Institute of Agricultural and Environmental Research

Tennessee State University, Nashville, TN, USA 37209-1561

Goat production in the United States is characterized as an emerging, non-traditional, alternative,

agricultural enterprise. Reproductive output of the doe herd is a major determinant of profitability in

a commercial meat goat enterprise. The Boer goat from South Africa is a breed developed for meat

production that evolved from selection pressures placed on common goats of the region by farmers

(Casey & Van Niekerk 1988). The Kiko from New Zealand is a composite goat breed exported to

the U.S. in the mid-1990s that was developed for meat production through systematic crossbreeding

of selected feral does with dairy bucks and interbreeding of crossbred offspring (Batten 1987). Boer

and Kiko importations created opportunities for U.S. producers to introduce new, unique germplasm

into breeding programs. No goat breed in the U.S. had been developed for meat production. Milk,

fiber, and brush control were primary reasons of raising goats with meat being a by-product (Glimp

1995). Non-descript range goats not of dairy- or fiber-type commonly called “Spanish” goats

evolved through natural selection from stock first imported to the semi-arid southwestern U.S. by

Spanish explorers (Shelton 1978; Mason 1981).

Reproductive merit is an important consideration when evaluating the strengths and weaknesses of

new breeds in particular production environments. Maternal breed has received limited research

attention in meat goats. Breed of dam affects kid performance among various sire breeds

(Goonewardene et al. 1998; Ward et al. 1998); however, such studies have not focused on doe

reproductive rates. An exploratory study suggested that Kiko does have higher reproductive rates

than Boer does (Browning et al. 2004). Reproduction and survival are fitness traits strongly

influenced by environmental origins and(or) associated selection pressures (van der Waaij 2004).

This report focused on reproductive rates and other fitness indicators of Boer, Kiko, and Spanish

does under the humid, subtropical pasture conditions of the southeastern United States.

Animals. Boer (n = 66), Kiko (n = 51), and Spanish (n = 51) straightbred (94 to 100%) does were

managed together on pasture over two years (September 2003 to August 2005). The Spanish

population was represented by six seedstock farms and at least 13 sires. The Boer and Kiko groups

were from larger numbers of seedstock farms and sires. Does were between 1.5 and 5 years old with

age and parity balanced across breeds. All goats were managed on the Tennessee State University

level and has a 30-year annual precipitation amount of 1222 mm. The 12-month precipitation

amount during the study was 1434 mm for Year 1 (September, 2003 to August, 2004) and 1338 mm

for Year 2 (September, 2004 to August, 2005).

consumption and 454 g/d of a commercial concentrate (160 g CP/kg, 69% TDN, as-fed) medicated

with monensin. Stocking rates were approximately 15 does/hectare. Does were exposed for 45 days

each fall to Boer, Kiko, and Spanish bucks in a three-breed diallel mating scheme and kidded on

pasture in March and May. The breeding program resulted in a total of 98 Boer, 89 Kiko, and 97

Spanish doe matings across the two years. Kids were not creep-fed and buck kids were not castrated.

Dams and kids were weighed at birth and at weaning (3 months). Does were strategically dewormed

kidding. Additional dewormings were administered to does displaying clinical signs of internal

parasitism (e.g., weakness, anemia, diarrhea, edema). Fecal samples were collected from a subset of

Does were also treated individually for hoof scald/hoof rot upon observation of lameness. The herd

was not vaccinated for hoof rot.

Statistics. Data were tested with ANOVA techniques using MIXED model procedures of SAS (SAS

Institute, Cary, NC, USA). Fixed effects in the models included breed of doe, service sire breed,

month of kidding and study year. Animal within breed of doe was specified as a random term in the

mixed effects models. Fecal egg counts (FEC) were log-transformed using a log10(FEC+100)

conversion before analysis. Binary responses such as successfully weaning kids and doe survival

were also analyzed using MIXED models. Probability levels less than .05 for the F-statistic indicated

significant differences among breeds of doe. The Tukey-Kramer means separation test was used to

compare least squares means for all traits (alpha = 0.01).

The proportion of doe matings resulting in at least one live kid at birth was lower for Boer (81.1 ±

6.32 ± 0.21 kg), Kiko (1.89 ± 0.07 kids, 5.93 ± 0.22 kg), and Spanish dams (1.94 ± 0.07; 6.20 ±

0.22 kg). Stillbirths were not included in the dataset. Litter characteristics at birth were not affected

by breed of dam. However, Boer does exhibited lower levels of fertility as expressed by parturition

rates as compared with Kiko and Spanish doe contemporaries.

Boer (69.5 ± 3.7%) than for Kiko (91.7 ± 3.9%) and Spanish does (86.2 ± 3.8%). Within the

population of does delivering kids, the proportion of does that weaned kids tended to be higher for

50.2 and 48.1 ± 1.0 kg). Does did not experience significant weight loss during the preweaning

period. Reproductive performance and efficiency as characterized by litter traits as weaning were

generally lower for Boer does than for Kiko and Spanish does in the herd (Table 1).

Postpartum weight loss would not seem to explain the differences expressed between the dam breeds

for reproductive output at weaning. Internal parasitism and hoof infections are obstacles to efficient,

profitable goat production in high rainfall regions. Annual cases of lameness and internal parasitism

requiring treatment in this study were more numerous in Boer does than in Kiko and Spanish does

(Table 2). A larger proportion of Boer does experienced lamensss (78.3 ± 5.2%), multiple incidents

of lameness (53.5 ± 4.6%) and required unscheduled anthelmintic treatment (43.2 ± 4.0%) than Kiko

(40.1 ± 5.5%, 12.7 ± 4.9%; 9.8 ± 4.2%) and Spanish (41.6 ± 5.3%, 22.5 ± 4.7%; 13.9 ± 4.1%) does

per year. Geometric mean fecal egg counts for Boer, Kiko, and Spanish does were 521.7, 298.1, and

181.3 eggs/g, respectively. Survival rates in Table 2 include does that died and does culled due to

proven infertility or chronic health problems.

Data pertaining to fitness indicators may help to explain the lower reproductive rates of the Boer

does. The need for frequent anthelmintic treatments (at 4- to 6-week intervals) in Boer-influenced

herds is a common remark of producers in this region. Doe genotypes with hardiness on parasitecontaminated

pastures would benefit these producers. Internal parasite resistance has been

demonstrated in other doe breeds (Baker et al. 1998). Spanish and Kiko does seem to possess this

characteristic. An unexpected result was Spanish does performing at levels similar to the Kiko. It

was thought that Spanish does would perform more like Boer does given their similar semi-arid

origins as opposed to the humid origin of the Kiko. In computer simulations involving Boer and

Spanish does, reproductive traits under excellent forage conditions were similar for the breeds or

tended to favor Boer does, whereas Spanish does had higher reproductive output under poor forage

conditions (Blackburn 1995). The separation of Spanish and Boer does in the current project concur

with Blackburn (1995) for moderate to low forage conditions. The divergence of Kiko and Boer does

in the current project agree with the earlier exploratory project at this research station (Browning et

al. 2004). Reasons for relatively poor reproductive performance and generally poor disease

resistance of the Boer does are not clear. Explanations may lay in relationships between selection for

growth traits under less than challenging environments and correlated negative responses for

reproductive and health traits as environmental sensitivities develop (van der Waaij 2004).

Blackburn (1995) and van der Waaij (2004) both suggest that genotype x environmental interactions

can exist that put larger, high growth rate genotypes at a disadvantage in a limited resource

environment. Unimproved goats have been reported to be more disease resistant than Boer goats in

South Africa (Ramsay et al. 1978).

Reproductive performance of the doe herd has a major impact on the sustainability and profitability

of a commercial meat goat enterprise. Under the environmental conditions of this research station,

Boer does were not as fit or productive as Kiko or Spanish does. Poor fitness in a herd results in

lower reproductive output, higher maintenance costs, and(or) higher attrition rates. Each of these

responses would be expected to increase break-even prices, thus reducing the chance of profit.

Grazing environments are dynamic and often less than ideal. In the southeastern U.S., efficient meat

goat production is difficult because warm, humid pasture environments provide ideal habitat for

gastrointestinal parasites and hoof pathogens. Spanish and Kiko does displayed general disease

resistance and appear to be more suited for commercial meat goat production in this humid,

subtropical region.

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II:1369.

76(Suppl. 1):77.