Greater Litter Size Research Articles

A novel nonsynonymous SNP in the OLR1 gene associated with litter size in Guizhou white goats

Oxidized low-density lipoprotein receptor-1 (OLR1) encodes a low-density lipoprotein receptor belonging to the C-type lectin superfamily, which is closely related to reproduction. OLR1 is associated with fecundity in Awassi sheep. However, its effect on litter size has not been investigated in goats. In this study, OLR1 sequences and their mRNA expression levels in the gonadal axis of Guizhou white goats were evaluated to investigate the relationship between gene polymorphisms and litter size. In addition, the potential effects of a nonsynonymous substitution were evaluated using a bioinformatics approach. The expression levels of OLR1 were highest in the uterus of mothers with multiple kids and highest in the ovaries of mothers with single kids. OLR1 mRNA expression levels in the ovaries of mothers with single kids were two times higher than in the ovaries of mothers with multiple kids. The sequencing results revealed five SNPs in OLR1; however, only g.294 T > A, g.2260 T > C, and g.2268 C > T were significantly associated with litter size (P < 0.05). Linkage disequilibrium was detected between g.2260 T > C and g.2268 C > T (r2 = 0.322, D′ = 0.6). Additionally, goats with the Hap 1/1 diplotype had a greater litter size than others (P < 0.05). g.2260 T > C was a nonsynonymous mutation that resulted in the replacement of valine with alanine at the amino acid residue 54 of the OLR1 protein. Bioinformatic analyses revealed that the p.V54A locus was relatively conserved in cloven-hoofed species. Mutations at this locus could change the local conformation and reduce the stability of OLR1, affecting its half-life and the litter size of the nanny goat. These findings confirm that OLR1 affects goat kidding traits and provide a novel insight into the regulatory mechanism underlying the effect of OLR1 on litter size.

Growth Curves and Body Condition of Young Cats and Their Relation to Maternal Body Condition.

Simple SummaryThe aim of this study was to assess the effect of the litter, the individual and the mother on the likelihood that kittens become overweight by 8 months of age. Since efforts to investigate these factors in cats often do not account for variables that increase the likelihood of obesity in adult life (e.g., neutering), data on an intact cat family over 14 years were used. Both males and kittens (regardless of sex) from overweight mothers were more prone to being overweight at 8 months. A greater litter size appeared to protect kittens from becoming overweight, in contrast to a greater birthweight, which seemed to predispose them for it. The growth rate of all kittens differed according to their own (lean vs. overweight and male vs. female) and their mother’s (overweight vs. variable vs. lean) phenotype. In females but not in males, own and maternal phenotype affected the time to reach peak weight as well. Based on the results from this study, birthweight, growth rate and maternal overweight can indicate a predisposition of kittens to become overweight.The aim of the present study was to assess factors like litter, individual and maternal effects on kitten overweight at 8 months of age, defined as body condition score (BCS) ≥ 6, in an intact cat family. To minimize confounding, a homogenized cat population was used. After categorization of the life weight data according to the kittens’ sex, BCS and maternal non-pregnant phenotype (overweight (OM), lean (LM), variable (VM)), analyses including Pearson’s correlation coefficients, two-way ANOVA, linear, linear broken-line regression and repeated measures mixed model analyses were performed. Overweight and OM kittens gained weight most quickly, and females reached their peak weight earlier than males (6.2 ± 0.6 vs. 7.4 ± 0.2 months). In females but not in males the age to reach peak weight differed markedly according to category. Male (5.82 ± 0.09, p < 0.01) and OM kittens’ (5.80 ± 0.11, p = 0.07) BCS at 8 months was higher and they were heavier than their counterparts, from 3 and 5 months onwards, respectively. Litter size negatively correlated with overweight (r = −0.30, p < 0.01) and birthweight showed a positive correlation to live weight (R2 = 0.05, p = 0.05) and monthly weight gain (R2 = 0.18, p < 0.01) over time. This study supports routine monitoring of birthweight, growth rate and maternal phenotype prior to pregnancy to identify kittens at risk for becoming overweight.

Heat shock protein family D member 1 in boar spermatozoa is strongly related to the litter size of inseminated sows

BackgroundSperm quality evaluation is the logical first step in increasing field fertility. Spermatozoa contain cytoplasmic organelles and biomolecules known as sperm-intrinsic factors, which play key roles in sperm maturation, sperm-oocyte fusion, and embryo development. In particular, sperm membrane proteins [e.g., arginine vasopressin receptor 2, beta-actin, prohibitin, and heat shock protein family D member 1 (HSPD1)] and RNA could be used as functional indicators of male fertility. We sought to clarify the effects of differential mRNA expression of selected genes on several fertilisation parameters, including sperm motility, motion kinematics, capacitation, and litter size, in a porcine model.ResultsOur results demonstrated that HSPD1 expression was significantly correlated with male fertility, as measured by the litter size of inseminated sows. The expression of HSPD1 mRNA was linked to sperm motility and other motion kinematic characteristics. Furthermore, HSPD1 had a 66.7% overall accuracy in detecting male fertility, and the high-litter size group which was selected with the HSPD1 marker had a 1.34 greater litter size than the low-litter size group.ConclusionsOur findings indicate that HSPD1 might be a helpful biomarker for superior boar selection for artificial insemination, which could boost field fertility.

Dietary fiber sources for gestation sows: Evaluations based on combined in vitro and in vivo methodology

An in vitro-in vivo methodology was used to evaluate the potential value of different sources of fiber for gestation sows. Soluble and insoluble dietary fiber of 9 feed ingredients were isolated and fermented in vitro with sow faecal inoculum, using the cumulative gas production technique, to examine the kinetics, end-products and microbiota of fermentation after 72 h. It was shown that all fermentation kinetics parameters of gas production varied among feed ingredients. The production of short chain fatty acids (SCFA), branched-chain fatty acids (BCFA) and ammonia (NH3) were greater for wheat grain and maize compared to other feed ingredients on insoluble dietary fiber (IDF) fermentation for 36 h, and higher for maize compared to other feedstuffs on IDF fermentation for 72 h. However, SCFA, BCFA and NH3 were the highest of sorghum grain compared to other feedstuffs on soluble dietary fiber (SDF) fermentation for 36 and 72 h. The capacity of SCFA, BCFA and NH3 produced by SDF were significantly greater than that of IDF from different ingredients. IDF and SDF of beet pulp exhibited lower pH, higher Bacteroidetes and lower Firmicutes phylum after fermentation. The observed species and Shannon index in the beet pulp IDF and SDF were significantly lower than others. In genus level, Parabacteroides and unidentified_Prevotellaceae were higher but unidentified_Lachnospiraceae was lower in SDF fermentation compared to IDF fermentation. Further, a total of 75 multiparous gestation sows (Landrace × Yorkshire) were randomly assigned three fiber-rich diets provided by beet pulp (BP), soybean hull (SH), and wheat bran (WB) after mating. The sows were fed with three different fiber diets during gestation, but all the sows were similarly fed ad libitum during lactation. Sows fed BP diets farrowed a greater number of total (+1.7 pigs, P<0.05) and alive (+1.1 pigs, P<0.1) piglets compared with sows fed SH diets. In summary, beet pulp, irrespective of fiber type maybe have a better potential to be used in sow nutrition to manipulate the fermentation activity, microbiota and a greater litter size. Moreover, IDF and SDF from different feed ingredients, as well as the same feedstuff IDF and SDF, due to differences in fiber structure and composition may affect microbiota composition and ultimately affect the level of fermentation metabolites produced.

Relationship between SNPs of POU1F1 Gene and Litter Size and Growth Traits in Shaanbei White Cashmere Goats.

Simple SummaryPOU (Pit-Oct-Unc) class 1 homeobox 1 (POU1F1, or Pit-1) is a key transcription factor that directly regulates pituitary hormone-related genes and was considered as a candidate gene for reproduction and growth traits in goat breeding. Three important single nucleotide polymorphisms (SNPs), c.682G > T, c.723T > G and c.837T > C, were found in Shaanbei white cashmere (SBWC) goats by direct DNA sequencing, and c.876 + 110T > C was monomorphic. Further analyses showed that the c.682G > T and c.837T > C loci were associated with litter size, and c.682G > T, c.723T > G and c.837T > C strongly affected growth traits (p < 0.05). It is an interesting phenomenon for this population that individuals with the same genotypes had more offspring and that their body status was also better. Thus, we speculated that there was a positive correlation between growth and lambing ability. Besides this, female goats with H3H7 (combined from haplotype 3 and 7) diplotype (GTTT-TTTT), which was consistent with the combination of the optimal genotype of four SNPs, had a better litter size and growth status than other diplotypes. This study provides the first association analyses between the SNPs of POU1F1 and economic traits in SBWC goats, which could be considered as effective SNP markers for genomic selection in goat breeding.POU (Pit-Oct-Unc) class 1 homeobox 1 (POU1F1, or Pit-1) is a transcription factor that directly regulates pituitary hormone-related genes, as well as affects the reproduction and growth in mammals. Thus, POU1F1 gene was investigated as a candidate gene for litter size and growth performance in goats. In the current study, using direct DNA sequencing, c.682G > T, c.723T > G and c.837T > C loci were genotyped in Shaanbei white cashmere (SBWC) goats (n = 609), but c.876 + 110T > C was monomorphic. Besides, the c.682G > T locus was first identified by HinfI (Haemophilus influenzae Rf) restriction endonuclease. Association analysis results showed that the c.682G > T, c.837T > C loci and diplotypes were significantly associated with goat litter size (p < 0.05). The positive genotypes were GT and TT for the two SNPs, respectively, and the optimal diplotype was H3H7 (GTTT-TTTT). On the other hand, the c.682G > T, c.723T > G and c.837T > C strongly affected growth traits and body measurement indexes in SBWC goats (p < 0.05). The positive genotypes or allele of these SNPs were GT, G and TT, respectively. Additionally, the goats with H3H7 diplotype also had a greater growth status than others (p < 0.05). Here, individuals with same genotype had both a better litter size and growth traits, showing a positive correlation between these economic traits. Meanwhile, the positive genotypes of four SNPs were combined to obtain the optimal diplotype, which was also H3H7. These SNPs, especially the diplotype, could be used for the genomic selection of excellent individuals with a greater litter size and better growth status in goat breeding.

Mutation -388 C>G of NR5A1 gene affects litter size and promoter activity in sheep

The Nuclear receptor superfamily 5, group A, member 1 (NR5A1) gene encodes a nuclear receptor that regulates the transcription of genes involved in steroidogenesis, follicular development and female fertility. Little, however, is known about the relationship of this gene with reproductive performance in sheep. In this study, the transcription initiation site of Hu sheep NR5A1 gene was located 193 nucleotides (i.e., at −193 nt) before the translational start site (ATG). The core promoter region of the NR5A1 gene ranged from −696 nt to −298 nt, and a C>G mutation at −388 nt was detected in this region. Association analysis indicated ewes with the GG genotype had greater litter size at the second and third parity than those with the CC genotype (P < 0.05). The results from the luciferase assay provided evidence that the -388 G allele increased luciferase activity compared with that of the −388 C allele. Furthermore, the -388 C>G mutation lost a CpG site and gained a novel binding site for the transcription factor, SP1, and results from an overexpression experiment and methylation analysis indicated transcription factor SP1 and methylation of the -388 C>G mutation were both involved in alteration of NR5A1 transcription activity. Results of the present study revealed that the -388 C>G mutation lost a CpG site and promoted NR5A1 gene expression, which completely superimposed positive effects on NR5A1 gene transcription activity by transcription factor SP1, resulting in a fecundity increase in Hu sheep.

English

Genetic information especially of the Quantitative Trait Loci (QTL) which affect different performance traits is considered one of the most effective tools in the breeding programs of livestock. Several genes were reported as candidate genes that effect litter size performance and one of these genes is the KISS1 which is considered as a regulator of puberty onset. The polymorphisms of KISS1 gene have some relationships with high prolific and sexual precocity. The objective of this study was the detection of the restriction fragment length polymorphism (RFLP) and single nucleotide polymorphisms (SNPs) of KISS1 gene in six major Egyptian small ruminant breeds. The primers used in this study flanked a 377 bp fragment from intron 1 of KISS1 gene in sheep and goat. These PCR amplified fragments were digested with XmnI endonuclease. According to the presence or absence of the restriction site (GAANN^NNTTC) at position 121^122, we genotyped the 122 tested animals as AT (54.92%) and TT (45.08) with the absence of AA genotype. The overall frequencies of alleles A and T were 27.46 and 72.54%, respectively. The sequence analysis of purified PCR products representing these two detected genotypes declared the presence of a SNP (T→A) at position 125 in the amplified fragment which is responsible for the elimination of the restriction site and consequently the presence of two different alleles T and A. The nucleotide sequences of sheep KISS1 alleles T and A as well as goat KISS1 alleles T and A were submitted to GenBank database and have accession numbers: KP835797, KP835798, KP835799 and KP835800, respectively. It is concluded that small ruminant breeds have high frequency of KISS1 allele T which was associated with greater litter size. We recommend to increase this allele in Egyptian small ruminant breeds and also to select the animals which possess TT genotypes of KISS1 gene and enter them in breeding programs of Egyptian small ruminants to increase their fecundity traits. Key words: Sheep, goat, KISS1, polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), single nucleotide polymorphisms (SNPs).

Two mutations in the 5'-flanking region of the KITLG gene are associated with litter size of dairy goats.

In this study, Xinong Saanen (SN) and Guanzhong (GZ) dairy goat breeds were used to detect single nucleotide polymorphisms (SNPs) in the 5'-flanking region of the KITLG gene by DNA sequencing and primer-introduced restriction analysis-polymerase chain reaction. Two novel SNPs (g.13090G>T and g.13664C>A) were identified (GenBank Accession no. KM658964). Furthermore, g.13090G>T and g.13664C>A loci were closely linked in SN and GZ breeds (r(2) > 0.33). Association analysis results showed that g.13090G>T and g.13664C>A SNPs significantly affected litter size (P < 0.05). The litter size of individuals with the combined genotype GG/CC from both dairy goat breeds was greater than that of individuals with TT/AA in average parity (P < 0.05). Known biochemical and physiological functions, along with our results, indicated that GG/CC could be used in marker-assisted selection to choose individuals with greater litter size from both breeds. These results extend the spectrum of genetic variation in the caprine KITLG gene and may contribute to genetic resources and breeding of goats.

No Evidence for a Trade-Off between Reproductive Investment and Immunity in a Rodent

Life history theory assumes there are trade-offs between competing functions such as reproduction and immunity. Although well studied in birds, studies of the trade-offs between reproduction and immunity in small mammals are scarce. Here we examined whether reduced immunity is a consequence of reproductive effort in lactating Brandt's voles (Lasiopodomys brandtii). Specifically, we tested the effects of lactation on immune function (Experiment I). The results showed that food intake and resting metabolic rate (RMR) were higher in lactating voles (6≤ litter size ≤8) than that in non-reproductive voles. Contrary to our expectation, lactating voles also had higher levels of serum total Immunoglobulin G (IgG) and anti-keyhole limpet hemocyanin (KLH) IgG and no change in phytohemagglutinin (PHA) response and anti-KLH Immunoglobulin M (IgM) compared with non-reproductive voles, suggesting improved rather than reduced immune function. To further test the effect of differences in reproductive investment on immunity, we compared the responses between natural large (n≥8) and small litter size (n≤6) (Experiment II) and manipulated large (11–13) and small litter size (2–3) (Experiment III). During peak lactation, acquired immunity (PHA response, anti-KLH IgG and anti-KLH IgM) was not significantly different between voles raising large or small litters in both experiments, despite the measured difference in reproductive investment (greater litter size, litter mass, RMR and food intake in the voles raising larger litters). Total IgG was higher in voles with natural large litter size than those with natural small litter size, but decreased in the enlarged litter size group compared with control and reduced group. Our results showed that immune function is not suppressed to compensate the high energy demands during lactation in Brandt's voles and contrasting the situation in birds, is unlikely to be an important aspect mediating the trade-off between reproduction and survival.

Crecimiento y comportamiento reproductivo de ovinos Poll Dorset y Suffolk bajo condiciones intensivas

With the aim of comparing Poll Dorset and Suffolk breeds, data collected between 2000 and 2003 in a flock in Huitzilac, Morelos, Mexico were used. Data analyzed using mixed linear models included preweaning growth traits (n≥,,, 113 for Poll Dorset and n≥,,, 567 for Suffolk), postweaning growth traits (n≥,,, 72 for Poll Dorset and n≥,,, 208 for Suffolk), and reproductive traits (n≥,,, 120 for Poll Dorset and n≥,,, 290 for Suffolk). Suffolk had higher weights at birth (8.1 %) (4.94 vs 4.57 kg) and at weaning (9.5 %) (25.57 vs 23.35 kg), higher preweaning average daily gain (11.1 %) (0.30 vs 0.27 kg, from 0 to 67 d of age) and postweaning average daily gain (28.6%) (0.18 vs 0.14 kg from 76 to 182 d of age), compared to Poll Dorset (P<0.01). Suffolk had also greater litter size at birth (5.8 %) (1.63 vs 1.54 lambs), at weaning (5.2 %) (1.41 vs 1.34 lambs), and higher litter weights at birth (3.8 %) (7.44 vs 7.17 kg) and at weaning (12.3 %) (36.37 vs 32.40 kg), compared to Poll Dorset (P<0.01). Suffolk had a greater number of services per conception (17.5 %) (1.34 vs 1.14) than Poll Dorset (P<0.01), while no differences were found between breeds for gestation length (P=0.1892). It is concluded that Suffolk breed has a higher potential for growth and reproductive performance traits than Poll Dorset, under stall fed conditions in the Valley of Mexico, except for the number of services per conception.

A substitution within erythropoietin receptor gene D1 domain associated with litter size in Beijing Black pig, Sus scrofa

Studies of uterine capacity and litter size in swine have suggested that erythropoietin receptor (EPOR) plays an important role in fetal survival through maturation of red blood cells. In this study, we screened the porcine EPOR gene for mutations and identified three single nucleotide polymorphisms (SNPs): two missense mutations and one synonymous mutation. We then genotyped 272 Beijing Black sows, Sus scrofa, and compared this data with litter sizes from a total of 1523 parities among the sows. The G allele of the nonsynonymous SNP, EPOR c.434A>G, was associated with greater litter size at both first parity (P < 0.05) and at later parities (P < 0.01). This SNP causes His92Arg adjacent to the fourth conserved cysteine residue in the mature protein and is in the D1 domain of the protein. Additionally, we determined the allele frequencies for this SNP among six Chinese indigenous pig breeds (Bamei, Erhualian, Laiwu Black, Mashen, Meishan and Min) and three Western commercial pig breeds (Duroc, Landrace and Large White). The c.434G allele was significantly more common among the more prolific Chinese breeds than the Western breeds, implying that EPOR c.434A>G could be a useful genetic marker to improve litter size in swine.

Erythropoietin Receptor Gene ( EPOR) Polymorphisms are Associated with Sow Litter Sizes

The erythropoietin receptor (EPOR) has shown to play an important role in fetal survival by promoting the maturation of red blood cells in many studies of uterine capacity and litter size in swine. In this study, we screened the porcine EPOR gene for mutations and identified five single nucleotide polymorphisms (SNPs): g.705G>T in intron 1, g.2 373C>T in intron 4, and g.2 882C>T, g.3 035A>G, and g.3 132A>T in intron 6. We then genotyped 247 Beijing Black (BB) sows and compared the polymorphism data with the litter sizes of 1 375 parities among the sows. At first parity, there was no association of g.2 882C>T and g.3 132A>T with litter sizes. However, the CT sows in g.2 882C>T had 2.13 higher total number born (TNB) ( P<0.01) and 1.81 higher number born alive (NBA) ( P<0.01) than the CC sows and the heterozygous sows in g.3 132A>T had the highest litter size when compared to the two homozygotes for the later parities ( P<0.05). In the g.3 035A>G SNP, for the later parities, the TNB of the sows with the GG genotype was 3.81 higher ( P<0.01) and the NBA was 2.75 higher ( P<0.01) than that with the AA genotype but no difference at first parity. The G allele of the EPOR g.705G>T SNP was associated with a greater litter size at both the first parity ( P<0.05) and later parities ( P<0.01). Furthermore, we determined the allele frequencies for this SNP among five Chinese indigenous pig breeds (Erhualian, Laiwu Black, Meishan, Min, and Rongchang) and three western commercial pig breeds (Duroc, Landrace, and Large White). The G allele of the EPOR g.705G>T SNP was significantly more common in the more prolific Chinese breeds. These results indicated that the EPOR could be an important candidate gene for litter size and g.705G>T can serve as a useful genetic marker for improving litter size in both first and later parities in swine.

Effects of Breeding at the Second Oestrus or After Post‐Weaning Hormonal Treatment with Altrenogest on Subsequent Reproductive Performance of Primiparous Sows

This study investigated the effects of breeding at the second oestrus after weaning or after feeding an orally active progestagen (altrenogest) on the subsequent reproductive performance of primiparous sows. After 3 weeks of lactation, 663 weaned sows of two genotypes were allocated into three groups: G1--breeding at the first oestrus after weaning; G2--breeding at the second oestrus after weaning and G3--treatment with altrenogest for 5 days after weaning and breeding at the first oestrus after the end of the treatment. Body weight at breeding was lower in G1 and G3 than in G2 sows (p < 0.05). The interval to show oestrus was similar for G1 and G2 groups (p > 0.05) but higher (p < 0.05) than that observed in G3 group. Within genotype A, percentages of females in oestrus within 10 days were not different (p > 0.05) among groups, whereas in genotype B, more G1 and G2 sows (p < 0.05) showed oestrus than G3 sows. In both genotypes, lower farrowing rates were observed in G3 than in G1 and G2 sows (p < 0.05) and a greater litter size (p < 0.05) was observed in G2 sows. In genotype A, the number of total born piglets was similar for G1 and G3 groups (p > 0.05), whereas in genotype B, G1 sows had a greater litter size than G3 sows (p < 0.05). Body weight at weaning and at breeding was similar (p > 0.05) between farrowed and non-farrowed sows in all groups. Reproductive performance is not improved in primiparous sows treated with altrenogest during 5 days after weaning. The reproductive performance of genotype B sows is compromised in Control and Altrenogest-treated sows but not in those bred at the second oestrus after mating. Breeding at the second oestrus after weaning allows primiparous sows to gain weight between weaning and service, and increases their farrowing rate and subsequent litter size.

Factors affecting piglet mortality in loose farrowing systems on commercial farms

Crating sows in farrowing systems greatly restricts their normal behaviour (e.g. movement, nest-building, leaving the nest site for defecation), which is usually justified by the assumption that piglet mortality is higher with loose-housed sows. Based on experiments showing that this is not the case, farrowing crates were banned in Switzerland in 1997, with a 10-year transitional period. Since then, many farms have introduced loose farrowing systems, enabling an analysis of risk factors for piglet mortality in crateless farrowing systems based on a large sample size. Data from a Swiss sow recording scheme (UFA2000) were analysed using generalised linear mixed-effects models with an underlying Poisson distribution. Average total piglet mortality for the years 2002 and 2003 on 99 farms ( N = 12457 litters) with loose farrowing systems amounted to 1.36 liveborn piglets per litter. The number of crushed piglets was 0.64 piglets per litter, whereas the number of piglets that died for other reasons was 0.72 piglets per litter. Herd size, pen size, possibility of confinement of the sow, presence of piglet protection bars and year of data collection did not significantly influence total piglet losses, losses due to crushing and losses due to reasons other than crushing. With greater litter size at birth, significantly more losses occurred due to all reasons (total, crushed, others). Total piglet mortality and losses for reasons other than crushing were significantly higher in older sows. Losses were therefore mainly attributable to sow-related characteristics rather than to the design of the farrowing pen.

The Relationship between Linear Type Traits and Fertility Traits in High‐yielding Dairy Goats

Reproductive data collected from 13 medium-size goat farms in central Mexico (582 goats), were used to investigate if linear type traits influenced reproductive performance of high-yielding dairy goats. Data were analysed using multiple stepwise forward logistic regressions. Goats with the higher scores for strength were 1.43 times more likely (p < 0.05) to have larger litters (1.49 vs 1.39) than goats with lower strength. Goats approaching level rump angles were 1.68 times more likely (p < 0.01) to have larger litters, compared with goats with extremely sloped rump angles (1.48 vs 1.37). Goats with rear legs nearly straight (posty) in hock tended (p < 0.08) to presented larger litters than goats with rear legs slightly angled (sickled) in hock (1.49 vs 1.38). Less pronounced rump angle was favourable associated (p < 0.05) with litter weight (4.88 vs 4.53 kg) compared with goats with low pin bones. Goats with poorer udder texture were 1.42 more likely (p < 0.05) to have heavier litters than goats with good udder texture. Goats with faulty mammary system tended (p < 0.07) to have heavier litters than goats with good mammary system. Increasing udder height was associated (p < 0.05) with increasing number of services per conception. Goats with good fore udder attachment and non-refined heads were at reduced risk (p < 0.05) for stillbirths. Goats with stronger median ligament were 65% less likely (p < 0.05) to lose their foetuses than those with looser udder support. Our findings indicate that a greater litter size and litter weight is expected in goats as rump angle becomes less sloped. This study showed that a relationship exists between strength of goats and litter size, and that some traits linked to high milk yield were antagonist to some reproductive traits.

Mutations in BMPR-IB and BMP-15 genes are associated with litter size in Small Tailed Han sheep (Ovis aries)1

The Small Tailed Han is a prolific local sheep breed in China. The bone morphogenetic protein receptor IB (BMPR-IB) gene, which affects the fecundity of Booroola Merino sheep, and the bone morphogenetic protein 15 (BMP-15) gene, which affects the fecundity of Inverdale, Hanna, Belclare, Cambridge, and Lacaune sheep, were studied as candidate genes associated with the prolificacy of Small Tailed Han sheep. Single nucleotide polymorphisms of BMPR-IB and BMP-15 genes were detected in Small Tailed Han ewes (n = 188) by PCR-RFLP. The combined effect of the 2 genes on the prolificacy of Small Tailed Han sheep was studied. The results indicated that the same FecB mutation (Q249R) occurred in the BMPR-IB gene in Small Tailed Han ewes as found in Booroola Merino ewes. The Small Tailed Han ewes with genotypes FecB(B)/FecB(B) and FecB(B)/FecB(+) had 1.40 (P < 0.01) and 1.11 (P < 0.01) more lambs, respectively, than those with genotype FecB(+)/FecB(+). The same FecX(G) mutation (Q239Ter) of the BMP-15 gene was found in Small Tailed Han ewes as in Belclare and Cambridge ewes. The Small Tailed Han ewes with the heterozygous mutant FecX(G)/FecX(+) had 0.55 (P < 0.01) more lambs than those with the wild-type FecX(+)/FecX(+). The Small Tailed Han ewes carrying mutations in both BMPR-IB and BMP-15 genes had greater litter size than those with either mutation alone. In view of our results, marker-assisted selection using both BMPR-IB and BMP-15 genes is warranted to increase litter size in sheep and will be of considerable economic value to sheep producers.

Correlated responses in maternal performance following divergent selection for heat loss in mice1

Divergent selection in mice was applied in 3 independent replicates for high (maintenance high; MH) and low (maintenance low; ML) heat loss for 16 generations. An unselected control (maintenance control; MC) was also maintained in all replicates. Selection ceased for 26 generations; heat-loss measurement and selection resumed at generation 42. Lactation performance, dam weight, dam feed intake, and efficiency of production of pup weight were recorded or calculated for MH and ML dams in all 3 replicates at generation 46 or 47 with the objective of determining whether selection for heat loss has created correlated responses in maternal performance. One-half of the dams reared their own litters, and one-half reared cross-fostered (across lines) litters. Between 10 and 12 litters were used from each replicate-line-rearing class. Litter size was recorded, and litters were standardized to 8 pups within 24 h of birth. For cross fostering, MH litters were matched to ML litters born within 24 h of each other, and MH-ML litter pairs were cross-fostered at 3 d of age. A weigh-suckle-weigh protocol was used to obtain milk production estimates over a 2-h suckling period at 6, 9, 12, and 15 d. Dam (plus litter) feed intake was also recorded at these times and was calculated as the disappearance of feed over 3-d intervals. Dams of the MH selection tended (P < 0.11) to have greater litter size than those of the ML selection; litter size of MC dams was intermediate. Line of dam affected milk production (P = 0.04) and dam feed intake (P < 0.03) as MH dams produced more milk and consumed more feed than ML dams. Average milk production for the 2-h measurement period was 1.70 +/- 0.07 and 1.41 +/- 0.07 g, and average 3-d feed consumption was 50.8 +/- 1.2 and 45.2 +/- 1.2 g for MH and ML dams, respectively. Cross-fostering had no effect (P > 0.86) on milk production. Line of dam tended to affect 21-d litter weight (P = 0.15) with litters reared by MH dams weighing more than those reared by ML dams, but there was no difference (P > 0.86) in 21-d dam weights. Efficiency of producing litter weight (litter 15-d weight: dam plus litter feed intake from d 6 to 15) was greater (0.49 vs. 0.46, SE = 0.009; P = 0.03) for ML than for MH dams. Selection for reduced heat loss (lower maintenance feed intake in the ML line) resulted in reduced milk production and feed intake in dams and greater efficiency of litter weight production.

Statistical Analysis of Stillbirths in Different Genotypes of Sows

Statistical analysis was conducted on sow stillbirth traits of three genotypes with 2,400 litters including the Erhualian, Large White and the F 1 cross of these two breeds. Number of stillborn piglets per litter in the Erhualian, Large White and the F 1 averaged 0.85, 0.31 and 0.70, and percentage bom alive averaged 95.0%, 97.0% and 95.5%, respectively. Erhualian sows with a greater litter size also had a higher stillbirth rate. Results of analysis of variance indicated that genotype, parity, farrowing year×farrowing season interaction and total number bom had highly significant effects on both number of stillborn piglets per litter and percentage born alive in sows (p 0.05), and highly significant effect on percentage born alive (p<0.01). Farrowing season had highly significant effects on both number of stillborn piglets per litter and percentage bom alive (p<0.01). From parity one to parity ten, least squares means for number of stillborn piglets per litter progressively increased with increasing parity and least squares means for percentage bom alive progressively decreased with increasing parity. Sows that farrowed in winter had the highest number of stillborn piglets per litter and the lowest percentage bom alive, sows that farrowed in autumn had the lowest number of stillborn piglets per litter and the highest percentage born alive. With increasing total number born, least squares means for number of stillborn piglets per litter markedly increased and least squares means for percentage born alive markedly decreased. Results from analysis of paternal half sibs indicated that the heritabilities for number of stillborn piglets per litter and percentage born alive were 0.110 and 0.124, and the genetic, phenotypic and environmental correlations between them were -0.989, -0.951 and -0.948, respectively. These results indicated that number of stillborn piglets per litter and percentage born alive were traits with the similar genetic background.

Beneficial effects of chrysin and benzoflavone on virility in 2-year-old male rats.

This work describes the potential usefulness of bioflavonoids for countering the deleterious effects of aging on male sexuality in 2-year-old rats. A flavone chrysin from Passiflora caerulea Linn. and a benzoflavone moiety (BZF) recently isolated from Passiflora incarnata Linn. were administered to 2-year-old male rats for a period of 30 days. After cessation of these treatments, there was a significant improvement in overall sexual functions in the rats given bioflavonoids, compared with control rats. The rats receiving chrysin (1 mg/kg) and BZF (10 mg/kg) exhibited increased libido when they were allowed to interact with nonestrous female rats. Additionally, both treated groups had increased sperm count, greater fertilization potential, and greater litter size when they were allowed to interact with proven proestrous female rats of a similar strain. BZF was more potent than chrysin as an antiaromatase agent and exhibited better effects on the sexual system of the 2-year-old male rats. Plant flavonoids have great potential for clinical and therapeutic applications against the physiological and biochemical effects of aging.

Effects of lead exposure before pregnancy and dietary calcium during pregnancy on fetal development and lead accumulation.

Millions of women of child-bearing age have substantial bone lead stores due to lead exposure as children. Dietary calcium ingested simultaneously with lead exposure can reduce lead absorption and accumulation. However, the effects of dietary calcium on previously accumulated maternal lead stores and transfer to the fetus have not been investigated. We studied the effects of lead exposure of female rats at an early age on fetal development during a subsequent pregnancy. We gave 5-week-old female Sprague-Dawley rats lead as the acetate in their drinking water for 5 weeks; controls received equimolar sodium acetate. This was followed by a 1-month period without lead exposure before mating. We randomly assigned pregnant rats (n = 39) to diets with a deficient (0.1%) or normal (0.5%) calcium content during pregnancy. A total of 345 pups were delivered alive. Lead-exposed dams and their pups had significantly higher blood lead concentrations than controls, but the concentrations were in the range of those found in many pregnant women. Pups born to dams fed the calcium-deficient diet during pregnancy had higher blood and organ lead concentrations than pups born to dams fed the 0. 5% calcium diet. Pups born to lead-exposed dams had significantly (p<0.0001) lower mean birth weights and birth lengths than controls. There were significant inverse univariate associations between dam or pup organ lead concentrations and birth weight or length. The 0.5% calcium diet did not increase in utero growth. Stepwise regression analysis demonstrated that greater litter size and female sex were significantly associated with reduced pup birth weight and length. However, lead exposure that ended well before pregnancy was significantly (p<0.0001) associated with reduced birth weight and length, even after litter size, pup sex, and dam weight gain during pregnancy were included in the regression analysis. The data demonstrate that an increase in dietary calcium during pregnancy can reduce fetal lead accumulation but cannot prevent lead-induced decreases in birth weight and length. The results provide evidence that dietary nutrients can influence the transfer of toxins to the fetus during pregnancy. If these results are applicable to women, an increase in diet calcium during pregnancy could reduce the transfer of lead from prepregnancy maternal exposures to the fetus.