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Introduction: Feeding bamboo powder is a kind of fiber raw material mainly composed of insoluble dietary fiber (IDF). In this study, IDF-based rice husk meal and feeding bamboo powder were used to compare the effects of bamboo fiber on fecal microflora and the performance of lactating sows and their offspring piglets. Methods: Thirty healthy crossbred gilts (Yorkshire × Landrace) at day 105 of gestation were randomly allocated into three groups: CON, TRE1 supplemented with 2% BBF1 (feeding bamboo powder), and TRE2 supplemented with 2% BBF2 (99% feeding bamboo powder +1% bamboo fiber polymer material). The reproductive performance, serum indexes, and fecal microbiota of sows and piglets were analyzed. The results showed that, compared with CON, the average feed intake of sows in TRE1 during the second week of lactation was significantly increased by 21.96% (p < 0.05), the average daily gain (ADG) per litter in TRE1 on 11-21 days and 3-21 days of lactation was significantly increased by 50.68 and 31.61%, respectively (p < 0.05), and the serum triglyceride content of sows in TRE1 on the 21st day of lactation was significantly increased (p < 0.05). The 16S rRNA analysis showed that dietary bamboo fiber significantly increased the fecal microbial richness index Ace, Chao, and Sobs of sows (p < 0.05) and tended to increase the Sobs index of suckling piglets on day 21 (p < 0.10). Compared with CON, BBF1 supplementation significantly decreased the abundance of Christensenellaceae_R-7_group in feces of sows on days 7 and 21 after delivery (p < 0.05), while BBF2 decreased the genera Christensenellaceae_R-7_group on days 7 (p < 0.10) and 21 (p < 0.05) after delivery. Spearman correlation analysis showed that the abundance of Phascolarctobacterium in the feces of piglets on the 21st day after delivery was significantly positively correlated with diarrhea rate and significantly negatively correlated with ADG per litter, day 21 litter weight, and 3- to 21-day survival rate. In contrast, Christensenellaceae_R-7_group was significantly negatively correlated with diarrhea rate and positively correlated with ADG per litter. Discussion: These results indicated that maternal BBF1 supplementation improved the litter weight gain of suckling piglets, which was associated with the improvement of diversity and structure of the fecal microbiota in the piglets.

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This study aimed to estimate two reproductive efficiency indices in sheep based on the ratio between litter weight (at birth and weaning) and dam weight, as well as their genetic parameters. Phenotypic and pedigree data comprising the period from 1990 to 2018 were obtained from the Santa Inês sheep database of Embrapa Tabuleiros Costeiros. For estimation of the genetic parameters of the indices, a repeatability model was applied in single- and two-trait analyses by a Bayesian approach. The mean reproductive efficiency index was 0.069 ± 0.0163 and 0.43 ± 0.0955 at birth and weaning, respectively. These values indicate that, on average, ewes give birth to 69 g of lamb per kg body weight and wean 430 g of lamb per kg body weight. Described here for the first time, the heritability estimate obtained in single- and two-trait analyses was 0.24 for the index based on birth weights and ranged from 0.13 to 0.15 for the index based on weaning weights. The estimates indicate the possibility of genetic gain by selection and are similar to those reported for reproductive traits in sheep, representing an option for selection criterion. The genetic correlation between indices was positive and moderate (0.26). The repeatability estimates were high (0.49 for the birth weight index and 0.71 for the weaning weight index). These values indicate good prediction of future performance with few observations. The weaning weight index might be a good culling criterion of females.

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Increasing litter size and weight during the marketing time by decreasing mortality among lambs per ewe is the objective of the community-based breeding program (CBBP). This study aims to find out litter size, litter weight per ewe, and preweaning lamb mortality of Doyogena sheep managed under CBBP. The study analyzed the data records of 4530 animals for 8 years from 2013 to 2020. A logistic regression procedure was used to analyze pre-weaning lamb survival rates. Results showed that the overall least-squares means of litter size at birth (LSB), litter size at weaning (LSW), total litter weight at birth (TLWB), and total litter weight at weaning (TLWW) were 1.57 ± 0.02 lambs, 1.50 ± 0.02 lambs, 5.24 ± 0.09 kg, and 24.14 ± 0.69 kg respectively. The incidence of pre-weaning lamb mortality was 4.72%. Year and breeder cooperative vary were observed for pre-weaning lamb losses. Females had lower odds of survival as compared to males. Odds of survival were low for triplets, quadruplets, and low birth weight (≤2 kg) born lambs. The ongoing selection program which aims to improve reproductive and growth performance had a positive influence on the survival rate of lambs. Improvement of the environment in the flock, special care for multiple-born and care for small lambs would lead to further lamb survival improvements.

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This study was conducted to genetically and environmentally characterize prolificacy (litter size and weight at birth; LSB and LWB and litter size and weight at weaning; LSW and LWW, respectively), milk yield at the 7th (MY7), 15th (MY15), 30th (MY30), 60th (MY60), 90th (MY90) day of lactation and monthly milk yield (MMY) and milk composition traits in Egyptian Zaraibi goats. A total of 443 and 421 records produced by 121 Zaraibi lactating goats were used to assess prolificacy and milk production traits, respectively. The milk composition traits were measured using 371 milk samples obtained at random from 53 goats. The fourth parity showed the highest values for LWB, LWW, and MMY (3.62, 18.15, and 28.99 kg, respectively). Milk composition traits revealed an inverse tendency, decreasing until the second month and then increasing until the seventh month. The heritability estimates ranged from 0.07 to 0.13, from 0.04 to 0.39, and from 0.07 to 0.33 for prolificacy, milk yield, and milk composition traits, respectively. Negatively high genetic correlations between MMY and all milk composition traits were found. MMY had the highest estimate of heritability (0.39 ± 0.07), this means that the genetic improvement of this trait could be achieved through direct selection.

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Vitamin D improves the reproductive efficiency in animals. This study aimed to examine the effects of 1,25-dihydroxyvitamin D3-gylcosides (1,25-vitD) on the farrowing process in sows and the vitality of their piglets. In total, 100 sows were allocated into two groups at insemination ('1,25-vitD' and 'negative control'). The 1,25-vitD group received 260−300 mg/sow/day 1,25-vitD in their feed during the gestation period. Backfat thickness, fecal score, and the farrowing process was evaluated. The piglets were categorized into live born or stillborn, and vitality was evaluated by assessing the umbilical cord and the meconium score. The number of total-born piglets in sows of '1,25-vitD' was higher and the farrowing duration was shorter than in the negative control group without showing significance in the univariable analysis. In a linear multiple regression model including the variables 'farrowing duration', 'total born piglets' and '1,25-vitD' differences became evident. We found that 1,25-vitD was associated with a reduced farrowing duration (p = 0.055). Moreover, significantly more mummies (p < 0.01) and short ruptured umbilical cords (p < 0.05) were observed in the 1,25-vitD group. This study showed an effect of 1,25-vitD on the farrowing process. However, more research is needed to better describe the mechanism of 1,25-vitD in detail.

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The objective of the present study was to evaluate the effects of dietary supplementation of lysolecithin in sows' diets during the last three weeks of the gestation period and throughout the lactation period on performance and metabolic parameters. In total 60 sows were allocated to two treatments: (a) CG (control group): the sows were fed commercially control diets; (b) LLG (lysolecithin group): the sows were fed the control diets supplemented with 750 g/t of feed supplemented with lysolecithin (Lysoforte Booster DryTM, Kemin Europa N.V., Herentals, Belgium). Backfat was lower in LLG than CG at end of gestation and at weaning (p = 0.030 and 0.044, respectively), while the CG sows mobilized more backfat between day 14 to weaning (p = 0.006). Litter weight at weaning was higher in the LLG (p = 0.027). Fasted glucose levels at day 14 of lactation tended to be lower in LLG compared to CG (p = 0.074). Urea concentrations were higher in LLG than CG at day 14 (p = 0.002). Lysolecithin supplemented sows compared to the control mobilized less tissue during lactation to support lactation demands. In conclusion, lysolecithin supplementation in sows resulted in improved litter weight at weaning without an excessive catabolism of backfat tissue, most probably due to an efficient nutrient utilization, which warrants further investigation.

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The aim of the present study was to explore the influences of varying doses of micelle silymarin (0%, 0.05%, 0.1%, and 0.2%) supplementation on sows' feed intake, milk yields, serum hormones, and litter growth using 40 multiparous sows (Landrace × Yorkshire, parity from 3 to 5) from the 109th prenatal day to the 21st postnatal day. Each treatment included 10 sows and each sow was used as an experimental unit. On weaning day, litter weight and litter weight gain were linearly improved (P < 0.01, both), corresponding to the increasing dose of silymarin micelle in the diet. Also, litter weight, litter weight gain, and average daily gain (ADG) of piglets born to treated sows exceeded (P < 0.05) those of offspring from the control sows (0% micelle silymarin). Feed intake in week 1, week 2, and the entire lactation period was increased (linear, P < 0.01) as micelle silymarin dose increased. Body weight (BW) loss of sows during lactation was linearly reduced (P = 0.003) with the increasing amounts of micelle silymarin. Average daily milk yields during lactation were also linearly increased (P = 0.002) in treated sows, exceeding (P = 0.046) that of control sows. Also, uniform increases were observed (P = 0.037) in fat content in milk produced by treated sows on day 14 of lactation. Epinephrine concentrations and aspartate aminotransferase (AST) activity in sow serum on day 21 postpartum were linearly declined (P = 0.010) as micelle silymarin dose increased, and were both declined (P < 0.05) in treated sows compared with the control. In addition, treated sows' serum had higher activity of superoxide dismutase (SOD) at parturition and glutathione peroxidase (GSH-Px), lower oxidized glutathione (GSSG) concentrations, and GSSG/GSH (glutathione) ratio (all, P < 0.01) on day 21 of lactation. Moreover, offspring from micelle silymarin-treated sows tended to (0.05 < P <0.1) have higher serum catalase (CAT) activity and total antioxidant capacity (T-AOC) concentrations. Taken together, the results showed that sows fed increasing levels of micelle silymarin from the 109th prenatal day to the 21st postnatal day had an incremental dose-dependent effect on higher feed intake, diminished BW loss, greater milk yields, and greater litter weight at weaning, and 0.2% of micelle silymarin could be optimal to achieve the better effect.

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Sow milk production ability is an important limiting factor impacting suboptimal growth and the survival of piglets. Through pig genetic improvement, litter sizes have been increased. Larger litters need more suckling mammary glands, which results in increased milk from the lactating sow. Hence, there is much significance to exploring sow lactation performance. For milk production ability, it is not practical to directly measure the milk yield, we used litter weight gain (LWG) throughout sow lactation as an indicator. In this study, we estimated the heritability of LWG, namely, 0.18 ± 0.07. We then performed a GWAS, and detected seven significant SNPs, namely, Sus scrofa Chromosome (SSC) 2: ASGA0010040 (p = 7.73E-11); SSC2:MARC0029355 (p = 1.30E-08), SSC6: WU_10.2_6_65751151 (p = 1.32E-10), SSC7: MARC0058875 (p = 4.99E-09), SSC10: WU_10.2_10_49571394 (p = 6.79E-08), SSC11: M1GA0014659 (p = 1.19E-07), and SSC15: MARC0042106 (p = 1.16E-07). We performed the distribution of phenotypes corresponding to the genotypes of seven significant SNPs and showed that ASGA0010040, MARC0029355, MARC0058875, WU_10.2_10_49571394, M1GA0014659, and MARC0042106 had extreme phenotypic values that corresponded to the homozygous genotypes, while the intermediate values corresponded to the heterozygous genotypes. We screened for flanking regions ± 200 kb nearby the seven significant SNPs, and identified 38 genes in total. Among them, 28 of the candidates were involved in lactose metabolism, colostrum immunity, milk protein, and milk fat by functional enrichment analysis. Through the combined analysis between 28 candidate genes and transcriptome data of the sow mammary gland, we found nine commons (ANO3, MUC15, DISP3, FBXO6, CLCN6, HLA-DRA, SLA-DRB1, SLA-DQB1, and SLA-DQA1). Furthermore, by comparing the chromosome positions of the candidate genes with the quantitative trait locus (QTLs) as previously reported, a total of 17 genes were found to be within 0.86-94.02 Mb of the reported QTLs for sow milk production ability, in which, NAV2 was found to be located with 0.86 Mb of the QTL region ssc2: 40936355. In conclusion, we identified seven significant SNPs located on SSC2, 6, 7, 10, 11, and 15, and propose 28 candidate genes for the ability to produce milk in Yorkshire pigs, 10 of which were key candidates.

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The effect of concentrate supplementation to crossbred goats on rangeland during the dry period on their reproductive performance was investigated. Goats were assigned into two groups: a concentrate supplemented (S; n = 91) group and an unsupplemented (UNS; n = 118) group. S goats received 350 g/day of concentrate per head, 30 days prior to breeding (flushing in winter) and 30 days during the last trimester of pregnancy. UNS goats presented a lower (P < 0.01) liveweight at the onset of the breeding period than did the S group (38.2 ± 3.7 vs. 44.4 ± 3.6 kg). Average daily gains during pregnancy were higher (P < 0.01) in the S group than UNS goats (15.5 ± 1.2 vs. - 0.5 ± 5.1 g/d). S goats had a higher (P < 0.01) kidding rate (87.1%) than the UNS goats (54.7%). Litter size for UNS and S goats was 1.39 and 2.00, respectively (P < 0.01). Serum triiodothyronine, tetraiodothyronine, and cortisol concentration at the end of the flushing period were not affected by concentrate supplementation. Serum glucose (88.7 ± 3.8 vs. 95.7 ± 5.3 mg/dL), total protein (6.9 ± 1.1 vs. 8.2 ± 1.2 mg/dL), and blood urea nitrogen (17.1 vs. 21.0 ± 4.3 mg/dL) concentrations were lower for UNS goats as compared with S goats. In conclusion, concentrate supplementation in crossbred goats on rangeland markedly improved body mass changes during gestation and the reproductive performance, which implies that malnutrition is a major barrier affecting fertility of goats and liveweight of kids in this rangeland.

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We estimated genetic parameters in Landrace and Large White pig populations for litter traits at farrowing (total number born, number born alive, number stillborn, total litter weight at birth (LWB), and mean litter weight at birth) and those at weaning (litter size at weaning (LSW), total litter weight at weaning (LWW), mean litter weight at weaning (MWW), and survival rate from farrowing to weaning). We analyzed 65,579 records at farrowing and 6,306 at weaning for Landrace, and 52,557 and 5,360, respectively, for Large White. Single-trait and two-trait repeatability animal models were exploited to estimate heritability and genetic correlation respectively. Heritability estimates of LSW were 0.09 for Landrace and 0.08 for Large White. Genetic correlations of LSW with MWW were -0.43 for Landrace and -0.24 for Large White. Genetic correlations of LSW with LWW and LWB ranged from 0.5 to 0.6. The genetic correlation of MWW with LWW was positive, but that with LWB was negligible. The results indicate that utilizing LWW or LWB could improve LSW efficiently, despite the antagonistic genetic correlation between LSW and MWW.

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This study used pedigree information and data collected from 1979 to 2012 at the Raeini Cashmere goat breeding station, located in Baft City in Kerman Province in southeastern Iran. Genetic and phenotypic parameters for early reproductive traits of breeding does, including total numbers of kids born at first kidding (LSB1), total numbers of kids weaned at first kidding (LSW1), total birth weight of all kids born at first kidding (LWB1), total weaning weight of all kids weaned at first kidding (LWW1), and age at first kidding (AFK), were estimated using a Bayesian approach via Gibbs sampling. Posterior means for heritability estimates of LSB1, LSW1, LWB1, LWW1, and AFK were statistically significant, with values of 0.12, 0.23, 0.17, 0.15, and 0.46, respectively. Low-to-moderate additive genetic variation was present for the studied reproductive traits. Estimated genetic correlations among LSB1, LSW1, LWB1, and LWW1 were statistically significant and ranged from 0.12 between LWB1 and LWW1 to 0.72 between LSB1 and LSW1. Corresponding phenotypic correlation estimates were also statistically significant and ranged from 0.04 between LWB1 and LWW1 to 0.55 between LSB1 and LSW1. Posterior means of genetic and phenotypic correlations between AFK and other studied traits were statistically significant only for LSB1 and LWB1. For LSB1, LSW1, LWB1, and LWW1, we conclude that genetic and phenotypic improvement in any of these traits in Raeini Cashmere does would favorably influence all of the other traits. However, does that first kidded at younger ages have smaller litters at birth and lower litter birth weights at their first parity.

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Genetic parameters and genetic trends for growth, reproduction, milk production and composition traits were estimated for Syrian (S) and Turkish (T) Awassi sheep and their crosses maintained at the International Center for Agricultural Research in the Dry Areas Tal Hadya station, Aleppo, Syria (now in Terbol station in Lebanon). The data were spread over 9 years. The individual breed additive effects of T were positive and significant (P0.05) for most growth traits. Crossing of T with S, however, resulted in desirable and significant (P<0.05) individual heterosis effects for all the reproduction, milk production and constituent yields. The heritability (h²) estimates, both direct and maternal, were low for BW, WW, WG and all reproductive traits indicating major influence of environmental factors, whereas milk yield and composition had medium values. Birth weight had moderate genetic correlation with WW and WG. The genetic correlation between WW and WG was high (0.724±0.951). Lambing interval had large negative genetic correlation with LWB and LWW. However, LI had medium significant correlations with all the milk production and composition traits. Larger litter weights at birth had high and negative influence on milk yield of the dam and its constituents. Genetic changes over years for all traits were non-significant. The lack of genetic change in the studied traits calls for systematic and organized selection scheme.

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A study was conducted for 22 weeks to determine the effects of concentrate supplementations at three crude protein (CP) levels, i.e. low protein diet-LPD 12.42% CP (124.93 g day-1); medium protein diet-MPD 14.18% CP (145.87 g day-1) and high protein diet-HPD 16.35% CP (168.19 g day-1) on some pregnancy variables, reproductive performance, birth types and weight of kids kidded by pregnant Kalahari Red goats grazed on Chloris gayana. Thirty-three matured Kalahari Red goats of first parity within age range of 2 to 21/2 years with an average body weight of 38.10 ± 1.13 kg were randomly allotted to the diets with 11 goats per treatment. Data obtained were subjected to analysis of variance in a completely randomised design. It was observed that goats fed HPD had the highest (p < 0.05) values for products of pregnancy (10.35 kg) taken within 24hour before kidding and foetal growth rate (88.37 g day-1) during pregnancy. Goats fed MPD had the lowest values (p < 0.05) of 9.28 kg and 80.07 g day-1 for each of the respective parameters. Afterbirth weight was also the highest and lowest (p < 0.05) for goats supplemented with HPD (3.38 kg) and MPD (3.04 kg), respectively. On the other hand, MPD-supplemented goats had the highest values (p < 0.05) for litter size (2.14) and litter weight (6.80 kg) at birth, the value which was the least for HPD supplementation. From the results obtained from this study, it could be concluded that concentrate diet supplementation with 14.18% CP improved litter size and weight at birth with resultant reduction in weights of pregnancy variables of pregnant Kalahari Red goats grazed on Rhodes grass.

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An adequate colostrum intake, in order to ensure the survival and weight gain of piglets, depends on the sow's ability to produce enough colostrum for the whole litter. The aim of this study was to evaluate factors involved in colostrum yield (CY) variability related to the sow, the litter and the farrowing process. The experiment was conducted with 96 Camborough 25(r) sows of parities one to seven, whose farrowing was spontaneous. Colostrum production of each sow was estimated by summing up the colostrum intake of each piglet in the litter, estimated by an equation that takes into account the birth weight and weight gain during the first 24h of life. The multiple regression model explained 28% of variation in CY, with 24% and 4% respectively of variation being explained by the litter birth weight and the width of the first mammary glands. Litter birth weight was positively correlated with the number of total born (r= 0.73) and born alive piglets (r= 0.83). When categorised into two groups of colostrum yield (LOWCY; ≤3.4kg; n= 46 vs HIGHCY; >3.4kg; n= 50), LOWCY sows had fewer total born and born alive piglets and lighter litters (P<0.05). The logistic regression analysis showed that sows from parities 1, 2 and >3 had greater odds (P≤0.05) of belonging to the LOWCY group than parity 3 sows. Sows with two or more obstetrical interventions had higher odds (P<0.05) of belonging to the LOWCY group than sows without interventions during farrowing. The higher colostrum yield observed in sows of parity 3 and sows with less than two obstetrical interventions during farrowing was associated with a greater number of nursed piglets. This study showed that total birth weight of born alive piglets is the most important factor involved in colostrum yield variability, indirectly representing the number of piglets nursed by the sow.(AU)

Um consumo adequado de colostro, para assegurar a sobrevivência e o ganho de peso, dos leitões, depende da capacidade da porca em produzir colostro suficiente para toda a leitegada. O objetivo deste estudo foi determinar fatores relacionados com a porca, com a leitegada ou com o parto que possam influenciar a produção de colostro (PC). O experimento foi conduzido com 96 porcas Camborough 25, de ordem de parto (OP) 1 a 7, cujo parto foi espontâneo. A produção de colostro das porcas foi estimada pela soma do consumo individual de colostro pelos leitões, o qual foi estimado por equação que considera o peso ao nascimento e o ganho de peso nas primeiras 24h de vida. Por meio de modelo de regressão múltipla, 28% da variação na PC foi explicada pelo peso da leitegada (24%) e pela largura do primeiro par de glândulas mamárias (4%). O peso da leitegada foi positivamente correlacionado com o número total de leitões nascidos (r= 0.73) e com o número de leitões nascidos vivos (r= 0.83). Quando separadas em dois grupos de PC (BAIXAPC; ≤3.4kg; n=46 e ALTAPC; >3.4kg; n=50), as porcas do grupo BAIXAPC tiveram menor número total de leitões nascidos, menor número de leitões nascidos vivos e leitegadas mais leves (P<0.05). Por regressão logística, foi observado que porcas da OP 1, 2 e >3 tiveram maior chance (P≤0.05) de pertencer ao grupo BAIXAPC do que porcas de OP 3. Porcas com duas ou mais intervenções obstétricas tiveram maior chance (P<0.05) de pertencer ao grupo BAIXAPC do que as porcas sem intervenção durante o parto. A maior PC observada nas porcas de OP 3 e nas porcas com menos intervenções obstétricas foi associada com um maior número de leitões amamentados. Foi mostrado, neste estudo, que o peso total da leitegada viva, o qual indiretamente representa o número de leitões amamentados pela porca, é o fator mais importante envolvido na produção de colostro.(AU)

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O objetivo foi avaliar a produtividade e uniformidade da produção de ratos Wistar (Rattus norvegicus) em três sistemas de acasalamento: monogâmico permanente, com um casal mantido permanentemente em cada gaiola; poligâmico permanente, com duas matrizes e um macho, mantidos permanentemente em cada gaiola; e poligâmico temporário, em que o macho foi mantido na gaiola com duas matrizes até a certificação de cada cópula e, em seguida, foi retirado, retornando após o desmame das ninhadas. Para isso, 69 fêmeas de 90 dias de idade (matrizes) foram aleatoriamente distribuídas nos três grupos. As avaliações compreenderam cinco ciclos reprodutivos por matriz. Foram obtidas ninhadas mais pesadas a desmama no sistema poligâmico temporário. Além disso, não houve mortalidade de matrizes neste sistema, o que é um indicador importante de bem estar animal. No sistema monogâmico permanente, o intervalo de tempo necessário para produzir um filhote desmamado por matriz foi menor que nos sistemas poligâmicos. Deve-se considerar, no entanto, que este sistema requer o dobro do número de gaiolas e de machos reprodutores que os poligâmicos. Portanto, o sistema poligâmico temporário pode ser recomendado nas colônias de expansão e produção de ratos Wistar, com a ressalva de que necessita de mão de obra qualificada para identificação de cópula nas matrizes e manejo de rotação dos machos.

The objective was to evaluate the productivity and production uniformity of Wistar female rats (Rattus norvegicus) submitted to three mating systems: permanent monogamous, with a couple permanently maintained in each cage, permanent polygamous, with two females and one male permanently maintained in each cage, and temporary polygamous in which a male was maintained in a cage with two females until each mating was verified and was removed afterwards, returning after both litters were weaned. For that, 69 90-days-old females were randomly assigned to three groups. The evaluations comprised five reproduction cycles per dam. Litters that were heavier at weaning were obtained in the temporary polygamous systems. In addition, dam mortality was null in this system, which is an important animal welfare indicator. In the permanent monogamous system, the interval of time required to produce one weaned pup per dam was shorter than in the polygamous systems. One should consider, however that this system requires twice as many cages and sires than the polygamous systems. Therefore, the temporary polygamous mating system may be recommended for the expansion and production Wistar rats colonies, provided that qualified personnel is available to identify copulation in breeding females and to perform male rotation.

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INTRODUCTION: Infertility is common among couples of child-bearing age and approximately half of known causes of primary infertility are attributable to male factor. It is still unclear whether the injurious effects of cigarette smoking on sperm characteristics and infertility are due to nicotine. Therefore, the present study investtigated the effects of orally administered of nicotine on sperm characteristics and libido in adult male albino rats. The study also sought nicotine effects on fertility rate, litter size and weight in female animals cohabited with nicotine treated male rats. METHODS: Forty male and twenty-five female rats were used for the study. The male rats were divided into five groups and were treated for a period of 30 days with nicotine 0.5 mg/kg (low dose) and 1.0 mg/kg (high dose) per body weight while the control rats received 0.2 ml/kg normal saline. The fourth and fifth groups were gavaged with 0.5 mg/kg and 1.0 mg/kg body weight of nicotine but were left untreated for another 30 days. These groups served as the recovery groups. At the end of each experimental period, sperm analysis, fertility study, litter weight and size were determined. RESULTS: Sperm motility and count significantly decreased (P < 0.05) while the percentage of abnormality significantly increased (P < 0.05) in both treatment groups. However, there was an insignificant decrease (P > 0.05) in the viability and semen volume of the treated groups. Fertility studies revealed that nicotine reduced libido in male rats, litter weight and number delivered by the untreated female during the experiments. CONCLUSION: The present study showed that nicotine has a dose-dependent deleterious effect on the sperm characteristics and that fertility is ameliorated by nicotine cessation in male rats.

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The genetic parameters for growth, reproductive and maternal traits in a multibreed meat sheep population were estimated by applying the Average Information Restricted Maximum Likelihood method to an animal model. Data from a flock supported by the Programa de Melhoramento Genético de Caprinos e Ovinos de Corte (GENECOC) were used. The traits studied included birth weight (BW), weaning weight (WW), slaughter weight (SW), yearling weight (YW), weight gain from birth to weaning (GBW), weight gain from weaning to slaughter (GWS), weight gain from weaning to yearling (GWY), age at first lambing (AFL), lambing interval (LI), gestation length (GL), lambing date (LD - number of days between the start of breeding season and lambing), litter weight at birth (LWB) and litter weight at weaning (LWW). The direct heritabilities were 0.35, 0.81, 0.65, 0.49, 0.20, 0.15 and 0.39 for BW, WW, SW, YW, GBW, GWS and GWY, respectively, and 0.04, 0.06, 0.10, 0.05, 0.15 and 0.11 for AFL, LI, GL, LD, LWB and LWW, respectively. Positive genetic correlations were observed among body weights. In contrast, there was a negative genetic correlation between GBW and GWS (-0.49) and GBW and GWY (-0.56). Positive genetic correlations were observed between AFL and LI, LI and GL, and LWB and LWW. These results indicate a strong maternal influence in this herd and the presence of sufficient genetic variation to allow mass selection for growth traits. Additive effects were of little importance for reproductive traits, and other strategies are necessary to improve the performance of these animals.

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We determined the polymorphism C242T of the aromatase gene (Cyp19) and its allelic frequency, as well as the effect of the variants on productive and reproductive traits in 71 purebred Santa Inês sheep, 13 purebred Brazilian Somali sheep, nine purebred Poll Dorset sheep, and 18 crossbred 1/2 Dorper sheep. The animals were genotyped using the PCR-RFLP technique. The influence of the animal's genotype on its performance or on the performance of its lambs was analyzed by the least square method. Another factor assessed was the importance of the animal's genotype in analysis models for quantitative breeding value estimates, and whether there were differences among the averages of breeding values of animals with different genotypes for this gene. In the sample studied, no AA individuals were observed; the AB and BB frequencies were 0.64 and 0.36, respectively. All Brazilian Somali sheep were of genotype BB. All 1/2 Dorper BB animals presented a lower age at first lambing, and the Santa Inês BB ewes presented a lower lambing interval. In these same genetic groups, AB ewes presented higher litter weight at weaning. This is evidence that BB ewes have a better reproductive performance phenotype, whereas AB ewes present a better maternal ability phenotype. However, in general, animals with genotype AB presented better average breeding values than those with genotype BB.

RESUMEN

The genetic parameters for growth, reproductive and maternal traits in a multibreed meat sheep population were estimated by applying the Average Information Restricted Maximum Likelihood method to an animal model. Data from a flock supported by the Programa de Melhoramento Genético de Caprinos e Ovinos de Corte (GENECOC) were used. The traits studied included birth weight (BW), weaning weight (WW), slaughter weight (SW), yearling weight (YW), weight gain from birth to weaning (GBW), weight gain from weaning to slaughter (GWS), weight gain from weaning to yearling (GWY), age at first lambing (AFL), lambing interval (LI), gestation length (GL), lambing date (LD - number of days between the start of breeding season and lambing), litter weight at birth (LWB) and litter weight at weaning (LWW). The direct heritabilities were 0.35, 0.81, 0.65, 0.49, 0.20, 0.15 and 0.39 for BW, WW, SW, YW, GBW, GWS and GWY, respectively, and 0.04, 0.06, 0.10, 0.05, 0.15 and 0.11 for AFL, LI, GL, LD, LWB and LWW, respectively. Positive genetic correlations were observed among body weights. In contrast, there was a negative genetic correlation between GBW and GWS (-0.49) and GBW and GWY (-0.56). Positive genetic correlations were observed between AFL and LI, LI and GL, and LWB and LWW. These results indicate a strong maternal influence in this herd and the presence of sufficient genetic variation to allow mass selection for growth traits. Additive effects were of little importance for reproductive traits, and other strategies are necessary to improve the performance of these animals.

RESUMEN

We determined the polymorphism C242T of the aromatase gene (Cyp19) and its allelic frequency, as well as the effect of the variants on productive and reproductive traits in 71 purebred Santa Inês sheep, 13 purebred Brazilian Somali sheep, nine purebred Poll Dorset sheep, and 18 crossbred 1/2 Dorper sheep. The animals were genotyped using the PCR-RFLP technique. The influence of the animal's genotype on its performance or on the performance of its lambs was analyzed by the least square method. Another factor assessed was the importance of the animal's genotype in analysis models for quantitative breeding value estimates, and whether there were differences among the averages of breeding values of animals with different genotypes for this gene. In the sample studied, no AA individuals were observed; the AB and BB frequencies were 0.64 and 0.36, respectively. All Brazilian Somali sheep were of genotype BB. All 1/2 Dorper BB animals presented a lower age at first lambing, and the Santa Inês BB ewes presented a lower lambing interval. In these same genetic groups, AB ewes presented higher litter weight at weaning. This is evidence that BB ewes have a better reproductive performance phenotype, whereas AB ewes present a better maternal ability phenotype. However, in general, animals with genotype AB presented better average breeding values than those with genotype BB.

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