Biomedical subjects

M A Froetschel

Publications and source records attributed to M A Froetschel.

29 records · Page 2Linked to original sources

PubMed1991

Dietary fat, protein degradability, and calving season: effects on nutrient use and performance of early lactation cows.

Twelve multiparous Holstein cows calving in fall and 12 calving in summer were blocked into four groups and used in a 2 x 2 x 2 factorial to determine the effects of season of calving, dietary fat, and protein degradability on milk production and efficiency of NEL utilization in a 16-wk study. Blocks were assigned randomly to one of four dietary treatment combinations: 1) control concentrate plus soybean meal (high degradability protein supplement); 2) control concentrate plus a mixture of heated soybean meal and corn gluten meal (low degradability protein supplement); 3) a blend of the control concentrate and a concentrate containing 12.1% fat to provide 1 kg d-1 fat, plus soybean meal; and 4) concentrate as in diet 3 plus heated soybean meal and corn gluten meal. Nutrient intake, milk yield and composition, BW changes, and daily ambient temperature were monitored. Intake of DM appeared to be related to NDF intake but was not affected by fat, protein degradability, or calving season. Intake of NEL was increased by feeding fat. Digestabilities of DM and CP were increased and fiber was decreased by feeding fat. Percentage and yields of milk fat, SNF, and protein and 4% FCM production were higher in cows calving in fall. Milk fat percentage was low in all cows in the study. Efficiency of energy utilization for milk production was decreased in cows fed fat and calving in the summer and by low protein degradability during wk 5 to 8 of lactation. At high concentrate intake, calving season had more effect on milk production than level of fat or protein degradability.

Animal Feed↗

PubMed1990

Effects of zinc sulfate concentration and feeding frequency on ruminal protozoal numbers, fermentation patterns and amino acid passage in steers.

Effects of zinc sulfate (0 vs 1,142 ppm supplemental zinc from zinc sulfate) and feeding frequency (1 x vs 12x daily) on ruminal protozoa numbers, fermentation patterns and amino acid passage were investigated using four ruminally and abomasally cannulated mature Jersey steers in a 4 x 4 Latin square experiment. Steers (530 kg) were fed a 50:50 roughage:concentrate diet at 1.5 times their NEm requirement. Experimental periods were 14 d in duration; ruminal, abomasal and fecal samples were collected at 6-h intervals during the last 3 d of each period. Protozoa numbers tended to be lowest (1.82 x 10(6)/ml) in steers fed zinc 1 x and tended to be highest (3.83 x 10(6)/ml) in steers fed zinc 12 x daily (P less than .10). Frequent feeding decreased ruminal pH .24 units and increased total VFA 20.7%, ammonia 22.7% and ruminal digestion of dietary amino acids (AA) 61.6% (P less than .05). Zinc supplementation decreased ruminal digestion of dietary AA 35.8% (P less than .05) and the abomasal passage of bacterial OM and AA 21.2% (P less than .05) and increased ruminal output of amino acids as a percentage of intake 15.1% (P less than .05). Although it increased escape of dietary AA, zinc sulfate decreased postruminal passage of bacterial AA and resulted in a net negative effect on total postruminal AA passage as a percentage of intake. The effects of zinc on ruminal AA digestion may be more closely related to an interaction of zinc with dietary CP rather than to an effect of Zn on ruminal microbial populations.

Amino Acids↗

PubMed1990

Cholinergic manipulation of digestive function in ruminants and other domestic livestock: a review.

Exocrine secretions in the digestive tract of domestic livestock are controlled by a combination of neural and endocrine inputs. The parasympathetic domain of the autonomic nervous system is responsible for efferent signals that regulate most exocrine secretory processes. Exocrine tissues possess cholinergic muscarinic receptor subtypes that are different from those found in brain, heart and muscle tissues. Cholinergic stimulation of specific muscarinic receptor subtypes has enhanced secretions of the salivary glands and pancreas. These changes in output of exocrine glands can alter digestive function that may benefit production of cattle and swine.

Animals↗

PubMed1989

Effects of a salivary stimulant, slaframine, on ruminal fermentation, bacterial protein synthesis and digestion in frequently fed steers.

Slaframine (SF), a parasympathomimetic salivary stimulant, was administered i.m. (10, 15 or 20 micrograms SF/kg BW) to ruminally and abomasally fistulated steers at 12-h intervals for 18-d periods in a latin square-designed experiment. Steers were fed semicontinuously (12 times daily) a 40:60 roughage:concentrate diet at twice their net energy requirement for maintenance. Ruminal digestion coefficients for DM, ADF and starch were 10 to 16% lower and linearly related in an inverse manner to the level of SF administered (P less than .05). Postruminal digestion of DM, ADF and starch increased as much as 46.7, 9.5 and 44.0%, respectively, in a fashion linearly related (P less than .05) to the level of SF administered. Total tract digestion of DM and ADF were not affected by SF; however, total tract starch digestion was increased as much as 5% and was related linearly (P less than .05) to SF treatment. With SF administration, as much as 13% more bacterial protein exited the rumen, resulting in a 16.5% linear improvement (P less than .1) in the efficiency of ruminal bacterial protein production per 100 g of OM fermented. Ruminal concentrations of VFA, ammonia and pH were not affected by SF. These results demonstrate a positive relationship between salivation and ruminal bacterial protein synthesis and suggest that feed utilization by ruminants may be improved by pharmacological stimulation of salivary secretions.

Abomasum↗

PubMed1987

Effects of slaframine on ruminant digestive function: liquid turnover rate and fermentation patterns in sheep and cattle.

Two trials were initiated to determine if slaframine (SF) can be used to alter fluid digesta flow and fermentation patterns in the rumen. In trial 1, a preliminary experiment, four Dorset X Barbados Black-belly ruminal-cannulated wethers (avg weight 41.6 8.7 kg) given ad libitum access to a pelleted concentrate/hay diet were injected intramuscularly with 0, 12, 24 or 48 micrograms SF/kg body weight (BW) in a 4 X 4 Latin-square design. Ruminal fluid dilution rate was determined using a single intraruminal infusion of polyethylene glycol (7 g), followed by seven hourly ruminal fluid samples. The administration of 48 micrograms SF/kg BW increased (P less than .10) ruminal volume and outflow by 27 and 25%, respectively, compared with controls. In trial 2, two Hereford and two Angus ruminal cannulated steers (avg weight 568 +/- 93 kg) were injected with 0, 6, 12 or 24 micrograms SF/kg BW at 8-h intervals over a 24-h period in a 4 X 4 Latin-square design. Steers were fed a concentrate diet at twice maintenance in 24 equal portions daily. Ruminal fluid dilution was measured using a single intraruminal infusion of cobalt-ethylenediamine tetraacetic acid (20 g) administered 9 h after the initial SF injection. Ruminal fluid was collected each hour during 8 to 24 h after the initial SF injection and analyzed for pH, osmolality and volatile fatty acids (VFA).(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaloids↗

PubMed1987

Effects of chronic administration of slaframine on production and digestive function in broiler chicks.

Slaframine (SF), 1-acetoxy-6-aminooctahydroindolizine a parasympathomimetic with a high affinity for the gastrointestinal tract, was administered by oral intubation daily to 240 broiler chicks at either 0, 8.9, or 17.8 micrograms/kg body weight.75 (BW.75) in saline for 21 days. Throughout the experimental period weight, feed intake, and fecal output were measured. On Day 21 birds were killed, eviscerated, and wet organ weights were obtained. Pancreas and small intestine digesta were homogenized with saline and frozen for analyses of trypsin, chymotrypsin, amylase, and lipase activity as well as total protein. Weight, feed intake and utilization, pancreatic weight, liver weight, and small intestine digesta weight were not affected by SF treatment. Protein content of the digesta decreased 16.6% with the 17.8 micrograms SF/kg BW.75 treatment. Digesta lipase activity was 13.3% (P greater than .05) and specific activity 24% less (P less than or equal to .02) in 17.8 micrograms/kg BW.75 treated birds in comparison with those of controls, and activities decreased in a linear fashion across treatment levels (P less than or equal to .04). Digesta trypsin-specific activity decreased linearly with SF treatment (P less than or equal to .05), averaging 5.5 to 16.9% lower than control treated birds. Pancreatic chymotrypsin-specific activity was not significantly different among treatments. These results suggest that relatively small dosages of SF may affect digestive function of broiler chicks.

Alkaloids↗

PubMed1987

Effects of slaframine on circulating concentrations of growth hormone and glucose.

The ability of slaframine (SF), a parasympathomimetic, to alter blood growth hormone (GH) and glucose concentrations in broiler chicks was investigated. Eighty male broiler chicks (average weight 225 g) were divided into 10 groups and dosed with either saline (control) or 1 mg SF/kg of body weight by oral intubation. Plasma samples were obtained from separate groups of chicks at 1, 2, 4, 8, and 12 hr after SF administration and analyzed for growth hormone and glucose. One hour after SF administration, glucose increased (P less than .05) 21.4% compared with controls. Growth hormone increased (P less than .05) 449 to 948% from 8 to 12 hr after SF administration. Administration of SF at 1 mg/kg of body weight was associated with increased plasma GH.

Alkaloids↗

PubMed1986

Effects of slaframine on ruminant digestive function: resting salivary flow and composition in cattle.

Four esophageal- and ruminal-cannulated Angus steers (avg weight, 308 kg) were used to investigate how salivation is affected by the administration of purified slaframine (SF; 1-acetoxy-6-aminooctahydroindolizine), a cholinergic secretagogue isolated from Rhizoctonia leguminicola. Steers were fed a concentrate diet at twice the net energy requirement for maintenance in hourly increments. In trial 1, a single injection of SF was administered to four steers intramuscularly at 0, 6, 12 and 24-micrograms/kg body weight (BW) in a 4 X 4 Latin-square design. Saliva was collected via esophageal cannula at 15-min intervals 30 min after each feeding, weighted, sampled and reinfused via ruminal cannula over a 10-h period. At 12- and 24-micrograms SF/kg BW, salivary flow was 31 to 43% greater (P less than .01) than at 0- or 6-micrograms SF/kg. Response peaked within the first 3 h and returned to baseline levels at 8 h. Buffering capacity and pH of saliva were not different (P greater than .10); however, osmolality and Na concentration increased and K concentration decreased (P less than .10) as salivation rates increased. Feed intake of steers did not appear affected at any level of SF administration. In trial 2, 0-, 12- and 24-micrograms SF/kg BW were repeatedly administered intramuscularly to three steers in a 3 X 3 Latin-square design at 8-h intervals for 24 h. Salivary flow was measured and sampled over the entire 24-h period, as in trial 1. Flow rates were increased 50 to 70% (P less than .01) by SF treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaloids↗

PubMed1986

Effects of slaframine on ruminant digestive function: ruminal motility in sheep and cattle.

Effect of purified slaframine (SF; 1-acetoxy-6-aminooctahydroindolizine), a parasympathomimetic secretagogue isolated from Rhizoctonia leguminicola, on ruminal motility was investigated in cattle and sheep. In trial 1, four ruminal cannulated wethers, fed a pelleted concentrate and hay diet, were injected intramuscularly with 0, 12, 24 and 48 micrograms SF/kg body weight (BW) in a 4 X 4 Latin-square design. Ruminal motility was recorded 1 h before and 1 to 2 h and 3 to 4 h after SF administration by measuring pressure changes exerted upon a fluid-filled, open-tipped catheter inserted into the dorsal sac of the rumen. The frequencies of both primary and secondary ruminal contractions were decreased as much as 20 to 78% with SF (P less than .05) depending upon the dosage level and time after administration. In trial 2, three ruminal-cannulated steers fed a concentrated diet were injected intramuscularly with 0, 12 and 24 micrograms SF/kg BW in a 3 X 3 Latin-square design. A water-filled balloon inserted into the cranial sac of the rumen was used to measure ruminal pressure changes 1 h before and 1 to 2 h, 3 to 4 h and 7 to 8 after SE administration. Frequency of primary and secondary ruminal contractions decreased with SF as much as 27 to 64% depending on the dosage level and time after administration. The frequency of secondary contractions increased 28% (P less than .05) as compared with control during the 7 to 8 h after administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaloids↗

PubMed1984

Influence of monensin and lasalocid on mineral metabolism and ruminal urease activity in steers.

Growing steers were used in a replicated 3 X 3 Latin square to study the influence of ionophores on mineral metabolism and ruminal urease activity. Treatments consisted of: 1) basal high energy diet; 2) basal plus 33 ppm lasalocid and 3) basal plus 33 ppm monensin. Each period was 33 days and apparent absorption and retention of macrominerals were measured during the last 5 days of each period. Mineral intake during the collection period was not affected by treatment. Both ionophores increased apparent absorption of sodium, magnesium and phosphorus. Retention of magnesium and phosphorus were higher for steers receiving either lasalocid or monensin. Potassium and calcium absorption were not significantly affected by treatment. Serum concentrations of macrominerals were similar for all treatments. Zinc and copper concentrations in serum were higher in animals fed monensin or lasalocid. Steers fed either ionophore had lower concentrations of soluble potassium and calcium in rumen fluid. Both ionophores also decreased ruminal osmolality. Bacterial urease, a nickel-dependent enzyme, was decreased by 28 and 66% in animals that received lasalocid and monensin, respectively. These findings indicate that lasalocid and monensin affect metabolism of certain minerals in ruminants.

Animals↗

PubMed1983

Effects of avoparcin on ruminal propionate production and amino acid degradation in sheep fed high and low fiber diets.

The effect of the antibiotic, avoparcin, on ruminal propionate production and amino acid degradation was investigated by using four rumen fistulated wethers. Wethers were fed each of four diets during 28-day periods in a 4 X 4 Latin square design. Diets were high fiber (HF), high fiber plus 50 ppm avoparcin (HF-AVO), low fiber (LF) and low fiber plus 50 ppm avoparcin (LF-AVO). Total digestible energy intake (1.25 X maintenance) and crude protein intake for each animal were similar for all diets. Propionate production was determined each period from all animals by using a single injection of [1-14C]propionate and polyethylene glycol. Avoparcin decreased total volatile fatty acid concentration, increased ruminal pH and molar proportions of propionate on both HF and LF diets. Daily propionate production and pool turnover rate increased in sheep fed LF-AVO. Similar changes were noted in HF-AVO animals, although they were not statistically significant. Avoparcin decreased ruminal ammonia (50 vs. 45 mg/100 ml) and increased alpha amino nitrogen (8.6 vs. 14.3 mM) in LF-fed sheep. In vitro studies demonstrated a decreased degradation of crystalline amino acids by mixed populations of rumen microorganisms from sheep receiving LF diets containing avoparcin. Avoparcin appears to modify rumen fermentation by increasing propionate production and inhibiting protein or amino acid degradation.

Amino Acids↗