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Spindale, NC, United States

Garcia-Peniche T.B.,Instituto Nacional de Investigaciones Nucleares | Montaldo H.H.,National Autonomous University of Mexico | Valencia-Posadas M.,University of Guanajuato | Wiggans G.R.,U.S. Department of Agriculture | And 3 more authors.
Journal of Dairy Science | Year: 2012

To aid in improvement of breeding programs for production and reproduction traits of US dairy goats, breed differences over time were documented and genetic parameters were estimated. Data were from herds with ≥2 breeds (Alpine, LaMancha, Nubian, Oberhasli, Saanen, or Toggenburg), but only purebred data were analyzed. Three kidding periods were examined: 1976 through 1984, 1985 through 1994, and 1995 through 2005. Univariate repeatability mixed models were used to estimate least squares means by kidding period-breed and genetic parameters for milk, fat, and protein yields, combined fat and protein yield, fat and protein percentages, protein:fat ratio, age at first kidding, and kidding interval. Trends across kidding periods were favorable for most yield traits for all breeds but generally unfavorable for reproduction traits. Saanens had the highest milk (1,063 to 1,125. kg) and protein yields (31 to 33. kg). Nubians had the highest fat yields (37 to 40. kg) and lowest milk yields (791 to 851. kg). Oberhaslis had the lowest fat (31 to 33. kg) and protein (23 to 27. kg) yields. Alpines had the largest increase in milk yield (7.4%); Oberhaslis had the largest increase in protein (17.4%) and combined fat and protein (13.2%) yields. Combined fat and protein yield was higher for Nubians, Saanens, and Alpines (65 to 72. kg) than for LaManchas, Toggenburgs, and Oberhaslis (53 to 67. kg). Nubians had the highest fat (4.7 to 4.8%) and protein (3.6 to 3.8%) percentages. Only Nubians increased in fat percentage (2.1%); protein percentage increased most for Toggenburgs (7.4%) and Alpines (7.1%). Protein:fat ratio was highest for Toggenburgs (0.84 to 0.89) and lowest for Nubians (0.76 to 0.81), but Nubians had the largest increase in protein:fat ratio (6.6%). Saanens were oldest at first kidding (509 to 589 d), and Toggenburgs and LaManchas generally were youngest (435 to 545 d); age at first kidding increased most for Alpines (21.8%) and LaManchas (21.6%). Kidding intervals generally were shorter for Oberhaslis, LaManchas, and Nubians (350 to 377 d) than for Toggenburgs, Alpines, and Saanens (373 to 387 d). Kidding interval increased most for Nubians (3.9%) and Saanens (3.8%) and decreased only for Oberhaslis (5.4%). Heritability estimates across breeds were 0.35 for milk and fat yields, 0.37 for protein yield and protein:fat ratio, 0.36 for combined fat and protein yield, 0.52 for fat percentage, 0.54 for protein percentage, 0.23 for age at first kidding, and 0.05 for kidding interval. Genetic selection within breed is feasible for production and reproduction traits of US dairy goats. © 2012 American Dairy Science Association. Source


Montaldo H.H.,National Autonomous University of Mexico | Valencia-Posadas M.,University of Guanajuato | Wiggans G.R.,U.S. Department of Agriculture | Shepard L.,American Dairy Goat Association | Torres-Vazquez J.A.,Instituto Nacional de Investigaciones Nucleares
Journal of Dairy Science | Year: 2010

First-parity 305-d milk yield and intervals between first and second kiddings from 1975 through 2005 were analyzed to estimate genetic and environmental parameters for United States Alpine, LaMancha, Nubian, Saanen, and Toggenburg dairy goats. The data set included 43,612 does with first-parity milk yield and 25,863 does with first kidding interval. Parameters were estimated by REML using bivariate mixed models within and across breeds. Fixed effects were month and herd-year of kidding within breed and month and breed-herd-year of kidding across breeds. Random effects were animal and residual. The heritability estimate for first-parity milk yield was 0.36±0.01 across breeds and ranged from 0.35 to 0.38 within breed; heritability for first kidding interval was 0.05±0.01 across breeds and ranged from 0.00 to 0.15 within breed. The estimate of the genetic correlation between first-parity milk yield and first kidding interval was positive (unfavorable) across breeds (0.35±0.09). Estimates of environmental correlations within and across breeds were positive (0.16-0.25). The presence of unfavorable genetic relationships between milk yield and kidding interval indicates a need to include reproductive performance as a selection criterion. © 2010 American Dairy Science Association. Source


Castaneda-Bustos V.J.,Colegio de Mexico | Montaldo H.H.,National Autonomous University of Mexico | Torres-Hernandez G.,Colegio de Mexico | Perez-Elizalde S.,Colegio de Mexico | And 3 more authors.
Journal of Dairy Science | Year: 2014

Heritabilities and correlations for milk yield (MY), fat yield (FY), protein yield (PY), combined fat and protein yield (FPY), fat percentage (F%), protein percentage (P%), age at first kidding (AFK), interval between the first and second kidding (KI), and real and functional productive life at 72. mo (FPL72) of 33,725 US dairy goats, were estimated using animal models. Productive life was defined as the total days in production until 72. mo of age (PL72) for goats having the opportunity to express the trait. Functional productive life was obtained by correcting PL72 for MY, FY, PY, and final type score (FS). Six selection indexes were used, including or excluding PL72, with 6 groups of different economic weights, to estimate the responses to selection considering MY, FY, PY, and PL72 as selection criteria. The main criteria that determined the culling of a goat from the herd were low FS, MY, and FY per lactation. Heritability estimates were 0.22, 0.17, 0.37, 0.37, 0.38, 0.39, 0.54, 0.64, 0.09, and 0.16 for PL72, FPL72, MY, FY, PY, FPY, F%, P%, KI, and AFK, respectively. Most genetic correlations between the evaluated traits and PL72 or FPL72 were positive, except for F% (-0.04 and -0.06, respectively), P% (-0.002 and -0.03, respectively), and AFK (-0.03 and -0.01, respectively). The highest genetic correlations were between FPL72 and MY (0.39) and between PL72 and MY (0.33). Most phenotypic correlations between the traits evaluated and FPL72 and PL72 were positive (>0.23 and >0.26, respectively), except for F% (-0.004 and -0.02, respectively), P% (-0.05 and -0.02), KI (-0.01 and -0.07), and AFK (-0.08 and -0.08). The direct selection for PL72 increased it by 102.28. d per generation. The use of MY, FY, PY, KI, or AFK as selection criteria increased PL72 by 39.21, 27.33, 35.90, -8.28, or 2.77. d per generation, respectively. The inclusion of PL72 as selection criterion increased the expected response per generation from 0.15 to 17.35% in all selection indices studied. © 2014 American Dairy Science Association. Source


Barron-Bravo O.G.,University of Guanajuato | Gutierrez-Chavez A.J.,University of Guanajuato | Angel-Sahagun C.A.,University of Guanajuato | Montaldo H.H.,National Autonomous University of Mexico | And 2 more authors.
Small Ruminant Research | Year: 2013

To estimate the losses in milk yield, fat content and protein content according to different levels of somatic cell count (SCC), and to evaluate the influence of some variation factors on SCC in Saanen, Alpine and Nubian U.S. goats, data obtained from twelve dairy goat farms and seven different breeds for the period 2003-2010 were used. Individual milk yield was measured monthly during lactation. Somatic cell count, fat (%F) and protein (%P) contents were determined using automated equipment. SCC was transformed to a log scale (SCS). In a first analysis, the fix effects ANOVA procedure was used to evaluate the influence of different variation factors on SCS. In an additional analysis and using only first lactation data, losses in test day milk yield and test day %F and %P according to the SCS recoded level, were estimated for Alpine, Nubian and Saanen breeds. Effects of test day milk yield level (MY), %F level, %P level, flock, breed, year and season of kidding, lactation number, litter size, length of dry period, lactation days at each sampling as covariate, significantly influenced SCS (P < 0.01). The estimated losses in test day milk yield according to the recoded level of SCS used for Alpine, Nubian and Saanen breeds were 0.5-12.9%, 0.4-29.1% and 0.2-15.4%, respectively. For %F loss estimated for Alpine, Nubian and Saanen goats these were 0.01-10.8%, 0.5-7.6% and 1.1-16.0%, respectively. Estimated losses in %P for the same breeds were from 0.30% to 7.8%, 0.5% to 7.2% and 2.0% to 15.0%, respectively. Results suggest the need for the establishment of prevention and control programs of subclinical mastitis based on SCS routine monitoring in commercial goat herds. © 2013 Elsevier B.V. Source

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