本文由澳大利亞羊駝協會供稿
KEY REPRODUCTIVE FEATURES
關鍵生殖特徵
Male Anatomy
雄性羊駝解剖學
The male has two testiclesin a non- pendulous scrotum situated below the anus. The function of thescrotum is to maintain the testicles, which are the source of sperm, at aslightly lower temperature than the rest of the body. The prepuce is the sacholding the penis. This normally points backwards during urination, but whenthe male is sexually aroused the prepuce points forward and the penis isextruded for mating. The tip of the penis has a slightly clockwise curvature.In young males the penis is adherent to the prepuce and they are usually unableto extrude the penis sufficiently for mating until they are about 2.5-3 yearsold. Eruption of fighting teeth appears to correlate with approximate time ofsexual maturity.
雄性羊駝肛門下方的非下垂陰囊中有兩個睪丸。睪丸是精子的來源，陰囊的功能是使睪丸保持在比身體其它部位稍低的溫度。包皮是包住陰莖的囊。通常在排尿期間向後指向，但當雄性羊駝被性喚起時，包皮向前指向，陰莖被擠壓以進行交配。陰莖尖端略微向順時針方向彎曲。年幼羊駝的陰莖附著在包皮上，通常無法充分擠壓陰莖以交配。羊駝通常要到大約兩歲半至三歲性發育成熟。對抗牙齒萌出的時間與性成熟的時間大致。
Figure 1: Reproductive anatomy of a malealpaca /雄性羊駝的生殖解剖
Female Anatomy
雌性羊駝解剖學
The female has a small opening called thevulva situated below the anus. The vulva leads to the vagina which is theactual birth canal and passage for the penis during copulation. (Fig. 2). Thevagina leads to the cervix which is the opening into the uterus. The uterusconsists of a body and two uterine horns. During mating the male deposits spermdirectly into the uterus of the female.
雌性羊駝的肛門下方有一個小開口，是其外陰。外陰通向陰道，陰道是產道及交配過程中陰莖的通道。 (圖2)。陰道通向子宮頸，子宮頸是通向子宮的開口。子宮由一個主體和兩個子宮角組成。在交配期間，雄性羊駝將精子直接沉積到雌性羊駝的子宮中。
The oviduct carries the egg from the ovary tothe uterus and is also the site of fertilization of the egg by sperm. In alpacas most pregnancies occur in the lefthorn. Young females usually reach sexual maturity at about 12-15 months of ageand when they are 45-50kg. This gives the female adequate time to mature andreduces the risk of problems during parturition. Potentially adult femalealpacas can remain productive up to 13-15 years of age.
輸卵管將卵子從卵巢運送到子宮，也是精子受精卵子的部位。羊駝大多妊娠發生在左子宮角。雌性羊駝通常在12-15個月、體重45-50公斤時達到性成熟。雌性羊駝有足夠的時間發育，並降低其在分娩過程中出現問題的風險。通常成年雌性羊駝在13-15歲時仍有生育力。
Figure 2: Reproductive anatomy of a femalealpaca /雌性羊駝的生殖解剖
REPRODUCTIVE PHYSIOLOGY
生殖生理學
Most domestic species show regular distinctperiods of 'heat' or sexual receptivity. At each 'heat' one or more maturefollicles (fluid sacs) on the ovaries ruptures spontaneously releasing an egg(ovulation). The number of follicles depends on the species. Alpaca females donot 'come on heat' but show prolonged periods of sexual receptivity duringwhich time they will allow the male to mate (Fig. 3). Ovulation generally doesnot occur spontaneously and it is the act of copulation itself which inducesovulation. During copulation, the penis of the male stimulates the vagina andcervix of the female. This stimulation causes the release of hormones from thebrain of the female which circulate in the blood to the ovaries and cause finaldevelopment and ovulation of the ovarian follicle (Fig. 2).
大多數物種表現出明顯的性接受期。在每次性接受期，卵巢上的一個或多個成熟卵泡 (液囊) 破裂，自發地釋放卵子(排卵)。卵泡的數量取決於物種自身。雌性羊駝不會「發情」，但會表現出較長時間的性接受性，在此期間它們會允許雄性羊駝與其交配(圖3)。排卵一般不會自發發生，而是交配行為本身誘導了排卵的發生。在交配過程中，雄性羊駝的陰莖刺激雌性羊駝的陰道和子宮頸。這種刺激導致雌性羊駝大腦中荷爾蒙的釋放，荷爾蒙通過血液循環到卵巢，促使卵巢卵泡的最終發育和排卵 (圖2)。
In mature alpacas, providing there is anabsence of a corpus luteum and progesterone, the female is usually sexuallyreceptive. Generally, only one follicle, on one of the ovaries, reachesmaturity. It can remain at this stage for up to 10-12 days. If mating occursduring this time, ovulation may be induced (Fig. 3). If mating does not occurthe follicle regresses. However, at the same time, another follicle isgenerally maturing (on either the same or the opposite ovary). This providesoverlapping waves of follicular development and regression. Hence, prolongedperiods of sexual receptivity may be shown (Fig. 3). There may be intermittentperiods of non-receptivity of 1-2 days' duration, as new follicular wavescommence. Ovulation occurs approximately 30-40 hours after mating. Afterovulation, as in other domestic species, the cells around the collapsedfollicle proliferate and form a corpus luteum, which secretes the hormoneprogesterone.
在成熟的羊駝中，如果體內沒有黃體和黃體酮的產生，雌性羊駝通常會表現出性接受性。一般來說，只有一個卵泡在一個卵巢內達到成熟，並在這個階段保持長達10-12天。如果在此期間交配，可能會誘發排卵 (圖3); 如果沒有發生交配，卵泡就會消退。然而，與此同時，另一個卵泡通常會成熟（在同一或相反的卵巢上）。由此構成了卵泡發育和消退的重疊波。因此，雌性羊駝可能會表現出較長時間的性接受性(圖3)。隨著新的卵泡波的開始，雌性羊駝可能會有1-2天的間歇性非接受期。排卵大約發生在交配後30-40小時。排卵後，與其它被馴服物種一樣，卵泡周圍的細胞增生並形成黃體，從而分泌激素黃體酮。
Progesterone suppresses receptivity for aslong as the corpus luteum remains functional. Hence spit-offs (see Alpaca Note2 Mating Behaviour) are a useful tool for seeing if there is a corpus luteumpresent – an indirect method of pregnancy testing. If the alpaca does notconceive, the corpus luteum remains functional for 10-13 days then regresses,and another follicle begins to develop to maturity (again). As the folliclematures the female once again becomes sexually receptive (Fig. 3). If thefemale conceives and becomes pregnant, the corpus luteum does not regress butcontinues to produce the hormone progesterone throughout the entire pregnancy.
只要黃體功能正常，孕酮就會抑制其性接受性。因此，吐唾沫(參見羊駝注2交配行為)是檢測黃體是否存在的一種實用的間接測試妊娠的方法。如果羊駝沒有受孕，黃體功能可保持10-13天，然後消退，另一個卵泡開始發育成熟(再次)。隨著卵泡的成熟，雌性羊駝再次表現出性接受性(圖3)。如果雌性羊駝受孕並懷孕，黃體則不會消退，而是在整個妊娠期間繼續產生激素黃體酮。
Ovulations are generally single, i.e. onlyone follicle ruptures. Multiple ovulations occur in 10% of natural matings buttwin births are extremely rare (approx. 1 in 10,000 births). Spontaneousovulation occasionally occurs in alpacas.
排卵通常是單一的，即只有一個卵泡破裂。多次排卵在的自然交配中佔10％，但雙胞胎極為罕見（大約10,000次中有1次）。羊駝偶爾發生自發排卵。
Figure 3 : Normal pattern of ovarian activity in alpaca/
Further Reading
擴展閱讀
Fowler, M.E.
Medicine and Surgery ofSouth American Camelids. Iowa State University Press, Iowa, U.S.A. 1989
Hoffman, C., and Asmus, I.
Caring for Llamas: A health and managementguide.
Rocky Mountain Lama Association, Colorado,U.S.A. 1989
Johnson, L.W.
The Veterinary Clinics ofNorth America, Volume 5, No. 1: Llama Medicine.
W.B. Saunders Co., Philadelphia, U.S.A. 1989
Johnson, L.W.
The Veterinary Clinics ofNorth America, Volume 10, No. 2: Update on Llama Medicine. W.B. Saunders Co.,Philadelphia, U.S.A. 1991
McMillan, E. and Jinks C. & A.
Alpaca BreedersReproduction Handbook. Alpaca Publications Australia. 1998
Much of this material has been adapted fromAn introduction to the unique reproductive physiology and breeding activity of SACs by Dr. Deidre Bourke:Proceedings of the International AlpacaConference, held in Fremantle, WA 1998, with significant contributions from Dr. Jane Vaughan, Dr. Ewen McMillan, Dr.George Jackson, and Carolyn Jinks.
這些材料中的大部分內容是根據Deidre Bourke博士，在華盛頓州弗裡曼特爾1998舉行的國際羊駝會議上，對SAC獨特的生殖生理學和繁殖活動的介紹改而成。 Ewen McMillan博士, Dr. George Jackson博士, 及Carolyn Jinks對此做出了重大貢獻。
Australian Alpaca AssociationLtd.
澳大利亞羊駝協會
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Disclaimer:The management practices detailed in this overview do not constituteveterinary advice.Any alpacaappearing to have an adverse condition should be assessed by a veterinarian.
免責聲明：本概述中詳述的管理實踐不構成獸醫意見。任何患病羊駝，應由獸醫進行診治。