TRITICALE IN DIETS FOR YOUNG DAIRY CALVES

Thermoregulatory response of dairy cows fed ergotized barley during summer heat stress

Claviceps purpurea infects the seed heads of cereal grains and grasses and produces ergopeptine alkaloids that cause hyperthermia and agalactia in cattle during periods of heat stress. A field experiment was undertaken to examine the effects of ergopeptine alkaloids found in barley on thermal status of dairy cattle during periods of heat stress. Production end points were also measured to identify the effect of the change in thermal status. Contaminated barley screenings containing known levels of ergopeptine alkaloids were fed to lactating Holstein cattle (10 microg total ergopeptine alkaloids/kg BW/day) for 10 days during summer heat stress. Air temperature increased 14.4 C during the first 8 days of treatment and then declined the same during the last 2 days. Extreme daily values for rectal temperature and respiration rate, using averages of all animals, showed maximum increases of 2.3 C and 56.8 breaths/minute, respectively, during this period. Group afternoon milk production decreased 2 kg/day during the heat stress period, with no measurable change in feed intake. A greater level of hyperthermia occurred in cattle consuming the diet with ergopeptine alkaloids, with only marginal symptoms of ergot toxicosis reflected in feed intake and milk production. Therefore, the ergopeptine alkaloid dose used in this study represents a level for minimal induction of the ergot toxicity response.

An HPLC method for the detection of ergot in ground and pelleted feeds

A high performance liquid chromatography (HPLC) method is described for detecting ergot in ground or pelleted forages and grains. Samples were extracted with alkaline chloroform, filtered, and applied to silica gel/organic binder cleanup columns. Following elution of pigments with acetone: chloroform, ergopeptine alkaloids were eluted with methanol and analyzed by HPLC with fluorescence detection. Average recovery of ergotamine, the major ergopeptine alkaloid produced by Claviceps, was 93%, with a relative standard deviation of 4.9%. The detection limit of ergotamine was approximately 50 ppb in all feedstuffs. Confirmation of ergopeptine alkaloids was accomplished by treating the parent ergopeptine alkaloids with 0.2% acetic acid to produce their -inine isomers and reexamining by HPLC with fluorescence detection or silica gel/organic binder column cleanup in combination with tandem mass spectroscopy. The method described is a valid alternative to microscopic inspection for detecting ergot contamination in ground or pelleted feedstuffs.

Variability in the content and composition of alkaloid found in Canadian ergot. III. Triticale and barley

The total alkaloid content and individual alkaloid composition were determined by colorimetry and high performance liquid chromatography, respectively, for Canadian triticale and barley ergot (Claviceps purpurea). The total alkaloid content was highly variable between individual sclerotia from the same or different sources and ranged from 0.042 to 0.752% for triticale and from 0.082 to 1.04% for barley; average values were 0.239% for Ottawa triticale, 0.289% for Prairie triticale, and 0.264% for barley. Ergocristine and its isomer ergocristinine were the major constituents in both grains. On average, Canadian ergot pooled from rye, wheat, triticale, and barley consists of ergocristine (31%), ergocristinine (13%), ergocristinine (13%), ergotamine (17%), ergotaminine (8%), ergocryptine (5%), ergocryptinine (3%), ergometrine (5%), ergometrinine (2%), ergosine (4%), ergostinine (2%), ergocornine (4%), ergocorninine (2%), and unidentified alkaloids (3%), and an average total alkaloid content of 0.236%. With the exception of rye and barley ergot from the maritime regions, Canadian rye, wheat, triticale, and barley ergot is fairly uniform in individual alkaloid composition.

EVALUATION OF TRITICALE SILAGE FOR LACTATING COWS

The nutritive values of corn and triticale silage were compared in a changeover experiment using eight lactating Holstein cows. Intake of silage dry matter was significantly greater (P < 0.05) for corn silage (9.41 vs. 7.49 kg/100 kg0.75 body weight) than for triticale silage. Solids, corrected milk yield, and protein content were significantly higher (P < 0.01) for corn silage (25.0 vs. 21.4 kg/day and 3.34 vs. 3.11%) than for triticale silage. The apparent digestibility of dry matter for rations containing corn and triticale silage was 67.0 and 64.0%, respectively.