Performing Department
Agri & Extension Center
Non Technical Summary
The aim of this proposal is to develop studies for organic sheep management practices on pasture to increase the level and efficiency of organic sheep productivity for increased profitability from sheep production and promote lower cost to consumers of organic meat. The increased demand for organic meat products has attracted producers to convert from conventional farming to organic; however, there are limited data about lamb meat organically produced. Adequate nutrition and good management are essential to promote animal health and optimize growth rates, especially in an organic farming system, considering the reduced ability to use various drugs and chemicals to treat animal diseases. Therefore, it is crucial, especially for growing animals, to receive high-quality supplementation to prevent body weight loss, health issues, decreased growth rate and low reproductive performance in the future. Creep feeding is a management strategy to provide supplemental nutrients to livestock during the pre-weaning phase in an area that prevents the dams from gaining access to the feed, and despite the limited data, this practice is commonly used by small ruminant producers. Creep grazing is another management option, which aims to provide higher quality forage to suckling livestock in an area that excludes the dams in the main pasture. The addition of legumes in grass-based pastures for creep grazing area promotes an increase of the overall nutritive value of the pasture, which provides a better quality feed for small ruminants organically produced. The combined benefits of a high crude protein concentration, and possible protein protection and growth-promoting properties, can make forage legumes potentially attractive as a natural means of increasing live weight gain in lambs. In Missouri, alfalfa and red clover are the most common legumes used by small ruminant producers to improve their pastures. It might be advantageous to provide these legumes in a creep grazing area to lambs to increase pre-weaning growth performance. Thus, the outcomes of this project will be the great value and interest by organic farmers and small ruminant producers who are aiming to enhance their lamb meat production.
Animal Health Component
80%
Research Effort Categories
Basic
10%
Applied
80%
Developmental
10%
Goals / Objectives
The aim of the current project is to evaluate the effects of creep feeding and creep grazing and their possible interactions with other factors on growth, health, GIN, and financial characteristics of organic meat lambs and their dams, and consequently, increase organic sheep farming profitability.Experiment 1: Determine effects of creep feeding and its possible interactions with other factors on growth, health, and financial characteristics of organic Katahdin lambs and ewes at weaning and post- weaning.Experiment 2: Determine effects of creep supplementation of concentrate or legumes and its possible interactions with other factors on growth, health, and financial returns of organic Katahdin lambs and ewes at weaning.
Project Methods
Experiment 1: The experiment will be conducted at Lincoln University's Alan T. Busby farm, which has acquired organic production status and certification. Animals will be semi-intensively managed on fescue-based pastures and supplemented with hay for ad libitum consumption, with free access to water and mineral supplement. Sixty Katahdin mature ewes and their lambs will be used. Animals will start lambing in early October of 2021. Lambs will be assigned to creep feeding or no creep feeding treatments at 30 d of age on average. Each treatment will be replicated in two pens. Lambs will have unrestricted access to suckle theirs ewes on pasture. Since the median age of 30 d, creep-feed lambs will have access to an organic grower pellet for ad libitum consumption. All lambs will be weaned at 90 d. After weaning, all lambs will be moved to a fescue-based pasture and will have access to organic pelleted feed and will be subjected to the same management until 120 d. Ewes and lambs will be weighted at 30, 60 and 90 d, and all lambs will be weighed at 120 d. Blood samples will be collected from all animals at 60 d and at weaning, and from all lambs at 120 d. Blood samples will be analyzed for triglycerides, cholesterol, albumin, total protein, glucose and lactate. The packed cell volume (PCV) will also be performed (Schalm et al., 1975). Fecal samples will be collected, from all animals at 90 d and from all lambs at 120 d, and submitted to fecal egg counts per gram of feces (FEC) using the McMaster technique (Coles at al., 2006). FAMACHA® score of all animals will also be recorded at 60 d and at weaning, and from lambs at 120 d. At 90 and 120 d, all lambs will be scanned over the loin area for ultrasound-measured carcass trait measurements. The study will be analyzed as a completely randomized design. Linear mixed models by PROC MIXED (SAS, 2011) will be used to analyze 30 d initial weight, 60 d weight, 90 d weaning weight, 120 d final weight, ADG, PCV, blood, shrunk weight, and financial returns. Lamb survival will be analyzed utilizing a binomial distribution and logit function. Conformation and FAMACHA® scores will be analyzed using PROC GLIMMIX (SAS, 2011).Experiment 2: The experiment will be conducted at Lincoln University's Alan T. Busby farm. A stand of fescue grass (9.6-ha) will be fenced and divided into three blocks. Each block will be split into four equalized individually fenced pasture plots, with a total of 12 grazing plots (0.6-ha each). Two of the four pasture plots in each block will be connected to adjacent mix stands of either alfalfa with fescue or red clover with fescue (0.2-ha).The treatments will be: (control) continuous pasture grazing, no creep feeding/grazing; (feeder) continuous pasture grazing + creep feeding concentrate; (alfalfa) continuous pasture grazing + creep grazing alfalfa/grass mix; and (clover) continuous pasture grazing + creep grazing red clover/grass mix. Lambing will occur in April/May of 2022 and 2023. Sixty Katahdin ewes with their lambs will be used. The groups will be randomly assigned to one of 12 pastures where they will continuously graze for a period of 120 days. At the average age of 30 d, supplemented lambs will have access to the creep feeders or to the grass-legume mix areas. Two groups of lambs in each block will rotationally graze either alfalfa/grass or red clover/grass mix pastures, which will be separately grown on additional areas of 0.2-ha each. Another group of lambs in each block will have access to the creep feeders with organic pelleted concentrate feed ad libitum through a grain feeder placed in the adjacent area. Lambs in each group will be weaned at the median age of 120 d. All lambs will have unrestricted access to suckle theirs ewes on pasture. All animals will have free access to water, hay, and mineral supplement. Feed will be offer in the creep feeders daily until weaning, at 105% of consumption in the previous day. An iron creep gate with adjustable vertical bars will be installed in each of three legume subplots. Creep grazing alfalfa/grass and red clover/grass mix stands will be equally divided into three paddocks and will be rotationally grazed for a period of 7 d. Pastures will be sampled just before initiation of the grazing period and every 14 d during the experiment. Herbage mass will be determined by clipping three random 0.25-m2 quadrats, to a 5-cm stubble height, in each pasture and in each legume/grass creep area, respectively. Then forage will be dried at 60°C and herbage mass (HM) (kilograms dry matter [DM] per hectare) calculated. Cages (1-m2) will be placed in each pasture at the beginning of the experiment. Dry-matter production (kg DM ha-1) and herbage growth rates (kg DM ha-1 day-1) of pastures and legume/grass mix stands will be measured inside two 1-m2 grazing exclosure cages in each plot during active growth in spring, summer and autumn. Every 28 d during the trial, the cages will be moved to a new location where pasture canopy height is similar to the pasture. Herbage allowance (HA) will be calculated as the average HM divided by the average total sheep live weight during that month (Sollenberger et al., 2005). Apparent DM intake (herbage disappearance) in creep fed legume/grass mix pastures will be measured through exclosure cage cuts as described by Ates et al., 2017. Nutritive values of the main pastures and legume/grass mix will be determined by hand-plucked, snip samples. Snip samples, representative of herbage eaten by sheep, will be collected by hand randomly across herbage in each plot at approximately 3 wk intervals from the main pastures and at weekly intervals from the creep-grazed stands before the animals move into the new grazing legume/grass mix plots. All herbage from the snip samples will be dried in an air-forced oven at 60°C until constant weight and ground in a Wiley mill (Model 4, Thomas-Wiley Laboratory Mill, Thomas Scientific, Swedesboro, NJ) to pass a 1-mm stainless steel screen. Ground samples will be analyzed for CP by Kjeldahl method (AOAC, 2003). Neutral detergent fiber (NDF) and acid detergent fiber (ADF) will determined according to the methods as described by Van Soest et al. (1991). The ADF concentration will be used to calculate the digestible dry matter (DDM) = (88.9 - (0.779 9 x % ADF) (Horrocks & Vallentine, 1999). Animals will be weight at approximately 30, 60, 90, 120 d of age. Blood samples will be collected from all animals at 60, 90 and at 120 d (weaning) as described in experiment 1. FAMACHA® score of all ewes will be record at 30 d and of all animals at 60, 75, 90, 105, and at 120 d. At 90 and at 120 d, fecal samples will be collected and submitted to fecal egg counts per gram of feces (FEC) using McMaster technique (Coles at al., 2006). At 90 d and at weaning all lambs will be scanned over the loin area for the ultrasound-measured carcass trait measurements. A simple bio-economic model will be built for the optimization of the feeding strategies. The model takes into account the available amount of feed of each kind, amount of feed consumed by the lambs per period, live weight gain corresponding to each feed type per period, unit costs of each feed, and price per kg of lamb meat (gross carcass weight). The model that will be used for optimization is described by Ates et al., 2017. Dry-matter production, herbage growth rates, nutritive value and herbage mass on offer will be analyzed by ANOVA with repeated measures for each measurement period. The live weight gain per head (g/day) and per hectare (kg/ha) of lambs and ewes (as dependent variables) will be analyzed by one-way ANOVA.