Estimation of genetic parameters for productive life, reproduction, and milk-production traits in US dairy goats

Abstract

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 72mo (FPL72) of 33,725 US dairy goats, were estimated using animal models. Productive life was defined as the total days in production until 72mo 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 102.28d 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 2.77d 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.

Analysis of culling records and estimation of genetic parameters for longevity and some production traits in Holstein dairy cattle

“…Their estimates were in the range of 0.04-0.35 for milk yield and 0.02-0.18 for fat yield. In addition, positive and lower genetics correlation estimates of functional productive life and milk yield (0.33) and fat yield (0.23) have been reported in US dairy goats (Castañeda-Bustos et al 2014). On the other hand, Fuerst-Waltl et al (2013) reported unfavourable correlations between milk yield and LPL in both extensive (−0.159) and intensive (−0.192) management systems in Austrian Fleckvieh (dual-purpose Simmental).…”

Pseudopregnancy and aseasonal breeding in dairy goats: genetic basis of fertility and impact on lifetime productivity

“…Heritabilities of production traits Heritability for MY520 was within the expected range for this population, based on a random regression analysis on a larger sample of the present population (Mucha et al, 2014) and in line with estimates for dairy ewes and goats (El Saied et al, 2005;Rupp et al, 2011;García-Peniche et al, 2012;Castañeda-Bustos et al, 2014). Heritability for DIMLife was similar to that estimated by Torrero (2010;0.13), and lower The absolute number of weeks of first kidding relative to peak kidding season, as defined by the 4 weeks of the year where the greatest number of kids are born.…”

A Preliminary Study on Some Reproductive Traits and Heterosis Effects of Anglo Nubian and Etawah Grade Crossbred Does

“…This result was in agreement of some literature stated that age of first kidding in goats ranged between 321-534 days including local and exotic breed (Sutama et al 2011;Patel & Pandey 2013;Budisatria & Udo 2013;Bhowmik et al 2014;Dereje et al 2015). The pooled data of Saanen, Toggenburg, Anglo Nubian and La Mancha in USA dairy goats showed that age of first kidding was 507.97 days (Castañeda-Bustos et al 2014).…”