Integrating tropical legumes with condensed tannins into ruminant grass-based diets for sustainable production
Ruminant production in Puerto Rico and US Virgin Islands are crucial to their economies and are reliant on tropical grasses. Though grass is abundant in the wet season, they are of low quality and cannot meet the nutritional requirements of growing ruminants. In Puerto Rico, urban spawn has forced beef producers to diversify into sheep and goat production and move pastures to less productive marginal lands as they are more efficient in marginal lands. Concentrates typically used to bridge this nutrient requirement gap are imported at considerable costs ($20 per 50lb of concentrate feed) are not economically viable. In the emerging small ruminant industry (Mutton and Chevon sells for $4-5 lb in Puerto Rico), producers are now faced with parasitism of gastrointestinal nematodes (GIN) resulting in marked production losses pre- and post weaning, in addition to the developed resistance to anthelmintic drugs by GIN. Creep grazing or conserved tropical legumes containing condensed tannins (CT) to provide supplementary nutrients may reduce parasite loads and will likely enhance growth rates and increase profitability, but these hypotheses needs to be verified in on farm research trials.
Research objectives were: (i). Determine intake, digestibility and nitrogen balance of lambs fed diets of tropical grass hay (eg. blue stem; Dicanthium annulatum or guineagrass; Panicum maximun Jacq.) supplemented with tropical legumes with condensed tannin (CT) [perennial peanut (Arachis spp.); desmodium (Desmodium heterocarpum (L.) DC. Subsp. ovalifolium (Prain.) cv. Maquenque, calliandra (Calliandra calothyrus)] and pigeonpea (Cajanus cajan), (ii). Determine average daily gain and parasite load of lamb-crops creep grazing CT tropical legumes (perennial peanut, demodium, calliandra and pigeon pea), (iii) On-farm demonstrations of CT legumes and their effects on parasite control on small ruminants, and (iv). Prepare economic costs and returns of forage and small ruminant production on conventional dewormers vs. dewormer banks.
University of Puerto Rico: Elide Valencia, Professor of Agronomy, University of Puerto Rico, Mayaguez
Studies were conducted at the University of Puerto Rico, Agricultural Experiment Sub-Station of Corozal during the period between April-November, 2009 and repeated in 2010. St. Croix White hair sheep growing lambs [n=5; 15 kg body weight (BW)] and replicated twice were used for this study. There were two treatments; treatment 1 consisted of daily and night rotational grazing of an already established guineagrass (Panicum maximum Jacq.) – perennial peanut (PP; Arachis pintio) stand during the period between 1:00 PM to 7:00 AM and supplemented with guineagrass hay (3% BW) during the day, while treatment 2 consisted of rotational grazing of pure guineagrass stands during the same period. Mineral salt block was offered ad lib during the morning. Weekly, lambs were offered 200 g/animal of the condensed tannin (CT) containing Calliandra calothyrsus shrub and weight taken. FAMACHA to assess anemia was done biweekly and lambs with a score above 3 were treated with a dewormer. There were differences on average daily gain (ADG). Lambs on the legume association were higher (65 g/d) compared to 30 g/d on grass alone (a two-fold increase in ADG). Lambs on guineagrass-PP required less deworming (2 xs during the period of the study compared to 5 x those on grass alone in year 1 and 3 x in yr 2). The CT legume minimized GIN when offered on the low quality guineagrass and those in associations, but had little effect on ADG.
In 2010, an experiment assessed intake proportions of 75:25 guineagrass-calliandra and 50:50 feeding of Stylosanthes guianensis (Stylo), Cajanus cajan (pigeon pea)-guineagrass hay. Results indicate that 25% is as high proportion that lambs would accept in the diet, but pigeon pea and stylosanthes can be fed in higher proportions than calliandra (50%) without affecting intake. Crude protein intake and fiber digestibility and intake is being analyzed.
A study was conducted at farmer cooperator Vicente Ortíz, Barceloneta, Puerto Rico during the period between May to December 2010. The objective of the present study was to assess live weight performance of pre- and post weanling milk Nubian goats creep grazing CT Calliandra calothyrsus and followed by evaluating two contrasting diets using dried and ground Morus alba (MA) produced in situ within the farm compared to goat concentrate feed. Twelve kids (2-wks old) of Nubian milk goats creep grazed perennial peanut and CT Caliandra for 3-mo. There were no differences on weaning weight (17.5 kg BW). However, this weaning weight surpasses the traditional weaning on non-creep grazed legumes by 5 kg. At post weaning, kids (N=3) were randomly assigned to a semi-confinement feeding systems of a free choice offer of bluestem grass hay supplemented with ground MA (harvested at 3-mo regrowth and sun-dried for 5d) at 3% BW and a free choice offer of bluestem hay plus a goat concentrate (600 g/kid for the first 3 mo and 800 g/kid for the additional 3 mo.), a management practice used by the farmer for developing young goats. Animals allowed pasturing 5 h daily. Kids were weighed weekly. There were no differences between feeding systems. Average daily gains on supplemented MA were 58 g/d compared to 62 g/d on those fed with concentrates. Breeding stock was marketed at 9-mo age.
Farmer Cooperators: Guillermo Martinez, Altamira Norte, Vega Baja
In July-December 2009, a protein bank of Morus alba (MA) and a deworming bank of CT Calliandra were established. Four hundred seedlings of MA and CT Calliandra were planted in a 0.20-area. At 4-mo post-planting (January-June 2010, 17 adult lambs grazed both banks, and shrub plants were cut at 15-cm height to induce tillering. In addition, a 0.20-ha area of guineagrass and PP association was also established. Sheep flock was bred to lamb in the fall of 2010. Following the lambing period in January 2010, a creep grazing study was conducted using MA, CT Calliandra and the grass-peanut association and grass alone. Lambs weaned higher in MA protein bank (35 lbs) than in the grass-peanut association (30 lbs). Both nannies and lambs had less de-worming (2 x) versus those of the control (5 x).
The main objective of the economic analysis is to conduct a cost-benefit analysis of integrating CT legumes and de-wormer banks into ruminant diets. Specifically, we need to estimate the establishment and annual maintenance costs, and compare them to animal performance data to determine economic and financial feasibility. Data sources include the experimental plots and the farmer demonstration sites. As part of the data collection protocol, we developed a set of data logs or templates, in both English and Spanish versions. Using data from the establishment year of the experiments, we initiated a preliminary cost-benefit assessment comparing two production systems: (a) a conventional system, using concentrated feeds with traditional antihelminthic treatments; and (b) an innovative system using a de-wormer bank consisting of Morus Alba and Calliandra. Once production data from the subsequent years of experimentation and demonstration become available, we will use these data to calibrate the estimated budgets, calculate the expected annual maintenance costs and revenues, and then determine financial feasibility indicators (net present value and internal rate of return) assuming a 10-year horizon, which is the expected life of the de-wormer bank.
University of the Virgin Islands, Agriculture Experiment Station, St. Croix USVI: Prof. Stuart Weiss.
CT calliandra was successfully established and antihelmintic effects studied in 2010. Data was inconclusive as during the study there was excessive rains and high GIN contamination which masked the effects of CT calliandra and also resulted in high lamb mortality.
Impacts and Contributions/Outcomes
In addition to three farmer cooperators participating on the on-farm research, 20 additional small ruminant farmers have benefited from the use of MA and CT Calliandra. The local Department of Agriculture, Puerto Rico in 2010 and 2011 provided additional funds to our program and the Agricultural Experiment Station to prepare seedlings of calliandra and Morus alba to be distributed to small ruminant famers. In 2010, 4000 seedlings were distributed island wide to be used as deworming bank.
In May 2010, a field day was conducted at Guillermo Martinez farm to discuss the establishment and use of CT legumes. Forty farmers participated in this field day. A final workshop and field is planned for May 2011.
In December 2010, two graduate students provided assaitantships under the SARE grant defended their thesis. Publications will be submitted in 2011 to the Journal of Agriculture of Puerto Rico.
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