Population genetic structure of Santa Inês sheep in Brazil

This study aimed to describe the population genetic structure and evaluate the state of conservation of the genetic variability of Santa Inês sheep in Brazil. We used pedigree data of the Santa Inês breed available in electronic processing of the Brazilian Association of Sheep Breeders. A file with 20,206 records, which enabled the calculation of the genetic conservation index (GCI), individual inbreeding coefficient (F), change in inbreeding (ΔF), effective population size (Ne), effective number of founders (?_e), effective number of ancestors (?_ɑ), generation interval (L), average relatedness coefficient of each individual (AR), and Wright’s F-statistics (F _IT, F _IS, and F _ST). For pedigree analysis and calculation of population parameters, the program ENDOG was used. The average inbreeding coefficient (\( \overline{F} \)) was 0.97% and the mean average relatedness (\( \overline{\mathrm{AR}} \)) 0.49%. The effective numbers of founders and ancestors were, respectively, 199 and 161. The average values of F and AR increased significantly over the years. The effective population size fluctuated over the years concurrently to oscillations in inbreeding rates, wherein N _e reached just 68 in the year 2012. The mean average generation interval was 5.3 years. The Santa Inês breed in Brazil is under genetic drift process, with loss of genetic variation. It requires the implementation of a genetic management plan in the herd, for conservation and improvement of the breed.     

Methane emission of Santa Inês sheep fed cottonseed by-products containing different levels of gossypol

The aim of this study was to evaluate the methane (CH₄) emission of Santa Inês sheep fed cottonseed by-products, verifying if the gossypol content of these feedstuffs affects CH₄ emission. Twelve late-lactating Santa Inês sheep (44.8?±?7.5 kg body weight (BW)) were allocated in metabolic cages for an experimental period of 19 days, 14 days for adaptation and 5 days for measuring CH₄ emission and dry matter intake (DMI). The animals were divided into four treatments, established in accordance with the cottonseed by-product used in concentrate formulation: Control (CON - no cottonseed by-product), Whole cottonseed (WCS), Cottonseed cake (CSC), and Cottonseed meal (CSM). The free gossypol level of the concentrates were 0, 1,276, 350, and 190 ppm for CON, WCS, CSC, and CSM, respectively. Also, the animals received Cynodon dactylon cv. Coast Cross hay, water, and mineral salt ad libitum. The ether extract content of the diets was balanced between treatments by including soybean oil in concentrates. The technique used to measure the CH₄ emission was the sulfur hexafluoride (SF₆) tracer technique, and the gas samples collected were quantified by analysis in gas chromatography system. The CH₄ emission was evaluated considering the daily emission (g CH₄/day); DMI (g CH₄/kg DMI); and BW (g CH₄/kg BW). No statistical difference was found (P?>?0.05) between treatments for DMI and CH₄ parameters. In the regression analysis, no significant relation (P?>?0.05) between gossypol content and CH₄ emission was observed. These results suggest that gossypol does not affect rumen methanogenesis.     

Mineral requirements for weight gain in growing male Santa Inês and Morada Nova hair sheep

This study estimated the net macro and micromineral requirement from the 48 male uncastrated lambs (24 growing male Santa Inês and 24 growing male Morada Nova hair sheep), with initial weights of 21.7 ± 1.2 kg and 20.8 ± 0.8 kg using the comparative slaughter method. The experimental diet consisted of 30% forage (Buffel—Cenchrus ciliaris (L) hay) and 70% concentrate (corn grain 43.5%, soybean meal 22.0%, vegetable oil 3.0% and mineral supplement 1.5%). The experimental design was a completely randomized with two breeds, four weights, and six replicate. Mineral requirements sufficient to promote weight gain in Santa Inês sheep ranged from 1.75 to 1.03 g Ca, 1.01 to 0.61 g of P, 0.38 to 0.21 g of K, 0.38 to 0.16 of Na, 0.10 to 0.06 Mg, 28.5 to 16.0 mg of Fe, 6.14 to 3.22 mg of Cu, and Zn 23.0 to 14.0 mg/kg per unit of empty body weight (EBW) gain. In the Morada Nova breed, the requirements ranged from 1.96 to 0.84 g of Ca, 1.15 to 0.46 of P, 0.39 to 0.19 of K, 0.28 to 0.13 of Na, 0.10 to 0.05 Mg, 26.2 to 12.9 mg of Fe, 5.59 to 2.46 Cu, and Zn 23.6 to 10.3 mg/kg of EBW gain. Mineral requirements varied mainly in accordance with the proportion of bone mass and fat concentration in the carcass, which were influenced by the slaughter weight of the animals, and therefore should be used in the formulation of dietary mineral supplements.     

Is the Santa Inês sheep a typical non-seasonal breeder in the Brazilian Southeast?

This study aimed to characterize the annual reproductive cycle of Santa Inês sheep in the Fluminense lowland region (latitude 22° 27′ 45″ south, Rio de Janeiro, Brazil) between September 2011 and August 2012. Ten ewes were maintained in a semi-intensive system under natural photoperiods with access to pasture and shelter. Blood samples were collected every 2 weeks to determine plasma progesterone concentrations. The body condition score (BCS) was determined each month. There was no seasonal variation in the plasma progesterone concentration from the months of September to January, April, and May to August. In the months of February and April, the plasma hormone levels were higher than August to November. Seventy percent (7/10) of the sheep studied had short seasonal anestrus. The periods of anestrus were concentrated between the months of September and December (spring season) in 85.7 % (6/7) of the cases evaluated. In these cases, 57.1 % (4/7) also had short periods of reproductive inactivity during other months of the year. The progesterone values obtained in the spring corroborate the higher reproductive anestrus observed in this season. Higher plasma progesterone values were found in summer and autumn with reduction in the winter to lower values in the spring. No changes in the BCS during the study period were observed. Under the studied conditions, the Santa Inês sheep showed a low degree of reproductive seasonality. However, some individual ewes had seasonal anestrus during the spring. Further studies that include management techniques are needed to improve reproductive efficiency without hormone therapy in this breed under tropical conditions.     

Replacement levels of elephant grass by moist pineapple by-product silage in diets of Santa Inês crossbred sheep: performance and digestibility

The present study evaluated the effect of replacing elephant grass (EG) with moist pineapple by-product silage (PS) on the apparent digestibility, consumption of digestible nutrients and performance of 25 castrated male lambs Santa Ines crossbreds. The lambs had an initial body weight of 20.2?±?3.5 kg and were housed in individual pens in a completely randomised design with five treatments (replacement of EG by PS at five proportions of 0, 25, 50, 75 and 100 %) and five replicates during 74 days. There was no significant effect of PS replacement proportions on the intake of dry matter (DM), organic matter (OM), total carbohydrates (TC), non-fibrous carbohydrates or total digestible nutrients (TDN). The consumption of crude protein (CP) decreased linearly with the inclusion of PS in the diets. The digestibility of DM, OM and TCs as well as levels of TDN increased linearly with the addition of PS. The use of PS in the diets had no significant effect on the digestibility of CP and neutral detergent fibre corrected for ashes and protein (NDFom(n)). These results demonstrated that there was no difference in the performance of animals fed diets with or without PS.     

Genomic regions and pathways associated with gastrointestinal parasites resistance in Santa Inês breed adapted to tropical climate

Background: The aim of this study was to estimate variance components and to identify genomic regions and pathways associated with resistance to gastrointestinal parasites, particularly Haemonchus contortus, in a breed of sheep adapted to tropical climate. Phenotypes evaluations were performed to verify resistance to gastrointestinal parasites, and were divided into two categories: i) farm phenotypes, assessing body condition score(BCS), degree of anemia assessed by the famacha chart(FAM), fur score(FS) and feces consistency(FC); and ii) lab phenotypes,comprising blood analyses for hematocrit(HCT), white blood cell count(WBC), red blood cell count(RBC),hemoglobin(HGB), platelets(PLT) and transformed(log10) egg per gram of feces(EPG_(log)). A total of 576 animals were genotyped with the Ovine SNP12k Bead Chip(Illumina, Inc.), that contains 12,785 bialleleic SNP markers. The variance components were estimated using a single trait model by single step genomic BLUP procedure.Results: The overall linkage disequilibrium(LD) mean between pairs of markers measured by r2 was 0.23. The overall LD mean between markers considering windows up to 10 Mb was 0.07. The mean LD between adjacent SNPs across autosomes ranged from 0.02 to 0.10. Heritability estimates were low for EPG_(log)(0.11), moderate for RBC(0.18), PLT(0.17) HCT(0.20), HGB(0.16) and WBC(0.22), and high for FAM(0.35). A total of 22, 21, 23, 20, 26, 25 and 23 windows for EPG_(log)for FAM, WBC, RBC, PLT, HCT and HGB traits were identified, respectively. Among the associated windows, 10 were shown to be common to HCT and HGB traits on OAR1, OAR2, OAR3, OAR5, OAR8 and OAR15.Conclusion: The traits indicating gastrointestinal parasites resistance presented an adequate genetic variability to respond to selection in Santa Inês breed, and it is expected a higher genetic gain for FAM trait when compared to the others. The level of LD estimated for markers separated by less than 1 Mb indicated that the Ovine SNP12k Bead Chip might be a suitable tool for identifying genomic regions associated with traits related to gastrointestinal parasite resistance. Several candidate genes related to immune system development and activation, inflammatory response,regulation of lymphocytes and leukocytes proliferation were found. These genes may help in the selection of animals with higher resistance to parasites.     

Fatty acid,chemical, and tissue composition of meat comparing Santa Inês breed sheep and Boer crossbreed goats submitted to different supplementation strategies

Tropical Animal Health and Production - To compare the fatty acid (FA) composition, and chemical and tissue composition of meat, 24 uncastrated males, 12 sheep of the Santa Inês breed, and 12...     

Multivariate analysis of heat tolerance characteristics in Santa Inês and crossbred lambs in the Federal District of Brazil

Heat tolerance is an important trait for deciding on which genetic resource to use on farms in tropical regions. Three genetic groups of lambs were evaluated by physical and physiological parameters related to adaptation and multivariate analyses used to test if these traits were efficient in separating the genetic groups and which traits were more important in this separation. Crossbred lambs were more similar to each other than to Santa Inês, in general; but individually there was an overlap between Ile de France and Santa Inês lambs. Size traits had higher canonical correlation with physiological variables, while rectal temperature, heart rate, and hemoglobin were more highly correlated with physical traits. Error rates using only physiological traits were high, suggesting that these are inefficient in separating groups of lambs for heat tolerance, while separation with physical traits was more efficient.     

The effect of estrus synchronization treatments on somatic cell count of transitional-anestrus Awassi ewes’ milk

Fifty-three transitional-anestrus Awassi ewes, randomly assigned to three groups: fluorogestone acetate (FGA, n = 18), FGA-Prostaglandin (FGA-PGF, n = 18) and control (n = 17), were used to examine the effect of estrus synchronization protocols and steroid hormones concentrations on milk somatic cell count (SCC). Intravaginal FGA sponge was inserted for 13 days and 600 IU equine chorionic gonadotropin was administered for ewes of FGA and FGA-PGF groups at the time of sponge removal (day 0). In addition, 10 mg was administered to ewes of FGA-PGF group on day 0. Blood and milk samples were collected from all ewes on days -13, -6, 0, 1, 2, 7 and 14. Estradiol had significant positive correlation with the SCC during the periods of sponge insertion (P = 0.015, r = 0.235) and within two days (P = 0.063 r = 0.23) after sponge removal with no correlation with SCC of both udder halves during the luteal phase. Progesterone concentrations, on the other hand, had a significant positive correlation (P < 0.001; r = 0.420) with the SCC of both udder halves during the luteal phase of the experiment, but not during the periods of sponge insertion and expected estrus. SCC returned under the influence of endogenous progesterone on days 7 and 14 to pre-synchronization values. In conclusion, sheep milk SCC is affected significantly with induction of estrus and steroid hormones concentrations. However, peak SCC recorded during estrus was far below the upper limit of the current standard for normal milk. With the current standards for SCC of 1,000,000/ml as legal limit for abnormal milk control programs in sheep, estrus synchronization programs and the estrus status should not be considered when bulk-tank milk SCC is being investigated, but should be considered during the process of setting new standards.     

Influence of drinking water salinity on carcass characteristics and meat quality of Santa Inês lambs

This study aimed to evaluate the effects of different salinity levels in drinking water on the quantitative and qualitative characteristics of lamb carcass and meat. Ram lambs (n = 32) were distributed in a completely randomized design with four levels of salinity in the drinking water (640 mg of total dissolved solids (TDS)/L of water, 3188 mg TDS/L water, 5740 mg TDS/L water, and 8326 mg TDS/L water). After slaughter, blending, gutting, and skinning the carcass, hot and biological carcass yields were obtained. Then, the carcasses were cooled at 5 °C for 24 h, and then, the morphometric measurements and the cold carcass yield were determined and the commercial cuts made. In the Longissimus lumborum muscle color, water holding capacity, cooking loss, shear force, and chemical composition were determined. The yields of hot and cold carcass (46.10 and 44.90%), as well as losses to cooling (2.40%) were not affected (P > 0.05) by the salinity levels in the water ingested by the lambs. The meat shear force was 3.47 kg/cm² and moisture, crude protein, ether extract, and ash were 73.62, 22.77, 2.5, and 4.3%, respectively. It is possible to supply water with salinity levels of up to 8326 mg TDS/L, because it did not affect the carcass and meat characteristics of Santa Inês lambs.     

Tissue composition and allometric growth of carcass of lambs Santa Inês and crossbreed with breed Dorper

Tropical Animal Health and Production - This study aimed to assess the tissue composition and allometric growth of carcasses of Santa Inês and crossbred Dorper x Santa Inês lambs confined...     

The effect of sex and genotype on growth performance,feed efficiency,and carcass traits of local sheep group Pantaneiro and Texel or Santa Inês crossbred finished on feedlot

This study aimed to assess and compare the growth performance, feed efficiency, and carcass traits of Pantaneiro sheep and their Texel and Santa Inês crossbreds. Ninety-six lambs, fifty-one males, and forty-five females, with a mean weaning weight of 15.21?±?1.25 kg and 78?±?13 days of age, were slaughtered at a 32-kg body weight. The results showed better production efficiency from males compared with females. Texel-crossed lambs had a better growth performance than the other genotypes. The Texel?×?Pantaneiro lambs were more efficient with a better feedlot performance, higher ribeye muscle area, and better carcass characteristics with an adequate amount of fat cover. Pantaneiro lambs and their crosses with meat breeds could be useful in meat production systems under Savanna environmental conditions.     

Effect of Brazilian red propolis administration on hematological, biochemical variables and parasitic response of Santa Inês ewes during and after flushing period

Brazilian red propolis was administered orally to Santa Inês ewes, and evaluation was made of general health and hematological, biochemical, and parasitic responses during and after flushing. Thirty mature, nonlactating, nonpregnant Santa Inês ewes (40?±?2 kg and 2.5 years old) were grazing tropical pasture (Brachiaria decumbens and Pennisetum purpureum) and, as flushing after synchronization, were supplemented with a concentrate–roughage mixture at a rate of 4 % body weight (BW). Ewes were divided according to BW and fecal egg count (FEC) into two groups (n?=?15 each): control and propolis that received propolis ethanolic extract at rates of, respectively, 0 and 3 g/ewe/day. The treatments lasted 21 days until the end of flushing period. BW and body condition score (BCS) were recorded, and blood and fecal samples were taken weekly for 8 weeks. Mean values of BW and BCS were not (P?>?0.05) affected by propolis administration. Propolis increased (P?<?0.01) total leukocytes (WBC), but no significant differences were observed for other hematological parameters. Propolis increased (P?<?0.01) total protein and globulin concentrations and decreased (P?<?0.01) triglycerides, glutamate oxaloacetate transaminase, and glutamate pyruvate transaminase. Propolis decreased (P?<?0.05) FEC. Propolis administration had good impact on ewe health and may be a promising feed additive during critical periods such as flushing.     

Dietary supplementation for Santa Inês hair ewes on pasture at pre- and postpartum periods: dry matter intake,digestibility, milk production,and mineral metabolism

The aim of this study was to evaluate the impact of different levels of dietary supplementation and reproductive stages on dry matter intake, digestibility, milk production, and mineral metabolism in Santa Inês hair ewes. Two dietary supplement levels of 0.5 and 1.5%, based on body weight, were used. A total of 12 hair ewes (six subjected to 0.5 and six subjected to 1.5% of concentrate supplementation based on body weight—BW) of the Santa Inês breed were evaluated in a completely randomized design with fixed effects of supplementation level, period, and its interactions. Dry matter intake, digestibility, milk production, and mineral metabolism (calcium (Ca), phosphorus (P), magnesium (Mg), alkaline phosphatase (ALP), type I insulin-like growth factor (IGF-I), parathyroid hormone (PTH), and osteocalcin (OC)) were assessed. Dry matter digestibility was affected by the supplementation level (during both pregnancy and lactation), with higher values in ewes fed at a level of 1.5% of BW. A significant interaction between treatment × reproductive stages was found for the Mg concentration. A period effect (P?<?0.05) on serum concentrations of P, Ca/P, Mg, and IGF-I was observed. Serum P concentrations were influenced (P?<?0.05) by treatments and reproductive stages. There were significant differences in the Ca/P ratio among the reproductive stages. The enzymatic activity of ALP and serum IGFI differed among reproductive stages. Ewes supplemented at a level of 1.5% of BW produced 18.5% more milk than ewes supplemented at a level of 0.5% of BW. The use of 0.5% of body weight in concentrate supplementation is recommended for the reduction of production costs, without having an effect on the mineral metabolism of Santa Inês hair ewes.