Growth performance and methane emission of lambs supplemented with hydroponic barley fodder

Abstract

The demand for natural resources like water, grazing pastures and land for conventional green fodder production continues to rise, causing the livestock industry to be vulnerable. As a result, it is ideal to find alternative agricultural techniques to produce ample amounts and quality of forage for livestock production. The study aimed to evaluate the effects of supplementing the hydroponic barley fodder sprouts on growth performance, nutrient digestibility, ruminal fermentation and methane emission of Meat-master lambs. In total, 21 male meat-master lambs aged between 3 - 4 months, with an initial body weight of 23.1 ± 1.8 kg were used for this study. Before the experiment, animals were vaccinated for endo, and ecto-parasites and placed for 14 days of quarantine. After that, they were randomly divided into three equal groups; each group had seven lambs. The lambs in the first group (T1) were fed E. curvula hay (basal diet), those in the second group (T2) were fed the diet with grass hay plus 25% of hydroponic barley fodder sprouts and those of the third group (T3), were fed the diet that consisted of grass hay plus 50% of hydroponic barley fodder sprouts. Barley grains were washed and soaked for 30 minutes in sodium hypochlorite solution. After that, the seeds were then soaked in tap water overnight. The following morning, the seeds were transferred to the sprouting trays and manually irrigated with tap water three times a day, using a knapsack sprayer until harvested on day eight. All the animals had access to 300 g of concentrate mixture once a day and clean water ad libitum throughout the study. They were adapted to experimental diets for seven days. Then, the animals were subjected to a growth study for 61 days; from there, they adapted to faecal bags for five days and another five days for nutrient digestibility. The experimental period was 71 days. On day 52 of the growth study, four animals were randomly selected per treatment for methane detection for nine consecutive days using a laser methane detector (LMD). It was observed that the supplementation of hydroponic barley fodder sprouts had a significant (p < 0.05) effect on the growth performance of the animals. The inclusion of sprouted fodder increased feed intake by 42.26 g/day and 114.71 g/day, higher than the animals in T1. Valerate was significantly (p < 0.05) increased by the supplementation of sprouted fodder. The supplementation of hydroponic barley fodder sprouts significantly (p < 0.05) decreased the production level of NH3-N and methane emission per the unit of dry matter intake of the animals. The 50% inclusion level of hydroponic barley fodder sprouts can be adopted as supplementary fodder in lamb’s diet since it enhanced the growth performance and reduced methane emission. However, further studies are required to evaluate other parameters such as carcass characteristics and validate the adoption of hydroponic barley fodder sprouts as a supplement for optimal animal performance.