Water-Soluble Carbohydrate Recovery in Pastures of Perennial Ryegrass (Lolium perenne L.) and Pasture Brome (Bromus valdivianus Phil.) Under Two Defoliation Frequencies Determined by Thermal Time

Abstract

The objectives of the experiment were to (i) examine the dynamics of WSC use and the recovery of leaf sheaths and blades of Bromus valdivianus Phil. and Lolium perenne L. subjected to two defoliation frequencies (DFs) determined by thermal time (TT); (ii) evaluate how DF influenced regrowth and accumulated herbage mass (AHM) during fall. Defoliation was carried out at frequencies of 135 and 270 accumulated growing degree days (AGDDs) for both species. Twelve plots were arranged in a three-block design. All plots had a conditioning period to establish the assigned DF prior to sampling. From the start of the experiment, “cores” were collected from each plot every three days until the DF was reached. Every core was separated into leaf and sheath material before measuring the WSC concentration. Lolium perenne had concentrated more WSCs than B. valdivianus. Both species adapted their WSC recovery according to the DF. The recovery of WSC was faster under a DF of 135 AGDDs than that of 270 AGDDs. Leaf sheaths contained more WSCs than leaf blades and were identified as WSC storage organs. This period can be used as the optimal defoliation interval in B. valdivianus and L. perenne grazing systems.

Nitrogen Use Efficiency and Partitioning of Dairy Heifers Grazing Perennial Ryegrass (Lolium perenne L.) or Pasture Brome (Bromus valdivianus Phil.) Swards during Spring

“…It was observed that ADF and NDF content were greater for Bv, while WSC content was greater for Lp. Similar results have been previously reported in the literature [22,23], where WSC and NDF contents were greater for Lp and Bv, respectively.…”

“…In humid temperate regions such as Southern Chile, more than 50% of total annual herbage mass of grass pastures is produced during spring [22,39]; thus, spring was selected as the time period for this experiment. Although chemical composition varies between spring and autumn (with greater CP and lower WSC in autumn), no differences compared with the results from this study should be expected between Lp and Bv in autumn, as seasonal changes in the chemical composition of the two species occur in a similar pattern [23]. Additionally, research on the persistence and the use of Bv throughout the year is required to understand its impact on the forage system and the nitrogen balance (uptake/emission) in a heifer grazing system.…”

“…Despite the high nutritive value of Bv, several studies have reported an unbalance in its energy and protein content [21,22], which could reduce the rumen N utilization and increase N excretion into the environment [21]. Although there are studies reporting the good growing potential and nutritive value of Bv in countries such as Chile [22,23] and New Zealand [20], there is a lack of studies evaluating the impact of Bv on animal performance and measures of sustainability such as N excretions. Thus, the aim of the study was to evaluate the effect of grazing Lolium perenne and Bromus valdivianus on average daily weight and nitrogen use efficiency of Holstein Friesian heifers.…”

Selected soil properties and small-holder dairy farmers perceptions on improved forage varieties in the Southern highlands of Tanzania

“…The 40 days rotation is explained by the long rainy period (up to 9 months) in the studied area (Koskikala et al, 2020), hence farmers experienced prolonged rainy season. It could also be because at the younger stage pastures are highly digestible and have higher water soluble carbohydrates to meet the energy requirement of dairy cattle (Calvache et al, 2020). Some farmers (19%) were inter-cropping grass legume by mixing D. intortum with selected pasture varieties.…”

Development of Machine Learning Models to Predict Compressed Sward Height in Walloon Pastures Based on Sentinel-1, Sentinel-2 and Meteorological Data Using Multiple Data Transformations

“…It consisted of the daily rainfall and the degree-day-18 (DD_18): DD 18 = T max +T min 2 − 18, where T min and T max are the minimum and maximum temperature of the day. This formulation of the degree-day variables is introduced in studies like the ones of Moot et al [53] and Balocchi et al [54]. In some cases, the minimum and maximum temperatures may have upper and lower threshold whose value depends on various factors including the ability of the plant to take water [55], family and photosynthetic pathways (see the sensitivity of the Rubisco to temperature in Salvucci et al [56] and Greco et al [57]).…”