In this study, researchers studied the evolutionary effects on parasitoids of symbiont-mediated resistance by Acyrthosiphon pisum to the parasitoid, Aphidis ervi. They were able to take advantage of the parthenogenic life cycle of the aphid, allowing them to effectively rule out host evolution as the factor effecting results. They performed several experiments to determine what evolutionary eff...

Alfalfa use by dairy cattle has decreased in recent years because of excessive nonprotein nitrogen and low fiber digestibility. Ideal attributes for plant modification of alfalfa may include those that increase milk potential per acre and/or per ton, enhance digestible NDF, improve protein content and amino acid balance, improve agronomic traits for insect protection (safer forage supply), herb...

We investigated the possibility of interspecific water transfer in an alfalfa (Medicago sativa L.) and maize (Zea mays L.) association. An alfalfa plant was grown through two vertically stacked plastic tubes. A 5 centimeter air gap between tubes was bridged by alfalfa roots. Five-week old maize plants with roots confined to the top tube were not watered, while associated alfalfa roots had free ...

We evaluated the effect of forage quality on response of cattle to supplementation with cooked molasses blocks. In Exp. 1, 175 heifers had ad libitum access to prairie hay (5.2% CP, DM basis). Treatments were a 2 x 3 factorial: supplementation with 0 or 1.96 kg/d of alfalfa DM, and supplementation with no cooked molasses block or with a low-protein or a high-protein cooked molasses block (14.4 ...

Foraging, defense and waste disposal are essential for sustaining social insect colonies. Hence, their nest generally has an open structure, wherein specialized castes called workers and soldiers perform these tasks. However, some social aphids form completely closed galls, wherein hundreds to thousands of insects grow and reproduce for several months in isolation. Why these social aphids are n...

Lupin plants are frequently damaged by various herbivorous invertebrates. Significant among these are slugs and aphids, which sometimes attack the same plants. Relationships between aphids, slugs and food plant are very interesting. Grazing by these pests on young plants can lead to significant yield losses. There is evidence that the alkaloids present in some lupin plants may reduce grazing by...

Six ruminally cannulated cows were used in an experiment with a 3 x 3 Latin square design. Three all forage diets-alfalfa silage, alfalfa hay, or corn silage plus 2.2% urea (DM basis)-were fed for ad libitum intake four times daily. The microbial protein marker 15NH3 and the liquid marker Cr-EDTA were infused continuously into the rumen for 72 and 48 h, respectively; the solid marker, Yb-labele...

Feed deprivation is commonly used by the poultry industry to induce molting and stimulate multiple egg-laying cycles. However, feed deprivation has been observed experimentally to increase susceptibility of poultry to Salmonella infections. Previous studies indicated that alfalfa was efficacious in reducing Salmonella; the present investigation was designed to evaluate the efficacy of combined ...

The objectives of these experiments were to study the positive associative effects of supplementing barley straw-based diets with different levels of alfalfa hay on nutrient intake, rumen environment, and nutrient digestibility and to evaluate the minimal amount of alfalfa hay needed to produce such an effect in ewes. In experiment one, 15 Awassi ewes (®ve ruminally ®stulated; body weight ˆ 54 ...

Two Latin square trials, using 21 or 24 multiparous lactating Holstein cows, compared the feeding value of red clover and alfalfa silages harvested over 2 yr. Red clover silages averaged 2 percentage units lower in crude protein (CP) and more than 2 percentage units lower in neutral detergent fiber and acid detergent fiber than did alfalfa silage. In trial 1, diets were formulated to 60% dry ma...