• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1690-1694
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• 2002

Genetic parameters were estimated for birth weight and weaning weight from three year (1991-1993) data totalling 1100 records of 25 rams to 205 ewes of Indigenous Sabi flock maintained at Grasslands Research Station in Zimbabwe. AIREML procedures were used fitting an Animal Model. The statistical model included the fixed effects of year of lambing, sex of lamb, birth type and the random effect of ewe. Weight of ewe when first joined with ram was included as a covariate. Direct heritability estimates of 0.27 and 0.38, and maternal heritability estimates of 0.24 and 0.09, were obtained for birth weight and weaning weight, respectively. The total heritability estimates were 0.69 and 0.77 for birth weight and weaning weight, respectively. Direct-aternal genetic correlations were high and positive. The corresponding genetic covariance estimates between direct and maternal effects were positive and low, 0.25 and 0.18 for birth weight and weaning weight, respectively. Responses to selection were 0.8 kg and 0.14 kg for birth weight and weaning weight, respectively. The estimated expected correlated response to selection for birth weight by directly selecting for weaning weight was 0.26. Direct heritabilities were moderate; as a result selection for any of these traits should be successful. Maternal heritabilities were low for weaning weight and should have less effect on selection response. Indirect selection can give lower response than direct selection.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.6
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• pp.595-597
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• 1995

The mean birth weight and weaning weight estimated from 777 kids from 30 bucks of Teddy goats were $1.67{\pm}0.31$ and $8.50{\pm}2.18kg$, respectively. The estimates of heritability of birth weight and weaning weight by half sib correlation method were $0.048{\pm}0.022$ and $0.101{\pm}0.012kg$, respectively. The high heritability estimates of birth weight indicates that selection on the basis of individual's own record will be effective. The low estimates of heritability of weaning weight indicates more emphasis should be given to improve environmental conditions for better achievement.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.12
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• pp.1669-1673
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• 2004

Milk yield, lamb birth weight and weaning weight responses to shearing during winter in sheep were investigated. A total of 46 Karayaka ewes were allocated into two treatment groups. Pregnant ewes in one group were shorn on day 100 of gestation (Shorn, n=24) and the remaining ewes were left unshorn to serve as controls (Unshorn, n=22). The ewes were maintained on pasture during the day and housed in the evenings. Lamb birth weight, weaning weight and ewes'' daily milk yield in fifteen dayintervals until weaning (75 days) were recorded. Shearing ewes on day 100 of pregnancy increased gestation length (p<0.01) compared to unshorn ewes (147.8${\pm}$0.45 vs. 145.9${\pm}$0.42 days). Birth weights of lambs from shorn ewes on day 100 of their pregnancy were higher (p<0.01) than those from unshorn ewes (3.7${\pm}$0.11 vs. 3.2${\pm}$0.07 kg). Shearing pregnant ewes increased (p<0.05) the lamb weaning weight at day 75 post-lambing (23.6${\pm}$1.10 vs. 19.5${\pm}$0.91). It also increased milk yield (p<0.05). Milk yields on day 75 of lactation were 302${\pm}$33 and 425${\pm}$25 g per day for unshorn and shorn ewes on day 100 of pregnancy, respectively. Lamb survival at weaning was higher (p<0.05) in lambs from shorn ewes compared to those from unshorn ewes. In conclusion, shearing pregnant ewes in winter months enhanced milk yield, lamb birth weight, lamb weaning weight and lamb survival. It is suggested that increasing both lamb birth weight and subsequent milk yield of dams by shearing ewes on day 100 of pregnancy during winter may improve postnatal lamb viability.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.61-67
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• 1999

Data from 22837 lambings of Lohi and Kajli ewes from 1962 through 1994 were used to analyse productive and reproductive traits and wool production, Overall litter size at birth averaged 1.33 being 1.45 for Lohi and 1.21 for Kajli ewes. The corresponding values at weaning were 1.23, 1.32 and 1.14, respectively. Litter size was consistently lowest for one year old, with a substantial increase at two, three and four years of ewe age and marginal increase thereafter, Ewes lambing in spring weaned 0.08 more lambs per parturition than ewes lambed in Autumn (p<0,01). Lamb birth weights were affected by ewe breed (p<0.01) and increased with ewe age. Overall lamb weaning weight (120 d) of 17993 lambs was 20.3 kg. Weaning weight was affected by breed, sire, year of birth, sex, rearing rank and weaning age (p<0.01). The highest mean weaning weight was 21.9 kg for Lohi lambs followed by Kajli lambs (18.8 kg), Lambs from Kajli ewes were 9% heavier at birth but 14% lighter at weaning. Twin born lambs were 18% lighter at birth and 13% at weaning than single born lambs. Male lambs were 3% heavier at birth and 4.5% heavier at weaning than female lambs. Overall annual mean wool production was 2,64 kg, Kajli ewes were heavier at breeding than Lohi ewes (i.e. 46.2 vs 44.8 kg). Lohi ewes being 3% less body weight produced 38% more wool and 18% more litter weaning weight than Kajli ewes, When average weight of lamb weaned per ewe weaning lambs was adjusted for ewe average metabolic body size, Lohi ewes were most efficient (i.e. arbitrary assigned value of 100) compared to Kajli ewes achieving only 83% of Lohi level.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.10
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• pp.1394-1399
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• 2001

Influence of pre-weaning nutrition on post-weaning gain was assesses under intensive feeding in Malpura lambs. Thirty six Malpura (15 days old) lambs divided in to 3 equal groups were maintained on high (G1), medium (G2) and low (G3) energy and protein containing creep mixture with free suckling and ad libitum roughage (pala leaves: Ziziphus nummularia) up to 90 days of age. The lambs during post-weaning phase were fed on a 40:60 roughage and concentrate based composite diet to assess their post-weaning growth response. Total dry matter intake in pre-weaning phase was higher (p<0.01) in G3 than G2 and G1 while feed conversion efficiency was better in G1 than G2 and G3. The birth weight, 15 days body weight and weaning weight were however similar in the three groups. The finishing body weight, total body weight gain and average daily gain during post-weaning phase were higher (p<0.01) in G3 than in G1 and G2. The lambs in G3 consumed more (p<0.01) dry matter during post-weaning phase along with better feed conversion efficiency than other two groups. However, the DCP intake/kg body weight gain was higher in G1 than G2 and G3. Digestibility of DM, OM, CP, NDF, ADF and energy were similar among the three groups during post-weaning phase. Percent nitrogen retention as nitrogen intake was higher (p<0.01) in G3 (71.1%) than G1 (67.7%) and G2 (69.7%) during the post-weaning phase of study. The G1, G2 and G3 lambs in post-weaning phase consumed 8.1, 7.7 and 8.1 g DCP and 246.8, 227.2 and 246.1 kcal $DE/kg\;W^{0.75}/d$ and had 84.4, 80.0 and 111.1 g average daily gain, respectively. It is concluded that the lambs fed on low energy and protein containing creep mixture in pre-weaning phase showed improvement in growth during post-weaning phase under optimum feeding regime.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.2
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• pp.151-157
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• 2005

Sheep production is affected by genetic and non-genetic factors. A knowledge of these factors is essential for efficient management and for the accurate estimation of breeding values. The objective of this study was to establish the non-genetic factors which affect birth weight and weaning weight in Dorper, Mutton Merino and indigenous Sabi sheep breeds. A total of 2,625 birth and weaning weight records from Grasslands Research Station collected from 1991 through 1993, were used. The records were collected from indigenous Sabi (939), Dorper (807) and Mutton Merino (898) sheep. A mixed classification model containing the fixed effects of year, birth status and sex was used for identification of non-genetic factors. Sire within breed was included as a random effect. Two factor interactions and three factor interactions were important in indigenous Sabi, Mutton Merino and Dorper sheep. The mean birth weights were 4.37${\pm}$0.04 kg, 4.62${\pm}$0.04 kg and 3.29${\pm}$0.04 kg for Mutton Merino, Dorper and Sabi sheep, respectively. Sire had significant effects (p<0.05) on birth weight in Mutton Merino and indigenous Sabi sheep. Year of lambing had significant effects (p<0.05) on birth weight in indigenous Sabi, Mutton Merino and Dorper sheep. The effect of birth status was non significant in Dorper and Mutton Merino sheep while effect of birth status was significant on birth weight in indigenous Sabi sheep. In Indigenous Sabi sheep lambs born as singles (3.30${\pm}$0.05 kg) were 0.23 kg heavier than twins (3.07${\pm}$0.05 kg), in Mutton Merino lambs born as singles (3.99${\pm}$0.08 kg) were 0.07 kg heavier than twins (3.92${\pm}$0.08 kg) and in Dorper lambs born as singles (4.41${\pm}$0.04 kg) were 0.02 kg heavier than twins (4.39${\pm}$0.04 kg). On average males were heavier than females (p<0.05) weighing (3.32${\pm}$0.04 kg vs. 3.05${\pm}$0.07 kg) in indigenous Sabi, 4.73${\pm}$0.03 kg vs. 4.08${\pm}$0.05 in Dorper and 4.26${\pm}$0.07 kg vs. 3.66${\pm}$0.09 kg in Mutton Merino sheep. Two way factor interactions of sire*year, year*sex and sex*birth status had significant effects (p<0.05) on birth weight in indigenous Sabi, Mutton Merino and Dorper sheep while the effect of year*birth status was non significant on birth weight in Indigenous Sabi sheep. The three way factor interaction of year*sex*birth status had a significant effect (p<0.01) on birth weight in indigenous Sabi and Mutton Merino. Tupping weight fitted as a covariate had significant effects (p<0.001) on birth weight in indigenous Sabi, Mutton Merino and Dorper sheep. The mean weaning weights were 17.94${\pm}$0.31 kg, 18.19${\pm}$0.28 kg and 14.39${\pm}$0.28 kg for Mutton Merino, Dorper and Indigenous Sabi sheep, respectively. Effects of sire and sire*year were non significant on weaning weight in Dorper and Mutton Merino while year, sex and sex*year interaction had significant effects (p<0.001) on weaning weight. On average males were heavier than females (p<0.001) at weaning. The respective weaning weights were 18.05${\pm}$0.46 kg, 18.68${\pm}$0.19 kg, 14.14${\pm}$0.15 kg for males and 16.64${\pm}$0.60 kg, 16.41${\pm}$0.31 kg, 12.64${\pm}$0.32 kg for females in Mutton Merino, Dorper and Indigenous Sabi sheep. Lambs born as singles were significantly heavier at weaning than twins, 0.05 kg, 0.06 kg and 0.78 kg for Mutton Merino, Dorper and Indigenous Sabi sheep, respectively. Effect of tupping weight was highly significant on weaning weight. The three way factor interaction year*sex*birth status had a significant effect (p<0.01) on weaning weight. Correction for environmental effects is necessary to increase accuracy of direct selection for birth weight and weaning weight.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.10
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• pp.1378-1385
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• 2002

The importance of direct genetic, maternal, heterosis and epistatic effects were examined on post-weaning weight, height, length, girth, fat depth and muscle (ratio of stifle to hip width) with dry and wet season gains in these traits. The breeds used were two pure breeds (Jersey and Limousin), the Limousin${\times}$Jersey $F_1$, and two backcrosses ($F_1{\times}$Jersey dams and $F_1{\times}$Limousin dams). Direct genetic effects were large (p<0.001) for all traits except for length. Jersey maternal effects were large for weight, girth, fat depth and muscle in the post-weaning wet season gains which is an evidence of the impact of Jersey dam on progeny beyond weaning. There were large heterosis effects on fat depth and muscle relative to other traits. Epistatic effects were observed for post-weaning performance in weight, girth, fat depth and muscle. There are indications that there were different genetic effects for post-weaning compared to preweaning growth traits. Thus, it could be hypothesized from this study that different quantitative trait loci (QTL) affect early and late growth in Jersey and Limousin cross cattle breeds. The follow up work will examine the different chromosomal gene effects on pre- and post-weaning growth.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.6
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• pp.764-771
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• 2012

Direct and maternal genetic heritabilities and their correlations with body weight at 5 stages in the life span of purebred Berkshire pigs, from birth to harvest, were estimated to scrutinize body weight development with the records for 5,088 purebred Berkshire pigs in a Korean farm, using the REML based on an animal model. Body weights were measured at birth (Birth), at weaning (Weaning: mean 22.9 d), at the beginning of a performance test (On: mean 72.7 d), at the end of a performance test (Off: mean 152.4 d), and at harvest (Finish: mean 174.3 d). Ordinary polynomials and Legendre with order 1, 2, and 3 were adopted to adjust body weight with age in the multivariate animal models. Legendre with order 3 fitted best concerning prediction error deviation (PED) and yielded the lowest AIC for multivariate analysis of longitudinal body weights. Direct genetic correlations between body weight at Birth and body weight at Weaning, On, Off, and Finish were 0.48, 0.36, 0.10, and 0.10, respectively. The estimated maternal genetic correlations of body weight at Finish with body weight at Birth, Weaning, On, and Off were 0.39, 0.49, 0.65, and 0.90, respectively. Direct genetic heritabilities progressively increased from birth to harvest and were 0.09, 0.11, 0.20, 0.31, and 0.43 for body weight at Birth, Weaning, On, Off, and Finish, respectively. Maternal genetic heritabilities generally decreased and were 0.26, 0.34, 0.15, 0.10, and 0.10 for body weight at Birth, Weaning, On, Off, and Finish, respectively. As pigs age, maternal genetic effects on growth are reduced and pigs begin to rely more on the expression of their own genes. Although maternal genetic effects on body weight may not be large, they are sustained through life.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.4
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• pp.298-302
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• 2022

South Korea has a temperate climate with four distinct seasons. However, summers are extremely hot and humid, which negatively affects industrial animal production. Hanwoo are native cattle that have traditionally been raised in the natural environment of Korea. The present study investigated the effects of birth and lactation season on the birth and weaning weights of Hanwoo calves. Data were collected from 100 local breeding farms between 2016 and 2021. A total of 56,970 (males, 29,530; females, 27,440) Hanwoo calves were classified according to sex or birth and weaning season (March-May, spring; June-August, summer; September-November, fall; and December-February, winter). The birth weight of Hanwoo calves differed according to the birth season. As such, birth weight of the summer-born calves was the lowest. Additionally, the 90-day weaning weight was positively correlated with birth weight. Interestingly, however, the 90-day weaning weight was not related to the birth season but was related to the 2-month seasonal effect during the lactation period. Furthermore, the 90-day weaning weight was the lowest during the summer lactation period. In the beef cattle industry, daily weight gain is an important economic characteristic related to feed efficiency and growth. Our findings will contribute the management of Hanwoo cattle and analysis of changes in economic characteristics due to high temperatures.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.4
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• pp.478-483
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• 2008

Records of a Northeastern Thai indigenous cattle line population were used to estimate genetic parameters and annual trends for calf weights. The data set comprised records of 1,922 and 1,489 animals for birth and weaning weight, respectively born from 1993 to 2004. A bivariate analysis was carried out for variance and covariance components estimations using average information restricted maximum likelihood procedure. Average estimated breeding value and maternal breeding value of the animals born in 1993 were set to zero as a base group. Genetic trends of each trait were calculated by regressing average estimated breeding values and maternal breeding values on birth year of calves. Phenotypic trends for each trait were calculated by regressing the yearly adjusted weight on birth year of calves. The results revealed that the estimate of direct heritability, maternal heritability and maternal permanent environmental variance as a proportion of phenotypic variance for birth and weaning weight was 0.40, 0.14 and 0.04; 0.27, 0.05 and 0.23, respectively. Direct heritability was moderately heritable and genetic improvement through selection can be achieved. The estimate of phenotypic, direct genetic, maternal genetic and maternal permanent environmental correlation between birth and weaning weight was 0.48, 0.65, 0.98 and 0.73, respectively. The phenotypic trend, genetic trends of estimated breeding value and maternal breeding value for birth weight was 0.18, 0.04 and 0.01 kg/year, respectively. The phenotypic trend, genetic trends of estimated breeding value and maternal breeding value for weaning weight was -1.36, 0.32 and 0.03 kg/year, respectively. As maternal genetic effect was considerably less important than direct genetic effect, selection for improved weaning weight of this Northeastern Thai indigenous cattle line can place more emphasis on the direct genetic effect.