Sheep & Goat Research Journal. Volume 31, 2016

Contents

Sex of Littermate Twin Affects Lifetime Ewe Productivity
Author: J. Alison Brown, David P. Kirschten, Gregory S. Lewis and J. Bret Taylor

Factors Affecting Price Differences Between Wool and Hair Lambs in San Angelo, Texas Lambs
Author: D.F. Waldron, W.J. Thompson and R.J. Hogan

Selective Deworming Effects on Performance and Parameters Associated with Gastrointestinal Parasite Management in Lambs and Meat-Goat Kids Finished on Pasture
Author: K.E. Turner, D.P. Belesky, K.A. Cassida, A.M. Zajac and M.A. Brown

Genetic Parameters for Internal Parasite Resistance, Reproduction, and Growth Traits in a Closed Line of Kiko × Boer Goats Divergently Selected for Internal Parasite Resistance
Author: C.L. Thomas, W.R. Lamberson, R.L. Weaber, L.S. Wilbers, T. Wuliji, J.D. Caldwell, and B.C. Shanks

The Use of Organic Pinot Noir Grape Extract as a Natural Anthelmintic in Katahdin Lambs
Author: K.A. Cash, B.C. Shanks, J.D. Caldwell, H.D. Naumann, A.L. Bax, L.S. Wilbers, T.N. Drane1, K.L. Basinger, J.K. Clark, and H.L. Bartimus

Factors Affecting Meat Goat Prices in San Angelo, Texas
Author: W.J. Thompson, R.J. Hogan and D.F. Waldron


Article Summaries

Sex of Littermate Twin Affects Lifetime Ewe Productivity

Author: J. Alison Brown, David P. Kirschten, Gregory S. Lewis and J. Bret Taylor

View PDF File

Summary
Ewe productivity is synonymous with annual litter-weight weaned (LWW) per ewe exposed to rams for breeding, and LWW is largely a function of number of lambs born (NLB) and weaned (NLW). Selecting for LWW should increase litter size and numbers of ewe-ram co-twins. Thus, we used historical records to determine whether sex of co-twin affected lifetime productivity of twinborn ewes. United States Sheep Experiment Station (USSES) lambing records (n = 8,650) from 1991 through 1997 were queried to identify twinborn ewes that were reared with their biological dams and retained in the breeding flock (n = 1,628; Columbia, 383; Polypay, 536; Rambouillet, 383; and Targhee, 326). Corresponding records for lifetime-cumulative counts of lambs born (stillborn and live-born) with recorded birth weights and weaned with recordedweaning weights, cumulative weight of lambs weaned, lifetime count of lambing events, and age at first lambing (1 yr, 2 yr, or 3 yr) were evaluated using PROC GLM and PROC MIXED methods. Alpha was set at 0.10. Only the main effects of sex of co-twin, ewe-weaning weight, ewe breed, and ewe-birth year were significant. Per-ewe exposed to rams, but not per-ewe lambing, cumulative-lifetime weaning weight (P = 0.03) and numbers of lambs born (P = 0.07) and weaned (P = 0.04) were greater for ewes with a ram co-twin than for ewes with a ewe co-twin. Sex of co-twin did not affect number of lifetime-lambing events or age at first lambing for ewes exposed (P = 0.14 and P = 0.59, respectively) or ewes lambing (P = 0.67 and P = 0.27, respectively). Ewe-weaning weight affected cumulative-lifetime weaning weights (P = 0.0003), lifetime numbers of lambs born (P = 0.001) and weaned (P = 0.02), and lifetime-lambing events (P = 0.001), but not age at first lambing (P = 0.44) per-ewe exposed. Productivity of Polypay and Rambouillet ewes generally exceeded that of Columbia and Targhee ewes, although breed ranking was not constant among productivity traits of twinborn ewes. Based on the data, we concluded that ewes born co-twin to a ram had an advantage over ewes born co-twin to a ewe. This advantage amounted to 15.55 kg in lifetime litter-weight weaned per-ewe exposed. We believe that sex of co-twin should be evaluated further to determine whether it is a useful environmental adjustment, beyond lamb sex and type of birth and rearing, for lamb weights and traits related to ewe productivity.

Key words:
Sheep, Production, Efficiency, Reproduction

Factors Affecting Price Differences Between Wool and Hair Lambs in San Angelo, Texas Lambs

Author: D.F. Waldron, W.J. Thompson and R.J. Hogan

View PDF File

Summary
Transaction records of 286,764 lambs sold in 25,916 lots at the largest sheep and lamb auction in the United States were collected from 2010 through 2014, in order to estimate factors affecting lamb prices. The data set was restricted to those lots where the average weight per lamb was between 40 pounds and 100 pounds. Lots were classified according to type (hair or wool). Type is an indicator of breed that best represents the lot. Wool lambs were primarily Rambouillet. Hair lambs were primarily Dorper. A hedonic price model was used to estimate price differentials for lambs sold at auction in San Angelo, Texas. The fixed effects for type of lamb, year, month, weight class, lot size and 2-way interactions with type were significant sources of variation. The results indicate an overall discount of $3.42 ± $0.33 per hundredweight for hair lambs relative to wool lambs. The discount was largest in 2011 ($30.72 ± $0.51 per hundredweight). In 2012 the price paid for hair lambs was $9.62 ± $0.61 per hundredweight higher than the price paid for wool lambs. The discount relative to wool lambs increased as lamb weights increased. Hair lambs sold for $3.18±$0.83 per hundredweight more than wool lambs in the 40-pound to 50- pound weight class. Wool lambs sold for $9.09 ± $0.68 per hundredweight more than hair lambs in the 90-pound to 100- pound weight class. Prices increased as lot size increased. Wool lambs sold for a larger premium in the larger lot sizes. Wool lambs sold for $8.59 ± $0.39 per hundredweight more than hair lambs when there were 35 or more lambs in the lot. The difference in price between hair lambs and wool lambs varied across years, months, weight class, and lot size.

Key words:
Hedonics, Hair Sheep, Price Differentials, Lamb Auction, Texas

Selective Deworming Effects on Performance and Parameters Associated with Gastrointestinal Parasite Management in Lambs and Meat-Goat Kids Finished on Pasture

Author: K.E. Turner, D.P. Belesky, K.A. Cassida, A.M. Zajac and M.A. Brown

View PDF File

Summary
This study evaluated performance and health parameters associated with gastrointestinal parasite control when lambs and meat-goat kids were finished on a mixed sward of orchardgrass (Dactylis glomerata L.), red clover (Trifolium pratense L.), and white clover (Trifolium repens L.) with and without supplemental whole cottonseed (Gossypium hirsutum; WCS). Overall average daily gain (ADG) for this 90-d period was increased by supplementation with WCS in Suffolk lambs (P < 0.003), Katahdin lambs (P < 0.17) and goat kids (P < 0.10). Fecal egg count (FEC) was variable over the grazing season each year, but was not impacted by supplementation of WCS at 0.5 percent body weight (BW). Katahdin lambs had lower FEC than Suffolk lambs and typically goat kids. Goat kids and Suffolk lambs had lower (P < 0.001) blood albumin and higher (P < 0.001) globulin concentrations than Katahdin lambs. Supplementation with WCS did not improve FAMACHA© scores, but Katahdin lambs consistently had lower (P < 0.001) FAMACHA© scores than Suffolk lambs and goat kids. Goat kids had the highest FAMACHA© scores. Using FAMACHA© as a means to identify Haemonchus contortus-induced anemia resulted in a mean 56-percent reduction in doses of dewormer administered compared to a theoretical monthly dosing of each animal. After the initial administration of dewormer, days to next dosing of dewormer were fewest for goat kids (33 d), followed by Suffolk lambs (67 d), and greatest for Katahdin lambs (77 d). By considering the use of breed groups resistant to or having high resilience to internal parasites and coupling with the use of the FAMACHA© system to determine the need to deworm individual animals, producers can improve livestock performance and reduce overall cost of production.

Key words:
Lambs, Goat Kids, Breed, Supplementation, Dewormer Doses

Genetic Parameters for Internal Parasite Resistance, Reproduction, and Growth Traits in a Closed Line of Kiko × Boer Goats Divergently Selected for Internal Parasite Resistance

Author: C.L. Thomas, W.R. Lamberson, R.L. Weaber, L.S. Wilbers, T. Wuliji, J.D. Caldwell, and B.C. Shanks

View PDF File

Summary
Prevalence of gastrointestinal nematodes is a major challenge for goat producers. One approach to combating internal parasites is to utilize the host animal’s natural or acquired resistance to parasites in a selection program. Therefore, our objective was to estimate genetic parameters for parasite resistance, reproduction, and growth traits in a closed line of Kiko (K) × Boer (B) goats divergently selected for internal parasite resistance. Beginning in 2011, 146 mixed-age (1-yr-old to 6-yr-old) B does were assigned to one of two selection lines: a high line (HL) selected for high resistance to internal parasites and a low line (LL) selected for low resistance to internal parasites. Unrelated K bucks, purchased on the basis of parasite resistance, were exposed to each corresponding doe line. Resulting F1 doe progeny were selected based on parasite resistance and were then backcrossed within line to K bucks to produce F2 ¾ K × ¼ B progeny. Fecal egg count (FEC), blood packed cell volume (PCV), and FAMACHA© scores were measured monthly to evaluate impact of Haemonchus contortus parasite load. Genetic parameters were estimated with linear mixed models using restricted maximum-likelihood procedures. Heritability estimates for FEC, PCV, and FAMACHA© score were 0.13, 0.06, and 0.11, respectively and estimates for litter size, birth weight, and weaning weight were 0.23, 0.18, and 0.17, respectively. The genetic correlation between FEC and FAMACHA© was 0.46, while genetic correlations between FEC and PCV and FAMACHA© and PCV were 0.00 and -0.09, respectively. Results indicate that parasite resistance may be lowly heritable, regardless of parasite indicator trait measured, suggesting that selection progress would be possible, yet slow.

Key words:
Genetic Correlation, Goat, Heritability, Parasite, Resistance

The Use of Organic Pinot Noir Grape Extract as a Natural Anthelmintic in Katahdin Lambs

Author: K.A. Cash, B.C. Shanks, J.D. Caldwell, H.D. Naumann, A.L. Bax, L.S. Wilbers, T.N. Drane, K.L. Basinger, J.K. Clark, and H.L. Bartimus

View PDF File

Summary
Gastrointestinal nematode parasitism is one of the greatest threats to economic sheep production in the United States. With increased incidences of anthelmintic resistance and constraints of organic production, there is heightened interest in alternative natural dewormers, such as plants containing condensed tannins. Therefore, the objective of this study was to evaluate effects of organic fermented Pinot Noir (PN) grape extract on parasite level and performance in Katahdin lambs. On October 14, 2014, Katahdin ewe and ram lambs (n = 45; 23.13 kg ± 0.60 BW) were stratified by fecal egg count, weight, sex, and were allocated randomly to one of three treatments: 1) an oral dose (10-mL per 4.5 kg of BW) of fermented PN at 7 d (D7) intervals, 2) the same dose of PN at 14 d (D14) intervals, or 3) control (C; 30-mL oral dose of water at 14 d intervals). Condensed tannins were extracted, purified, and standardized from organic PN and were found to have a concentration of 0.20 mg/mL. Lambs were maintained on tall fescue [Lolium arundinaceaum (Schreb.) Darbysh] pasture, with no additional feed for the duration of the 63-d study. Data were analyzed using PROC MIXED of SAS. Two contrast statements were used to compare the mean of C compared with D7 and D14 and the mean of D7 compared with D14. Average daily gain and total weight gain were greater (P = 0.02) from D7 and D14 compared with C. Start, end, and start to end change body condition scores and FAMACHA© scores did not differ (P ≥ 0.05) across treatments. End of study and change from start to end fecal egg counts were greater (P ≤ 0.05) from C compared with D7 and D14. Change in packed cell volume from start of study to end were greater (P = 0.05) from D7 compared with D14. End monocytes and white blood cell counts were less (P = 0.05 and P = 0.03, respectively) from D7 compared with D14. Other blood parameters were similar across treatments. Therefore, fermented grape extract may be an effective organic and sustainable strategy for controlling gastrointestinal nematodes and increasing performance in Katahdin lambs.

Key words:
Anthelmintic, Condensed Tannin, Lambs, Organic Grape Extract

Factors Affecting Meat Goat Prices in San Angelo, Texas

Author: W.J. Thompson, R.J. Hogan and D.F. Waldron

View PDF File

Summary
The objective of this study was to estimate factors affecting auction prices of kid goats at San Angelo, Texas from 2010 to 2015. Transaction records of 395,009 goat kids sold in 38,862 lots were analyzed with a hedonic-price model that included fixed effects for year and month of sale, weight class, and the size of the lot, and random effects for week of sale, nested within year, and residual. From 2010 to 2015 the Texas-goat population decreased, sales volume decreased, and prices increased. The least squares means price estimates per hundredweight were $150.23 ± $2.41 in 2010 and $251.50 ± $2.38 in 2015. Prices were highest in the first three months of the year, $207.82 ± $1.99 per hundredweight and $38.96 ± $2.78 per hundredweight greater (P < 0.01) than prices in the months of July, August, and September, which had the lowest prices of the year, $168.86 ± $1.94 per hundredweight. The highest unit price received occurred in the 50 to 59 pound weight class ($197.95 ± $1.00 per hundredweight) and was significantly greater than prices for all other weight classes (P < 0.01). Lots that included 35 or more kids, received a $9.96 ± $0.47 per hundredweight greater price (P < 0.01) than lots that sold in lots of 1 or 2 kids ($191.76 ± $1.00 vs $181.79 ± $1.08) Significant differences in prices can be captured by producers who market kids early in the year and within the highest priced weight range and in larger lots.

Key words:
Meat Goats, Auction Prices, Texas, Seasonality, Non-Traditional Markets, Hedonics