Effect of whole cottonseed on serum constituents, fragility of erythrocyte cells, and reproduction of growing Holstein heifers.

A 431-d experiment was conducted to determine the effects of whole cottonseed containing gossypol (7400 mg/kg) on growth and development from weaning until pregnancy in Holstein heifers. Treatment diets (n = 5) contained 0, 15, or 30% whole cottonseed. The basal diet included alfalfa hay, corn grain, soybean meal, molasses, and dicalcium phosphate. Gossypol content of the treatment diets was 0, 1300, and 2000 mg/kg, and gossypol content in feces was 0, 290, and 1170 mg/kg, respectively, for treatments containing 0, 15, and 30% whole cottonseed. Estimated ingestion of gossypol (accumulated) was 0, 8, and 12 g/kg of BW, respectively, for treatments containing 0, 15, and 30% whole cottonseed during the 431-d experiment. Erythrocyte fragility was similar among treatment groups on d -3; on d 228, erythrocyte fragility was similar for heifers fed treatments containing 0 and 15% whole cottonseed, but was lower than that for heifers fed the 30% whole cottonseed diet. However, on d 430, fragility of erythrocytes increased linearly as the percentage of whole cottonseed increased. Clinical profiles of serum suggest possible impairment of liver and kidney function on d 144 and 430. Age and BW at onset of puberty and pregnancy rates were similar among treatments. One heifer fed the 30% whole cottonseed died on d 396, possibly from gossypol toxicosis. Long-term dietary supplementation at 15 to 30% whole cottonseed for long periods should be examined further for gossypol content and toxicity response of heifers and for effects on growth and development.

Effects of whole cottonseed and live yeast culture on ruminal fermentation and fluid passage rate in steers.

The effects of adding whole cottonseed (WCS) and live yeast culture (YC) to a diet of 60% alfalfa and 40% concentrate on ruminal fermentation and liquid dilution rate in steers were examined in two trials. Twelve ruminally cannulated Hereford steers (approximately 420 kg) were used. Concentrates were 1) a basal grain mix composed of ground corn, ground barley and rice bran, 2) basal mix with 10% WCS, 3) basal mix with 1.6% YC and 4) basal mix with 10% WCS and 1.6% YC. No differences were detected (P greater than .10) in ruminal pH of steers fed WCS or YC in either trial. Ruminal ammonia levels tended to be higher (P greater than .10) in steers fed WCS. Acetate was higher and butyrate was lower in steers receiving 10% WCS (P less than .10) compared with controls. Molar proportions of acetate and butyrate increased while propionate decreased (P less than .05) over time after feeding. Intake and apparent digestibility of dry matter was not influenced by treatments. Whole cottonseed and(or) YC appear to have minimal effects on ruminal fermentation, but they might alter ruminal liquid passage rate with diets containing 60% ground alfalfa and 40% concentrate.

Kochia (Kochia scoparia) toxicosis in cattle: results of four experimental grazing trials.

Four kochia grazing trials were completed over a period of 3 years. Yearling steers were allowed to graze pure stands of irrigated and fertilized kochia (Kochia scoparia) for periods of 14 to 105 days. A total of 116 steers were given kochia as their sole forage. Twenty control steers were allowed to graze native grass pasture, and 20 steers were allowed to graze both native grass and kochia pastures. Steers grazing only kochia lost weight or gained poorly compared with control steers grazing native grass. Steers that grazed both kochia and native grass had intermediate rates of gain. Signs of toxicosis were observed only in steers grazing kochia alone. Considerable variability in the degree of toxicosis was observed from one year to another. Morbidity in the steers grazing only kochia varied from 0% (Trial 4) to 28% (Trial 1), and mortality varied from 0% (Trials 3 and 4) to 10% (Trial 2). The most common signs observed in clinically affected steers were depression, dehydration, weight loss, muscular weakness, photosensitization, ocular discharge, and crusty muzzle. In all 4 trials, significant elevations in serum glutamic oxaloacetic transaminase (GOT) and serum gamma glutamyl transpeptidase (GGT) were observed in steers grazing kochia. In 3 of the 4 trials, significant elevations in serum bilirubin, serum calcium, and serum protein were also observed in kochia-fed steers. Necropsies were performed on 6 of 9 steers that died or were euthanized. The primary pathologic findings were severe chronic nephrosis (5 steers) and degenerative hepatopathy (5 steers).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of pecan shells and hulls as a roughage source on milk production, rumen fermentation, and digestion in ruminants.

In Experiment 1, 20 lambs (36 kg) were fed five diets containing 0, 5, or 10% pecan shells or hulls to evaluate digestion and nitrogen balance. Digestion was not depressed by diets containing 5% shells. Protein digestibility was not reduced and nitrogen balance was higher for lambs fed 5% hulls than for lambs in other groups. In Experiment 2, 8 Holstein cows (29.3 kg milk/d) were assigned to two diets: basal and basal with 5% shells in the grain mix. Cows fed diets containing shells produced the same amount of milk and milk fat as control cows. In Experiment 3, 12 Holstein cows (27.3 kg milk/d) were assigned to the same two diets used in Experiment 2 and a third treatment received 5% pecan hulls in the grain mix. Cows fed shells or hull diets reduced concentrate intake and milk production. In Experiment 4, 12 Hereford X Angus steers (474.5 kg) were fed diets used in Experiment 3 to examine rumen fermentation, digestion, and passage rates. Steers fed hulls had lower rumen ammonia N and higher rumen pH compared with steers fed the basal diet. Total rumen volatile fatty acid concentration was not different among treatments. Generally, rumen fluid from steers fed hulls had higher proportions of acetate and lower proportions of butyrate. Rumen fluid and particulate passage rates and digestion measurements were not affected by addition of shells or hulls.

Effects of receiving and growing diets on compensatory gains of stressed calves.

Three hundred seventy-seven male stocker calves were used to study the effects of three receiving diets, two growing-finishing diets and two levels of shipping shrink on compensatory gains during the post-receiving feeding period. Calves received on a 75% concentrate diet gained 19 kg more during the first 42 d than those received on hay plus .91 kg daily of protein supplement (P less than .01). Calves received on hay plus protein supplement gained 11 kg more than the calves received on hay alone during the same period (P less than .01). When calves were fed an 85% concentrate diet throughout finishing, there was no difference in the rate of compensatory gain made by calves fed hay alone or hay plus protein supplement. Neither of the latter two groups completely compensated for the slow rates of gain made during receiving. When calves were fed a 50% concentrate growing diet from the end of the receiving period to a body weight of 272 kg then finished on an 85% concentrate diet, those received on hay alone lacked only 1 kg of compensating fully for the low gains of the receiving period. However, this procedure had no effect on the compensatory gains of those received on hay plus protein supplement. High-shrink calves received on hay alone or hay plus protein never compensated fully for the low gains made in the receiving period. However, with low-shrink calves, those received on hay alone fully compensated for the low gains of the receiving period and those received on hay plus protein lacked only 2 kg of making full compensation.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of steam-flaked, steamed-whole or whole shelled corn on performance and digestion in beef steers.

Three trials were conducted to evaluate finishing diets containing 67% steam-flaked corn (SFC), steamed-whole corn (SWC) or whole corn (WC). In a feeding trial, steers fed SWC consumed more (P less than .05) dry matter per day (7.6 kg) than those fed WC (7.0 kg) or SFC (6.7 kg). Average daily gain was greater (P less than .05) for steers fed SFC (1.33 kg) and SWC (1.31 kg) than for those fed WC (1.25 kg), and feed efficiency was better (P less than .05) for steers fed SFC (5.06 kg dry matter/kg gain) than for those fed WC (5.62) and SWC (5.79). Carcass characteristics were not different among the three groups. In a digestion trial, method of corn processing did not affect digestibility of dry matter and crude protein. Starch digestibility was greater (P less than .05) for SFC (99.1%) than for SWC (93.8%) and WC (93.0%). There were no differences in nitrogen (N) intake or fecal N among the three diets; however, urinary N was less (P less than .05) for SWC (19 g/d) than for SFC (27 g/d) and WC (32 g/d), and N retention was higher (P less than .05) for the SWC diet. In vitro dry matter digestibility of the SFC diet was higher (P less than .05) than for WC at 4 and 8 h of incubation and higher (P less than .05) than the SWC diet at 8, 12 and 24 h of incubation. In vitro gas production after 6 h was greater (P less than .05) for SFC than for SWC grain, which was greater (P less than .05) than WC.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of limestone level in high concentrate and high roughage diets on site and extent of digestion in lambs.

Two digestion and slaughter trials were conducted to evaluate the influence of limestone level on site and extent of digestion and rumen fermentation in lambs. In trial 1, 11 wether lambs (avg wt 40.7 kg) were fed 75% concentrate diets supplemented with .6, 1.5 or 3.0% limestone (.6,1.2,1.7% dietary Ca, respectively) in a completely randomized design. Dry matter intake increased linearly (P less than .10) with limestone level; therefore, other data were analyzed with dry matter intake as a covariate. Total tract organic matter digestion decreased linearly (P less than .05) with increasing limestone but dry matter and fiber digestion were not affected by limestone. Ruminal digestion of dry matter and organic matter declined linearly (P less than .05) with increasing limestone. Ruminal neutral detergent fiber (NDF) digestion was higher with the 1.5 than the .6 and 3.0% limestone diets (quadratic effect, P less than .05) but ruminal digestion of other fiber components was not affected by limestone. Ruminal volatile fatty acids were not affected by limestone level; however, rumen ammonia concentrations decreased linearly (P less than .05) with increasing limestone level. In trial 2, 12 wether lambs (avg wt 43.3 kg) were fed a 35% concentrate diet with .1, 1.5 or 3.0% limestone (.5, 1.2 and 1.6% dietary Ca, respectively) in a completely randomized design. Dry matter intake was not affected by limestone level, but digestibility of dry matter, organic matter and starch (P less than .10), energy, crude protein, acid detergent fiber (ADF) and cellulose (P less than .05) responded quadratically to limestone level, with increases at the 1.5% limestone level. Ruminal dry and organic matter (P less than .05), NDF (P less than .10), ADF (P less than .01), cellulose (P less than .05) and starch (P less than .05) digestion responded quadratically to limestone level with higher values at the 1.5% limestone level. Proportions of ruminal propionate increased linearly (P less than .01) with increasing limestone level and acetate: propionate ratio declined linearly (P less than .01) with limestone level.

Millet and alfalfa hays alone and in combination with high-energy diet for receiving stressed calves.

Calves subjected to stresses of weaning, marketing, shipping and processing ate more feed, gained more weight and gained more efficiently when fed a 75% concentrate receiving diet, alone or with free choice hay, than when fed hay alone (P less than .01). Diets with greater bulk or lower energy densities did not promote higher feed intake in these stressed calves, as would be the case in unstressed animals. No differences due to receiving diets were observed in number of calves treated, days treated per sick calf, death loss or relapses. There was a trend (P less than .1) for calves on hay diets to have fewer total sick days than those fed a 75% concentrate diet alone or with free choice hay. Feed intake, weight gains and conversion of feed to gain for calves on alfalfa hay alone were superior (P less than .05) to the corresponding measures for calves on millet hay alone. Both hays fed alone were inferior (P less than .01) to a 75% concentrate diet alone or in combination with either hay in promoting weight gains and conversion of feed to gain. Gastrointestinal tract fill estimated from apparent and predicted gains amounted to 93 and 76% of apparent gains for calves fed millet or alfalfa hay respectively, but only 58% or less for those fed diets containing the 75% concentrate milled feed. Growing lambs were in negative N balance when fed millet hay alone but retained approximately 15% of N intake when fed diets containing the 75% concentrate milled feed. N retention on alfalfa hay alone was intermediate. The data indicate net tissue growth in calves fed millet hay alone is near zero during a 28-day receiving period. No differences were noted between calves receiving grubicide as a dip and those given grubicide as a pour on.

Effects of dietary energy, free choice alfalfa hay and mass medication on calves subjected to marketing and shipping stresses.

Five-hundred and fourteen calves subjected to the stresses of marketing and shipping from Florida to New Mexico were used to study performance after arrival at the feedlot. Flaked milo diets containing 50 and 75% concentrates promoted more rapid recovery of purchase weight and more efficient gains than a diet containing 25% concentrates. Free-choice alfalfa hay with the flaked milo diets reduced death loss, number of calves requiring medication and number of treatments per medicated calf. A 3-day mass medication with oxytetracycline injected intramuscularly at 11 mg/kg body weight reduced death loss and number of calves requiring subsequent medication. Calves requiring subsequent medication, however, needed more treatments than control calves. Dry matter and energy digestion determined with lambs increased with concentrate level but decreased with addition of alfalfa hay. New energy intake was highest for the 50% concentrate diet during the first week and for the 75% concentrate diet during the next 3 weeks of the 4-week receiving period.