Editing User:Raven/ignore me (section)

=== Reproduction ===

[[File:Cow giving birth, in Laos (step by step).jpg|thumb|alt=Nine sequential photos showing the calf being born|A cow giving birth]]

The [[gestation period]] for a cow is about nine months long. The [[secondary sex ratio|ratio of male to female offspring at birth]] is approximately 52:48.<ref name="Roche Lee Berry 2006 pp. 2119–2125">{{cite journal |last1=Roche |first1=J.R. |last2=Lee |first2=J.M. |last3=Berry |first3=D.P. |year=2006 |title=Pre-Conception Energy Balance and Secondary Sex Ratio—Partial Support for the Trivers-Willard Hypothesis in Dairy Cows |journal=[[Journal of Dairy Science]] |publisher=[[American Dairy Science Association]] |volume=89 |issue=6 |pages=2119–2125 |doi=10.3168/jds.s0022-0302(06)72282-2 |pmid=16702278 |doi-access=free}}</ref> A cow's [[udder]] has two pairs of [[mammary gland]]s or teats.<ref name="Frandson 2013">{{cite book |last1=Frandson |first1=Rowen D. |last2=Wilke |first2=W. Lee |last3=Fails |first3=Anna Dee |title=Anatomy and Physiology of Farm Animals |date= 2013 |publisher=John Wiley & Sons |isbn=978-1-118-68601-0 |pages=449–451}}</ref> Farms often use [[artificial insemination]], the artificial deposition of [[semen]] in the [[Female Reproductive System|female's genital tract]]; this allows farmers to choose from a wide range of bulls to breed their cattle. [[Estrus]] too may be artificially induced to facilitate the process.<ref name="Hopper2014">{{cite book |last=Hopper |first=Richard M. |chapter=32. Artificial Insemination; 33. Pharmacological Intervention of Estrous Cycles |title=Bovine Reproduction |url=https://books.google.com/books?id=gxZTBAAAQBAJ |year=2014 |publisher=[[Wiley (publisher)|Wiley]] |isbn=978-1-118-47085-5}}</ref> [[Copulation (zoology)|Copulation]] lasts several seconds and consists of a single [[pelvic thrust]].<ref>{{Cite book |last1=Youngquist |first1=Robert S. |url=https://books.google.com/books?id=7qogKGcOENAC&dq=copulation&pg=PA940 |title=Current Therapy in Large Animal Theriogenology |last2=Threlfall |first2=Walter R. |date=2006-10-10 |publisher=Elsevier Health Sciences |isbn=978-1-4377-1340-4 |page=940 }}</ref>

Cows seek secluded areas for calving.<ref>{{cite journal |last1=Edwards |first1=S.A. |last2=Broom |first2=D.M. |year=1982 |title=Behavioural interactions of dairy cows with their newborn calves and the effects of parity |journal=[[Animal Behaviour (journal)|Animal Behaviour]] |volume=30 |issue=2 |pages=525–535 |doi=10.1016/s0003-3472(82)80065-1 |s2cid=53145854 }}</ref> Semi-wild [[Highland cattle]] heifers first give birth at 2 or 3 years of age, and the timing of birth is synchronized with increases in natural food quality. Average calving interval is 391&nbsp;days, and calving mortality within the first year of life is 5%.<ref name="Reinhardt1986">{{cite journal |last1=Reinhardt |first1=C. |last2=Reinhardt |first2=A. |last3=Reinhardt |first3=V. |year=1986 |title=Social behaviour and reproductive performance in semi-wild Scottish Highland cattle |journal=[[Applied Animal Behaviour Science]] |volume=15 |issue=2 |pages=125–136 |doi=10.1016/0168-1591(86)90058-4}}</ref> Beef calves suckle an average of 5 times per day, spending some 46 minutes suckling. There is a diurnal rhythm in suckling, peaking at roughly 6am, 11:30am, and 7pm.<ref>{{cite journal |last1=Odde |first1=K. G. |last2=Kiracofe |first2=G.H. |last3=Schalles |first3=R.R. |year=1985 |title=Suckling behavior in range beef calves |journal=Journal of Animal Science |volume=61 |issue=2 |pages=307–309 |doi=10.2527/jas1985.612307x |pmid=4044428 }}</ref> Under natural conditions, calves stay with their mother until weaning at 8 to 11 months. Heifer and bull calves are equally attached to their mothers in the first few months of life.<ref name="Johnsen2015">{{cite journal |last1=Johnsen |first1=J.F. |last2=Ellingsen |first2=K. |last3=Grøndahl |first3=A.M. |last4=Bøe |first4=K.E. |last5=Lidfors |first5=L. |last6=Mejdell |first6=C.M. |year=2015 |title=The effect of physical contact between dairy cows and calves during separation on their post-separation behavioural |journal=[[Applied Animal Behaviour Science]] |url=https://www.researchgate.net/publication/274013035 |doi=10.1016/j.applanim.2015.03.002 |volume=166 |pages=11–19 |url-status=live |archive-url=https://web.archive.org/web/20170707160417/https://www.researchgate.net/profile/Julie_Johnsen/publication/274013035_The_effect_of_physical_contact_between_dairy_cows_and_calves_during_separation_on_their_post-separation_behavioural_response/links/551541630cf2d70ee26fee97.pdf |archive-date=7 July 2017 }}</ref>