Mohammad hadi Khabbazan; Abdollah Rezagholivand Lahrud; Saeed mokhtarzadeh; Hojatollah Moosapour
Volume 24, Issue 4 , December 2022, , Pages 395-401
Abstract
The objective of this study was to compare growth performance, birth and weaning body weights, and survivability between purebred Balouchi (n=53) and crossbred Balouchi×Romanov (n=114) lambs. In addition, carcass characteristics (n=24) were determined. Balouchi ewes were inseminated with Romanov ...
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The objective of this study was to compare growth performance, birth and weaning body weights, and survivability between purebred Balouchi (n=53) and crossbred Balouchi×Romanov (n=114) lambs. In addition, carcass characteristics (n=24) were determined. Balouchi ewes were inseminated with Romanov semen to produce crossbred lambs. All experimental lambs were weaned at 77 d of age and slaughtered at 10 months of age. Birth body weight of the purebred Balouchi lambs was significantly greater than for the crossbred lambs (3.75 vs. 3.56 kg, P<0.01). However, weaning body weight and average daily gain from birth until weaning and slaughter were greater (P<0.05) for the crossbred lambs than for the purebred lambs. Slaughter body weight at 10-month age were not different brtween the tow groups (P=0.08). Litter size was also increased by crossbreeding and using hormone (1.13 vs. 1.00), but lamb survivability was not different between the two groups. The fat yield decreased with crossbreeding. Crossbreeding increased (P<0.05) the weights of testis, liver, heart, and lung. It is concluded that crossbreeding Balouchi ewes with Romanov semen resulted in improved litter size, weaning and slaughter body weights, average daily gains from birth until weaning and slaughter, and carcass characteristics without affecting lamb survivability. Therefore, crossbreeding can be a profitable strategy to increase lamb (meat) production in Balouchi sheep.
Abdollah Rezagholivand Lahrud; Mohammad Moradi Shahre Babak; Hossein Moradi Shahrbabak; Morteza Sattaei Mokhtari
Volume 20, Issue 4 , February 2019, , Pages 499-511
Abstract
The objective of the present study was the genetic evaluation of retained placenta (RP), metritis (MET), number of inseminations to conception (INS), and days open (DO) in Holstein cows using standard (SMMs) and recursive (RMMs) mixed models. Data on 50230 first-lactation Holstein dairy cattle, collected ...
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The objective of the present study was the genetic evaluation of retained placenta (RP), metritis (MET), number of inseminations to conception (INS), and days open (DO) in Holstein cows using standard (SMMs) and recursive (RMMs) mixed models. Data on 50230 first-lactation Holstein dairy cattle, collected during 2008 to 2017 in 17 large dairy herds were used. The data was analyzed using four-variate animal Threshold-Gaussian models under SMMs and RMMs. The existence of causal effects from RP on MET, INS and DO, from MET on INS and DO and from INS to DO were considered in RMMs. The causal effects of RP and MET on INS were 0.19 and 0.09 services, respectively; and those on DO were 4.74 and 5.38 days, respectively. Also, causal effect of INS on DO was obtained as 33 days. The considered causal relationships except that of RP on MET, phenotypic and residual correlations among the disorders and fertility traits were statistically significant and different under two models. Posterior means of heritability for RP, MET, INS and DO were 0.15, 0.17, 0.07 and 0.09 under SMMs, respectively; and 0.16, 0.17, 0.07 and 0.1 under RMMs, respectively. The difference between the corresponding heritability estimates under SMMs and RMMs were not statistically significant. Therefore; RMMs may be an alternative for SMMs in genetic evaluation of studied traits in first -lactation Holstein cows.