Sustainable Year-Round Forage System for Goat Production in the Southern USA

Sustainable Year-Round Forage System for Goat Production in the Southern USA

Summary

Series of experiments were conducted to evaluate most appropriate year-round production system for goats in southeastern U. S. Production systems utilizing feedlot style was compared to those mainly based on summer pasture (common bahiagrass pasture), winter pasture (Marshall ryegrass) or browse (mimosa). Preliminary carrying capacity or stocking rates of mimosa fields, when rotationally browsed, and Marshall ryegrass pasture, when continuously grazed by goats, were also determined. Another study was conducted to evaluate anthelmintic activities of mimosa. Preliminary results indicated that, animals on feedlot style or Marshall ryegrass grew faster and reached expected slaughter date in less time when compared to other systems. Their (Animals on feedlot and Marshall ryegrass) carcass quality was also superior to other systems. However, economically (when input-output to the system was calculated), Marshall ryegrass was superior fallowed by mimosa browse when compared to other two systems. It appeared that 3-4 goats/acre was sufficient for mimosa browse system and based on preliminary data of animal performance on Marshall ryegrass, 11 goats/acre were superior to 8, 14 or 17 goats /acre. Mimosa did not have an anthelmintic activity when fed for 21 days to goats, however, animals on mimosa fields needed less parasite control practices than bahaigrass pastures. Thus, long term feeding of mimosa under field conditions may have benefits as a parasite management tool because it allows the animal to browse rather than graze.

Objectives/Performance Targets

1. Study the pattern of foliage removal from mimosa by goats, and determine the optimal
   degree and frequency of defoliation.

   Establish the optimal stocking rates and associated animal weight gain for goats when
   feeding on mimosa in summer, and annual ryegrass in winter.

   Determine whether mimosa has any anthelmintic effect when browsed by goats.

   Determine carcass quality and if there is a consumer preference for meat from browse-
   fed goats.

   Compare productivity of goats on ryegrass with that of cattle.

   Evaluate (on an experiment station) and demonstrate (on two small farms) an
   integrated year-round forage system of mimosa in summer and annual ryegrass in winter for goat production by limited resource farmers.

Accomplishments/Milestones

Objective 1

Preliminary results obtained for this objective were applied for 2003 browsing study. Altering canopy structure by pruning stems to about 2 ft and allowing only limited re-growth prior to defoliation may be more effective in achieving more uniform partial de-foliation. Further observations were made this year and results will be reported when surmised.

Objective 2

Mimosa Study (Summer Browse):

In December, 2002-January, 2003, five previously fenced mimosa paddocks (one acre each) were prepared by pruning stems to about 2 ft and growth was allowed to accumulate without defoliation until June. Major annual weed infestations of the mimosa paddocks were also eliminated by hand on these five acres during this same period. Starting on June 11, 2003, sixteen goats with average initial BW of 20.49 kg were rotationally grazed on about 5 acres of mimosa plant fields for 100 days. Animals were stratified by purity of breed (based on visual evaluations without papers; we paid $10.00 more /head for better looking or >75% Boer kids.), 8 crossbreds (C) and 8 having at least 75% Boer blood (P). Animals were allowed to browse 24 h/d and crushed corn grain was provided at 100 g/h/d. Body weight was recorded every two weeks. Mimosa grab samples were collected every two weeks and composite were made monthly. To predict dry matter intake, animals were equipped with fecal collection bags and total fecal output was recorded daily, and a representative sample kept, for 7 days. In vitro dry matter digestibility of mimosa samples was determined and whole experiment was repeated twice during the entire experimental period. Blood samples were collected every 4 wk for blood urea and ammonia determination. Animals were humanely harvested and carcass characteristics were determined. Preliminary results indicated that animals lost weight during the first 2 wk, 72 g/ animal/d and 9 g/animal/d for P and C group, respectively. Average daily gain ranged from 100 g /d to 150 g/d and from 120 g/d to 153 g/d for P and C group, respectively. Overall average daily gain for 100 days was 73 g and 81 g for P and C group, respectively. The average final BW was 29.5 kg, which is about 5 kg less than expected average slaughter weight for goats. Data regarding intake, blood parameters and carcass characteristics will be summarized when available. Boer goat is an excellent meat goat and the degree in purity of the breed, properly documented, has shown to improve gain. These preliminary results indicated that degree of purity of breed without documentation is not sufficient to grant better genetics and performance, and producers should be wise in purchasing their animals this way. Preliminary results on input-output are very promising when compared to reported results for similar size goats kept indoors and consuming more than 40% grain in their diet.

Ryegrass Study:

Experiment 1, Feb.- April, 2003:

This experiment was conducted 1) to determine preliminary performance of goats on annual Marshall ryegrass and 2) to evaluate the effect of castration on animal performance and carcass quality. Twenty six goats (wether and buck kids) were placed on one of the two 2.3 acres of ryegrass pastures and were rotated between the two pastures as needed. Body weights were recorded every two weeks and experiment was carried out for 56 days. Forage samples were collected every 4 wk for forage quality determination. After day 56, 14 animals (7 wethers and 7 bucks) were harvested and hot carcass weight (HCW), cold carcass weight (CCW), dressing percent (DP), kidney and pelvic fat (KPF), longissimus muscle area (LMA), backfat (BF) and other carcass parameters were measured. Average daily gain over 56 days was greater (P 0.10) were observed in HCW, CCW or DP. Wethers had higher (P 0.10). These results indicated that castration of young market goats reduced growth and did not provide any distinct advantage in carcass characteristics. Elimination of castration practices will improve animal welfare. The rest of the animals were transported according to the marketing plan and were sold at Tennessee market. At Tennessee market, animals are sold according to their body weight and they bring more profit. At Alabama market, animals are sold by head and bring less profit. Alabama goat marketing strategies should change in order to secure more profit for the goat producers.

Experiment 2, December 15- 2003- present (ongoing now):

This experiment was conducted to determine the optimum stocking rate of goats grazing on annual Marshall ryegrass. Four approximately one-acre paddocks were prepared and 8, 11, 14 and 17 animals (buck kids) were randomly assigned to these paddocks and start grazing on December 15, 2003. Average daily gains were 164.5 g, 187.2 g, 117.1 g and 96 g for 8, 11, 14 and 17 goats/acre, respectively. Initial and 66 days disc meter readings were 5.9 vs. 5.4, 8.2 vs. 5.4, 4.9 vs. 2.8 and 7.7 vs. 2.7 for 8, 11, 14 and 17 bucks/acre pastures, respectively. At the end of the study, 8 animals will be randomly selected for carcass quality determination and rest of the animals will be sold in a buck sale and show.

Objective 3

This experiment was conducted to determine the effect of mimosa fed to goats, with experimentally induced Haemonchus contortus larvae, on parasite burdens and selected blood parameters. Eighteen Boer cross goat kids (BW 15.8 ± 0.07kg) were housed in individual pens and randomly assigned to two dietary treatments: 1) 90% fresh cut mimosa with 10% alfalfa hay (MA), as fed, and 2) a control treatment of 85% green chop soybeans with 15% of bermudagrass hay (SB), as fed. Dietary treatments were calculated to be isonitrogenous on a DM basis. Feed intake and refusals were monitored daily and intake was adjusted weekly for 4 wk. Body weight was recorded weekly after a 4 h withdrawal from water and feed. Fresh feces were collected from each goat weekly and fecal egg counts were conducted using a modified McMaster method. Blood samples were collected weekly, via the jugular vein, and were analyzed for pack cell volume and plasma protein. Dry matter intake was higher (P 0.10) between dietary treatments or over time. These results indicated that short-term treatment of goats with mimosa was not effective in eliminating or managing Haemonchus contortus under controlled feeding conditions. However, long term feeding of mimosa under field conditions may have benefits as a parasite management tool because it allows the animal to browse rather than graze.

Objective 4

Following experiments were conducted to evaluate animal performance and carcass quality for goat kids grazing on bahiagrass pasture or grain fed indoors. These data will be compared to that obtained from goats browsing mimosa under objective 2.

Experiment 1

Pasture fed (bahiagrass):

Starting on June 11, 2003, sixteen goats with average initial BW of 20.78 kg were rotationally grazed on two one-acre bahiagrass pastures for 100 days. Pastures were limed and fertilized by ammonium nitrate and animals were rotated between the pastures every two weeks. Animals were stratified by purity of breed (based on visual evaluations without papers; we paid $10.00 more /head for better looking or >75% Boer kids.) , 8 crossbreds (C) and 8 having at least 75% Boer blood (P). Animals were allowed to graze 24 h/d and a 16% crude protein concentrate mix was provided at 100-200 g/h/d. Body weight was recorded every two weeks. Pasture grab samples were collected every two weeks and composite were made monthly. To predict dry matter intake, animals were equipped with fecal collection bags and total fecal output was recorded daily, and a representative sample kept, for 7 days. In vitro dry matter digestibility of bahiagrass samples was determined and this experiment was repeated twice during the entire experimental period. Blood samples were collected every 4 wk for blood urea and ammonia determination. Animals were humanely harvested and carcass characteristics were determined. Preliminary results indicated that P group lost weight (4.5 g/d) and C group gained (21.5 g/d) during the first 2 wk. Average daily gain ranged from 17 g /d to 137.5 g/d and from 18.7 g/d to 87.5 g/d for P and C group, respectively. Overall average daily gain for 100 days was 46.6 g and 47 g for P and C group, respectively. The final average BW was 25.4 kg, which was 10 kg less than expected average slaughter weigh. Data regarding intake, blood parameters and carcass characteristics will be summarized when available. Preliminary results indicate that commonly used bahiagrass pasture even with supplementation cannot support economically viable production system. These results also indicated that purity of breed without documentation is not sufficient to grant better genetics and performance and producers should be wise in purchasing their animals this way. Results of this study will be compared to mimosa and grain study reported below.

Experiment 2

Feedlot (40% grain mix, 40% soy hulls, 20% bermudagrass hay)

Starting on June 11, 2003, sixteen goats with average BW of 21.0 kg were stratified by purity of breed (based on visual evaluations without papers; we paid $10.00 more /head for better looking or >75% Boer kids.), 8 crossbreds (C) and 8 having at least 75% Boer blood (P) and were housed indoors in individual pens. Animals were fed a 40:60 grain: roughage diet. Animals were offered once a day a 40% grain mix (16% crude protein), 40% soy hulls and 20% bermudagrass hay, to meet their requirements for maintenance and growth. Body weight was recorded every two weeks. Grain mix, soy hulls and hay samples were collected every two weeks and composite were made monthly. To predict dry matter intake, animals were equipped with fecal collection bags and total fecal output was recorded daily, and a representative sample kept, for 7 days. In vitro dry matter digestibility of mix diet samples was determined and these procedures were repeated twice during the entire experimental period. Blood samples were collected every 4 wk for blood urea and ammonia determination. . Average daily gain ranged from 108 g /d to 224 g/d and from 122 g/d to 181 g/d for P and C group, respectively. Overall average daily gain for 100 days was 141.4 g and 142.0 g for P and C group, respectively. These animals reached expected average slaughter weight of 35 kg in 100 days. Data regarding intake, blood parameters and carcass characteristics will be summarized when available. These preliminary results indicated that animals fed grain indoors gained faster and reached the targeted BW in 100 days. Also, purity of breed without documentations is not sufficient to grant better genetics and performance and producers should be wise in purchasing their animals this way.

Objective 5

18 acres of Marshall ryegrass were grazed with 36 heads of cattle, with a stocking rate of 2 head/acre. Grazing started on December 11, 2002, and continued for 147 days. ADG was 1.92 lb/day, and gain per acre was therefore 1.92 x 2=3.84 lb/acre/day x 147 days = 564lb. The 96-day ADGs for 8, 11, 14 and 17 goats/acre were 0.40, 0.42, 0.24 and 0.20 lb, respectively, with corresponding gain per acre of 3.2, 4.62, 3.36, and 3.4 or total gain for 96 days of 307, 444, 323 and 326 lb. Data of ADG from 11 goats per acre stocking rate (4.62 lb/acre) compares favorably with two cow/acre data (3.84 lb/acre). Pasture disk meter readings at the end of the experiment were 7.3, 6.5, 4.2 and 3.4 cm, respectively. The regression equation for ADG (y) vs. stocking rate (x) was y = 0.64 – 0.026x (r = -0.91), and for disk meter height (y) vs. stocking rate (x) it was y = 23.46 – 2.05x (r= -0.98).

Objective 6

Two independent producers have been identified. We have started preliminary preparations of the farms. Strength and weaknesses have been identified and recommendations have been given. We will continue working with these producers and their farms will be used as demonstration sites. As more information is collected, on goats grazing on ryegrass and browsing on mimosa, we will be more equipped to transfer the information to our producers.

First buck sale and show will take place this May-June. Our bucks from annual Marshal ryegrass study will be evaluated and sold at this show. Producers will be invited and will be informed on how to choose a good breeding buck. Live grade and body condition scores will be used to evaluate our sale bucks.

Impacts and Contributions/Outcomes

A combination of mimosa in the summer and annual Marshall ryegrass in the winter is likely to provide an outstanding year-round forage system for goat production by limited resource farmers in the southern US. However, more data is needed to develop the best management practices for this system, and to clearly demonstrate its superiority over typical systems currently being used. Preliminary data confirmed that mimosa provides an excellent alternative feed for summer and current production system using perennial grasses does not provide sufficient nutrients for optimum growth. Mimosa may not have anthelmentic property, however, browsing in summer may also reduce the infestation of GI parasites (major problem in Southeast), when goats spend less time grazing close to the ground where the larvae of these pathogens are present in large quantities.

Collaborators: