Altitudinal variation in reproductive strategy of the toad-headed lizard, Phrynocephalus vlangalii in North Tibet Plateau (Qinghai)

2007 ◽  
Vol 28 (4) ◽  
pp. 509-515 ◽  
Author(s):  
Yuan-Ting Jin ◽  
Nai-Fa Liu

Abstract Phrynocephalus vlangalii, a toad-headed viviparous sand lizard, is endemic in the Northern Tibet (Qinghai) Plateau in China. Lizards were collected from 14 localities along the large altitudinal gradient (2289-4565 m a.s.l) to analyze the variation of reproductive traits among localities. Both litter size and mean offspring (scaled embryo) mass were positively correlated with female snout-vent length (SVL). Females produced fewer and larger offspring with increasing elevation when the effect of body size (SVL) was removed. This strategy may possibly be correlated with early survival and growth of offspring. The decreased litter size cline along altitudinal gradient might be correlated with more anatomical constraints at higher altitudes. The lizard has lower coefficient of variation (CV) of litter size at higher environments. Moreover, females from higher elevations had less reproductive investment (relative litter mass, RLM). Study concluded that P. vlangalii fit into the common pattern of higher elevation animals that have smaller clutches of larger offspring and lower reproductive effort.

2020 ◽  
Vol 100 (2) ◽  
pp. 317-322 ◽  
Author(s):  
Rym Ezzeroug ◽  
Rafik Belabbas ◽  
Maria José Argente ◽  
Ali Berbar ◽  
Samir Diss ◽  
...  

The objective of this study was to obtain heritability estimates for reproductive (litter size at birth, number born alive, litter size at weaning) and growth traits (individual weaning weight, individual weight at the end of the fattening period), then determine the genetic correlation between them in a synthetic rabbit line. A total of 805 females, 3242 parities, and 18 472 growth records were measured from 2006 to 2017. A pentavariate animal model was used with reproductive and growth traits. Heritability ranged from 0.025 to 0.126 for reproductive traits and from 0.033 to 0.059 for growth traits. These traits showed a large coefficient of variation (from 32% to 56% for reproductive traits and from 21% to 28% for growth traits). The repeatability of reproductive traits was low and the common litter effect for growth traits was the most important component of total variance. The genetic and phenotypic correlations between reproductive and growth traits were high and negative, especially with weight at weaning (−0.848, −0.922, and −0.854 for litter size at birth, number born alive, and litter size at weaning, respectively). In conclusion, because of the high negative correlation between reproductive and growth traits, both reproductive and growth traits should be selected in independent lines and the response to selection should be due mainly to the high coefficient of variation of the traits.


1981 ◽  
Vol 59 (5) ◽  
pp. 785-789 ◽  
Author(s):  
Duncan G. L. Innes ◽  
John S. Millar

A forest vole, Clethrionomys gapperi, and a field vole, Microtus pennsylvanicus, were examined for differences in a number of reproductive traits, including the energy required to raise a litter. Average postpartum weight, litter weight, and neonate weight of C. gapperi were significantly less than those of M. pennsylvanicus. Although C. gapperi had a significantly larger litter size than M. pennsylvanicus, the latter species used more energy to raise a litter than C. gapperi. Only one of three measures of physiological reproductive effort showed a significant difference between species. We conclude that there is no clear pattern between reproductive traits and habitat. Many traits appear to vary with body weight.


Author(s):  
N Fetherstone ◽  
N McHugh ◽  
T M Boland ◽  
F M McGovern

Abstract The objective of this study was to investigate the impact of the ewe’s maternal genetic merit and country of origin (New Zealand or Ireland) on ewe reproductive, lambing and productivity traits. The study was performed over a four year period (2016 to 2019) and consisted of three genetic groups: high maternal genetic merit New Zealand (NZ), high maternal genetic merit Irish (High Irish) and low maternal genetic merit Irish (Low Irish) ewes. Each group contained 30 Suffolk and 30 Texel ewes, selected based on the respective national maternal genetic indexes; i.e. either the New Zealand Maternal Worth (New Zealand group) or the €uro-star Replacement index (Irish groups). The impact of maternal genetic merit on reproductive traits such as litter size; lambing traits such as gestation length, birth weight, lambing difficulty, mothering ability, and productivity traits such as the number of lambs born and weaned were analyzed using linear mixed models. For binary traits, the impact of maternal genetic merit on reproductive traits such as conception to first AI service; lambing traits such as dystocia, perinatal lamb mortality and productivity traits such as ewe survival were analyzed using logistic regression. New Zealand ewes outperformed Low Irish ewes for conception to first AI (P<0.05) and litter size (P=0.05). Irish ewes were more likely to suffer from dystocia (6.84 (High Irish) and 8.25 (Low Irish) times) compared to NZ ewes (P<0.001); birth weight and perinatal mortality did not differ between groups (P>0.05). Lambs born from NZ ewes were 4.67 (95% CI: 1.89 to 11.55; P<0.001) and 6.54 (95% CI: 2.56 to 16.71; P<0.001) times more likely to stand up and suckle unassisted relative to lambs born from High or Low Irish ewes, respectively. New Zealand and High Irish ewes had a greater number of lambs born and weaned throughout the duration of the study compared to their Low Irish counterparts (P<0.001). New Zealand ewes tended to be more likely to survive from one year to the next compared to Low Irish ewes (P=0.07). Irish ewes of high maternal genetic merit outperformed their Low counterparts in total number of lambs born and weaned per ewe, but performance did not differ across other traits investigated. This highlights the importance of continuous development of the Irish maternal sheep index to ensure favourable improvements in reproductive, lambing and productivity traits at farm level. Overall, results demonstrate the suitability of NZ genetics in an Irish production system.


Copeia ◽  
1975 ◽  
Vol 1975 (4) ◽  
pp. 767 ◽  
Author(s):  
S. S. Khanna ◽  
S. Kumar
Keyword(s):  

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
A. Marantidis ◽  
G. P. Laliotis ◽  
M. Avdi

PCR-RFLP was applied to a commercial crossbred pig population in order to investigate the association between polymorphism (SNP) of Retinol-binding protein 4 (RBP4) gene and reproductive performance. 400 sows were genotyped and 2000 records of reproductive traits were used in order to retrieve information about the allele frequencies and the association of the RBP4 gene with main reproductive characteristics of the population. A deviation from the Hardy-Weinberg equilibrium was observed as a result of the AB genotype excess. In addition, the AA genotype saw statistically significant higher values of (i) the total number of born piglets (p<0.05), (ii) the number of piglets born alive (p<0.01), and (iii) the number of weaned piglets (p<0.01). The number of the mummified piglets and the number of the piglets born dead did not differ between the various RBP4 genotypes. Interestingly, the AA genotype had a negative impact (p<0.05) on the number of piglets born dead, resulting indirectly in a larger litter size. In conclusion, the AA genotype and in extension the A allele of RBP4 gene are in favor of producing larger litter size, suggesting that the RBP4 gene may be used in Marker-Assisted Selection (MAS) programs for a rapid improvement of the reproductive characteristics in pigs.


Author(s):  
Emre Şirin ◽  
Ümit Uçan ◽  
Uğur Şen ◽  
Ercan Soydan

This study was carried out to determine of effect of supplemental feeding during the late gestation on birth and other weights of lambs from Akkaraman sheep breed raised in Kırşehir. Data were collected from 554 Akkaraman lambs from 580 Akkaraman sheep which were born during 2015 birth season. Akkaraman sheep were divided into two groups. Wheat straw is given to both groups during pregnancy. Supplemental feeding group group (EYG), was given to concentrated feed supplement (400 g/animal) in addition to wheat straw during the last gestation period. Control group (KG) was given only wheat straw during pregnancy. In this study, the live weights, survival rates of the lambs in various periods and reproductive traits of Akkaraman ewes were investigated. The averages of reproductive traits of Akkarman sheep such as sterility, fertility, twins, abortion, fecundity and litter size in EYG and KG groups were %12, %9, %86, %91, %13, %5, %2, %0, 0.96, 0.95 and 1.12, 1.04, respectively. The survival rates of lambs on 90th days and 150th days in EYG and KG groups were determined as 84, 80% and 91, 91%, respectively. The means of the birth, 90 and 150. days age live weights in EYG and KG groups were found as 5.82±0.06 kg, 30.94±0.44 kg, 34.47±0.44 kg and 3.43±0.04 kg, 30.17±0.04 kg, 30.96±0.38 kg respectively. The effects of supplemental feeding, sex and birth type were found to be significant on the 120. days age on birth and live weights of sheep. The effects of birth type were found to be significant on the 90. days age live weights of sheep. As a result, supplemental feeding during the late gestation are increased live weights.


2015 ◽  
Vol 58 (2) ◽  
pp. 317-323 ◽  
Author(s):  
T. Kumchoo ◽  
S. Mekchay

Abstract. Osteopontin (OPN) gene is a secreted phosphoprotein which appears to play a key function in the conceptus implantation, placentation and maintenance of pregnancy in pigs. The objectives of this study were to verify the non-synonymous single nucleotide polymorphisms (SNPs) and their association with litter size traits in commercial Thai Large White pigs. A total of 320 Thai Large White sows were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Three SNPs at c.425G> A, c.573T> C and c.881C> T revealed amino acid exchange rates of p.110Ala> Thr, p.159Val> Ala and p.262Pro> Ser, respectively, and were then segregated. These three SNPs were significantly associated with total number born (TNB) and number born alive (NBA) traits. No polymorphisms of the two SNP markers (c.278A> G and c.452T> G) were observed in this study. Moreover, the SNPs at c.425G> A and c.573T> C were found to be in strong linkage disequilibrium. The association of OPN with litter size emphasizes the importance of porcine OPN as a candidate gene for reproductive traits in pig breeding.


Animals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 460 ◽  
Author(s):  
Weimin Wang ◽  
Yongfu La ◽  
Fadi Li ◽  
Shijia Liu ◽  
Xiangyu Pan ◽  
...  

The luteinizing hormone beta polypeptide (LHβ) is a glycoprotein hormone secreted by basophilic granular cells of the adenohypophysis, and plays an important role in mammalian follicular development. In this study, we cloned and analyzed the cDNA sequence of the ovine LHβ gene. RT-qPCR analysis showed that ovine LHβ was widely expressed in tissues, with significantly higher expression in the hypophysis than that in other tissues (heart, liver, spleen, lung, kidney, rumen, duodenum, muscle, fat, hypothalamus, and sex glands) (p < 0.01). Hypophyseal expression of LHβ mRNA in lamb increased with age and reached a peak at 70 days, although a slight decrease was observed at 84 days of age. In addition, the synonymous mutation g.727C > T detected in the LHβ gene was confirmed to be significantly associated with the litter size (p < 0.01). Ewes carrying the TT genotype produced more lambs than those carrying the TC and CC genotypes (0.42 and 0.39 per delivery, respectively; p < 0.05). Our results confirm the association of ovine LHβ with litter size in Small-Tailed Han Sheep and implicate LHβ as a candidate for improving reproductive traits in agricultural sheep breeding programs.


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