Dorper Rams Research Articles

The Post-weaning Growth of Lambs from Crossbreeding Between Garut Ewes with Dorper Rams

This study investigates the performance of post-weaning growth of Garut lambs and the results of crossing Garut ewes with Dorper rams. This research phase occurred in the post-weaning phase period of 3–7 months using 168 lambs consisting of 85 Garut lambs and 83 crossed Dorper lambs in the post-weaning phase with an average body weight of 15.15±3.23 kg. The lambs were assigned to a factorial completely randomized design (2 x 2 factorial experiment). They were then divided into two groups based on breed (Garut and Crossed Dorper) and two sex groups (male and female). Data observed included feed consumption, as fed feed consumption, dry matter (DM) consumption, DM consumption per body weight, crude protein (CP) consumption, total digestible nutrient (TDN) consumption, average daily gain (ADG), and feed conversion. Results showed that consumption of as fed, DM, CP, TDN, and ADG were higher (<i>P</i><0.05) in crossed Dorper lambs than in Garut lambs; a total ADG of crossed Dorper, Garut, male, and female lambs were 106.92±11.68, 79.25±10.02, 102.49±17.54, and 86.79±14.48 g/day, respectively. Male lambs showed higher results (<i>P</i><0.05) in as-fed feed consumption, DM, DM consumption per body weight, CP, TDN, and ADG than female lambs. The feed conversion of crossed Dorper lamb and male lamb was lower (P<0.05) than that of Garut and female lamb. There was an interaction between male breed and sex at seven months ADG and feed conversion at 4 and 7 months. Sheep from Garut ewes crossed with Dorper rams improved the growth performance of their offspring.

La presencia de cuernos determina el rango social de carneros Dorper

The aim was to determine if the presence of horns on rams defines whether they are high-ranking or low-ranking. Dorper rams (n = 20) were evaluated to determine their social rank (SR), either high (HSR) or low (LSR), under intensive management conditions. Upon SR classification, the morphometric variables horns presence (HP) or absence (HA) and distance between them, the height at the withers, body length, thoracic perimeter, and scrotal circumference, male odor, body weight, and body condition score were registered. Afterward, semen evaluations were performed, recording the ejaculated volume, sperm concentration, and mass motility. There were no differences (p > 0.05) for the morphometric variables between the groups. However, HP as well as semen quality were higher (p < 0.05) in HSR males. The presence of horns in the rams determined their social rank and the dominant males showed better semen quality than the subordinate males.

Use of coenzyme Q-10 to improve the pregnancy rate in sheep

One of the factors responsible for less pregnancy rates is the use of frozen semen in sheep due to the oxidative stress created by the process. The aim of this experiment was to test the effects of adding coenzyme Q-10 (CoQ10) to the seminal extender on sperm quality and the pregnancy rate of sheep. In this study, ejaculates from eight Dorper rams of reproductive age were used and tested in four treatments: Control (pure BotuBov®), C1 (175 µM of CoQ10), C3 (350 µM of CoQ10), and C7 (700 µM of CoQ10). Samples were collected in triplicate from each animal, and sperm analysis was performed by CASA after thawing at 0 h and 2 h. The samples were also analyzed by flow cytometry for plasma and acrosomal membrane integrity, stability, lipid peroxidation, mitochondrial potential, and superoxide anion production. In total, 198 ewes were inseminated by laparoscopy and divided into two groups: control (n=98) and C7 (n=100). Pregnancy diagnosis was performed at 30 days. Coenzyme Q10 proved to be safe for semen cryopreservation, not altering sperm kinetic values between the groups post-thawing. In flow cytometry, the C1 and C7 groups achieved a better index of plasma membrane integrity and membrane stability (P<0.05). A increased pregnancy rate was observed in C7 (52 %) compared to the control (38 %). In conclusion, coenzyme Q10 assists in the cryopreservation process, protecting the sperm cell and improving pregnancy rates in ewes.

Comparison of methods for morphological evaluation of sheep spermatozoa using the SPERM BLUE kit and Romanovsky-Giemse staining

The purpose of this study is to test and comparatively evaluate the method of morphological examination of ram sperm using a differentiated staining Sperm Blue and Romanovsky-Giemsa staining. The sperm of Dorper rams was collected and examined. The obtained samples (n=10) were diluted in a ratio of 1:100 (PBS solution) to conduct a morphological assessment of sperm. Two methods were used for the morphological assessment of spermatozoa: a set of differentiated staining Sperm Blue (Microptic, exposure of the smear in the fixative – 10 minutes, in the main dye - 18 minutes) and Romanovsky-Giemsa staining (exposure of the smear in the fixative - 10 minutes, in the main dye – 20 minutes). After routine staining, the smears were washed with distilled water, dried, and microscopy was performed (magnification using a 100x10 immersion objective, oil immersion), followed by a manual method of counting the number of morphological forms of sperm. According to the results of a comparative analysis of stained smears, staining with Sperm Blue allows for a detailed morphological study and differentiation of teratozoospermic characteristics. When stained with Romanovsky-Giemsa, normal spermatozoa were clearly visible, but the acrosome was poorly visualized. Manual calculation of the percentage of normal sperm using both dyes resulted in the same decimal result. A statistically insignificant difference in head and tail defects was found between the dyes used (p = 0.41 and p = 0.77, respectively): Romanovsky-Giemsa staining (7.8% and 34.1%) detected these defects more often than Sperm Blue (6.3% and 32.9%). Considering the results obtained, the use of the Sperm Blue dyes dye in veterinary andrology is relevant, in particular for assesment the morphology of sperm of different animal species with the further development of appropriate protocols in terms of the duration of exposure of the smears themselves to the main dye.

Quantitative phosphoproteomics explain cryopreservation-induced reductions in ram sperm motility

Sperm cryopreservation decreases motility, probably due to changes in protein phosphorylation. Our objective was to use quantitative phosphoproteomics for systematic comparative analyses of fresh versus frozen-thawed sperm to identify factors causing cryo-injury. Ejaculates were collected (artificial vagina) from six Dorper rams, pooled, extended, and frozen over liquid nitrogen. Overall, 915, 3382, and 6875 phosphorylated proteins, phosphorylated peptides, and phosphorylation sites, respectively, were identified. At least two modified sites were present in 57.94% of the 6875 phosphosites identified, of which AKAP4 protein contained up to 331 modified sites. There were 732 phosphorylated peptides significantly up-regulated and 909 significantly down-regulated in frozen-thawed versus fresh sperm. Moreover, the conserved motif [RxxS] was significantly down-regulated in frozen-thawed sperm. Phosphorylation of sperm-specific proteins, e.g., AKAP3/4, CABYR, FSIP2, GSK3A/B, GPI, and ODF1/2 make them potential biomarkers to assess the quality of frozen-thawed ram sperm. Furthermore, these differentially phosphorylated proteins and modification sites were implicated in cryopreservation-induced changes in sperm energy production, fiber sheath composition, and various biological processes. We concluded that abnormal protein phosphorylation modifications are key regulators of reduced sperm motility. These novel findings implicated specific protein phosphorylation modifications in sperm cryo-injury. SignificanceThis study used phosphorylated TMT quantitative proteomics to explore regulation of epigenetic modifications in frozen-thawed ram sperm. This experiment demonstrated that ram sperm freezing affects phosphorylation site modifications of proteins, especially those related to functions such as sperm motility and energy production. Furthermore, it is important to link functions of phosphorylated proteins with changes in sperm quality after freezing and thawing, and to clarify intrinsic reasons for sperm quality changes, which is of great importance for elucidating mechanisms of sperm freezing damage. Based on these protein markers and combined with cryoprotectant design theory, it provides a theoretical basis and data reference to study sperm cryoprotectants.

Reproductive and productive behavior of hair sheep under an intensive production system

Objective: To evaluate the reproductive and productive behavior of four hair sheep breeds in an intensive production system.&#x0D; Design/Methodology/Approach: Data recorded over 4 years (2016-2019) from a production unit that works with Blackbelly, Pelibuey, Dorper, and Katahdin breeds were analyzed. The following variables were evaluated: fertility, prolificacy, birth weight (BW), weaning weight (WW), weaned lamb yield (WLY), daily weight gain during lactation (DWGL), offspring born alive (OBA), male offspring (MO), and female offspring (FO). All information was analyzed using Chi-square tests and analysis of variance.&#x0D; Results: The fertility, BW, WW, and WYL variables recorded different values between breeds (P&lt;0.05). The greatest fertility and prolificacy were recorded by Blackbelly, while Dorper recorded the lowest values (P&lt;0.05). BW and WW were highest in Dorper and lowest in Blackbelly (P&lt;0.05). Finally, the sheep that recorded the highest WYL were the Blackbelly, while the Dorper registered the lowest values (P&lt;0.05). BW and DWGL values reached maximum values (P&lt;0.05) in Dorper rams, followed by Katahdin. The greatest number of OBA was observed in Blackbelly and Pelibuey (P&lt;0.05).&#x0D; Study Limitations/Implications: Further studies should be carried out to validate this research.&#x0D; Findings/Conclusions: Blackbelly ewes produced more kilograms of weaned lambs per lambing ewe. The Dorper and Katahdin rams in the pre-weaning period recorded higher weight at weaning.

Use of Andromed® and OviXcell® diluents in the processing of sheep semen with the addition of HTF

Objective: To assess the effect of two ovine semen diluents, Andromed® and OviXcell®, on the mass motility, vitality, and acrosomal integrity of spermatozoa processed at different temperatures and with the addition of post-thawed HTF (human tubal fluid).&#x0D; Design/Methodology/Approach: Semen from 2 Dorper ram was used. Four ejaculations per male were collected and diluted with Andromed® and Ovixcell®. There were four treatments with Ovixcell®: 1) fresh Ovixcell®, 2) refrigerated Ovixcell®, 3) post-thawed Ovixcell®, and 4) post-thawed Ovixcell® + HTF. Four treaments with Andromed® were also carried out: 1) fresh Andromed®, 2) refrigerated Andromed®, 3) post-thawed Andromed®, and 4) post-thawed Andromed® + HTF. Mass motility, vitality, and acrosomal integrity were performed with a CASA computer system and statistically analyzed with the GLM procedure of the SAS software.&#x0D; Results: When the effect of Ovixcell® mass motility was assessed, the following results were obtained, with differences (p˂0.05) between treatments: 87% in fresh semen, 72% refrigerated semen, 55% in post-thawed semen, and 68% in post-thawed semen + HTF. A clear difference (p˂0.05) was observed when HTF was added to post-thawed semen (13%). Andromed® behaved in the same way as Ovixcell® (p˂0.05) and a 18% recovery was observed with the addition of HTF. A high percentage of live spermatozoa with intact acrosome was observed for fresh semen (97.8%), while it diminished (p&lt;0.05) as the temperature of refrigerated and frozen semen gradually decreased.&#x0D; Study Limitations/Implications: More experimental units should be used, despite the increase in maintenance costs per animal.&#x0D; Findings/Conclusions: The use of Andromed® and OviXcell® diluents was satisfactory in relation to the mass motility, vitality, and acrosomal integrity in spermatozoa processed at different temperatures (fresh, refrigerated, and post-thawed). Furthermore, the addition of HTF increased post-thawed mass motility.

Effect of β-caryophyllene on Sperm Cryopreservation.

This study aimed to assess the impact of β-caryophyllene (BC) supplementation in the extender on the post-cryopreservation quality of semen from Dorper rams. Six Dorper rams were utilized for semen collection over 16 weeks, with BC concentrations determined via the MTT test. Animals were divided into a control group and three treatment groups receiving BC at concentrations of 1.0mM, 2.0mM, and 3.0mM in the Trisegg yolk diluent. Semen was cryopreserved and stored in liquid nitrogen for at least 15 days. After thawing, in vitro assessments including CASA, acrosomal integrity, plasma membrane integrity, mitochondrial membrane potential, and thermo-resistance tests were conducted. Additionally, the TBARS assay was performed to evaluate oxidative stress. While BC supplementation did not significantly affect sperm motility, it notably improved mitochondrial potential and mitigated oxidative stress in cryopreserved ram semen. Incorporating β-caryophyllene into the extender exhibited beneficial effects on the quality of Dorper ram semen post-cryopreservation, enhancing mitochondrial functionality and reducing oxidative stress.

Evaluation of pharmacological alternatives to reduce the pain and discomfort produced by electroejaculation in rams

AbstractElectroejaculation (EE) represents the main technique for semen collection from domestic and wild animals independently of libido. However, the technique is associated with intense involuntary muscle contractions, vocalization, ataxia and lying down, caused by the electric stimulation of the nerves in the caudal epigastric region. These clinical manifestations represent important indicators of discomfort. In this context, the objective of this study was to evaluate two protocols of local anaesthetic blockade and two anatomical access for pharmacological desensitization of the caudal epigastric innervation as alternatives to promote comfort and reduce stress associated with EE in rams. For the study, four clinically healthy Dorper rams were selected. All animals were subjected to a design consisting of five semen collection treatments (n = 3 collections per treatment): T1—control, conventional EE without local anaesthetic blockade; T2, EE with ventral blockade (VB) of epigastric innervation using lidocaine hydrochloride 2%; T3, EE with VB of epigastric innervation using a combination of lidocaine hydrochloride 2% and fentanyl citrate; T4, EE with blockade of epigastric innervation through the perineal access using lidocaine hydrochloride 2%; T5, EE with blockade of epigastric innervation through the perineal access using a combination of lidocaine hydrochloride and fentanyl citrate. Seminal samples resulting from EE were subjectively evaluated for sperm motility and concentration, vigour and volume. Additionally, blood serum samples were collected for quantification of cortisol and creatine kinase (CK) enzyme. Assessments of stress and discomfort were conducted by measuring blood pressure, heart rate (HR) and respiratory rate (RR), as well as observing involuntary muscle contractions, ataxia and animal vocalization. No variations in blood pressure, sperm motility, vigour, CK, and cortisol were observed among the treatments. Individual variations were observed for the occurrence of vocalization (p = .0066), but there were no differences between the groups. Anaesthetic blockades conducted using the combination of lidocaine and fentanyl resulted in a lower incidence of ataxia during EE (p &lt; .0001). It is concluded that the combination of fentanyl citrate and lidocaine hydrochloride results in less discomfort for animals undergoing EE, regardless of the anatomical access used for local anaesthetic blockades.

Seasonal heat stress compromises testicular thermoregulation and semen quality of Dorper rams raised in a desert climate

Dorper rams are widely distributed throughout the world under different climatic conditions, however, little is known about their reproductive performance in desert regions. Ten Dorper rams were individually housed and exposed to thermoneutrality for 35 d in spring (23.6 ± 5.6 °C, mean ± SD) and outdoor heat stress (HS) for 35 d in summer (33.6 ± 2.0 °C) to evaluate the effect of seasonal HS on physiological responses, testicular biometry, and seminal quality under desert climatic conditions. Rectal temperature, respiration rate and coat surface temperatures in different body regions were measured every 7 d (0600, 1200, and 1800 h); also, testicular biometry was registered at 0600 h. Semen was collected via an artificial vagina 3 d after physiological variables were measured and seminal traits were evaluated. Rectal temperature, respiration rate and coat surface temperatures were higher (P < 0.01) at each hour of measurement in summer compared to spring. Overall, scrotal length and circumference, as well as testicular volume were higher (P < 0.01) in summer than in spring. Compared to spring conditions, summer HS caused lower (P ≤ 0.05) sperm concentration and viability combined with a higher percentage of sperm abnormalities without affecting ejaculate volume. Both mass and sperm motility were similar between seasons in the first two sampling weeks, and then decreased (P ≤ 0.03) due to summer HS. In conclusion, Dorper rams developed testicle hyperthermia and, consequently, showed poor semen quality due to the high environmental temperatures prevailing in desert regions.

The heavy suckling lamb of Sarda dairy sheep and its crossbreed with Dorper rams: Performance, meat quality and consumer perceptions

The increase of meat production in dairy sheep farms, has been evaluated by the extension of the suckling period from the traditional 28 days to 75 days to obtain a new product, the heavy suckling lamb. Nineteen single-born Sarda (S) lambs (10 male, 9 female) and 20 single-born Dorper x Sarda (DS) lambs (9 male, 11 female), randomly selected from autumn lambing season, were fed exclusively with maternal milk until slaughtering at 20 ± 0.28 kg of body weight (BW, mean ± standard deviation, SD) and approximately 11 weeks of age. Body weight were recorded at birth and every 15 days until slaughter to estimate average daily gain (ADG). At slaughter, carcass measurements, pH and colour traits were recorded from the left side of the carcass. Proximate composition, fatty acid (FA) profile, cooking and drip losses were evaluated using the Longissimus thoracis et lumborum (LTL) muscle. In addition, Visual Panel Test (VPT) and Taste Panel Test (TPT) were performed. Experimental results evidenced that ADG did not differ between pure and crossbreed lambs and between sexes. The S lamb carcasses showed a higher fat content and rib fat thickness compared to that of crossbreed. No significant differences were found between genetic types and sex for colour and pH determinations, cooking and drip losses, whereas LTL fat of DS displayed a higher nutritional FA profile with higher content of 22:5n-3, 22:6n-3, branched-chain FA, and odd- and branched chain FA. No differences emerged during VPT and TPT, demonstrating that both DS and S lamb meats present no distinguishable visual and eating quality characteristics. The production of heavy suckling lambs from Sarda and Dorper crossbreed by the extension of suckling period appeared a promising strategy for producing meat of high quality, well appreciated by the consumers.

Proteomic analysis reveals the potential positive effects of Mito-TEMPO on ram sperm motility and fertility during cryopreservation

The aim of this study was to investigate the effects of mitochondria-targeted antioxidant Mito-TEMPO on the protein profile of ram sperm during cryopreservation and evaluate the cryoprotective roles of Mito-TEMPO on ram sperm quality and fertilization capacity. Semen collected from 8 Dorper rams was cryopreserved in TCG-egg yolk extender supplemented with various concentrations of Mito-TEMPO (0, 20, 40 and 60 μM). After thawing, sperm characteristics, antioxidant status and the abundance of hexose transporters (GLUT 3 and 8) were analyzed. The cervical artificial insemination (AI) was performed to evaluate the fertilization ability of cryopreserved ram sperm. The alterations of sperm proteomic profile between the control and MT40 groups were determined using iTRAQ-coupled LC-MS. Supplementation with 40 μM of Mito-TEMPO resulted in the highest post-thaw sperm motility and kinematics. Sperm quality, antioxidant capacity and glucose transporter abundance of frozen-thawed ram sperm were elevated in the MT40 group. The inclusion of 40 μM Mito-TEMPO in freezing extender also resulted in the higher pregnancy rate of ewes. A total of 457 proteins including 179 upregulated proteins and 278 downregulated proteins were defied as differentially expressed proteins (DEPs) using fold change (FC) > 1.2 with P < 0.05. Sixty-one DEPs with (FC > 1.5) were dramatically regulated by Mito-TEMPO. These DEPs are mainly involved in sperm motility, energy metabolism and capacitation. Our data suggest that the beneficial effects of Mito-TEMPO on sperm motility and fertility potential of cryopreserved ram semen are achieved by regulating sperm antioxidant capacity and sperm proteins related to energy metabolism and fertility.

Ram sperm cryopreservation disrupts metabolism of unsaturated fatty acids

In ram sperm, metabolites are important components of the plasma membrane, energy metabolism cycle, and precursors for other membrane lipids, and they may have important roles in maintaining plasma membrane integrity, energy metabolism, and regulation of cryotolerance. In this study, the ejaculates from 6 Dorper rams were pooled and sperm were systematically investigated by metabolomics at various steps of cryopreservation (37 °C, fresh [F]; from 37 to 4 °C, cooling [C]; and from 4 to −196 to 37 °C, frozen-thawed [FT]) to identify differential metabolites (DM). There were 310 metabolites identified, of which 86 were considered DMs. Regarding the DMs, there were 23 (0 up and 23 down), 25 (12 up and 13 down), and 38 (7 up and 31 down) identified during cooling (C vs F), freezing (FT vs C), and cryopreservation (FT vs F), respectively. Furthermore, some key polyunsaturated fatty acids (FAs), particularly, linoleic acid (LA), docosahexaenoic acid (DHA), and arachidonic acid (AA) were down-regulated during cooling and cryopreservation. Significant DMs were enriched in several metabolic pathways including biosynthesis of unsaturated FAs, LA metabolism, mammalian target of rapamycin (mTOR), forkhead box transcription factors (FoxO), adenosine monophosphate-activated protein kinase (AMPK), phosphatidylinositol 3-kinase/protein kinase B (PI3K-Akt) signaling pathways, regulation of lipolysis in adipocytes, and FA biosynthesis. This was apparently the first report to compare metabolomics profiles of ram sperm during cryopreservation and provided new knowledge to improve this process.

Effect of rams’ social hierarchy upon scrotal circumference, semen quality, and copulation performance under arid land conditions

Social hierarchies among animal species are based on the animal ́s dominance-aggressiveness level aligned with the subordination oftheir mates. Social order is mostly defined by animal size, live weight, or age. This study aimed to evaluate the association betweenodor score (OS), horn presence (HP), horn size (HS), and body temperature on social rank hierarchy, scrotal circumference (SC), semenquality (SQ), and sexual drive (SD). Adult Dorper rams (n=24) with similar live weight (LW), body condition score (BCS), and age (AG)were subjected to a behavioral test to define a success index (SI) based on male-to-male interactions. OS was highest (P&lt;0.05) for ramswith high social rank (HSR; 2.5±0.4) and lowest for rams with low social status (LSR; 0.75±0.01). Scrotal circumference was highest(P&lt;0.05) for HSR rams (40.0±3.5) and lowest for rams with medium social rank (MSR; 29.3±1.20). Sperm cell concentration/mL washighest (P&lt;0.05) for HSR rams (3848±187) and lowest for LSR (2660±463). 80% of the HSR rams had horns, while 33.3 of the LSRrams were hornless. The percentage of rejection to mount an estrous ewe was 77.7 for LSR and 20% for HSR and MSR rams (P &lt;0.05).To conclude, the HSR rams presented the highest successful copulation, scrotal circumference, and sperm cell concentration comparedto rams with lesser social rank scores

The Dorper breed as a stage in the sustainable development of the agroindustry.

The economic condition, national economic significance and prospects for the development of sheep breeding in our country directly depend on the meat productivity of sheep. The purpose of our research was to study the qualitative indicators of sheepskins and the histological structure of the skin of Kalmyk fat-tailed rams and crossbreeds obtained on the basis of crossing of Kalmyk fat-tailed ewes with Dorper rams. The work was carried out in LLC "Agrofirma Aduchi", Republic of Kalmykia. It was found that the coarser wool of the rams of group I was 4.7 microns or 12.9%, in contrast to the peers of group II. The control animals have 40 quality wool, and the experimental ones - 36, that is, the wool of hybrid young animals is thinner by two whole qualities, which is a very good indicator for the textile industry. The fineness of the awn was thicker in purebred rams by 8.5%, the fineness of transitional hair and fluff by 17.8%, in contrast to hybrid young. In the study of the histological parameters of the skin, it was revealed that the rams of group I had 352.57 µm thicker skin (14.52%) in comparison with their peers in group II. In this case, the thickness of the layers of the total thickness of the skin in animals of group I is: epidermis - 0.8%, pilar - 69.8%, reticular - 29.4%; Group II - epidermis - 1.2%, pilar - 60.5%, reticular - 38.3%. The densest epidermis was found in crossbred young animals of group II. Their superiority in this indicator over their peers in the control group was 6.12 microns or 27.7%. This is due to the fact that in animals of the meat direction, the epidermal part (flesh) is thicker. Crossbred rams have a larger area of ​​sheepskins, the skin is more elastic, durable and less thick, such sheepskins are first-class raw materials for the industrial production of fur products. The density of the coat (the ratio of WF / PF) in crossbred rams is greater than that of purebred peers.

Increasing the meat productivity of young sheep based on the use of the gene pool of the Dorper and Hissar breeds.

In the pursuit of enhanced mutton production, improving the genetic reservoir of sheep with early maturation and high meat productivity is imperative. This study aims to assess the efficacy of integrating Dorper and Hissar rams into the breeding program of Kazakh fat-tailed coarse-haired ewes for generating young mutton. The research involved forming three groups, each comprising 40 ewes of the Kazakh fat-tailed coarse-haired breed, based on analog pairs. Ewes in Group I were inseminated with Dorper ram semen, those in Group II were inseminated with Hissar ram semen, and Group III served as a control with purebred Kazakh fat-tailed coarse-haired sheep breeding. Results revealed that crossbred rams in Group II achieved a significantly higher live weight of 45.2 kg at 120 days of age, surpassing the other groups by 9.7 kg and 10.6 kg. Crossbred gimmers in Group II reached a live weight of 42.0 kg by 4 months, outpacing the other groups by 12.2 kg. The crossbred lambs exhibited an expansive, deep, and sturdy physique, indicative of elevated meat productivity. Physique index analysis displayed that crossbred rams exhibited elongated limbs, bulkiness, and massiveness compared to purebred Kazakh fat-tailed coarse-haired lambs. In the 4.0-4.5-month age range, crossbred rams demonstrated a higher carcass muscle yield than their purebred counterparts, albeit the latter exhibited a 0.18% greater bone yield. Moreover, the meat of groups I and II sheep contained 19.6% and 20.1% protein content, respectively, surpassing the local Kazakh fat-tailed sheep population by 0.7% and 1.2% in absolute terms.

Multifaceted Interplay among Social Dominance, Body Condition, Appetitive and Consummatory Sexual Behaviors, and Semen Quality in Dorper Rams during Out-Of-Season and Transition Periods.

Dorper rams (n = 24) were evaluated during the sexual resting season to determine their social rank (SR), either high (HSR) or low (LSR), under intensive management conditions in northern Mexico (25° N). Aggressive behaviors were quantified during male-to-male interactions, and appetitive and consummatory sexual behaviors during male-to-female interactions. Morphometric, live weight (LW), and body condition score (BCS) were recorded. During the early reproductive season, male-to-female behaviors were newly itemized simultaneously by seminal quality and quantity sampling. Finally, the dependent variables of the hemogram components were also quantified. Neither LW (61.25 ± 2.4 kg) nor morphometric variables differed between SR groups. However, BCS (2.25 vs. 2.66 u), sexual behaviors (i.e., approaches: 59.6 vs. 21.73 n, mating with ejaculation: 77.7 vs. 42.86 %, latency to ejaculation: 16.6 vs. 143.07 s), ejaculate volume (0.57 vs. 0.23 mL), and hemogram components favored the HSR rams (p < 0.05). Moreover, in their first male-to-female interaction, >50% of the LSR rams failed to display any sexual activity. HSR rams displayed a greater number of threatening behaviors, managing to displace LSR rams when exposed to estrus ewes during the male sexual resting season; more sexual behaviors; and an increased seminal volume in a non-live weight-dependent fashion.

The pre-weaning growth of lambs from crossbreeding between Garut ewes with Dorper rams

Abstract. Athifa IR, Sari APZNL, Maharani D, Budisatria IGS, Bintara S, Noor YG, Hidayat R, Panjono. 2022. The pre-weaning growth of lambs from crossbreeding between Garut ewes with Dorper rams. Biodiversitas 23: 5738-5743. This study was aimed at determining the productivity of lamb from mating between Garut ewes and Dorper rams. The animals used were 108 sheep. A total of 98 heads of Garut ewes were randomly divided into two groups; the first group was mated with Dorper rams (5 heads), while the second group was mated with Garut rams (5 heads) as a control group. The data observed were birth weight, weaning weight, average daily gain (ADG), reproduction index (RI), and productivity index (PI). The data were analyzed with an independent sample T-Test. Birth weight, weaning weight, and ADG of Garut and Dorper crossbred lambs were 2.20±0.54 and 2.60±0.71 kg; 14.91±3.57 and 16.27±3.69 kg; and 90.21±32.11 and 119.12±42.64 g/day, respectively. Pre-weaning growth of Dorper-crossed lambs was higher (P&lt;0.05) than those of Garut lambs. The RI and PI of Garut ewes mated with Garut and Dorper rams were 3.15±1.38 and 2.87±1.33 head/year; and 32, 10±15.53 and 38.91±21.00 kg/year, respectively. The PI of ewes mated with Dorper rams was higher (P&lt;0.05) than that of Garut ewes mated with Garut rams. It is concluded that the cross of the Garut ewes with the Dorper rams improved productivity by increasing the pre-weaning growth of the lambs.

​In the Absence of Sexual Competition, Rams with Low Social Ranks Show more Appetitive Sexual Behaviors than Males with High Ranks

Background: Usually, social order is defined by the animals´ size, live weight, or age. This study evaluated the effect of social rank and morphometric characteristics upon appetitive and consummatory sexual behaviors in Dorper rams in absence of sexual competition. Methods: The research took place in northern Mexico (26°N), 36 rams allocated into two groups were used: Low social rank (LR; n = 17) and high social rank (HR; n = 19). Behavior tests were performed for all the males, for which each one was placed in contact with a female in estrus. Result: There were no differences between ranks and morphometric characteristics (P less than 0.05). A correlation of 29% was found for the success index concerning odor in HR. Likewise, a relationship existed between the presence of horns (Pho) and all the other variables, but not between PHo vs success index (rho 0.07). Appetitive sexual behavior was the highest (P less than 0.05) for LR, while HR had more consummatory sexual behaviors (P less than 0.05). We conclude that sexual hierarchy exists even when the males have the same morphometric characteristics, nonetheless, males with low social ranks show more appetitive sexual behaviors while those with high ranks show a higher number of consummatory sexual behaviors when managed in intensive farming conditions.

PSVI-14 Effect of Morphometric Traits Upon Social Hierarchy of Dorper Rams from Northern Mexico

Abstract Usually, social order is defined by the animal size, live weight, or age. This study aimed to evaluate the association among horn presence (HP), and horn size (HS) on social rank hierarchy. Adult Dorper rams (n=24) with similar live weight (LW), body condition score (BCS), and age (AG) were subjected to a behavioral test to define the success index (SI, ranked form 0 to 1) based on male-to-male interactions, determining three social ranks: low hierarchy rams (LHR; SI = 0-0.33; n=9), medium hierarchy rams (MHR; SI=0.34-0.66; n=10) and high hierarchy rams (HHR; SI= 0.67-1; n=5). Afterward, skull, horn (HP and HS), and body morphometrics were measured. The GLM procedure of SAS (SAS Institute, Cary, NC) was used to analyze LW, AG, BCS, HS and HP with three social ranks and five to ten replicates per group. Rams within social rank were the experimental units. Differences were considered as significant at P &amp;lt; 0.05. Regarding HP, 80% of the HHR rams had horns, while 77.7% of the LHR rams were hornless, with intermediate values for MHR (50%), but no differences were found regarding HS between low, medium and high hierarchy rams (85.1±2.6, 84.3±3.3, and 90.7±4.7, respectively). In conclusion, while presence of horns have an important role for establishing social hierarchy, it is a complex trait influenced by factors other than horn presence or size so, we recommend more research in relation to other factors that could influence the position of rams in the hierarchy rank levels of the herds.