Limited research has examined the effects that dietary protein sources have on copper (Cu) and zi... more Limited research has examined the effects that dietary protein sources have on copper (Cu) and zinc (Zn) absorption, interactions and utilization in rainbow trout. Therefore, the objective of the first trial was to determine what effect Cu source (complex vs. inorganic) and Cu concentration (0, 5, 10, 15, 20 ppm) had on rate and efficiency of gain and Cu tissue concentration in rainbow trout fed both plant-protein and animal-protein based diets. The second trial then examined if interactions occur due to increasing dietary content of Zn (0, 30, 300, 1500 ppm) in rainbow trout fed a plant-based diet. Results from the first trial demonstrated differences in growth and tissue mineral concentrations due to Cu concentration but not source. Trout fed plant-based diets had higher weight gain, improved feed conversion ratio and higher hepatic Cu concentration when compared to fishmeal-fed trout. Results from the second trial show that increasing dietary Zn supplementation increased whole body Zn and Cu at 12 weeks. No significant antagonism between Cu and Zn was observed in rainbow trout fed plant-based diets. Zn deficiency signs were observed at 12 weeks in trout fed a plant-based diet without Cu and Zn supplementation which included mortality, cataracts and caudal fin erosion. Results of these studies indicate that rainbow trout fed plant-based diets require both Cu and Zn supplementation at concentrations higher than those previously reported to maximize growth.
Targhee ewes (n = 22, average age 5 yr) rearing twin lambs were used to investigate serum growth ... more Targhee ewes (n = 22, average age 5 yr) rearing twin lambs were used to investigate serum growth hormone (GH), IGF-I, triiodothyronine (T 3) , thyroxine (T 4) , and prolactin (PRL; ewes only) concentrations associated with selection pressure for lifetime production of kilograms of lamb weaned per ewe. Period 1 started on d 4 after birth and was conducted in confinement. Periods 2, 3, and 4 were conducted on fenced intermountain sagebrush-bunchgrass range starting at an average of 49, 84, and 112 d after birth, respectively. Blood samples were collected hourly for 6 h on d 4, 11, 18, 25, 49, 84, and 112 after lambing. Ewe models included the fixed effect for line, with ewe age, lambing date, and starting weight nested within line as potential covariables. Lamb models included fixed effects for line, sex, and sibling sex, with lamb age and birth weight nested within line tested as possible covariables. Growth hormone concentrations were greater (P = .06) for selected than for control ewes, but lamb GH concentrations did not differ (P = .90) between selected and control lambs. Ewe prolactin concentration tended (P = .13) to be greater for control than for selected ewes. Ewe and lamb IGF-I did not differ (P > .55) between selected and control ewes and lambs. Ewe T 3 and T 4 concentrations did not differ (P > .19) between selected and control ewes; however, lamb T 3 and T 4 concentrations were greater (P < .01) for control than for selected lambs. Increased GH concentration in selected ewes seemed to be associated with greater milk production. Differences in selected and control lamb T 3 and T 4 concentrations could be an indicator of receptor sensitivity, metabolic activity, or seasonal reproductive transitions in ewe lambs.
Altering nutrient partitioning after calving from milk production to positive energy balance may ... more Altering nutrient partitioning after calving from milk production to positive energy balance may improve reproductive performance. A 2004 study conducted at the Corona Range and Livestock Research Center evaluated responses of 2- (n = 17), 3- (n = 23), and 4-yr-old (n = 31) postpartum cows grazing native range (11.3% CP and 80% NDF, OM basis) to 3 protein supplements with increasing glucogenic potential (GP). Supplements were fed at 1,135 g·cow -1 ·d
One-seed juniper (Juniperus monosperma; JM) encroachment on rangelands is a problem in the Southw... more One-seed juniper (Juniperus monosperma; JM) encroachment on rangelands is a problem in the Southwest. A proposed method of JM control is defoliation by small ruminants. Juniper produces secondary metabolites that may be antimicrobial in nature. Ruminants depend on ruminal microbes for digestion of feed. Five ruminally fistulated wethers (BW 55 ± 15 kg) were used in two cross-over experiments composed
The study focused attention on the relationships between body condition score (BCS) at mating and... more The study focused attention on the relationships between body condition score (BCS) at mating and the reproductive performance of Barki ewes. A number of 541 ewes were mated naturally in autumn for three consecutive years. The flock was managed under a semi-intensive production system, with feeding based on natural pasture grazing over the mating period. Grain flushing was given to the ewes before mating. A five category BCS scale was used to classify ewes one week before joining Average values for BCS at mating were 3.32, fertility, 83 % and prolificacy, 1.03. Year were highly significant (P<.0.01) for body weight but not significant for fertility and prolificacy. Age of dam had a significant effect on weight of dam, fertility and prolificacy. Significant differences were observed for BSC effects on fertility, prolificacy and weight of ewe (P<0.05 to P<0.l), which gave highest values between BCS of (3) and (4) categories. In conclusion, the BCS at mating seemed to affect fertility more than prolificacy.
Two experiments were conducted to evaluate effects of supplemental protein source and ME intake (... more Two experiments were conducted to evaluate effects of supplemental protein source and ME intake (Exp. 1) on ewe nutritional status during pregnancy. Forty-two mature Targhee ewes were allotted randomly in Exp. 1 to one of six treatments (n = 7) using a 2 x 3 factorial arrangement. Ewes were individually fed chopped barley straw and supplements containing either urea (U), soybean meal (SBM), or blood meal (BM) plus SBM during the 84-d experiment. Straw and supplement intakes were adjusted to meet either 80 or 100% of ME requirements. In Exp. 2, 30 pregnant Targhee ewes that were allotted randomly to one of three groups (n = 10) were individually fed protein supplements similar to those in Exp. 1 and had group access to long-stem barley straw. In Exp. 1, ewes fed BM + SBM gained more (P less than .05) weight, lost less (P less than .05) body condition, and had increased (P less than .05) wool fiber length compared with ewes fed U; SBM ewes were intermediate (P less than .05) in response. Ewes fed BW + SBM had increased (P less than .05) blood urea N and albumin concentrations compared with ewes fed U. Metabolizable energy intake did not affect (P greater than .05) ewe performance or serum metabolite concentrations. Ewes fed BM + SBM in Exp. 2 gained more (P less than .05) weight than ewes fed either SBM or U, and ewes fed SBM lost less weight (P less than .05) than ewes fed U.(ABSTRACT TRUNCATED AT 250 WORDS)
Two metabolism trials were conducted with yearling steers fed mature native forage to measure the... more Two metabolism trials were conducted with yearling steers fed mature native forage to measure the effect of supplemental protein degradability on selected metabolic variables. Supplements contained 40% crude protein equivalence. In Trial 1, four abomasal-cannulated steers weighing 290 to 379 kg were fed supplements containing the following N sources: (1) 15% corn, 85% urea (U); (2) 100% soybean meal (SBM); (3) 10% corn, 40% soybean meal, 50% urea (SBM-U) and (4) 14% corn, 36% blood meal, 50% urea (BM-U). Equal portions of the daily diet (2.2% of body weight) were fed every 2 h. Treatment differences were not significant for organic matter digestibility, abomasal organic matter flow, nonammonia N flow, feed N flow, bacterial N flow and efficiency of microbial protein synthesis. There was a positive (P less than .05) relationship between quantity of slowly degraded protein fed and nonammonia N flow (r = .97) or feed N flow (r = .98). Escape N was determined to be 21.5, 16.5 and 54.2% in SBM, SBM-U and BM-U supplements, respectively. In the second trial, no supplement, SBM, SBM-U and BM-U were fed in a N balance trial. Dry matter, crude protein and neutral detergent fiber digestibilities were higher (P less than .05) for steers fed supplemented diets. Acid detergent fiber digestibility was higher (P less than .05) for steers supplemented with SBM than steers fed the unsupplemented diets. Nitrogen retention was greater (P less than .05) for cattle fed SBM and BM-U than for cattle fed SBM-U or no supplement.(ABSTRACT TRUNCATED AT 250 WORDS)
A 3 X 3 replicated Latin square design was used to evaluate three isonitrogenous supplements desi... more A 3 X 3 replicated Latin square design was used to evaluate three isonitrogenous supplements designed to supply 250 g crude protein (CP) daily. Measurements included in situ dry matter (DM) and neutral detergent fiber (NDF) fermentation and ruminal dilution rates. Supplements contained beet pulp plus DL-methionine and urea (MET), ammonium sulfate and urea (U) or soybean meal (SBM). Six mature, ruminaUy cannulated crossbred beef cows were individually fed supplement and a mixture (63% NDF and 6.1% CP) of chopped 75% grass hay and 25% barley straw in ad libitum. Fermentation rate of DM was increased (P < .05) by 30% with MET in comparison to SBM or U (9.54 vs 7.28% and 7.74%/h for MET, SBM and U, respectively). Even though MET improved fermentation rate by 30%, particle dilution rate was more important in affecting ruminal digestibility than fermentation rate. Two 90-d heifer growth trials were conducted to evaluate similar supplements. Supplements similar to those used in the in situ trial were mixed with roughage to provide a complete diet balanced for .3 kg daily gain. Heifers consumed 112% of the National Research Council CP requirement. Weight gain, intake and feed conversion were similar (P > .10) for all treatments. In heifer trial 2, 90% of the National Research Council CP requirement was fed. The heifers supplemented with MET and SBM had faster (P < .05) weight gains than heifers receiving U. These studies show that feeding DL-methionine with urea, as compared with feeding an isonitrogenous supplement containing SBM, increased the fermentation rate of DM. Heifer weight gains were improved when DL-metbionine was added to urea to a point equal to that of heifers fed a SBM-based supplement.
Kentucky bluegrass straw (KBS) ensiled with hydroxide(NaOH, Ca[OH] 2 or NaOH + Ca[OH] 2) and(or) ... more Kentucky bluegrass straw (KBS) ensiled with hydroxide(NaOH, Ca[OH] 2 or NaOH + Ca[OH] 2) and(or) supplemental protein sources (soybean meal [SBM], cull beans or peas) was evaluated in a laboratory study and one lamb metabolism trial. In vitro organic matter digestibility (IVOMD) of alkali-treated silage was greater (P<.05) than that of untreated silages (Exp. 1). Silage treated with NaOH had a higher (P<.05) IVOMD than did those treated with Ca(OH)2. Addition of 2% NaOH + 2% Ca(OH)2 produced an intermediate value that was not different (P>.05) from that observed with either alkali alone. Straw ensiled with supplemental crude protein (SCP) had higher (P<.05) IVOMD than did the control. SCP tended to decrease the neutral detergent fiber (NDF) content of silage; however, this response was not consistent across all treatment combinations. Four percent NaOH or 2% NaOH + 2% Ca(OH)2 were equally effective (P>.05) in reducing NDF when straw was ensiled with cull beans or peas. Acid detergent fiber (ADF) was unchanged (P>.05) by alkali treatment. Silage containing cull peas or beans had lower (P<.05) ADF concentrations than did those with SBM or no SCP. Acid detergent lignin (ADL) was higher (P<.05) in alkali-treated silages. Crude protein concentration of silage was higher (P<.05) when SCP was added or with no alkali addition. Silages treated with alkali had higher (P<.05) pH values than did 1 Idaho Agr. Exp. Sta. Pub. No. 8042. 2This research was supported in part by a grantin-aid from the Idaho Research Council. a Dept. of Anita. Sci.
This study was designed to determine the influence of soybean meal supplementation, with or witho... more This study was designed to determine the influence of soybean meal supplementation, with or without additional ruminal escape protein or fat, on the nutritional status of pregnant winter-grazing beef cows. During two winters (Trials 1 and 2), approximately 60 prepartum beef cows grazed native foothills range each year. Cows were allotted randomly to five groups and supplemented (dd) with either none (control); 570 soybean meal (SOY); 450 soybean meal plus 230 blood meal (SOY + BM); 140 soybean meal, 16 urea plus 450 corn gluten meal (SOY + CGM); or 570 soybean meal plus 210 animal fat (SOY + FAT). These supplements were designed to supply similar quantities of ruminal degraded protein while varying in escape protein quantity and source (SOY + BM and SOY + CGM). Condition scores and body weights were determined at mal initiation (mid-December) and conclusion (early March). Eight blood samples obtained over 4 d during three periods (9, 4 and 1 wk prior to parturition) were analyzed for concentrations of glucose, urea nitrogen (N), total bilirubin, creatinine, albumin, total protein and cholesterol. Cows in the control treatment experienced the greatest BW loss in both aids. In Trial 2, escape protein tended to decrease (P < .06) BW loss compared to SOY, though loss tended to be greater (P < .08) with SOY + CGM than with SOY + BM. Escape protein can enhance nutritional status when supplemented with .6 kg/d of soybean meal.
Rambouillet wethers, surgically fitted with ruminal and duodenal cannulas, were used to determine... more Rambouillet wethers, surgically fitted with ruminal and duodenal cannulas, were used to determine the influence of substituting soybean meal (SBM) with blood meal (BM) in grass hay diets (8.0% CP) on N flow to the small intestine. Treatments were arranged in a 3 x 4 Latin square design and included diets (10.6% CP) supplemented with SBM; 2/3 SBM:1/3 BM; 1/3 SBM:2/3 BM; or BM. Ruminal NH3 N concentration decreased linearly (P = .03) as BM replaced SBM; however, feeding BM did not affect (P &amp;amp;gt; .10) the total N, microbial N, or nonammonia N flows to the small intestine. A second experiment was conducted to determine the influence of substituting SBM with BM on ewe BW and condition score changes, blood metabolite profiles, wool growth, and progeny wool follicle development. Thirty-two pregnant Targhee ewes fed a grass hay diet were allotted randomly to four groups (n = 8) and supplemented with either SBM; 2/3 SBM:1/3 BM; 1/3 SBM:2/3 BM; or BM. Soybean meal, BM, or their combinations provided 22 g of dietary CP daily. Dietary treatments had no influence on ewe BW (P = .40) or body condition score (P = .77) changes, and ewes gained 7.6 kg of BW during the 84-d experiment. Protein source did not influence (P &amp;amp;gt; .10) serum protein, urea N, creatinine, glucose, or nonesterified fatty acid concentrations. Lamb wool follicle density per square millimeter and secondary:primary follicle ratios were 22.4 and 10.8, respectively, and were not different (P &amp;amp;gt; .10) among dietary treatments. Compared with SBM, no advantages were detected for BM supplementation of grass hay diets in these studies.
Increasing longevity of beef cows by decreasing the proportion culled due to reproductive failure... more Increasing longevity of beef cows by decreasing the proportion culled due to reproductive failure provides an efficient process to rebuild a cow herd and can reduce number of replacements needed to sustain a constant herd size. Rate of reproductive failure varies due to cow age, where failure in cows 2 to 4 yr of age is often greater than in cows 5 to 7 yr of age. In addition, BW of cow and calf at weaning increase as cows advance from 2 to 5 yr of age. The cumulative effect of increasing retention of young cows is improved production efficiency through decreased replacement rate and changing age structure of the herd resulting in a greater proportion of cows at maximal production potential for calf BW at weaning and cow BW at time of culling. Calculations from cow age-specific culling and BW data from commercial and research herds indicated that reducing replacement rate from 18% to 14% resulted in a 23% increase in calf BW weaned and a 2% increase in cull cow BW per pregnant replacement heifer going into the herd. Although improving longevity increases production efficiency, genetic advancement in sustained reproductive function is challenging, as it is the sequential culmination of the annual repetition of numerous discrete physiological processes, each ending in a qualitative response. Successful completion of one process is prerequisite to evaluating subsequent processes. These physiological processes are subject to nutritional threshold requirements that may vary due to genetic potential for other production traits such as milk, growth, and mature size resulting in genetic-by-nutrition interactions. This is in contrast to most traits for which EPD exist, where genetic-by-environment interactions are not considered to be significant. Extensive research concerning impact of limited nutrition on reproduction has led to recommendations that heifers and cows be fed to a threshold BW or BCS to ensure reproductive success; a process that masks nutritional interactions that might otherwise result in reproductive failure. This management approach minimizes selection for animals capable of sustained reproductive function under limited nutritional environments. Rearing and managing cows under nutritionally limited environments may lead to adaptations that result in relatively high levels of reproductive success under lower input levels. Such adaptation may improve chances for longer retention in their offspring in nutrient-limited environments.
Diet and physiological state have been implicated in altering insulin sensitivity in range cows. ... more Diet and physiological state have been implicated in altering insulin sensitivity in range cows. An increase in diet glucogenic precursors (GP) may improve sensitivity to insulin. A study at the Corona Range and Livestock Research Center in 2006 (n = 29) and 2007 (n = 24) evaluated metabolic and lactational responses of postpartum 2 and 3 yr old cows grazing
Twelve Hereford  Angus heifers, 2.5 year, 492 AE 17 kg (BCS 5 AE 0:5), were randomly assigned to... more Twelve Hereford  Angus heifers, 2.5 year, 492 AE 17 kg (BCS 5 AE 0:5), were randomly assigned to one of three supplements, strati®ed by calving date and calf sex. Treatments consisted of a daily equivalent of: (1) low undegradable intake protein (UIP) (L: 908 g per cow per day; 36% CP, 108 g UIP), (2) middle UIP (M: 908 g per cow per day; 36% CP, 165 g UIP), and (3) high UIP (H: 908 g M 243 g feather meal per cow per day; 46% CP, 335 g UIP). Cows were fed sudan grass hay (7.3% CP, as fed) daily at 2% BW (as fed). Supplement was individually fed twice weekly from Week 2 to Week 11 post-partum. Cow body weight (BW), backfat (BF) and rumpfat (RF) thicknesses decreased in all cows, (P < 0:05) yet did not differ among treatments (P > 0:10). There were no differences among treatments in calf BW (P > 0:10). Serum insulin, blood urea nitrogen (BUN), milk components and yield did not differ among treatments (P > 0:10). Area under the curve (AUC) for serum LH was greater (P 0:07) in H versus L and M (809 versus 599 and 607 AE 69 U, respectively). No differences were observed in FSH AUC or mean serum concentrations (P > 0:10). Uterine pH did not differ among treatments or between supplement versus non-supplement days (P > 0:10). Serum progesterone remained below 1 ng/ml for all cows indicating absence of return to estrus. Under the conditions of this study, BW, BF, RF, serum insulin, BUN, milk components, and yield, uterine pH and serum FSH were not affected by level of UIP. However, supplement containing high levels of UIP enhanced GnRH-induced LH release.
Young beef cows experience a negative energy balance after parturition and during lactation when ... more Young beef cows experience a negative energy balance after parturition and during lactation when grazing dormant New Mexico range. As a result, sensitivity to insulin may be decreased due to the physiology of lactation and poor forage quality. However, with adequate precipitation during the growing season, forage quality improves, and insulin sensitivity may increase. An experiment was conducted to investigate seasonal changes in nutrient status of young range cows (n = 22) at the New Mexico State University Livestock Research Center and the Corona Range and Livestock Research Center. Two glucose tolerance tests (GTT) were conducted, one at 35 d postpartum (winter/spring) and one at 165 d postpartum (summer). At the time of the winter/spring GTT, 2-year-old cows were group fed a mixture of wheat straw and alfalfa hay (7 to 8% CP, OM basis) similar to New Mexico native range in March and April. Cows were grazing New Mexico green forage at the time of the summer GTT. For each GTT, 50%...
Limited research has examined the effects that dietary protein sources have on copper (Cu) and zi... more Limited research has examined the effects that dietary protein sources have on copper (Cu) and zinc (Zn) absorption, interactions and utilization in rainbow trout. Therefore, the objective of the first trial was to determine what effect Cu source (complex vs. inorganic) and Cu concentration (0, 5, 10, 15, 20 ppm) had on rate and efficiency of gain and Cu tissue concentration in rainbow trout fed both plant-protein and animal-protein based diets. The second trial then examined if interactions occur due to increasing dietary content of Zn (0, 30, 300, 1500 ppm) in rainbow trout fed a plant-based diet. Results from the first trial demonstrated differences in growth and tissue mineral concentrations due to Cu concentration but not source. Trout fed plant-based diets had higher weight gain, improved feed conversion ratio and higher hepatic Cu concentration when compared to fishmeal-fed trout. Results from the second trial show that increasing dietary Zn supplementation increased whole body Zn and Cu at 12 weeks. No significant antagonism between Cu and Zn was observed in rainbow trout fed plant-based diets. Zn deficiency signs were observed at 12 weeks in trout fed a plant-based diet without Cu and Zn supplementation which included mortality, cataracts and caudal fin erosion. Results of these studies indicate that rainbow trout fed plant-based diets require both Cu and Zn supplementation at concentrations higher than those previously reported to maximize growth.
Targhee ewes (n = 22, average age 5 yr) rearing twin lambs were used to investigate serum growth ... more Targhee ewes (n = 22, average age 5 yr) rearing twin lambs were used to investigate serum growth hormone (GH), IGF-I, triiodothyronine (T 3) , thyroxine (T 4) , and prolactin (PRL; ewes only) concentrations associated with selection pressure for lifetime production of kilograms of lamb weaned per ewe. Period 1 started on d 4 after birth and was conducted in confinement. Periods 2, 3, and 4 were conducted on fenced intermountain sagebrush-bunchgrass range starting at an average of 49, 84, and 112 d after birth, respectively. Blood samples were collected hourly for 6 h on d 4, 11, 18, 25, 49, 84, and 112 after lambing. Ewe models included the fixed effect for line, with ewe age, lambing date, and starting weight nested within line as potential covariables. Lamb models included fixed effects for line, sex, and sibling sex, with lamb age and birth weight nested within line tested as possible covariables. Growth hormone concentrations were greater (P = .06) for selected than for control ewes, but lamb GH concentrations did not differ (P = .90) between selected and control lambs. Ewe prolactin concentration tended (P = .13) to be greater for control than for selected ewes. Ewe and lamb IGF-I did not differ (P > .55) between selected and control ewes and lambs. Ewe T 3 and T 4 concentrations did not differ (P > .19) between selected and control ewes; however, lamb T 3 and T 4 concentrations were greater (P < .01) for control than for selected lambs. Increased GH concentration in selected ewes seemed to be associated with greater milk production. Differences in selected and control lamb T 3 and T 4 concentrations could be an indicator of receptor sensitivity, metabolic activity, or seasonal reproductive transitions in ewe lambs.
Altering nutrient partitioning after calving from milk production to positive energy balance may ... more Altering nutrient partitioning after calving from milk production to positive energy balance may improve reproductive performance. A 2004 study conducted at the Corona Range and Livestock Research Center evaluated responses of 2- (n = 17), 3- (n = 23), and 4-yr-old (n = 31) postpartum cows grazing native range (11.3% CP and 80% NDF, OM basis) to 3 protein supplements with increasing glucogenic potential (GP). Supplements were fed at 1,135 g·cow -1 ·d
One-seed juniper (Juniperus monosperma; JM) encroachment on rangelands is a problem in the Southw... more One-seed juniper (Juniperus monosperma; JM) encroachment on rangelands is a problem in the Southwest. A proposed method of JM control is defoliation by small ruminants. Juniper produces secondary metabolites that may be antimicrobial in nature. Ruminants depend on ruminal microbes for digestion of feed. Five ruminally fistulated wethers (BW 55 ± 15 kg) were used in two cross-over experiments composed
The study focused attention on the relationships between body condition score (BCS) at mating and... more The study focused attention on the relationships between body condition score (BCS) at mating and the reproductive performance of Barki ewes. A number of 541 ewes were mated naturally in autumn for three consecutive years. The flock was managed under a semi-intensive production system, with feeding based on natural pasture grazing over the mating period. Grain flushing was given to the ewes before mating. A five category BCS scale was used to classify ewes one week before joining Average values for BCS at mating were 3.32, fertility, 83 % and prolificacy, 1.03. Year were highly significant (P<.0.01) for body weight but not significant for fertility and prolificacy. Age of dam had a significant effect on weight of dam, fertility and prolificacy. Significant differences were observed for BSC effects on fertility, prolificacy and weight of ewe (P<0.05 to P<0.l), which gave highest values between BCS of (3) and (4) categories. In conclusion, the BCS at mating seemed to affect fertility more than prolificacy.
Two experiments were conducted to evaluate effects of supplemental protein source and ME intake (... more Two experiments were conducted to evaluate effects of supplemental protein source and ME intake (Exp. 1) on ewe nutritional status during pregnancy. Forty-two mature Targhee ewes were allotted randomly in Exp. 1 to one of six treatments (n = 7) using a 2 x 3 factorial arrangement. Ewes were individually fed chopped barley straw and supplements containing either urea (U), soybean meal (SBM), or blood meal (BM) plus SBM during the 84-d experiment. Straw and supplement intakes were adjusted to meet either 80 or 100% of ME requirements. In Exp. 2, 30 pregnant Targhee ewes that were allotted randomly to one of three groups (n = 10) were individually fed protein supplements similar to those in Exp. 1 and had group access to long-stem barley straw. In Exp. 1, ewes fed BM + SBM gained more (P less than .05) weight, lost less (P less than .05) body condition, and had increased (P less than .05) wool fiber length compared with ewes fed U; SBM ewes were intermediate (P less than .05) in response. Ewes fed BW + SBM had increased (P less than .05) blood urea N and albumin concentrations compared with ewes fed U. Metabolizable energy intake did not affect (P greater than .05) ewe performance or serum metabolite concentrations. Ewes fed BM + SBM in Exp. 2 gained more (P less than .05) weight than ewes fed either SBM or U, and ewes fed SBM lost less weight (P less than .05) than ewes fed U.(ABSTRACT TRUNCATED AT 250 WORDS)
Two metabolism trials were conducted with yearling steers fed mature native forage to measure the... more Two metabolism trials were conducted with yearling steers fed mature native forage to measure the effect of supplemental protein degradability on selected metabolic variables. Supplements contained 40% crude protein equivalence. In Trial 1, four abomasal-cannulated steers weighing 290 to 379 kg were fed supplements containing the following N sources: (1) 15% corn, 85% urea (U); (2) 100% soybean meal (SBM); (3) 10% corn, 40% soybean meal, 50% urea (SBM-U) and (4) 14% corn, 36% blood meal, 50% urea (BM-U). Equal portions of the daily diet (2.2% of body weight) were fed every 2 h. Treatment differences were not significant for organic matter digestibility, abomasal organic matter flow, nonammonia N flow, feed N flow, bacterial N flow and efficiency of microbial protein synthesis. There was a positive (P less than .05) relationship between quantity of slowly degraded protein fed and nonammonia N flow (r = .97) or feed N flow (r = .98). Escape N was determined to be 21.5, 16.5 and 54.2% in SBM, SBM-U and BM-U supplements, respectively. In the second trial, no supplement, SBM, SBM-U and BM-U were fed in a N balance trial. Dry matter, crude protein and neutral detergent fiber digestibilities were higher (P less than .05) for steers fed supplemented diets. Acid detergent fiber digestibility was higher (P less than .05) for steers supplemented with SBM than steers fed the unsupplemented diets. Nitrogen retention was greater (P less than .05) for cattle fed SBM and BM-U than for cattle fed SBM-U or no supplement.(ABSTRACT TRUNCATED AT 250 WORDS)
A 3 X 3 replicated Latin square design was used to evaluate three isonitrogenous supplements desi... more A 3 X 3 replicated Latin square design was used to evaluate three isonitrogenous supplements designed to supply 250 g crude protein (CP) daily. Measurements included in situ dry matter (DM) and neutral detergent fiber (NDF) fermentation and ruminal dilution rates. Supplements contained beet pulp plus DL-methionine and urea (MET), ammonium sulfate and urea (U) or soybean meal (SBM). Six mature, ruminaUy cannulated crossbred beef cows were individually fed supplement and a mixture (63% NDF and 6.1% CP) of chopped 75% grass hay and 25% barley straw in ad libitum. Fermentation rate of DM was increased (P < .05) by 30% with MET in comparison to SBM or U (9.54 vs 7.28% and 7.74%/h for MET, SBM and U, respectively). Even though MET improved fermentation rate by 30%, particle dilution rate was more important in affecting ruminal digestibility than fermentation rate. Two 90-d heifer growth trials were conducted to evaluate similar supplements. Supplements similar to those used in the in situ trial were mixed with roughage to provide a complete diet balanced for .3 kg daily gain. Heifers consumed 112% of the National Research Council CP requirement. Weight gain, intake and feed conversion were similar (P > .10) for all treatments. In heifer trial 2, 90% of the National Research Council CP requirement was fed. The heifers supplemented with MET and SBM had faster (P < .05) weight gains than heifers receiving U. These studies show that feeding DL-methionine with urea, as compared with feeding an isonitrogenous supplement containing SBM, increased the fermentation rate of DM. Heifer weight gains were improved when DL-metbionine was added to urea to a point equal to that of heifers fed a SBM-based supplement.
Kentucky bluegrass straw (KBS) ensiled with hydroxide(NaOH, Ca[OH] 2 or NaOH + Ca[OH] 2) and(or) ... more Kentucky bluegrass straw (KBS) ensiled with hydroxide(NaOH, Ca[OH] 2 or NaOH + Ca[OH] 2) and(or) supplemental protein sources (soybean meal [SBM], cull beans or peas) was evaluated in a laboratory study and one lamb metabolism trial. In vitro organic matter digestibility (IVOMD) of alkali-treated silage was greater (P<.05) than that of untreated silages (Exp. 1). Silage treated with NaOH had a higher (P<.05) IVOMD than did those treated with Ca(OH)2. Addition of 2% NaOH + 2% Ca(OH)2 produced an intermediate value that was not different (P>.05) from that observed with either alkali alone. Straw ensiled with supplemental crude protein (SCP) had higher (P<.05) IVOMD than did the control. SCP tended to decrease the neutral detergent fiber (NDF) content of silage; however, this response was not consistent across all treatment combinations. Four percent NaOH or 2% NaOH + 2% Ca(OH)2 were equally effective (P>.05) in reducing NDF when straw was ensiled with cull beans or peas. Acid detergent fiber (ADF) was unchanged (P>.05) by alkali treatment. Silage containing cull peas or beans had lower (P<.05) ADF concentrations than did those with SBM or no SCP. Acid detergent lignin (ADL) was higher (P<.05) in alkali-treated silages. Crude protein concentration of silage was higher (P<.05) when SCP was added or with no alkali addition. Silages treated with alkali had higher (P<.05) pH values than did 1 Idaho Agr. Exp. Sta. Pub. No. 8042. 2This research was supported in part by a grantin-aid from the Idaho Research Council. a Dept. of Anita. Sci.
This study was designed to determine the influence of soybean meal supplementation, with or witho... more This study was designed to determine the influence of soybean meal supplementation, with or without additional ruminal escape protein or fat, on the nutritional status of pregnant winter-grazing beef cows. During two winters (Trials 1 and 2), approximately 60 prepartum beef cows grazed native foothills range each year. Cows were allotted randomly to five groups and supplemented (dd) with either none (control); 570 soybean meal (SOY); 450 soybean meal plus 230 blood meal (SOY + BM); 140 soybean meal, 16 urea plus 450 corn gluten meal (SOY + CGM); or 570 soybean meal plus 210 animal fat (SOY + FAT). These supplements were designed to supply similar quantities of ruminal degraded protein while varying in escape protein quantity and source (SOY + BM and SOY + CGM). Condition scores and body weights were determined at mal initiation (mid-December) and conclusion (early March). Eight blood samples obtained over 4 d during three periods (9, 4 and 1 wk prior to parturition) were analyzed for concentrations of glucose, urea nitrogen (N), total bilirubin, creatinine, albumin, total protein and cholesterol. Cows in the control treatment experienced the greatest BW loss in both aids. In Trial 2, escape protein tended to decrease (P < .06) BW loss compared to SOY, though loss tended to be greater (P < .08) with SOY + CGM than with SOY + BM. Escape protein can enhance nutritional status when supplemented with .6 kg/d of soybean meal.
Rambouillet wethers, surgically fitted with ruminal and duodenal cannulas, were used to determine... more Rambouillet wethers, surgically fitted with ruminal and duodenal cannulas, were used to determine the influence of substituting soybean meal (SBM) with blood meal (BM) in grass hay diets (8.0% CP) on N flow to the small intestine. Treatments were arranged in a 3 x 4 Latin square design and included diets (10.6% CP) supplemented with SBM; 2/3 SBM:1/3 BM; 1/3 SBM:2/3 BM; or BM. Ruminal NH3 N concentration decreased linearly (P = .03) as BM replaced SBM; however, feeding BM did not affect (P &amp;amp;gt; .10) the total N, microbial N, or nonammonia N flows to the small intestine. A second experiment was conducted to determine the influence of substituting SBM with BM on ewe BW and condition score changes, blood metabolite profiles, wool growth, and progeny wool follicle development. Thirty-two pregnant Targhee ewes fed a grass hay diet were allotted randomly to four groups (n = 8) and supplemented with either SBM; 2/3 SBM:1/3 BM; 1/3 SBM:2/3 BM; or BM. Soybean meal, BM, or their combinations provided 22 g of dietary CP daily. Dietary treatments had no influence on ewe BW (P = .40) or body condition score (P = .77) changes, and ewes gained 7.6 kg of BW during the 84-d experiment. Protein source did not influence (P &amp;amp;gt; .10) serum protein, urea N, creatinine, glucose, or nonesterified fatty acid concentrations. Lamb wool follicle density per square millimeter and secondary:primary follicle ratios were 22.4 and 10.8, respectively, and were not different (P &amp;amp;gt; .10) among dietary treatments. Compared with SBM, no advantages were detected for BM supplementation of grass hay diets in these studies.
Increasing longevity of beef cows by decreasing the proportion culled due to reproductive failure... more Increasing longevity of beef cows by decreasing the proportion culled due to reproductive failure provides an efficient process to rebuild a cow herd and can reduce number of replacements needed to sustain a constant herd size. Rate of reproductive failure varies due to cow age, where failure in cows 2 to 4 yr of age is often greater than in cows 5 to 7 yr of age. In addition, BW of cow and calf at weaning increase as cows advance from 2 to 5 yr of age. The cumulative effect of increasing retention of young cows is improved production efficiency through decreased replacement rate and changing age structure of the herd resulting in a greater proportion of cows at maximal production potential for calf BW at weaning and cow BW at time of culling. Calculations from cow age-specific culling and BW data from commercial and research herds indicated that reducing replacement rate from 18% to 14% resulted in a 23% increase in calf BW weaned and a 2% increase in cull cow BW per pregnant replacement heifer going into the herd. Although improving longevity increases production efficiency, genetic advancement in sustained reproductive function is challenging, as it is the sequential culmination of the annual repetition of numerous discrete physiological processes, each ending in a qualitative response. Successful completion of one process is prerequisite to evaluating subsequent processes. These physiological processes are subject to nutritional threshold requirements that may vary due to genetic potential for other production traits such as milk, growth, and mature size resulting in genetic-by-nutrition interactions. This is in contrast to most traits for which EPD exist, where genetic-by-environment interactions are not considered to be significant. Extensive research concerning impact of limited nutrition on reproduction has led to recommendations that heifers and cows be fed to a threshold BW or BCS to ensure reproductive success; a process that masks nutritional interactions that might otherwise result in reproductive failure. This management approach minimizes selection for animals capable of sustained reproductive function under limited nutritional environments. Rearing and managing cows under nutritionally limited environments may lead to adaptations that result in relatively high levels of reproductive success under lower input levels. Such adaptation may improve chances for longer retention in their offspring in nutrient-limited environments.
Diet and physiological state have been implicated in altering insulin sensitivity in range cows. ... more Diet and physiological state have been implicated in altering insulin sensitivity in range cows. An increase in diet glucogenic precursors (GP) may improve sensitivity to insulin. A study at the Corona Range and Livestock Research Center in 2006 (n = 29) and 2007 (n = 24) evaluated metabolic and lactational responses of postpartum 2 and 3 yr old cows grazing
Twelve Hereford  Angus heifers, 2.5 year, 492 AE 17 kg (BCS 5 AE 0:5), were randomly assigned to... more Twelve Hereford  Angus heifers, 2.5 year, 492 AE 17 kg (BCS 5 AE 0:5), were randomly assigned to one of three supplements, strati®ed by calving date and calf sex. Treatments consisted of a daily equivalent of: (1) low undegradable intake protein (UIP) (L: 908 g per cow per day; 36% CP, 108 g UIP), (2) middle UIP (M: 908 g per cow per day; 36% CP, 165 g UIP), and (3) high UIP (H: 908 g M 243 g feather meal per cow per day; 46% CP, 335 g UIP). Cows were fed sudan grass hay (7.3% CP, as fed) daily at 2% BW (as fed). Supplement was individually fed twice weekly from Week 2 to Week 11 post-partum. Cow body weight (BW), backfat (BF) and rumpfat (RF) thicknesses decreased in all cows, (P < 0:05) yet did not differ among treatments (P > 0:10). There were no differences among treatments in calf BW (P > 0:10). Serum insulin, blood urea nitrogen (BUN), milk components and yield did not differ among treatments (P > 0:10). Area under the curve (AUC) for serum LH was greater (P 0:07) in H versus L and M (809 versus 599 and 607 AE 69 U, respectively). No differences were observed in FSH AUC or mean serum concentrations (P > 0:10). Uterine pH did not differ among treatments or between supplement versus non-supplement days (P > 0:10). Serum progesterone remained below 1 ng/ml for all cows indicating absence of return to estrus. Under the conditions of this study, BW, BF, RF, serum insulin, BUN, milk components, and yield, uterine pH and serum FSH were not affected by level of UIP. However, supplement containing high levels of UIP enhanced GnRH-induced LH release.
Young beef cows experience a negative energy balance after parturition and during lactation when ... more Young beef cows experience a negative energy balance after parturition and during lactation when grazing dormant New Mexico range. As a result, sensitivity to insulin may be decreased due to the physiology of lactation and poor forage quality. However, with adequate precipitation during the growing season, forage quality improves, and insulin sensitivity may increase. An experiment was conducted to investigate seasonal changes in nutrient status of young range cows (n = 22) at the New Mexico State University Livestock Research Center and the Corona Range and Livestock Research Center. Two glucose tolerance tests (GTT) were conducted, one at 35 d postpartum (winter/spring) and one at 165 d postpartum (summer). At the time of the winter/spring GTT, 2-year-old cows were group fed a mixture of wheat straw and alfalfa hay (7 to 8% CP, OM basis) similar to New Mexico native range in March and April. Cows were grazing New Mexico green forage at the time of the summer GTT. For each GTT, 50%...
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