity of beef operations based on Bos taurus feeder cattle reared in extensive rangeland systems until weaning whereas acclimation to handling ameliorated cattle temperament but did not benefit feedlot receiving performance.

Effects of polyunsaturated fatty acid supplementation on ruminal in situ forage degradability, performance, and physiological responses of feeder cattle.

Two experiments were conducted to compare ruminal, physiological, and performance responses of forage-fed cattle consuming grain-based supplements without (NF) or with the inclusion (10%; DM basis) of a rumen-protected PUFA (PF) or SFA source (SF). Supplements were offered and consumed at 0.6% of BW/animal daily (DM basis). In Exp. 1, DMI and ruminal in situ forage degradability were evaluated in 3 Angus × Hereford cows fitted with ruminal cannulas and allocated to a 3 × 3 Latin square design. Within each experimental period, hay was offered in amounts to ensure ad libitum access from d 1 to 13, DMI was recorded from d 8 to 13, and cows were limited to receive 90% of their average hay DMI (d 1 to 13) from d 14 to 21. On d 16, polyester bags containing 4 g of ground hay (DM basis) were incubated within the rumen of each cow for 0, 4, 8, 12, 24, 36, 48, 72, and 96 h. Hay and total DMI were reduced (P < 0.05) in cows receiving PF compared with cows receiving SF and NF. No treatment effects were detected (P > 0.48) for ruminal disappearance rate and effective ruminal degradability of hay DM and NDF. In Exp. 2, preconditioning DMI, ADG, carcass traits, and plasma concentrations of cortisol, fatty acids, acute-phase proteins, and proinflammatory cytokines were assessed in 72 Angus × Hereford steers receiving supplement treatments during a 28-d preconditioning period. All steers were transported to a commercial growing lot after preconditioning (d 1) and were later moved to an adjacent commercial finishing yard (d 144), where they remained until slaughter. No treatment effects were detected (P ≥ 0.52) for preconditioning ADG and G:F, but DMI tended (P = 0.09) to be reduced in steers receiving PF compared with those receiving NF and SF. Plasma PUFA concentrations were greater in steers receiving PF compared with those receiving NF and SF (P = 0.01). After transportation, concentration of tumor necrosis factor-α increased for steers receiving NF, did not change for steers receiving SF, but decreased for steers receiving PF (treatment × day interaction, P < 0.01). Steers fed PF had greater (P = 0.02) ADG compared with those fed NF during the growing phase. Carcass yield grade and marbling were greater (P < 0.05) for steers fed PF compared with those fed NF. In conclusion, PUFA supplementation did not affect ruminal forage degradability but did impair DMI in beef cows. Further, PUFA supplementation to steers during preconditioning reduced plasma concentrations of tumor necrosis factor-α after transportation, and benefited growing lot ADG and carcass marbling.

Catechol conjugation with hemolymph proteins and their incorporation into the cuticle of the American cockroach, Periplaneta americana.

Newly ecdysed American cockroaches, Periplaneta americana (sixth to last instar) were injected with radioactive dopamine (DA) and hemolymph was collected at 10-60 min post-ecdysis. Size-exclusion chromatography established the presence of at least three proteins that serve as catecholamine carriers. Reinjection of the smaller radiolabeled phenol-bound proteins into newly ecdysed animals results in in vivo aggregation, with the radiolabel bound to large MW proteins (30- > 200 kDa). In addition, the reinjection of radiolabeled protein of any size resulted in the incorporation of the label into the newly sclerotized cuticle. Hemolymph proteins were synthesized in vivo using [14C]leucine and subsequently double labeled in vivo with [3H]dopamine. After sclerotization (7 h post-ecdysis) the cuticle was extirpated, hydrolyzed and counted. An identical ratio of 14C to 3H was found in cuticle extracts as in the double-labeled hemolymph proteins, suggesting that the phenol-bound protein was incorporated in the cuticle unchanged. It appears that the catechol bound to the proteins exists as a beta-glucoside.

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.

Sexual differences and steroid-induced changes in metabolic activity in toadfish sonic muscle.

Since the male oyster toadfish (Opsanus tau) is more active in sound production than the female, we hypothesized that sonic muscles of the male are biochemically specialized to perform more work. In order to categorize the muscle biochemically and test for sexual differences, we measured the activity of two anaerobic enzymes, 3-phosphoglyceraldehyde dehydrogenase (3PG) and lactic dehydrogenase (LDH), and two aerobic enzymes, malate dehydrogenase (MDH) and glutamic oxaloacetic transaminase (GOT). Males exhibited greater 3PG and GOT activity than females (p less than 0.05). Both MDH and LDH showed little activity in either sex. High 3PG and low LDH levels indicate a sustained level of glycolysis, with pyruvate shuttled into aerobic metabolism, and high GOT activity indicates a high level of aerobic metabolism. From this and other data, we conclude that toadfish sonic muscle can be classified as fast-twitch oxidative glycolytic or fast-twitch fatigue resistant. The endocrine basis for these sexual differences was examined by implanting steroid pellets into ovariectomized females. Testosterone induced a doubling of 3PG activity (p less than 0.02), and dihydrotestosterone induced an eight-fold increase (p less than 0.0005) in GOT concentration over controls. The steroids had no effect on LDH and MDH activities. Hormones, therefore, trigger one of the fundamental sexual differences underlying toadfish communication, namely a difference in metabolism, providing the male with the capacity for increased sound production.

The response of dietary stressed Periplaneta americana to chronic intake of pure aflatoxin B.

In general these studies seem to indicate that adult male P. americana are not particularly sensitive, toxicologically, to aflatoxin B1, even when maintained on a marginally inadequate diet containing a low level of sucrose and no protein. Also they may be capable of detecting low levels of aflatoxin B1 in their diet (12 mug/ml) and seem not to concentrate aflatoxin B1 in their bodies. Even in dietary stressed conditions adult male American cockroaches showed a very limited potential as a bioassay organism for this toxin. Actually it appears that they may be quite resistant to the toxin. Currently there is no definite answer as to the advantages or disadvantages of insufficient dietary proteins or even carbohydrates providing protection against this toxin. The results show that the toxin would not be an effective cockroach-killing agent and thus could not serve as a bioassay system. However, this insect could serve as a model system in further investigating the mode of action and possible detoxification of aflatoxin B1.