And the 'risk' of giving calcium in that article is... what exactly?? And what great resource is that website!?
Compare this to the very real risk of eclampsia:
https://www.petmd.com/dog/conditions/reproductive/c_dg_eclampsia Eclampsia is at one end of the spectrum and is an extreme form of what can happen if a dog has insufficient calcium during lactation. But there is a whole range of 'less' severe behavioural and physical issues that can occur - from poor mothering, dams which growl at pups, dams which show a disinterest in puppies, dams which pace around and seem unsettled for no apparent reason, dams which dig in their boxes excessively, disturbing their new puppies and so on. At the first sign of any of these behavioural issues at all, calcium supplementation should be started. This is recommended by Avidog.com - an organisation which advises breeders on the latest research available so they can implement it in raising litters and puppies. It is recommended by Cheryl Lopate in her excellent book about neonatal puppies and whelping.
Or maybe we should look at the AKC:
https://www.akc.org/expert-advice/dog-breeding/the-care-and-feeding-of-the-breeding-bitch-part-three/ "Heavy lactation places such a dramatic drain on the bitch's reserves of this mineral that sometimes her body's calcium metabolism is unable to compensate for the loss. This unique syndrome is called eclampsia (or puerperal tetany). As the blood-calcium level drops, the bitch becomes restless and nervous... "
As for spaying, of course there are many functions of estrogen and progesterone beyond reproduction:
Shall we start with the increase in cancer risk amongst spayed and neutered dogs?
https://www.ncbi.nlm.nih.gov/m/pubmed/29067194/?fbclid=IwAR0eBrDTbC4ubO_KM-UWjL4JB47RxbLugGLHpJgIulxOPrOpkn9NwSZe7gohttps://healthypets.mercola.com/sites/healthypets/archive/2014/06/13/neutering-spaying-cancer-risk.aspx?fbclid=IwAR15PCgVfo7SU7JJoLwQ5dfCaT_26jEsSTD-MqLh3sNQhRkEDK_eC35mihYhttps://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0102241&fbclid=IwAR2o-BrJFnyY3czJE8qMLdaEgMXl2p0uwi96ttl15GBwu2zCoNnSZuGIMrEhttp://cebp.aacrjournals.org/content/11/11/1434.full?fbclid=IwAR2dgIwJxoT4Y2JYLh22tyMaWd_FrMTJBuy1ZI4L-AmxxSgwLQ1OLYKtvpsIncluding long-term effects on the immune system:
https://www.parsemus.org/wp-content/uploads/2015/03/Zwida-and-Kutzler-2016.pdf?fbclid=IwAR3kfWFkYIBj0-4uQNl16flamMDYO6u4X8aC06PC1_ZaBbUU_3L5cP_ajjwPerhaps the role of the uterus in the development of memory and spatial awareness?
https://www.the-scientist.com/news-opinion/rat-study-points-to-role-of-uterus-in-memory-65188?fbclid=IwAR1zC-pkrFuM6RFRfkFiuNT7fIHMvRcaSWIDmxwDY__VIFRDRsS-a5F3Ux0 Or the fact that dogs live longer (on average) the longer they retain their ovaries:
https://www.ncbi.nlm.nih.gov/pubmed/19732047?fbclid=IwAR36YldesnxXf2UHPCf-ooO2QhcHzk0dz3EI1dQsPxEJqbBW63NZEFI7jNM The risk of urinary incontinence developing after spaying, requiring a lifetime of medication:
http://europepmc.org/abstract/med/11787155?fbclid=IwAR0Ug-891T_tPdUuNPHN9kWKWx3yYDrZlbp4BGcJP1VxQQDFREAqjwlp5Es The increase in risk factors for obesity, joint disease and orthopaedic issues after neutering:
http://veterinarynews.dvm360.com/research-update-earlier-age-spayneuter-risk-factor-obesity-and-orthopedic-injuries?fbclid=IwAR0Zv7Hv22k3GMk15nxewl4vbiBHGhKlqCeLDPlpt0K2Mjfi4MauNOSRTO0 The increase in incidence of IVDH for dachshunds when neutered:
https://cgejournal.biomedcentral.com/articles/10.1186/s40575-018-0067-7?fbclid=IwAR2019tpb2ttH4udxs7O3gTsmSyIV1Ej3khtmv39c5-mufu39HisKv-7_hs Double the risk of hip dysplasia in neutered dogs:
https://www.dogsnaturallymagazine.com/new-study-neuter-risk-hip-dysplasia-dogs/?fbclid=IwAR2_0jwudnh2IM43GK5EE-rYpW5uDZk3YX-Kumdy1KLhr8iDvmcnOSx-BE4And:
http://www.naiaonline.org/uploads/WhitePapers/EarlySNAndBehaviorDuffySerpell.pdf?fbclid=IwAR3puJZUE65N69_X2uXrGUOK5V9wRb-8KGfN-h-3FWWgPR3nTRidMbMllYsReduced communication skills in spayed female dogs:
https://www.psychologytoday.com/intl/blog/canine-corner/201902/spayed-female-dogs-may-have-reduced-communication-skills?fbclid=IwAR1fG2T9pRtYbyC-5e8sKVTt83oCduGcafXrR3YEa91WrxOp8pZrdZ09xzk#_=_An increase in the incidence of aggression towards other dogs and people amongst spayed or neutered dogs:
https://www.frontiersin.org/articles/10.3389/fvets.2018.00018/full?&utm_source=Email_to_authors_&utm_medium=Email&utm_content=T1_11.5e1_author&utm_campaign=Email_publication&field&journalName=Frontiers_in_Veterinary_Science&id=284353&fbclid=IwAR3QzPC8Qpsw2AT-DIgR1e17vdVyhRCHdfCGT6qR2r0ooSDO8On5Q9pwbBM An increase in separation anxiety amongst spayed or neutered dogs:
https://www.avma.org/News/Journals/Collections/Documents/javma_219_4_460.pdf?fbclid=IwAR30dwhXbenq_btSEubJdR-aGwNo6NGkfNcOjBwwPT0VhrhyPujSsafANYU An increase in the risk for senility or dementia in elderly dogs if they are neutered:
https://www.avma.org/News/Journals/Collections/Documents/javma_219_1_51.pdf?fbclid=IwAR22YraWZ4Q3K2PrncWrUi-rRMDwmvXd8HCMWCt06Ma4b1Uq7Se81AjXr5II could go on, but I think I'll leave it there