R.L. Kincaid

The role of essential trace elements in embryonic and fetal development in livestock

This review addresses the concept that essential trace minerals play a vital role in many enzymatic and metabolic pathways that are critical for conceptus development during pregnancy in livestock species. The conceptus relies entirely on the maternal system for a sufficient supply of trace minerals and other nutrients needed for normal development. If this supply is inadequate, growth and/or health of the conceptus can be affected adversely, and many of these effects carry over into the neonatal period. Information, accumulated in our laboratory and presented herein, indicates that zinc, copper and manganese are among the trace minerals that have the greatest impact on reproduction. For example, levels of zinc, copper and manganese were several fold greater in the conceptus than in other reproductive tissues, indicating that the conceptus preferentially accumulates these minerals, an action that may be important for conceptus development, growth and survival. Moreover, some recent results indicate that increasing the biological availability of zinc, copper and manganese, by attachment to short peptide chains (i.e., proteinated trace minerals) can enhance reproductive performance of swine. Mineral concentrations in conceptuses from female pigs consuming proteinated trace minerals were greater than those from females that consumed only inorganic mineral salts. Elucidating the mechanisms whereby conceptus development and survival are enhanced by essential trace minerals may lead to development of specific feeding programs to increase the number and health of offspring at parturition, thereby allowing for further improvements in production efficiency in animal agriculture.

Effects of prenatal source and level of dietary selenium on passive immunity and thermometabolism of newborn lambs

The objective of this study was to determine the effects of the amount and chemical form of Se fed to pregnant ewes on concentrations of thyroid hormones, Se in tissues, immunoglobulins (Ig) in serum, and measures of thermometabolism in ewes and their newborn lambs. Pregnant ewes (n=21) were randomly assigned to receive a diet deficient of Se (<0.02ppm) or supplemented to provide 0.3ppm Se from either sodium selenite or selenized yeast (SeY). Pregnant ewes which were fed additional Se had increased (P<0.05) concentrations of Se in whole blood and serum, greater activity of glutathione peroxidase (GSHpx), and higher concentrations of tri-iodothyronine (T(3)) and thyroxine (T(4)). At 12h of age, lambs of ewes given Se had higher (P<0.05) concentrations of Se in blood and liver, greater activities of GSHpx, and tended (P<0.1) to have higher T(3) levels. When the two Se supplements were compared, lambs of ewes which were fed with SeY had higher (P<0.001) concentrations of Se and activities of GSHpx (P<0.05) in blood than lambs of ewes fed with selenite. Concentrations of Se in colostrum were increased (P<0.05) with Se supplementation and the ewes fed with SeY tended (P<0.1) to have higher Se in colostrum than ewes fed with selenite. Although IgG in serum and colostrum of ewes was not affected by supplemental Se, IgM in serum of ewes was increased (P<0.05). Lambs of ewes which were given Se had increased (P<0.05) absorption of IgG, but not IgM. No treatment effects on measures of thermometabolism were detected. In conclusion, Se supplementation of pregnant ewes affected measures of thyroxine metabolism and immunity. Compared to selenite, Se from SeY was more readily transferred to the fetus and colostrum.

Inorganic Versus Complexed Trace Mineral Supplements on Performance of Dairy Cows1

To determine the effects of chemical form of trace mineral supplements on performance of dairy cows, Holstein cows (n = 36) were assigned to dietary treatments of inorganic trace minerals or a combination of inorganic and complexed trace minerals (CTM). Starting at 21 d prepartum, dry cows were fed hay and a grain supplement that contained one of the trace mineral supplements. Cows continued to receive their respective trace mineral treatment from parturition until 150 d in milk (DIM). Cows fed the CTM lost less BW prepartum (P<0.05); however, there was no difference between treatments in postpartum BW change or body condition score (BCS). The DMI of lactating cows were similar between treatments. Actual milk yield (42.2 vs 41.7 kg/d), 3.5% fat-corrected milk (FCM) (42.3 vs 42.3 kg/d), and measures of production efficiency also were similar between treatments. There was a week × treatment interaction (P<0.05) for yield of milk, energy-corrected milk, and 3.5% FCM; the response to CTM was greatest from wk 5 through wk 10 postpartum. Colostrum of cows fed the CTM prepartum had greater IgG (P<0.05) and lesser Zn concentrations. There was no difference between treatments in concentrations of IgM, Co, Mn, or Cu in colostrum. Although there were period effects on serum concentrations of IgG, IgM, nonesterified fatty acids (NEFA), Zn, Co, and Ca, there were no treatment effects. These results indicate that CTM may benefit cows at peak production.

Effect of sex and time of sampling on selenium and glutathione peroxidase activity in tissues of mature rats

Sprague-Dawley rats were used to investigate variations in measures of gluthathione peroxidase (GSH-Px) and selenium (Se) concentration resulting from diurnal cycles and sex. Mature rats (equal numbers of males and females) were killed at 4 h intervals over a 48 h period (0200, 0600, 1000, 1800 and 2200 h each day). Selenium and GSH-Px were measured in plasma, erythrocytes, and liver and kidney cytosols. Selenium concentrations did not vary diurnally, but plasma GSH-Px activities were higher during the light than dark periods. Males had greater plasma GSH-Px activities and Se concentrations (42 EU and .45 mg/kg, respectively) than females (35 EU and .41 mg/kg respectively). GSH-Px activities were also higher in male kidney cytosols than females (117 and 76 EU, respectively). Selenium and GSH-Px activities, however, were lower in male liver cytosols (.48 mg/kg and 272 EU) than females (1.19 mg/kg and 795 EU, respectively). These data suggest that Se is distributed differently in male and female rats and the difference in Se distribution is accomplished by differences in GSH-Px activities.

Effectiveness of potassium carbonate sesquihydrate to increase dietary cation-anion difference in early lactation cows

The effect of additional dietary potassium in early lactation dairy cows was evaluated with the addition of potassium carbonate sesquihydrate, which increased dietary K from 1.3 to 2.1% of dry matter (DM) from wk 3 to 12 of lactation. Cows fed potassium carbonate sesquihydrate in the form of DCAD Plus (Church & Dwight Co. Inc., Princeton, NJ) had increased DM intake, milk fat percentage and yield, energy-corrected milk, and efficiency of milk production per unit of DM intake. Milk fat of cows fed higher dietary K had a lower concentration of trans fatty acids, suggesting a role for potassium carbonate sesquihydrate in the rumen in the biohydrogenation processes converting linoleic to stearic acid. Cows fed the diet with 2.1% K had greater apparent balance of K, and no effects were noted on the concentration of blood Mg or amount of fecal Mg. The data support the feeding of greater amounts of K in the early lactation cow.

Gestational changes in concentrations of selenium and zinc in the porcine fetus and the effects of maternal intake of selenium.

The effect of maternal dietary selenium (Se) and gestation on the concentrations of Se and zinc (Zn) in the porcine fetus were determined. Mature gilts were randomly assigned to treatments of either adequate (0.39 ppm Se) or low (0.05 ppm Se) dietary Se. Gilts were bred and fetuses were collected throughout gestation. Concentrations of Se in maternal whole blood and liver decreased during gestation in sows fed the low-Se diet compared to sows fed the Se-supplemented diet. Maternal intake of Se did not affect the concentration of Se in the whole fetus; however, the concentration of Se in fetal liver was decreased in fetuses of sows fed the low-Se diet. Although fetal liver Se decreased in both treatments as gestation progressed, the decrease was greater in liver of fetuses from sows fed the low-Se diet. Dietary Se did not affect concentrations of Zn in maternal whole blood or liver or in the whole fetus and fetal liver. The concentration of Se in fetal liver was lower but the concentration of Zn was greater than in maternal liver when sows were fed the adequate Se diet. These results indicate that maternal intake of Se affects fetal liver Se and newborn piglets have lower liver Se concentrations compared to their dams, regardless of the Se intake of sows during gestation. Thus, the piglet is more susceptible Se deficiency than the sow.

DEVELOPMENT OF STANDARD METHODS TO ESTIMATE MANURE PRODUCTION AND NUTRIENT CHARACTERISTICS FROM DAIRY CATTLE

Total collection data from many universities were pooled for statistical analyses to evaluate existing data from dairy animals and determine if one or more modifications were needed for Standard Table D384.1. Many of these studies were carried out to evaluate nutritional characteristics associated with different diets. The data collected were sufficient to evaluate total manure, total and volatile solids, and N excretion values. Some experiments had sufficient number of samples analyzed to evaluate P, K, Ca, Mg, Na, Cl, S, and micro-elements. Statistical analyses were conducted to determine if a single column value was appropriate and define the regression equations necessary to estimate excretions if the assumptions of the column inputs were not met. The results indicate that separate classifications are needed for replacement heifers and mature animals. Final classifications for replacement heifers included: milk fed calves, weaned calves weighing less than 274 kg, heifers weighing between 273 and 613 kg, and veal calves. Additionally, classifications for lactating and dry animals are needed. Previously, the estimates for manure production and nutrient excretion were based on body weight. These findings indicate that a better predictor for lactating cattle is daily milk production instead of body weight. Milk production drives feed intake in the lactating animal. It is most appropriate that estimated manure and nutrient excretion values reflect the relationship between feed intake, milk production (nutrient utilization) and nutrient excretion.

Maternal Selenium Deficiency Increases Hydrogen Peroxide and Total Lipid Peroxides in Porcine Fetal Liver

To investigate the role of selenium (Se) in the developing porcine fetus, prepubertal gilts (n=42) were randomly assigned to either Se-adequate (0.39 ppm Se) or Se-deficient (0.05 ppm Se) gestation diets 6 wk prior to breeding. Maternal and fetal liver was collected at d 30, 45, 70, 90, and 114 of pregnancy. Concentrations of Se in maternal liver decreased during gestation in gilts fed the low-Se diet. The activity of cellular glutathione peroxidase (GPx) was decreased at d 30 and 45 of gestation in liver of gilts fed the low-Se diet. Concentrations of malondialdehyde (MDA) and hydrogen peroxide (H2O2) were greater in liver homogenates from gilts fed the low-Se diet. Within the fetuses, liver Se decreased in those fetuses of gilts fed the low-Se diet. Although the activity of GPx in fetal liver was not affected by the maternal diet, concentrations of H2O2 and MDA in fetal liver were greater in fetuses from gilts fed the low-Se diet. Maternal liver GPx activity was approx 12-fold greater than fetal liver GPx activity regardless of dietary treatment. These results indicate that maternal dietary Se intake affects fetal liver Se concentration and feeding a low-Se diet during gestation increases oxidative stress to the fetus, as measured by fetal liver H2O2 and MDA.

Body weight loss in beef cows: II. Increased antioxidant messenger ribonucleic acid levels in skeletal muscle but not erythrocyte antioxidant activity.

Twenty-six Angus-cross cows were used to examine the effect of BW loss (WL) on skeletal muscle and erythrocyte markers of oxidative stress. Serum NEFA concentrations, erythrocyte superoxide dismutase, and glutathione peroxidase activities were measured during WL and BW maintenance. Real-time reverse-transcription-PCR was used to determine mRNA levels of antioxidant genes during both periods to assess skeletal muscle response to WL. Body weight loss resulted in elevated serum NEFA concentrations but no change in erythrocyte superoxide dismutase and glutathione peroxidase activities. During WL, mRNA levels of the antioxidant genes glutathione peroxidase 4, mitochondrial superoxide dismutase, thioredoxin reductase 1, and selenoprotein W increased. Abundance of mRNA of genes involved in antioxidant signaling, specifically, PPARgamma coactivator-1 alpha, nuclear respiratory factor 1, estrogen-related receptor alpha, and tumor protein 53, was also increased. In summary, during WL cows had no change in peripheral antioxidant enzyme activity, but mRNA abundance of proteins involved in protecting the body from oxidative stress increased in skeletal muscle. During times when NEFA are used as a fuel source, signals such as mild reactive oxygen species production or increased concentration of lipid by-products activate the transcription of nuclear signaling molecules such as PPARgamma gamma coactivator-1 alpha, nuclear respiratory factor 1, estrogen-related receptor alpha, and tumor protein 53. These genes work to activate antioxidant genes such as mitochondrial superoxide dismutase, glutathione peroxidase 4, and thioredoxin reductase 1 to aid in the detoxification of reactive oxygen species. These data suggest an important role for antioxidant genes to protect cattle that are mobilizing body fat.

Ammonia and sulfur dioxide treated wheat straw as a feedstuff for cattle

Abstract Wheat straw was treated with anhydrous NH 3 at 0, 1.75 or 3.50% of dry matter (DM) and then with SO 2 (0, 2, 3, 4 and 5% DM) for either 3 or 7 days. Dry matter degradability (DMD) was measured using an in situ nylon bag technique. Nitrogen retention and DMD of the wheat straw was increased by the ammoniation ( P 3 × SO 2 interaction ( P 2 also showed increased DMD and crude protein (CP) at 0, 2, 3, 4 and 5% levels ( P 2 resulted in increased DMD (62.0% vs. 59.7%, P Two feeding trials were conducted with wheat straw treated with either NH 3 alone or a combination of NH 3 and SO 2 . In Study 1, growing beef heifers were fed: (a) untreated straw (US); (b) ammoniated straw (AS); (c) NH 3 + SO 2 treated straw; (d) NH 3 + SO 2 treated straw (43% DM) and hay (57% DM); (e) bromegrass hay (H) alone fed ad libitum. All heifers received 1.3 kg of supplement in two daily meals. Intake of NH 3 + SO 2 treated straw for the first 28 days was very low compared with AS (1.8 kg vs. 3.8 kg), resulting in severe weight loss (−600 g day −1 ). This treatment was replaced by a mixture of NH 3 + SO 2 treated straw (43% DM) and haylage (57% DM) for the rest of the trial (10 weeks). Ammoniation of wheat straw did not significantly increase DM intakes (DMI) compared with US (5.99 kg day −1 vs. 5.12 kg day −1 , P > 0.05) but improved average daily gain (ADG) (510 g vs. 347 g, P 3 + SO 2 treated straw and either haylage or hay consumed more feed (7.27 kg day −1 and 8.07 kg day −1 vs. 5.99 kg day −1 ) and gained more weight (833 g day −1 and 816 g day −1 vs. 510 g day −1 ) than animals fed AS. Animals fed H had DMI and ADG values similar to those fed NH 3 + SO 2 treated straw and hay ( P > 0.05). The second trial was done to determine the effects of chemical treatment of straw on ruminal function and fiber digestion. The diets, offered ad libitum with a supplement, were US, AS, NH 3 + SO 2 treated straw alone and with hay. There was no effect of diet on ruminal dilution rate. The DMD values of the US, AS, NH 3 + SO 2 treated straw, and H were 48%, 58%, 68% and 62%, respectively. When fed as the only forage, NH 3 + SO 2 treated straw resulted in anorexia and weight loss; however, when fed at 43% of diet DM, feed intakes and weight gains of heifers were better than AS and similar to H. In summary, the combined use of NH 3 and SO 2 at ambient temperatures has potential as a practical method for treatment of wheat straw.