Dominance and mating behavior of rams under paddock conditions

Contents A total of 30 ewes in three-sire or four-sire breeding pens were observed continously during daylight for four consecutive days of a synchronised estrus period. A linear dominance hierarchy was observed between the rams which was consistent and stable for each observation period. The highest ranking ram had more mounting encounters and was more aggressive than the subordinate rams. This activity disturbed his ejaculatory mechanism and sometimes resulted in the absence of ejaculation or energetic ejaculation. In the four-sire breeding pens the dominant ram often found it impossible to completely curtail the sexual activity of the subordinate rams. He made 70.9% and 49.0% of the total number of mounts in the three-sire and our-sire breeding pens, respectively. At the beginning of each observation period the highest ranking ram claimed most estrous ewes for his “harem”. The subordinate rams only had an opportunity to mate when several ewes were simultaneously in estrus. The average number of mounts per first copulation per ram was 2.2 (range 1.3–3.1). The time spent from first contact with the ewes until completion of the copulatory act in first copulation varied from 0.2–16.2 min. with an average of 4.0 min., whereas this interval was increased during the second copulation (average = 5.8 min.). Furthermore, the mating behavior of single rams was also observed. Inhalt: Rangordnung und Paarungsverhalten von Schafbocken unter Stallhaltungsbedingungen Es wurden insgesamt 30 Mutterschafe in Zehnergruppen mit 3 bzw. 4 Böcken gleichzeitig in einer Buchte gehalten und wahrend einer Östrusperiode tagsüber beobachtet. Fur die Böcke konnte eine klare Rangordnung erkannt werden, die über alle Beobachtungsperioden unverändert blieb. Der an höchster Stelle stehende Bock vollzog mehr Aufsprungsversuche und war aggressiver als die untergeordneten Böcke. Diese Aktivitäten störten bei ihm wiederholt den Ejakulatonsmechanismus, so daß ein unvollständiger Deckakt bei fehlender Ejakulation die Folge war. Bei gleichzeitiger Anwesenheit von 4 Böcken in einer Gruppe way es für den dominanten Bock häufig unmöglich, die Sexualaktivität der untergeordneten Böcke vollständig zu unterbinden. Auf den dominanten Bock entfielen bei Anwesenheit von 3 Böcken 70,9% aller Auf sprünge, bei der Anwesenheit von 4 Böcken waren dies 49,0%. Zu Beginn einer jeden Beobachtungs-periode versuchte der an höchster Stelle rangierende Bock, die meisten östrischen Mutterschafe für seinen “Harem” zu beanspruchen. Die untergeordneten Böcke hatten nur dann Gelegenheit zu decken, wenn mehrere Mutterschafe gleichzeitig im Östrus waren. Im Durchschnitt betrug die Anzahl der Auf sprünge bei der ersten Belegung pro Bock 2,2 (Schwankungsbreite 1,3 -3, 1). Die erforderliche Zeit fur die erste Paarung uariierte bei einem Mittelwert uon 4,0 Alin. zwischen 0,2 und 16,2 Min.; diese Zeitspanne erhöhte sich allerdings für die zweite Belegung auf durchschnittlich 5,8 Min. Darüber hinaus wurde das Paarungsuerhalten einzelner Böcke ohne die Anwesenheit anderer beobachtet.     

Reproductive behavior in hair sheep rams under tropical conditions

The reproductive efficiency of sheep herds depends to a great extent on the ram. Male reproductive evaluation allows to select for the best and eliminate those with reproductive problems. The objective was to evaluate the effect of breed and age group on the reproductive behavior of hair sheep rams in the tropics of Mexico. Pelibuey (n?=?42), Blackbelly (n?=?30), Dorper (n?=?44), and Katahdin (n?=?30) rams of two age groups: young (n?=?74, 1–1.5 years old) and adult (n?=?72, 2–4 years old) were evaluated. Serving capacity (10-min duration) and breeding soundness evaluation (BSE) tests were carried out in each ram. In the first test, rams were classified as suitable and unsuitable, and in the BSE test, they were classified as satisfactory, questionable, or unsatisfactory. The response variables were analyzed using chi-square test or analyses of variance (ANOVA). ANOVA included the fixed effects of breed, age group, and their interaction. In the serving capacity test, 79.5% of the rams were considered suitable, with no breed differences (P?>?0.05). Adult rams (90.3%) had the highest proportion of suitable rams (P?<?0.05). In the BSE test, 80.2% of the rams were satisfactory; only breed being significant (P?<?0.05). Pelibuey breed had the highest proportion of satisfactory rams (91.4%). Breed × age interaction was no significant for any trait. After serving capacity and BSE tests, a high proportion of rams was found not suitable for reproduction (36.3%), which is expected to cause low fertility in the flock.

     

人工控制下熊蜂（Bombus lucorum）交配及影响因素的研究

对人工控制条件下熊蜂(B.lucorum)有性蜂性成熟期、性比、交配行为和影响因素进行了研究.研究表明,最佳交配日龄蜂王为8日龄,雄蜂为12日龄;影响熊蜂交配的因素包括温度、湿度和光照等;最佳交配雌雄性比为15;交配过程中蜂王和雄蜂的行为各不相同;交配时间大约持续30min.     

Relationship between serving capacity of beef bulls as predicted by the yard test and their fertility during paddock mating

Six experiments were conducted to determine the relationship between the serving capacity of bulls as predicted by a 40-min yard test and their fertility during paddock mating, measured by the conception rate at first oestrus and the pregnancy rate at the end of 10 weeks of mating. Twenty bulls varying in serving capacity from 1 to 11 were mated to 40 heifers each. As serving capacity of the bulls increased from 1 to 7, conception rate increased from 18 to 70%. Average conception rates achieved by 4 bulls with low serving capacity (25.3%), 8 bulls with medium serving capacity (61.4%) and 7 bulls with high serving capacity (72.3%) were all significantly different from one another. Bulls of low serving capacity (1 or 2 services) impregnated a significantly lower proportion of their heifers (40.3%) than bulls with medium (91.2%) or high (95.3%) serving capacity. It was concluded that bulls of serving capacity 1 or 2 (in 40 min) should be considered unsound for breeding. An explanation for the results and their implication in beef production is discussed.     

Influence of feeding level on live body weight and semen characteristics of Sardinian rams reared under intensive conditions

The aim of the present study was to assess the effects feeding level on body weight changes and semen parameters in adult Sardinian rams reared under intensive conditions in a semi-arid area of southern Italy. During an experimental period of 90 days, 24 healthy Sardinian rams were divided into three equal groups that differed in their feeding level, in terms of concentrate amount. The control-concentrate (CC; n = 8) group received 1.0 times their maintenance requirements, the medium-concentrate (MC; n = 8) group received a diet that supplied 1.2 times their maintenance requirements, and high-concentrate (HC, n = 8) group received a diet that supplied 1.5 times their maintenance requirements. Mixed vetch–oat hay was offered ad libitum to ram groups and water and mineral licks were freely available. Body weight and feed intake was recorded weekly, and semen characteristics were determined every 2 weeks. Dietary treatment affected final body weight (P < 0.01) as feeding level increased. Total dry matter and protein intake changed significantly (P < 0.05 and P < 0.01, respectively) among experimental groups. Semen volume and concentration were positively influenced by feeding level for HC group, whereas no differences were observed in sperm viability and scrotal circumference of rams. It was concluded that dietary level with higher concentrate supplementation resulted in improved body weight gain, feed intake, sperm production, and semen quality in Sardinian rams.     

Sexual behavior of medium-ranked rams toward non-estrual ewes is stimulated by the presence of low-ranked rams

In sheep, access to receptive females is affected by dominance relationships. The aim of the first experiment was to determine how the presence of high- or low-ranking rams affects sexual behavior of medium-ranked rams toward non-estrual ewes in pen tests. A complementary objective was to determine whether the presence of 1 or 2 rams has stronger effects. Social rank of 13 rams was determined using the food competition test. The number of courtship behaviors, mounts, and ejaculations was recorded in pen tests with non-estrual restrained ewes. In the first experiment, medium-ranked rams were subjected to 5 tests with: (1) the ewe alone, (2) the ewe and 1 restrained tied high-ranked ram, (3) the ewe and 2 restrained tied high-ranked rams, (4) the ewe and 1 restrained tied low-ranked ram, and (5) the ewe and 2 restrained tied low-ranked rams. The number of high- or low-ranked rams (1 or 2) present in the tests did not affect the results. There were no differences on courtship behaviors, but the number of mounts and mounts with ejaculation was greater when low-ranked rams were present. In a second experiment, it was determined whether the presence of medium- or low-ranked rams stimulates sexual behavior of high-ranked rams. The high-ranked rams were tested with: (1) the ewe alone, (2) the ewe and 1 restrained tied medium-ranked ram, and (3) the ewe and 1 restrained tied low-ranked ram. No differences were recorded in relation to presence of other rams during the tests. It was concluded that the presence of low-ranked rams stimulates sexual behavior of medium-ranked rams toward non-estrual ewes in pen tests. This effect was not related with the number of rams included in the test. The presence of medium- or low-ranked rams did not alter the sexual behavior of high-ranked rams toward non-estrual ewes.     

The behavior of calves under various housing conditions]

Investigations were performed regarding the length of rest, sucking and feeding and the daily rhythm of these activities in calves kept with their mothers on pasture or in stables and the motility of the calves. Length of rest and feeding in breeding calves kept in groups and length of rest and sucking in breeding and fattening calves (automatic feeding and bucket feeding) were examined too. The examinations were performed starting from the morning feeding to the end of the day over a period of appr. 10.5 to 12 hours. During this time, calves 2--4 weeks of age ran about 550,7 m, 6--8 weeks of age 423.7 and 10--12 weeks of age 388.1 m. The length of sucking under automatic feeding conditions was comparable to the datas obtained from calves kept with their mothers. Bucket feeding took 2--4 minutes regardless whether rubber teats were used or not. Fattening calves in groups or single showed feint sucking or licking activities of 70.0 and 114.0 minutes/day respectively, breeding calves 39.8 and 20.8 minutes/day resp. Feint sucking in connection with a deficit of real sucking was observed regularly under bucket feeding conditions but only in those cases of automatic feeding, where the calves pushed each other aside from the feeding facilities. Feint rumination was observed in all fattening calves when kept strawlessly and lasted for about 31 minutes/day. Neither the feint rumination nor the feint sucking ever reached physiological lengths. Both behavioural patterns may be important in regard to animal welfare considerations of special maintenance conditions.     

舍饲条件下肉用绵羊的主要行为特征

对内用绵羊在舍饲和放牧两种状态下的行为方式和特征进行细致的观察和记录，并比较研究舍饲条件下的绵羊行为。     

Monthly changes in some reproductive parameters and in testosterone and thyroxine values of rams throughout one year under continental climate conditions

Ten sexually mature rams were used in this study. Blood and semen was collected monthly from rams for one period of 12 months to study semen characteristics and to determine serum testosterone and thyroxine (T4) hormones. Results showed that all of the rams are continuous breeders as they show sexual desire and produce semen throughout the whole year. However, monthly variations in reproductive and semen characteristics were detected. Relative testes volume, ejaculate volume, sperm motility, sperm concentration and serum testosterone levels were higher during autumn months than at other months of the year. In addition, autumn months showed moderate percentage of abnormal spermatozoa. Furthermore, serum T4 was significantly higher in summer and autumn months than that observed in winter and spring. These results indicate that ram semen quality in Afyon continental climate conditions may be better during late summer and early autumn months than during other months of the year.     

The effect of individual liveweight and use of teaser rams prior to mating on the reproductive performance of ewe hoggets

AIM: To determine the effects of liveweight (LW) and use of teaser rams prior to mating on both the mating performance and pregnancy rate of ewe hoggets.

METHODS: Romney hoggets (n=841) were weighed and randomly assigned to one of two treatment groups; either exposed to seven harnessed, vasectomised (teaser) rams for 17 days prior to the breeding period (n=283); or not exposed to teaser rams (unteased, n=558). Harnessed Perendale rams were then introduced for two oestrous cycles. Using crayon marks, hoggets were identified as having been mated during the first 17 days only, during the second 17 days only, during both periods, or not mated. All mated hoggets were then scanned for pregnancy using ultrasound, 48 days after the end of the breeding period, and identified as being either non-pregnant, or as single-, twinor triplet-bearing.

RESULTS: Hoggets mated in either the first 17 days only or in both the first and second 17-day periods were heavier than those mated in the second period only (p<0.001). Those mated in the first or second 17-day period only, and those mated in both periods were all heavier prior to mating than those not mated at all (p<0.001). Twin-bearing hoggets were heavier than both their single-bearing and non-pregnant counterparts (p<0.001). A greater proportion of the teased hoggets were mated in the first 17 days only compared with unteased hoggets (62.6 vs 32.1%; p<0.001). In contrast, more of the unteased hoggets were marked in the second 17-day period only (p<0.001). A greater proportion of mated, unteased hoggets were found to be non-pregnant in comparison to their teased counterparts (17.8 vs 11.2%; p=0.02).

CONCLUSIONS: Heavier hoggets at breeding were more likely to be mated in the first 17 days of the breeding period and more likely to be twin-bearing. Use of teaser rams for 17 days prior to the breeding period increased the proportion of hoggets mated in the first 17 days, increased conception rates, and thus increased the proportion of pregnant hoggets. These results indicate that farmers should utilise teasers for 17 days prior to commencement of the breeding period and avoid mating hoggets that weigh below 36 kg.     

The effect of individual liveweight and use of teaser rams prior to mating on the reproductive performance of ewe hoggets

AIM: To determine the effects of liveweight (LW) and use of teaser rams prior to mating on both the mating performance and pregnancy rate of ewe hoggets. METHODS: Romney hoggets (n=841) were weighed and randomly assigned to one of two treatment groups; either exposed to seven harnessed, vasectomised (teaser) rams for 17 days prior to the breeding period (n=283); or not exposed to teaser rams (unteased, n=558). Harnessed Perendale rams were then introduced for two oestrous cycles. Using crayon marks, hoggets were identified as having been mated during the first 17 days only, during the second 17 days only, during both periods, or not mated. All mated hoggets were then scanned for pregnancy using ultrasound, 48 days after the end of the breeding period, and identified as being either non-pregnant, or as single-, twin or triplet-bearing. RESULTS: Hoggets mated in either the first 17 days only or in both the first and second 17-day periods were heavier than those mated in the second period only (p<0.001). Those mated in the first or second 17-day period only, and those mated in both periods were all heavier prior to mating than those not mated at all (p<0.001). Twin-bearing hoggets were heavier than both their single-bearing and non-pregnant counterparts (p<0.001). A greater proportion of the teased hoggets were mated in the first 17 days only compared with unteased hoggets (62.6 vs 32.1%; p<0.001). In contrast, more of the unteased hoggets were marked in the second 17-day period only (p<0.001). A greater proportion of mated, unteased hoggets were found to be non-pregnant in comparison to their teased counterparts (17.8 vs 11.2%; p=0.02). CONCLUSIONS: Heavier hoggets at breeding were more likely to be mated in the first 17 days of the breeding period and more likely to be twin-bearing. Use of teaser rams for 17 days prior to the breeding period increased the proportion of hoggets mated in the first 17 days, increased conception rates, and thus increased the proportion of pregnant hoggets. These results indicate that farmers should utilise teasers for 17 days prior to commencement of the breeding period and avoid mating hoggets that weigh below 36 kg.     

Pampas deer (Ozotoceros bezoarticus) courtship and mating behavior

Background

Pampas deer, Ozotoceros bezoarticus (Linnaeus 1758), is a South American grazing deer categorized as "near threatened". However, knowledge about pampas deer behavior including courtship and mating is scarce and incomplete. The aim of this study was to characterize the courtship and mating behavior of the pampas deer (Ozotoceros bezoarticus), an endangered species from South America.

Methods

We performed focal observations of 5 males allocated at the Estación de Cría de Fauna Autóctona Cerro Pan de Azúcar, Uruguay, 4 times a day from 5 to 20 minutes each time on a daily basis from February to May. During that period we recorded all courtship and mating behaviors, as well as quantified the frequency of the specific behaviors shown. As mating were rarely observed, we recorded that behavior when it was observed in the context of other studies performed in the same population during the following 2 years.

Results

During the observation period we recorded 928 courtships and 5 mating periods. In addition, we recorded 10 more matings performed during other studies, totaling 15. The duration of each mating calculated from the 15 recordings was 3.9 ± 0.4 s, and the total period of female receptivity (from first to last mating acceptance) was 8.2 ± 1.1 min. Main observed courtship behaviors in males were “chase” and “ostentation”, while the most observed close to mating were “chinning”, “raised head” and “anogenital sniffing”. The most observed behaviors in females during the mating period were “vulva exhibition” and “move away”.

Conclusion

This is the first detailed report in pampas deer mating behavior. Estrus lasted only 8 min accepting only 3 short copulations per estrus. However, female behavior during courtship can be characterized as highly proceptive.     

Relationship between sexual behavior classifications of rams and lambs sired in a competitive breeding environment

The objectives for this study were to 1) determine the relationship between sexual performance class and lambs sired in a competitive mating environment, and 2) determine whether the male-oriented ram test is valid. Fifteen 2- to 3-yr-old whitefaced rams classified as female-oriented, with high or low sexual performance, or classified as male-oriented were used in a multiple-sire breeding arrangement. Five groups of approximately 200 ewes each were exposed for 21 d to 3 rams per group consisting of 1 ram from each class. Rams were blocked for sexual class, and those with close genetic relationship were assigned to different pens. Genomic DNA was prepared from blood collected from 15 rams, 934 ewes, and 1,757 lambs. Up to 4 microsatellite markers were used to determine a lamb's sire. Of 884 ewes with identifiable lambs (known sires), 178 ewes had single lambs, 408 had multiples sired by 1 ram, and 298 had multiples sired by more than 1 ram. The sexual partner preference test used to identify male-oriented rams did not absolutely reflect their sexual performance during competitive breeding. In contrast to only mounting and servicing males in preference tests before breeding, male-oriented rams sired 480 lambs from 330 ewes. Serving capacity tests predicted sexual performance of high and low sexual performance rams. High performance rams impregnated more ewes (499 vs. 258; P < 0.05) and sired more lambs (756 vs. 357; P < 0.05) than did low performance rams, respectively. Low performance and male-oriented rams did not differ for ewes impregnated or lambs sired. We conclude that 1) sexual partner preference tests used to classify male-oriented rams were not absolute in reflecting their breeding performance in a competitive breeding environment; 2) serving capacity tests predicted that high performance rams would breed more ewes than low performance rams and sire more lambs than either low performance or male-oriented rams; and 3) under the conditions of this study, low performance and male-oriented rams did not have an adverse impact on the overall breeding outcome. Combined, low performance and male-oriented rams sired 81 more lambs than did high performance rams, but this required twice as many rams to obtain approximately equal breeding results. Therefore, we suggest that serving capacity tests should be used to select high performance rams, reduce number of rams with marginal sexual performance, and make decisions on ram numbers needed.     

The effect of length of use of teaser rams prior to mating and individual liveweight on the reproductive performance of ewe hoggets

AIM: To determine the effects of liveweight (LW) and duration of teasing with vasectomised rams prior to breeding on both the mating performance and pregnancy rate of ewe hoggets. METHODS: Five hundred and forty-six (1/2) Romney x (1/4) Texel x (1/4) Finnish Landrace ewe hoggets were weighed and randomly assigned to one of three treatment groups: either exposed to five harnessed vasectomised (teaser) rams for 17 days prior to the breeding period (T17; n =181); exposed to five harnessed teaser rams for 8 days prior to the breeding period (T8; n = 184); or not exposed to teasers (unteased; n = 181). Harnessed entire rams of the same breed were then introduced for the duration of two oestrous cycles. Using crayon marks, hoggets were identified as having been mated in the first 5 days, Days 6-10, Days 11-17, during the first 17 days only, during both 17-day periods, during the second 17 days only, or not mated. All hoggets that were mated were scanned for pregnancy, using ultrasound, 48 days after the end of the breeding period, and identified as being either non-pregnant, or as singleton- or twin-bearing. RESULTS: Hoggets mated in the second 17-day period only were significantly lighter than those mated in either the first 17-day period only (p < 0.001), or in both the first and second 17-day periods (p < 0.02). At Day 1, twin-bearing hoggets were heavier than singleton-bearing hoggets (p < 0.001) and tended to be heavier (p = 0.06) than non-pregnant hoggets. At Day 18, twin-bearing hoggets were heavier than non-pregnant (p = 0.01) and singleton-bearing (p < 0.01) hoggets. A lesser proportion (p < 0.001) of unteased hoggets was mated in the first 17-day period only, compared to T17 hoggets. Conversely, a greater proportion of unteased hoggets was mated in the second 17-day period only, compared to either T8 (p < 0.01) or T17 (p < 0.001) hoggets. A lesser proportion of unteased hoggets was mated in the first 17 days of breeding, regardless of whether they returned to oestrus or not, in comparison to either T8 (p = 0.001) or T17 (p < 0.001) hoggets. Of those mated in the first 17 days of the breeding period, T8 hoggets were less likely (p < 0.05) to be mated in the first 5 days of that period but more likely to be mated in the last 7 days, compared to unteased and T17 hoggets. T17 hoggets had higher pregnancy rates to the first 17 days of breeding compared with either unteased (p = 0.01) or T8 hoggets (p = 0.06), and were more likely (p < 0.05) to be twin-bearing. In addition, the scanning percentage of T17 hoggets was higher than either unteased or T8 hoggets (p < 0.05). CONCLUSIONS: Heavier hoggets at breeding are more likely to be mated during the first 17 days of breeding and to be twin-bearing. While teasing for just 8 days increased the numbers mated in the first 17 days of breeding it did not increase the numbers of hoggets pregnant to that period. In contrast, teasing for 17 days did increase the numbers pregnant to the first 17 days of breeding and also increased the overall scanning percentage. It is recommended that farmers use a 17-day period of teasing before the breeding of ewe hoggets.