repro across species SDL part 2

Question 1

at what age do the testes usually descend in rabbits

Answer 1

10 weeks

Question 2

Female reproductive anatomy is slightly different in rabbits than other species. Outline why they are different.

Answer 2

1. Duplex Uterus:
   Two Uterine Horns: Unlike many other mammals, rabbits have a duplex uterus, meaning they have two completely separate uterine horns with no uterine body. Each horn has its own cervix.
   Two Cervices: Rabbits possess two cervices (bifurcated cervix), which is uncommon in most mammals. This allows them to potentially be pregnant in both uterine horns at the same time with embryos from different matings.
2. No True Uterine Body:
   Since rabbits have no unified uterine body, implantation of embryos occurs directly within each uterine horn. This is different from species with a single uterine body where the embryo implants centrally.
3. Vaginal Structure:
   The vagina of a rabbit leads to two separate cervices and is relatively short compared to other species. This is adapted for their breeding patterns, allowing frequent mating.

Question 3

When is puberty typically in rabbits?

Answer 3

4-6 months
Smaller Breeds (e.g., Netherland Dwarf, Holland Lop):Puberty occurs earlier, usually around 4 to 5 months.

Medium-Sized Breeds (e.g., New Zealand, Rex): Puberty is generally around 5 to 6 months.

Larger Breeds (e.g., Flemish Giant): Puberty is later, occurring around 6 to 9 months.

Question 4

Outline the key points of the rabbit oestrous cycle, oestrous behaviour, type of ovulation, nesting behaviour and parturition.

Answer 4

induced ovulators, oestrus jan-october

Question 5

compare reproductive cycles in small rodents

Answer 5

Question 6

2. A 6-week-old rabbit is presented to you for sexing. On applying gentle pressure near to the genitals, you notice that the genital opening is rounded. It points caudally. What sex is the rabbit?

Answer 6

male

Question 7

3. How long is the gestation period in a rabbit?

Answer 7

30-33 days

Question 8

What is the optimal, recommended age for (electively) spaying rabbits?

Answer 8

6-9 months.
(At this age, the ovaries and uterus are well developed and so easier to locate and handle, but they have not yet accumulated too much fat in their mesometrium, which can make neutering more difficult).

Question 9

At what time of year can a rabbit get pregnant?

Answer 9

The breeding season is January to September, but rabbits can get pregnant all year round.

Question 10

When does ovulation occur in rabbits?

Answer 10

Rabbits are induced ovulators. They release an egg 10-13 hours after mating.

Question 11

8. How long does pseudopregnancy typically last in the rabbit?

Answer 11

16-18 days

Question 12

9. At what stage of pregnancy, can pregnancy in rabbits be detected by PALPATION?

Answer 12

10-14 days

Question 13

10. At what stage of pregnancy, can pregnancy in rabbits be detected by ULTRASOUND?

Answer 13

6-7 days

Question 14

11. At what stage of pregnancy, can pregnancy in rabbits be detected by RADIOGRAPHY?

Answer 14

10-14 days

Question 15

12. Neutering is recommended for all non-breeding does, to prevent adenocarcinoma. What proportion of intact does >3 years old, develop this condition?

Answer 15

50-80%

Question 16

Which method would you NOT use in the castration of a male rabbit?

Answer 16

Pre-scrotal incision, open technique.
(We should never use a fully open castration technique in a rabbit due to their inguinal canal which remains open throughout life, putting them at risk of post-op herniation.)

Question 17

What distinctive mating behaviour do camelids exhibit?

Answer 17

When a female is truly receptive, it will usually assume a position of sternal recumbency (kushing) within seconds to a few minutes after introduction of a male and allow the male to breed. While mounting, the male will typically begin a vocalization described as orgling. Mating can take up to 45 minutes, and ejaculation occurs over an extended period of time.

Question 18

What type of ovulators are camelids?

Answer 18

incuced - An ovulation induction factor in the semen stimulates reflex ovulation ~24–30 hours after mating.

Question 19

What influences the choice of method used for pregnancy diagnosis int he camelid?

Answer 19

A female with a functional CL will aggressively refuse the male’s efforts to mount. An indication of pregnancy is the female’s rejection of the male if reintroduced >15 days after the initial breeding. Progesterone concentrations >1 ng/mL are typical in females with a functional CL and can be used for confirmation of both ovulation at 6–9 days after mating and of pregnancy at >21 days after mating. Persistent CL are periodically seen and account for most false-positive results when using serum progesterone for pregnancy confirmation.

Rectal palpation for pregnancy diagnosis is practical in llamas at >45 days of gestation. It is usually not possible to safely perform rectal palpation in alpacas, unless the palpator is experienced and has small hands. Pregnancy can also be diagnosed by transrectal ultrasound from approximately 28 days of gestation, although the finding of fluid by 10–12 days after mating can raise suspicion, and diagnosis is reasonably sure by day 21 when a hyperechoic “embryo” is seen. Transcutaneous ultrasonography can confirm pregnancy starting 45 to 60 days after conception.

Question 20

in camelids What are the most likely findings of ultrasound in a pregnant animal in terms of number and uterine location?

Answer 20

• rare to see twins, most commonly singletons
• In camelids, the fetus is most commonly found in the left uterine horn, regardless of which horn ovulation occurred in. This is a unique feature of camelid pregnancy, as the left uterine horn appears to be the preferred site for implantation and fetal development.
  Right Uterine Horn: Pregnancies in the right uterine horn are rare, occurring in a small percentage of pregnancies (around 5–10%)

Question 21

What is the length of gestation for alpacas?

Answer 21

342 days +/- 10 days

Question 22

At what age do laying hens begin to lay, and how many weeks are they kept in lay commercially?

Answer 22

begin laying at 18-22 weeks
kept in production for about 72 to 80 weeks. During this period, they reach peak egg production at around 24 to 30 weeks and maintain a high rate of laying for several months.

Question 23

What are the consequences of bringing pullets (hen under 1 year been laying for only a few months) into lay too early, and what might be the cause?

Answer 23

• Smaller Eggs
• Reduced Overall Egg Production
• Health Issues
• Eggshell defects (e.g., thin or soft shells).
• Egg binding (difficulty laying eggs).
• Osteoporosis and weak bones, increasing the risk of fractures.
• Reproductive Disorders
• Stunted Growth

Causes of Early Laying:
- Incorrect Lighting Management
- Excessive protein or energy intake early in life can accelerate growth and cause pullets to reach sexual maturity sooner than they should.
- Genetic Factors
- Stress or Environmental Factors:

Question 24

How does increasing day-length influence egg production?

Answer 24

Chickens are photoperiodic animals, meaning their reproductive activity is heavily influenced by the length of daylight they are exposed to. Longer days (increased light exposure) stimulate the hypothalamus in the brain to release gonadotropin-releasing hormone (GnRH), which, in turn, triggers the release of reproductive hormones like follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
increasing daylight length = stimulates egg production, maintains consistent production and prevents molting

Question 25

What happens to shell quality over time?

Answer 25

• eggshell thins
• as hens get older produce larger eggs - requiring more shell
• calcium depletion
• more shell defects
• hormonal decline
• slower shell deposition

Question 26

What mineral is the major nutrient in layer-feed after protein?

Answer 26

calcium for
- eggshell formation
- bone health
- egg production efficiency