A study on the genetic and phenotypic factors affecting specific ewe productivity traits in Sangsari sheep.

The study's objectives were to assess the genetic parameters of reproductive characteristics in Sangsari sheep. A data set of reproductive information with pedigree details from 1995 to 2016 was used. Studied traits were litter size at birth (LSB), litter size at weaning (LSW), litter mean weight per lamb born (LMWLB), litter mean weight per lamb weaned (LMWLW), total litter weight at birth (TLWB) and total litter weight at weaning (TLWW). Test significance of the environmental factors to be included in the model was conducted using the general linear model procedure of the SAS program. All traits were significantly affected by the year of lambing and ewe age at lambing (P < 0.01). The AI-REML procedure of the Wombat program was used to evaluate genetic parameters. A series of bivariate animal models were employed to calculate genetic (rg) and phenotypic (rp) correlations between traits. The total least square means ± standard error of LSB and LSW were 1.04 ± 0.05 and 0.96 ± 0.03, while LMWLB, LMWLW, TLWB, and TLWW were 3.12 ± 0.08, 15.40 ± 0.13, 3.28 ± 0.04, and 19.31 ± 0.16 kg, respectively. The estimates of h2 were relatively low (P < 0.01) and ranged from 0.063 ± 0.028 for LSW to 0.181 ± 0.063 for TLWW. Repeatability estimates varied from 0.101 for LSW to 0.241 for TLWW. The sire service effects for LMWLB, TLWB, and TLWW were 0.012 ± 0.004, 0.023 ± 0.006, and 0.039 ± 0.009, respectively. The traits studied showed a greater magnitude of genetic correlation than phenotypic correlation, with values ranging from - 0.59 (LSB-LMWLB) to 0.87 (LMWLB-TLWB). It appears that focusing on TLWW for selection could result in more significant improvements in the reproductive performance of Sangsari ewes.

Detection of putative loci affecting milk yield in Turkish Awassi sheep using microsatellite markers.

On the basis of comparisons between bovine and ovine genome mapping information, the aim of the study was to analyze the genetic diversity of selected DNA microsatellites from the bovine genome and to investigate their correlation with the average daily milk yield in Awassi sheep. 18 informative microsatellite markers were selected from the significant QTL regions affecting milk yield identified in the bovine genome in previous studies. The selected microsatellite markers were then amplified by PCR as reciprocal amplifications on the genomic DNA of Awassi sheep, with standard daily milk yield records. Thus, in this study, 18 microsatellite markers associated with milk yield in the bovine genome were examined for both determination of genetic polymorphism within the flock and the effects of marker loci on average daily milk yield in Awassi sheep. Allele frequencies of markers were determined based on the results of fragment analysis. The analysis of variance showed that the 123 bp allele at the marker locus BMS1341 on BTA2 significantly influenced the average daily milk yield of Ivesi sheep (P < 0.01). On the other hand, the BMS381 locus with a 115 bp allele on BTA2, the MCM140 locus with a 185 bp allele on BTA6, the BMS2721 locus with a 155 bp allele, the BM1237 locus with 174 and 180 bp alleles on BTA7, and finally, the BMS1967 locus with a 117 bp allele, the BM4208 locus with 176 and 182 bp alleles, and the INRA locus with a185 bp allele on BTA8 showed moderately significant effects on the average daily milk yield of Ivesi ewes (P < 0.05).

The effect of Vachellia eriolaba leaf meal inclusion on growth performance, blood parameters and methane gas emission in lambs fed diets containing ammoniated maize stover.

The study evaluated the effect of Vachellia erioloba leaf meal in diets containing ammoniated maize stove on growth performance, methane emission and heath of growing lambs. Thirty-two female lambs were allocated to the following four dietary treatments: total mixed ration (TMR, control), 20% inclusion of untreated maize stover (UMS), 20% inclusion of ammoniated maize stover (AMS), and combined inclusion of 10% ammoniated maize stover and 10% Vachellia erioloba leaves (AMSVL). Each treatment was replicated 8 times and a lamb in an individual pen was regarded as an experimental unit in a completely randomized design. Feed intake was higher (P < 0.05) in lambs fed the AMS and AMSVL diets compared to those fed UMS. Final body weights were higher in lambs fed the AMS and AMSVL diets. Both average daily gain (ADG) and feed convention ratio (FCR) were not affected by diet. In comparison with the AMS and AMSVL diets, the lambs fed the UMS diet had the highest (P < 0.05) methane emission. Overall, lambs fed the control diets had the lowest (P < 0.05) methane gas emission. Blood hematological values were affected by diet with the AMSVL fed lambs having the highest (P < 0.05) mean platelet volume (MPV) and procalcitonin (PCT) values. Furthermore, total albumin, amylase and total bilirubin were the highest (P < 0.05) in lambs fed on the AMSVL diet. Lambs fed on AMS diet had the highest (P < 0.05) serum urea levels. It can be concluded that combined inclusion of ammoniated maize stover and Vachellia leaves improved feed value and lamb performance when compared to the individual inclusion of both UMS and AMS.

Effect of replacing Tifton 85 hay with Moringa hay (Moringa oleifera L.) on the nutrient metabolism, metabolic profile, and water balance of sheep.

This study aimed to evaluate the effect of replacing Tifton 85 hay (TH) with Moringa hay (MH) on the intake, apparent digestibility, ingestive behaviour, rumen parameters, serum attributes, nitrogen balance, water balance, and urinary attributes of sheep. Thus, 5 rams, ½ Dorper + ½ Santa Inês, that were 12 ± 4 months of age with an initial body weight of 32.8 ± 2.6 kg were distributed in metabolic cages in a Latin square design. The experiment lasted 85 days and was divided into five 17-day periods. The animals received rations with increasing replacement (0, 100, 200, 300, or 400 g/kg of dry matter in the total diet) of TH for MH. The forage: concentrate ratio of the diets was 40:60. Replacing TH with MH reduced (P < 0.05) the intake of organic matter, crude protein, neutral detergent fibre (NDFap), and total digestible nutrients by sheep. The apparent digestibility of NDFap and the feeding and rumination efficiencies of NDFap were reduced (P < 0.05) when MH replaced TH in the animals' diet. This replacement did not influence (P > 0.05) serum urea, total protein, creatinine, or aspartate aminotransferase in sheep. Replacing TH with MH decreased water intake and excretion (P < 0.05). In addition, nitrogen excretion via urine, urinary creatinine, and nitrogen absorption decreased (P < 0.05) when TH was replaced with MH. However, there was an increase in the sheep's nitrogen retention and urine pH. We recommend replacing 30% TH with MH in the diet of lambs because it does not compromise nutrient metabolism.

Evaluation of performance and estimation of genetic parameters for milk yield and reproductive traits in Awassi and Asaf sheep breeds and crosses in the Palestinian territory.

This study aimed to estimate genetic parameters, including heritability and repeatability, for milk yield and prolificacy in sheep. It included 3682 records from 1837 ewes across various breeds: Awassi, Assaf, and Awassi x Assaf crosses, two Awassi lines: Improved Awassi, AFEC Awassi. The study measured total milk yield (TMY), yield up to 120 days (TMY120), and yield up to 150 days (TMY150), alongside reproductive traits: litter size (LS), number of lambs born alive (NLBA), and lambing interval (LI). The analysis utilized a mixed model and the REML procedure to estimate genetic parameters. Results indicated that litter size (LS) had no significant impact on milk traits, whereas breed, location, ewe parity, and lambing season showed significant effects. Lactation length also significantly influenced TMY. For reproductive traits, treatment was significant for NLBA, with location associated with breed, parity, and season affecting all traits. Heritability estimates for TMY ranged from 0.00 in Awassi x Assaf crosses to 0.11 in Awassi, and for TMY120 and TMY150, from 0.00 in Awassi x Assaf crosses to 0.16 in Awassi. Estimates for LS and NLBA varied similarly. The heritability for LI was 0.03 in Awassi and zero in other breeds and crosses. The findings suggest that in the northern West Bank regions of Nablus and Jenin, Assaf or Awassi x Assaf breeds are preferable. The study underscores the importance of comprehensive performance and pedigree recording for effective sheep farm management.

Effects of drinking saline water on carcass traits and meat quality of growing and mature Blackhead Ogaden sheep and Somali goats.

Water salinity has a significant impact on water quality, posing challenges for livestock production and productivity, particularly in arid regions where climate change affects freshwater availability. This study aimed to determine the effect of drinking saline water on the carcass and meat quality traits of sheep and goats in Ethiopia. A total of 100 males with an average initial body weight of growing (18.17 ± 0.51) and mature (22.22 ± 0.52 kg) Blackhead Ogaden sheep and growing (17.99 ± 0.50) and mature (21.99 ± 0.54) kg) Somali goats were used. The design of the experiment was a three-way factorial RCBD with three-factor combinations (5 treatment levels, 2 species, and 2 age groups).Water treatments were natural water (Lake Basaka water (control), low saline water (L-SW), moderate saline water (M-SW), high saline water (H-SW), and very high saline water (VH-SW); that is, NaCl was added to natural water at concentrations of 7.95, 11.93, 15.90, and 19.88 g TDS/L, respectively. The finding showed that increasing salinity levels in drinking water reduced slaughter body weight (SBW), carcass weight (CW), dressing percentage (DP), rib eye area (RAE), total edible components (TEC), and increased total non-edible components (TNEC) (P < 0.05). Similarly, sheep and mature animals had higher (P < 0.001) SBW, CW, DP, RAE, and TEC than goats and growing animals. Sensory evaluation, shear force, and proximate analysis were affected by water salinity, species, and age groups (P < 0.05). Overall, the study revealed that consuming saline water above 11 g TDS/L affected carcass traits and meat quality in Somali goats and Blackhead Ogaden sheep.

Effects of chickpea grain feeding on the growth and carcass features of growing lambs.

An investigation was conducted to find out how diet formulation of chickpea grains (CHPE) rather than soybean meal and barely grain affected the performance, blood metabolites, carcass, and meat quality features of Awassi lambs. Thirty lambs, with an average age of 73 ± 0.85 days and an initial body weight of 21.0 ± 1.29 kg, were randomly assigned into one of three diets, with 10 lambs per treatment diet. The diets were designed to replace a portion of the barley grain and soybean meal and included no CHPE (CON), 7.5% CHPE (CHPE7.5), and 15% CHPE (CHPE15). Lambs were individually housed, fed every day, and weighed every two weeks to measure performance characteristics over the 60-day study period. Four lambs per treatment were chosen at random on day 42 to participate in an N balance study and assess diet digestibility. All lambs were slaughtered at the termination of the trial period to measure the features of the carcass characteristics and meat quality. As the amount of CHPE included in the diets increased, the cost of diets reduced. As the amount of CHPE in the diets increased, so did the intake of ether extract (EE). The CON group's cost per kilogram of increase was higher (P = 0.017) than that of the CHPE7.5 and CHEP15 groups. The digestibility of EE was higher (P = 0.024) in the CHPE15 diet as opposed to the CHPE7.5 and CON diets. The various treatments did not impact blood metabolites, carcass features, or meat quality. Therefore, the present study suggested that chickpeas might be added to the diets of finishing lambs up to 15% of dry matter.

Optimising Laparoscopic Artificial Insemination in Lohi Sheep: Effects of Timing, Sperm Concentration and Body Condition on Fertility Outcome in Subtropical Climates.

The objective of this study was to determine the optimal timing, sperm concentration, and body condition score (BCS) for laparoscopic artificial insemination (LAI) in the subtropical Lohi sheep breed. In Experiment 1, Lohi ewes (n = 80) were synchronised through progestin-sponges (day 0-day 11), administering PGF2α (d-cloprostenol 75 µg/mL; i.m. @ 75 µg /ewe) on day 09 and eCG (i.m. @ 300 IU/ewe) on day 11. Ewes were divided equally into four groups (n = 20 each) and then LAI was performed at 48 (T48), 60 (T60), 72 (T72) and 96 (T96) hours post-sponge removal using 200 million sperm/insemination. In Experiment 2, ewes (n = 81) were synchronised as in Experiment I. Following synchronisation ewes were divided into four groups, each subjected to LAI employing varying sperm concentrations: 10 (S10; n = 21), 20 (S20; n = 20), 50 (S50; n = 20), or 100 (S100; n = 20) million per insemination. Inseminations were performed within a time window of 48-60 h post-sponge removal, based on the findings from Experiment 1. In both experiments ewes were categorised according to BCS, that is, medium 3 and high > 3. Results of Experiment 1 revealed a quadratic response that ewes inseminated at 60-h post-sponge removal exhibited significantly higher pregnancy and twinning rates (p = 0.02). The results of Experiment 2 revealed that sperm concentration had a quadratic effect, 50 million sperm per insemination resulted in maximal pregnancy rates (p = 0.01). Additionally, ewes with medium BCS (≤ 3) had higher pregnancy rates than high BCS (> 3) ewes. In conclusion, ewes with medium BCS (≤ 3) are ideal candidate for LAI and can be inseminated at 60 h with minimal sperm 50 × 106/dose post-sponge removal to achieve a maximum pregnancy rate.

The use of infrared thermography as an indicator of methane production in hair sheep.

Infrared thermography may be an alternative technology for measuring the amount of CH4 produced and has the advantages of low cost, speed and efficiency in obtaining results. The study's objective was to determine if the infrared thermography is adequate for predicting the emission of CH4 in hair sheep and the best time after feeding to carry out the measurement. Twelve Santa Inês lambs (females, non-pregnant, with twelve months old and mean body weight of 39.3 ± 2.1 kg) remained for two days in respirometric chambers, in a semi-closed system, to determine the CH4 production. The animals were divided into two treatments, according to the diet provided. During this period, seven thermographic photographs were taken, at times - 1 h, -0.5 h, 0 h, 0.5 h, 1 h, 2 h, 3 h, 5 h, and 7 h, according to the feeding time, defined as 0 h. CH4 production was measured over 24 h. Thermographic images measured the maximum, minimum, average and point temperatures at the left and right flanks. The temperature difference between the left and right flanks (left minus right) was calculated each time. Pearson correlation coefficients, multiple regression and principal component analysis were carried out in SAS®. The best prediction of emission intensity of CH4 (kg of CH4 per dry matter intake) was obtained at 3 h after feeding: CH4/DMI = 13.9016-0,38673 * DifP2 + 3.39089 * DifMed2 (R² = 0.48), using the difference between left and right flanks for point and average temperature measures. Therefore, infrared thermography can be used as an indicator of CH4 production in hair sheep three hours after feeding.

Comparative study of the reproductive and growth performance of the Hamra and Rumbi ovine breeds.

Growth and reproductive performance traits are important economic indicators for analyzing the overall performance of breeding systems. This study aims to evaluate the comparative performance of two Algerian sheep (Rumbi and Hamra) in terms of growth and reproductive performance, and the effect of factors such as breed, season of birth, mode of birth and age of the mother on this performance in a semi-intensive breeding system. The reproductive performance of 577 Rumbi ewes and 1328 Hamra ewes bred at the Tiaret and Saïda experimental stations respectively, was analyzed using performance monitoring data. Fertility rates for the Rumbi and Hamra breeds of 87.14% and 78.8% respectively were practically similar (p > 0,05). Litter size at birth and weaning was significantly higher in the Hamra breed than in the Rumbi breed (p < 0,05). Weaning mortality was significantly higher in the Hamra breed than in the Rumbi breed, with an average of 22.60% versus 14.94% (p < 0,05). The effect of factors showed that there was a highly significant effect of the mother's age and season of birth on the reproductive performance of the Hamra and Rumbi breeds with a p < 0.0001 on fertility, litter size at birth, litter size at weaning and fertility. There was a significant effect of the year factor on reproductive performance with p = 0,013 for the Hamra breed and p = 0,031 for the Rumbi breed. The results of this study showed that Rumbi lambs were heavier at birth than Hamra lambs. The values observed were 4,86 kg versus 3,10 kg for the Hamra breed, with a highly significant difference (p < 0,0001), so that the average daily pre-weaning weight gains of Rumbi lambs were higher than those of Hamra lambs, at 0,195 kg/day versus 0,113 kg/day for Hamra lambs, with a high significance (p < 0,0001). The effect of factors showed that there was a significant effect of the mother's age on the ADGs (0-30), (30-70) and (70-90) of the Hamra and Rumbi breeds with a p = 0,034 and p = 0,02 respectively. There was also a highly significant effect of the birth mode effect on ADGs (0-30), (30-70) and (70-90) only for the Hamra breed with a p = 0,004. The effect of the birth weight on ADGs was not significant for both Hamra and Rumbi breeds with a p > 0,05. According to the findings of this study, the Hamra breed had superior reproductive potential and the Rumbi breed had superior growth. The Hamra breed showed better maternal skills in terms of fertility and prolificacy, while the Rumbi breed showed better lamb growth performance. Consequently, these results could be used for selective sheep breeding, taking into account the random effects of the environment and the potential of each breed.

Comparison of machine learning algorithms and multiple linear regression for live weight estimation of Akkaraman lambs.

This study was designed to predict the post-weaning weights of Akkaraman lambs reared on different farms using multiple linear regression and machine learning algorithms. The effect of factors the age of the dam, gender, type of lambing, enterprise, type of flock, birth weight, and weaning weight was analyzed. The data was collected from a total of 25,316 Akkaraman lambs raised at multiple farms in the Çiftlik District of Nigde province. Comparative analysis was conducted by using multiple linear regression, Random Forest, Support Vector Machines (and Support Vector Regression), Extreme Gradient Boosting (XGBoost) (and Gradient Boosting), Bayesian Regularized Neural Network, Radial Basis Function Neural Network, Classification and Regression Trees, Exhaustive Chi-squared Automatic Interaction Detection (and Chi-squared Automatic Interaction Detection), and Multivariate Adaptive Regression Splines algorithms. In this study, the test dataset was divided into five layers using the K-fold cross-validation method. The performance of models was compared using performance criteria such as Adjusted R-squared (Adj-[Formula: see text]), Root Mean Square Error (RMSE), Mean Absolute Deviation (MAD), and Mean Absolute Percentage Error (MAPE) by utilizing test populations in the predicted models. Additionally, the presence of low standard deviations for these criteria indicates the absence of an overfitting problem. [Formula: see text]The comparison results showed the Random Forest algorithm had the best predictive performance compared to other algorithms with Adj-[Formula: see text], RMSE, MAD, and MAPE values of 0.75, 3.683, 2.876, and 10.112, respectively. In conclusion, the results obtained through Multiple Linear Regression for the live weights of Akkaraman lambs were less accurate than the results obtained through artificial neural network analysis.

Investigating the chemical composition, digestion and fermentation of Alternanthera sessilis red plant and its effect on the performance of fattening lambs.

The present experiment was conducted to evaluate the nutritional value of red Alternanthera sessilis for fattening lambs when they were replaced with alfalfa forage. Forty growing lambs with an average weight of 21.12 kg and an age of 5 months were randomly assigned to four experimental treatments. Growth performance, nutrient digestibility, rumen fermentation parameters, protozoa population, blood parameters, and composition of carcass components were evaluated. The results of this experiment showed that the use of Alternanthera sessilis in the diet significantly reduced feed intake, increased the average daily weight gain, and improved the feed conversion ratio compared to the control treatment (P < 0.05). The digestibility of dry matter and protein was significantly increased (P < 0.05), while the digestibility of neutral detergent fiber, acid detergent fiber, and organic matter showed a numerical increase. Diets containing different levels of the Alternanthera sessilis plant did not affect pH, but the increase in the amount of this plant in the diet led to an increase ammonia nitrogen concentration and rumen protozoa population (P < 0.05). The addition of Alternanthera sessilis to the diet significantly reduced the concentration of blood glucose and cholesterol and increased the concentration of blood urea nitrogen (P < 0.05). Except for the weight of the thigh and neck, the effect of experimental treatments on other carcass components was not significant. Overall, the results of this experiment showed that using the Alternanthera sessilis plant in the rations of fattened lambs as a substitute for alfalfa forage not only had no negative effect on the studied parameters but also improved them in some cases. Therefore, Alternanthera sessilis can be used in rations of fattened lambs as a substitute for part of alfalfa forage.

Genetic evaluation of early reproductive traits of Harnali sheep.

The aim of this study is to examine early reproductive traits and assess genetic parameters associated with them in Harnali crossbred ewes through Bayesian inference. The dataset encompasses 555 reproduction records spanning 24 years from 1998 to 2021. The traits under investigation include age at first lambing (AFL), weight at first lambing (WFL), and first lambing interval (FLI). First, least-squares modeling was conducted, incorporating fixed effects such as the period of birth and the dam's weight at lambing for the targeted traits. Subsequently, Bayesian estimation involved a series of animal models that accounted for direct additive effects, with or without maternal effects, along with significant fixed effects. The overall least-squares mean for AFL, WFL and FLI was observed as 851.49 ± 12.20 days, 27.5 ± 0.16 kg, 455.04 ± 10.66 days, respectively. The period of birth significantly influenced AFL and WFL, while the dam's weight at lambing showed a significant association with WFL only. Bayesian estimates revealed low direct heritability for AFL, WFL, and FLI, ranging from 0.12, 0.16 and 0.04, suggesting limited potential for improvement through selection. However, maternal effects accounted for a proportion of phenotypic variance ranging from 0.04 to 0.14 across these traits. It was concluded that enhancing reproductive efficiency in Harnali ewes would require a greater focus on management aspects, particularly feeding and breeding practices, while also considering maternal influences within the existing breeding plan.

Soybean oil, linoleic acid source, in lamb diets: carcass traits and meat quality.

We developed a study to determine the ideal level of inclusion of soybean oil (SBOil) in the diet without affecting the quantitative and qualitative parameters of the carcass and meat of lambs in a feedlot system; therefore, determining the ideal level of inclusion. Forty male lambs (Santa Inês breed) were used. The initial body weight and age averaged 34.88 ± 3.19 kg and 5 months, respectively. Experimental units (lambs) were randomly distributed in 5 different diets: inclusion levels of SBOil: 0, 30, 60, 90, and 120 g/kg of dry matter (DM). The SOil inclusion reduced the DM intake (P < 0.001), Total digestible nutrients (P = 0.004), and crude protein (P < 0.001). Total weight gain (P < 0.001) decreased with the SBOil inclusion and subcutaneous fat thickness (P = 0.017) showed the same behaviour. The final body weight decreased by 42.9 g/kgDM until the inclusion level of 30 g/kgDM; from this level it was reduced by 145 g/kgDM. The hot and cold carcass weights (P = 0.013) decreased by 36.6 g/kgDM after including 30 g/kgDM of SBOil. Meat physicochemical composition was not altered (P > 0.05). Lower meat tenderness values ​​were obtained at the levels of 60 and 90 g/kgDM. The inclusion above 30 g/kgDM decreased meat tenderness. It is concluded that soybean oil should be included up to 30 g/kgDM in diets. It is important to note that with diets with 60% concentrate, SBOil levels greater than 30 g/kgDM promote yield losses.

The assessment of zeolite addition to diets with or without urea on some productive and physiological indicators in Awassi lambs.

BACKGROUND: Interest is growing in the search for alternatives to traditional feed additives, so this study aimed to investigate the effect of adding zeolite to the concentrate diets of Awassi lambs with or without urea on growth performance, nutrient digestion, and health status. A total of 45 Awassi lambs similar in weight (24 ± 2 kg) and age (3 months ± 4 days) were divided into three groups: the first group (G1) fed on a concentrate diet supplemented with 1% urea; the second group (G2) fed on the concentrate diet supplemented with 1% urea and 3% zeolite, and the third group (G3) fed on a urea-free diet supplemented with 3% zeolite. RESULTS: The results showed a significant increase (P ≤ 0.05) in final live weight, daily and total weight gain for group G2 compared to groups G1and G3, with a significant superiority (P ≤ 0.05) of group G3 over the control group G1. Significant improvement (P < 0.05) was also observed in feed consumption and feed conversion ratio in diets supplemented with zeolite for groups G2 and G3 compared to the control group G1. Additionally, there was a significant increase (P ≤ 0.05) in nutrient digestion and nutritional value in the diet of group G2 containing urea with added zeolite compared to groups G1 and G3. Zeolite did not affect the levels of glucose, triglycerides, cholesterol, and albumin in the blood, but a significant increase (P ≤ 0.05) in total blood protein level and a significant decrease (P ≤ 0.05) in blood urea level were noted for groups G2 and G3 compared to the control group G1. CONCLUSIONS: Adding zeolite to urea-containing concentrate diets improved growth rates and nutrient digestion, of Awassi lambs. In diets without urea, zeolite improved growth rates without affecting nutrient digestion coefficients, in both types of diets, zeolite increased total protein levels and decreased blood urea levels, with all physiological indicators in lambs blood remaining within normal limits.

Effect of thymol on the efficiency of feed utilization and compensatory growth in severe feed-restricted lambs.

The present study aimed to evaluate the effect of thymol on growth performance and apparent total tract digestibility of nutrients in severely feed-restricted lambs. Twenty-one male Baluchi lambs were randomly blocked by live weight into three groups: control without feed restriction (CON), feed restricted (FR), and feed restricted plus thymol (FR + T). The lambs underwent a four-week feed restriction period followed by four weeks of realimentation. Thymol was administered daily to the FR + T group during the feed restriction period. Average daily gain (ADG), average daily feed intake, feed efficiency (FE), partial efficiency of maintenance (PEM), and residual feed intake (RFI) were measured as growth performance parameters. Results showed that the severe feed restriction had adverse effects on ADG and FE, but improved PEM (P < 0.05). The effects of thymol administration on ADG, FE, PEM, and apparent total tract digestibility were not significant (P > 0.05). However, the lambs that received thymol during the feed restriction period showed a negative RFI during realimentation (P < 0.05). Overall, these findings suggest that feed restriction as well as thymol may have the potential to improve efficiency of feed utilization in growing lambs. However, this positive effect is independent of the improvement in nutrient digestibility.

Do forage production and ingestive behavior of locally adapted sheep differ from an irrigated silvopastoral system to an irrigated monoculture in the semi-arid region?

This study aimed to evaluate forage production and ingestive behavior of Morada Nova sheep in an intensive system with capim-tamani grass in both monoculture and silvopastoral irrigated systems in the Semi-arid region. Eighteen adult sheep, approximately 3 years old, with an average body weight of 26.8 ± 4.3 kg, were allocated to treatments with capim-tamani grass cultivated in monoculture and in silvopastoral systems with Caatinga trees. The experiment followed a completely randomized complete block design with two plots and three replications. Forage production, consumption, and behavioral activities were the assessed variables. The animals remained in the pasture daily between 6 am and 6 pm. No effects of the monoculture and silvopastoral systems were observed on the structural and productive characteristics of the capim-tamani grass pasture. There were also no observed effects on body condition score, consumption, and disappearance rate of dry matter (DM) and other nutrients in both systems. However, there was an interaction between the time animals spent under shade in monoculture and silvopastoral systems. In general, the animals spent more time under shade where there were trees, except during the period between 2 pm and 4 pm, when the times were similar. On average, the animals spent approximately 15.6% (equivalent to 1.87 h) of their total time in the artificial shade available in the monoculture system, whereas in the silvopastoral system, they remained under natural shade for approximately 40% (five and a half hours) of their time spent in the pasture during the day. The grazing frequency in both systems was approximately 70% (8.4 h) in relation to the total time spent in the pasture. The capim-tamani grass pasture managed intensively with sheep in the silvopastoral system showed similar forage production and consumption compared to the monoculture system. There was a positive influence of trees on the duration of solar radiation exposure to the animals throughout the day. The results support the need to provide shade for sheep, as well as to promote these sustainable systems in semi-arid regions.

Economic and financial viability of the production of Brazilian somalis sheep fed with different nutritional plans.

The objective of this study was to evaluate the economic and financial viability of finishing of two sexes of Brazilian Somalis sheep in feedlot receiving diets with 0 and 15% reduction in the total digestible nutrients and crude protein contents. A completely randomized design was adopted, in a 2 × 2 factorial arrangement, with treatments consisting of two sexes (non-castrated males (21.13 ± 5.00 kg) and females (17.99 ± 3.79 kg) and two diets (0 and 15% reduction in the levels of total digestible nutrients and crude protein). Four simulations of productive scenarios were carried out: non-castrated males receiving the diet with 0% reduction; non-castrated males receiving the diet with 15% reduction; females receiving the diet with 0% reduction and females receiving the diet with 0% reduction, for a period of 70 days in feedlot. The highest costs of the system were with feeding and other costs, mainly the acquisition of animals. For both sexes, the 0% reduction diet showed the highest total cost, total revenue, break-even point. Non-castrated males fed a non-reduced diet and females fed a 15% reduction diet had higher net income, rate of return, total productivity, net present value, internal rate of return, profitability index and profitability rate. Less favorable situations were not profitable for any scenario. However, the increase in sales price favorability makes the activity viable. The reduction of total digestible nutrients and crude protein affects the economic and financial viability of Brazilian Somalis sheep. For non-castrated males it is recommended the diet without reduction and for females the diet with 15% reduction of nutrients.

Effects of yeast and exogenous fibrolytic enzyme additives on lamb performance and feed efficiency.

Yeast and fibrolytic enzymes serve as additives incorporated into the nutrition of ruminants to regulate rumen fermentation and increase the digestibility of fiber, thereby enhancing the efficiency of rumen fermentation. Two experiments were conducted to assess the impact of five diets: a control diet without additives, diets with yeast (Saccharomyces cerevisiae) or exogenous fibrolytic enzymes (EFE), and diets with a blend of 0.7yeast + 0.3EFE or 0.7EFE + 0.3Yeast (based on recommended levels in g/kg of total DM). In the first experiment, 40 five-month-old Santa Ines lambs (mean weight 25.0 ± 1.3 kg) were distributed in a completely randomized design (5 treatments and 8 lambs) for 81 days to evaluate performance, ingestive behaviour, and serum metabolites. In the second experiment, 25 Santa Ines male lambs weighing 25.7 ± 4.1 kg were housed in metabolic cages, in a randomized design with 5 treatments and 5 lambs, evaluating digestibility, nitrogen balance, and rumen pH. EFE supplementation increased intakes of dry matter (DM), total digestible nutrients (TDN), and apNDF (mean of 38.1, 5.26, and 27%, respectively) compared to yeast or the 0.7yeast-0.3EFE blend. Feed conversion was most efficient (mean of 27.1%) in lambs fed Yeast, 0.7EFE + 0.3yeast, and the control diet. Lambs fed 0.7yeast + 0.3EFE spent less time eating (mean of 16.5%) and more time idling (mean of 10.75%), whereas EFE-fed lambs spent more time eating (mean of 19.73%), and 0.7EFE + 0.3yeast-fed lambs spent more time ruminating (mean of 20.14%). Control group lambs chewed and ruminated less (means of 24.64 and 17.21%, respectively) compared to other treatments. Lambs on the 0.7yeast + 0.3EFE blend had higher eating and rumination efficiency rates for DM and apNDF (mean of 19.11 and 17.95%, respectively) compared to other additive treatments or individual additives. They also exhibited lower (means 7.59 g/d) urinary N excretion, with improved N retention (mean 3185 g/d) compared to the control group. There were significant effects on serum albumin and cholesterol concentrations, with the 0.7yeast + 0.3EFE blend showing higher albumin (mean 4.08 g/dL) levels, while diets without additives and yeast-EFE blends had higher cholesterol (mean of 62.51 g/dL) concentrations. Including Saccharomyces cerevisiae yeast along with 0.7 yeast + 0.3 EFE blend is recommended when feeding similar lamb diets to those used herein because it improves the efficiency of intake, rumination of DM and NDF, and nitrogen utilization without affecting the lamb performance.