Evaluation of Annual Companion Crops for the Establishment of Perennial Forage Crops in Eastern Canada

The use of companion crops when establishing perennial forages is desirable as it often reduces weed growth and increases forage biomass in the seeding year. In eastern Canada, oat (Avena sativa L.) is the main species used as companion crop; although other species are used, they have not been systematically evaluated. A field study was established in 2019 at three sites in Québec, Canada, to contrast the use of six annual species as companion crops for the establishment of lucerne (Medicago sativa L.)-timothy (Phleum pratense L.) mixtures. Species evaluated include berseem clover (Trifolium alexandrinum L.), annual ryegrass (Lolium multiflorum Lamarck), forage pea (Pisum sativum L.), forage oat, Japanese millet [Echinochloa esculenta (A. Braun) H. Scholz], and sudangrass [Sorghum × drummondii (Nees ex. Steud.) Millsp. & Chase]. The control treatment consisted of the perennial species seeded without companion crop. Treatments were seeded at three dates (mid-May to early-June, mid-June to early-July, and early August) and evaluated during the seeding year based on biomass production and botanical composition. Overall, across sites, for the first two seeding dates, highest annual forage yields were observed with sudangrass, Japanese millet, and oat as companion crops. The use of these species increased yields by 1.8 to 2.5 Mg ha-1 on a dry matter basis (DM) compared to the control which yielded an average of 3.7 Mg DM ha-1. For the early August seeding, response varied significantly across sites. Annual yields were the highest with the use of oat at two sites (avg. of 2.4 Mg DM ha-1), whereas no differences between treatments were observed at the other site. Companion crop species which maximized total forage yields in the seeding year often reduced weed biomass, but also that of perennial species. The impact of treatments on the survival of perennial forages and their production during the first post-seeding year will be presented in a later publication

Increased Sugar Concentration with PM-Cutting and Wide Swathing Improves Alfalfa Silage Fermentation

Extensive protein degradation during silage fermentation reduces the efficiency of N utilization by ruminants and excess N is excreted in the environment. Forage nonstructural carbohydrates (NSC) represent the main source of readily fermentable energy for lactic bacteria during silage fermentation. Increasing forage NSC concentration can enhance silage fermentation, lactic acid production, and the decline in pH with an overall reduction in the extent of protein degradation. The NSC concentration increases during the day in alfalfa (Medicago sativa L.) to reach a maximum by the end of the afternoon. Under good wilting conditions, PM-cut alfalfa wilted in wide swaths had a greater NSC concentration than AM-cut alfalfa (Morin et al. 2012). Our objective was to study the effect of PM cutting and wide swathing on alfalfa silage quality attributes

High-Sugar Alfalfa for Dairy Cows

Alfalfa proteins are extensively degraded during wilting, silage fermentation, and in the rumen. To efficiently use alfalfa non protein N, rumen microbes need a readily available energy source such as nonstructural carbohydrates (NSC); otherwise, surplus N in the form of rumen ammonia is converted into urea and excreted in the environment. Increasing the NSC concentration of alfalfa was thus the focus of our research program. Our objectives were to assess the impact of high NSC alfalfa on digestibility and microbial protein synthesis measured in vitro, and on ingestion, rumen metabolism, N use efficiency, and dairy cow performance. Increasing NSC concentration of alfalfa significantly enhanced in vitro dry matter (DM) digestibility and decreased NH3-N concentration in rumen fluid. An increase of 23 g/kg in alfalfa NSC concentration can improve forage DM intake (+5 %) and energy corrected milk production (+8 %). Feeding high-NSC alfalfa led to a higher rumen pH, suggesting that sugars do not cause rumen acidosis, and to a lower milk urea N (MUN) indicating an improvement in N utilization. Increasing NSC concentration of alfalfa is a low-cost tool to improve its utilisation in dairy rations and potentially mitigate the environmental footprint of milk production

Species and Chlorine Fertilisation Affect Dietary Cation-Anion Difference of Cool-Season Grasses

The Dietary Cation-Anion Difference [DCAD = (Na + K) - (Cl + S); Ender et al., 1971] is used in balancing rations for dry dairy cows. Low DCAD diets induce a mild, compensated metabolic acidosis that stimulates bone resorption, improves Ca homeostasis, and prevents milk fever. Dry cow rations contain a high proportion of forage and, therefore, forages fed two to four weeks prepartum should have a low or negative DCAD value. Our objectives were to evaluate the DCAD of five cool-season grass species grown in eastern Canada and to determine the effect of Cl fertilisation on the DCAD value of timothy (Phleum pratense L.)

Improving Forage Nonstructural Carbohydrates through Management and Breeding

Nonstructural carbohydrates (NSC) are an important source of readily fermentable energy available to rumen microbes. Limited concentrations of readily available energy in forages combined with fast and intensive protein degradation contribute to poor N use efficiency by dairy cows and other ruminants. Increasing NSC in forages has been shown to improve intake, milk yield, and N use efficiency (Brito et al. 2009). We assessed several strategies to increase forage NSC accumulation, including PM-cutting, species selection and genetic improvement

Red Clover Improves the Energy to Protein Balance of Lucerne-Grass Herbage

Low ratio of readily fermentable carbohydrate to soluble protein concentrations in lucerne (Medicago sativa L.) leads to inefficient use of herbage N by ruminants. To improve the energy to protein balance in lucerne-grass herbage, four proportions of lucerne:red clover (Trifolium pratense L.) were compared in mixtures with and without grasses: timothy (Phleum pratense L.) and tall fescue (Schedonorus arundinaceus Schreb. Dumort.) in Quebec (QC, Canada). In the first post-seeding year, red clover proportion averaged (across grasses and four harvests) 0, 37, 59, and 74% in herbage mixtures. Increasing the proportion of red clover caused a slight but significant decrease in herbage total nitrogen (TN) concentration (32 to 31 g kg-1 DM) but substantial decreases in non-protein N (PA), rapidly (PB1) and moderately (PB2) degraded protein fractions, and a significant increase in the slowly degraded protein fractions (PB3+PC) (157 to 308 g kg-1 TN). With the inclusion of 74% of red clover, the ratio of soluble sugar to crude protein (CP) in herbage increased from 0.25 to 0.36 because of the increase in the soluble sugar concentration (48 to 66 g kg-1 DM). The inclusion of red clover in mixture with lucerne improved the energy to CP balance compared to lucerne alone, and caused a linear increase in the herbage in vitro neutral detergent fiber digestibility from 568 to 639 g kg-1 aNDF with similar herbage dry matter yield (10.3 Mg ha-1)

Addition of Red Clover or Birdsfoot Trefoil in Alfalfa-based Mixtures to Improve the Forage Energy to Protein Balance

The low ratio of sugars (S) to crude proteins (CP) in alfalfa (AL, Medicago sativa L.) leads to inefficient use of nitrogen by ruminants. The objective was to determine if adding red clover (RC, Trifolium pratense L.) or birdsfoot trefoil (BT, Lotus corniculatus L.) with or without a grass species to AL improved the forage S/CP ratio. Treatments were 100% AL (control) or AL-based mixtures with RC or BT in three proportions (75, 50, or 25% of seeded legumes) with either no grass or with timothy (Phleum pratense L.) or tall fescue (Schedonorus arundinaceus Schreb. Dumort.), resulting in 21 treatments assigned to a randomized complete block design with four replications at three sites in Canada (Agassiz, BC; St-Anne-de-Bellevue, QC; StAugustin-de-Desmaures, QC). Species contribution and nutritive attributes measured at each harvest were weighted for yield as a proportion of the seasonal yield and expressed yearly for the first two post-seeding years. Regression analyses showed that forage S concentration increased, CP concentration tended to decrease, and the S/CP ratio increased from 0.3 to 0.5 (y = 0.002 x + 0.3; P = 0.003, R2 = 0.53) with the addition of up to 92% RC or up to 66% BT to AL-based mixtures. The addition of up to 61% TI or 55% TF did not impact the S/CP ratio of AL-based mixtures. Further studies are needed to determine if the improved forage S/CP ratio following the addition of RC or BT to AL-based mixtures leads to an improved N-use efficiency in ruminants

Timothy mineral concentration and derived indices related to cattle metabolic disorders: A review

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