Un interessante articolo di un grande veterinario e una sua interpretazione strumentale

Riportiamo un interessante articolo di Guillermo Couto, un grande veterinario e studioso dei levrieri, dal titolo provocatorio “Sono i levrieri realmente cani?” pubblicato sul sito www.coutovetconsultants.com

The dog was domesticated approximately 14,000 years ago. Due to both natural and human selection, there are now over 400 morphologically distinct breeds; these breeds are included within groups (per the American Kennel Club). The AKC Hound group is composed of over 25 breeds, and includes the sighthounds, dogs that pursue their prey by keeping it in sight. All sighthounds have similar phenotype; they are slender, dolichocephalic, agile, and fast. There are over 15 recognized breeds in this group, including the Afghan Hound, Azawakh, Borzoi, Chart Polski, Galgo Español, Greyhound, Hortaya Borzaya, Irish Wolfhound, Italian Greyhound, Magyar Agar, Saluki, Scottish Deerhound, Sloughi, Whippet, and Rajapalayam. Although one tends to think of sighthounds as “sprinters”, several of the breeds are indeed “endurance” runners (e.g.; Galgo Español). There are fossil records and paintings of sighthound-looking dogs dating back to 7,000-6,000 BC. In other words, this group has evolved quite tightly during several thousand years. Recent genetic work suggests that Greyhounds have unique genomic features that are different from those in other breeds. Anybody who has owned or worked with Greyhound patients knows how different they are from dogs of other breeds. Most sighthounds share similar biological features. It is estimated that over 200,000 Greyhounds live in homes as pets in the US and Canada, compared to 35,000 Greyhounds in racetracks. In the past few years, private Greyhound adoptions ranged from 15,000 to 18,000/year; there is also a large ongoing effort of Galgo and Irish Greyhound adoptions in Europe. EoGransHarperCroppedEoNoGranBurgerCropped Therefore, it is important to recognize the physiological peculiarities of this breed. From the hematologic standpoint, these athletic dogs have more red blood cells than other dogs; hence, higher packed cell volume (PCV) and hematocrit (HCT), hemoglobin concentration, red blood cell count, and whole blood viscosity than other dogs. A healthy Greyhound has a HCT of 50-63%, something than in a dog of any other breed will result in a presumptive diagnosis of polycythemia or erythrocytosis. The white blood cell (WBC), neutrophil (WBCs that fight bacteria), and platelet (blood cells that start blood clotting) counts are lower in Greyhounds than in other breeds. Most normal Greyhounds have WBC of 3-5X109/L, with neutrophil counts as low as 1.8X109/L; a typical platelet count in a healthy Greyhound is 80-120 X109/L2. In addition, Greyhound eosinophils (cell involved in allergic and parasitic reactions) lack the characteristic orange granules seen in all other breeds (top); the granules do not stain, thus resulting in the appearance of cytoplasmic vacuoles. These “vacuolated cells with bilobed nuclei” (bottom) can frequently be confused with toxic bands (a sign of severe inflammation/infection). The serum biochemical profiles in Greyhounds also have values that are typically outside the reference rage for dogs. Mainly, the serum creatinine (marker of kidney function) concentrations are high (1-2.2 mg/dL), and the total serum protein (5-6 gm/dL) and globulin (1.8-2.5 gm/dL) concentrations are lower than in other dogs; low serum acute phase protein concentrations account for the lower globulin concentration. Depending on the instrument used, other values may also be outside the reference range for dogs. We recently demonstrated that serum calcium (both total and ionized) and magnesium are lower than in no-Greyhound dogs. The results of venous or arterial blood gas analysis and cooximetry in Greyhounds also yields results outside the reference range for dogs […] Per leggere l’articolo integrale: http://www.coutovetconsultants.com/blog/are-sighthounds-really-dogs.html

Segnaliamo peraltro che qualcuno si è subito preoccupato di rileggere e interpretare in maniera piuttosto libera l’articolo, anche proponendo una traduzione piuttosto spericolata. Leggiamo per esempio in un gruppo che la frase

“There are fossil records and paintings of sighthound-looking dogs dating back to 7,000-6,000 BC. “

si tradurrebbe nel seguente modo:

“Ci sono reperti fossili e dipinti di cani levrieri risalenti al 7,000-6,000 aC”

Ora, l’espressione sighthound-looking dogs, va tradotta nel seguente modo: “cani che assomigliano ai levrieri”.

La differenza è rilevante, perché per quanto ne sappiamo ora, cani moderni con un fenotipo simile a cani di migliaia di anni fa non hanno necessariamente lo stesso corredo genetico.

Scrive Miklosi, in “Dog: Behaviour, Evolution and Cognition”, quanto segue, a proposito della somiglianza tra sculture e dipinti egiziani con gli attuali cani dei faraoni: “analysis of their DNA suggest that this breed has been relatively recently re-created by crossing other dog breeds”. In poche parole, somiglianze esteriori tra cani moderni e cani di migliaia di anni fa non significano in nessun modo che esista una continuità genetica.

Peraltro, il legame tra DNA e comportamento è molto complesso e per nulla deterministico e lineare. Lo stesso Miklosi mostra studi dai quali si evince che i greyhound hanno grandi similarità genetiche con i Rough Collies e i Belgian Tervueren, che certo non hanno comportamenti assimilabili.

L’articolo di Couto indica che esistono differenze biologiche e fisiologiche importanti tra i greyhound e altre razze, ma Couto non si sogna minimamente di usare differenze biologiche per giustificare l’affermazione che i levrieri sono completamente differenti da tutti gli altri cani sul piano comportamentale o che non siano cani.

Insomma, usare uno studio scientifico che parla di differenze nei valori del sangue per dire che i levrieri sono cani speciali nel comportamento e che non sono paragonabili ad altri cani è sbagliato e superficiale. E forse anche strumentale.

Fermo restando, come già detto in altre occasioni, che le caratteristiche genetiche sono solo punti di partenza che lasciano grandi margini allo sviluppo di caratteristiche individuali che dipendono dall’esperienza.