To answer your first question, I came across this here where after defining the mechanics of crossbreeding etc., and from which types of people a Jew can or cannot benefit from, he writes:

The Beefalo

Relatively recently, a new hybrid was developed, which is a cross between the ordinary beef cattle and a North American bison, which Americans colloquially call a buffalo. Is it permitted to make this crossbreed? One major authority contends that whether one may crossbreed buffalo and cattle depends on whether one is required to perform kisuy hadam, the mitzvah of covering the blood of shechitah, after slaughtering a buffalo. Kisuy hadam is required only on fowl and chayos but not on beheimos, such as cattle. If there is no requirement to perform kisuy hadam on buffalo, this demonstrates that it is considered a beheimah. Since there are only three species of beheimah -- sheep, goats, and cattle, then ruling that a buffalo does not require kisuy hadam means that halachah considers it to be a beheimah, and, if it is a beheimah, the process of elimination proves that it must be considered a variety of cattle, since it is certainly not a sheep or a goat.

Sefardim, Ashkenazim and buffalos

Is kisuy hadam required on a buffalo? This is a dispute between the Shulchan Aruch and the Rema, the Shulchan Aruch (Yoreh Deah 28:4) concluding that there is no requirement to perform kisuy hadam, whereas the Rema rules that one should do so without a brocha since we are uncertain whether it is considered a chayah. The Aruch Hashulchan (Yoreh Deah 297:8) notes that this dispute between the Shulchan Aruch and the Rema will also affect whether one is permitted to crossbreed buffalo with ordinary cattle, since the Shulchan Aruch, by concluding that it is a beheimah, must hold that they are halachically considered to be the same species. On the other hand, since the Rema is concerned that buffalo might be a variety of chayah, one would not be permitted to crossbreed it with cattle.

Halachic conclusion: According to the Aruch Hashulchan, a Sefardi would be permitted to crossbreed buffalo with cattle, and an Ashkenazi would not.

I came across this here where after defining the mechanics of crossbreeding etc., and from which types of people a Jew can or cannot benefit from, he writes:

The Beefalo

Relatively recently, a new hybrid was developed, which is a cross between the ordinary beef cattle and a North American bison, which Americans colloquially call a buffalo. Is it permitted to make this crossbreed? One major authority contends that whether one may crossbreed buffalo and cattle depends on whether one is required to perform kisuy hadam, the mitzvah of covering the blood of shechitah, after slaughtering a buffalo. Kisuy hadam is required only on fowl and chayos but not on beheimos, such as cattle. If there is no requirement to perform kisuy hadam on buffalo, this demonstrates that it is considered a beheimah. Since there are only three species of beheimah -- sheep, goats, and cattle, then ruling that a buffalo does not require kisuy hadam means that halachah considers it to be a beheimah, and, if it is a beheimah, the process of elimination proves that it must be considered a variety of cattle, since it is certainly not a sheep or a goat.

Sefardim, Ashkenazim and buffalos

Is kisuy hadam required on a buffalo? This is a dispute between the Shulchan Aruch and the Rema, the Shulchan Aruch (Yoreh Deah 28:4) concluding that there is no requirement to perform kisuy hadam, whereas the Rema rules that one should do so without a brocha since we are uncertain whether it is considered a chayah. The Aruch Hashulchan (Yoreh Deah 297:8) notes that this dispute between the Shulchan Aruch and the Rema will also affect whether one is permitted to crossbreed buffalo with ordinary cattle, since the Shulchan Aruch, by concluding that it is a beheimah, must hold that they are halachically considered to be the same species. On the other hand, since the Rema is concerned that buffalo might be a variety of chayah, one would not be permitted to crossbreed it with cattle.

Halachic conclusion: According to the Aruch Hashulchan, a Sefardi would be permitted to crossbreed buffalo with cattle, and an Ashkenazi would not.

To answer your first question, I came across this here where after defining the mechanics of crossbreeding etc. and from which types of people a Jew can or cannot benefit from he writes:

The beefalo

Relatively recently, a new hybrid was developed, which is a cross between the ordinary beef cattle and a North American bison, which Americans colloquially call a buffalo. Is it permitted to make this crossbreed? One major authority contends that whether one may crossbreed buffalo and cattle depends on whether one is required to perform kisuy hadam, the mitzvah of covering the blood of shechitah, after slaughtering a buffalo. Kisuy hadam is required only on fowl and chayos but not on beheimos, such as cattle. If there is no requirement to perform kisuy hadam on buffalo, this demonstrates that it is considered a beheimah. Since there are only three species of beheimah -- sheep, goats, and cattle, then ruling that a buffalo does not require kisuy hadam means that halachah considers it to be a beheimah, and, if it is a beheimah, the process of elimination proves that it must be considered a variety of cattle, since it is certainly not a sheep or a goat.

Sefardim, Ashkenazim and buffalos

Is kisuy hadam required on a buffalo? This is a dispute between the Shulchan Aruch and the Rema, the Shulchan Aruch (Yoreh Deah 28:4) concluding that there is no requirement to perform kisuy hadam, whereas the Rema rules that one should do so without a brocha since we are uncertain whether it is considered a chayah. The Aruch Hashulchan (Yoreh Deah 297:8) notes that this dispute between the Shulchan Aruch and the Rema will also affect whether one is permitted to crossbreed buffalo with ordinary cattle, since the Shulchan Aruch, by concluding that it is a beheimah, must hold that they are halachically considered to be the same species. On the other hand, since the Rema is concerned that buffalo might be a variety of chayah, one would not be permitted to crossbreed it with cattle.

Halachic conclusion: According to the Aruch Hashulchan, a Sefardi would be permitted to crossbreed buffalo with cattle, and an Ashkenazi would not.

To answer your first question, I came across this here where after defining the mechanics of crossbreeding etc., and from which types of people a Jew can or cannot benefit from, he writes:

The Beefalo

Relatively recently, a new hybrid was developed, which is a cross between the ordinary beef cattle and a North American bison, which Americans colloquially call a buffalo. Is it permitted to make this crossbreed? One major authority contends that whether one may crossbreed buffalo and cattle depends on whether one is required to perform kisuy hadam, the mitzvah of covering the blood of shechitah, after slaughtering a buffalo. Kisuy hadam is required only on fowl and chayos but not on beheimos, such as cattle. If there is no requirement to perform kisuy hadam on buffalo, this demonstrates that it is considered a beheimah. Since there are only three species of beheimah -- sheep, goats, and cattle, then ruling that a buffalo does not require kisuy hadam means that halachah considers it to be a beheimah, and, if it is a beheimah, the process of elimination proves that it must be considered a variety of cattle, since it is certainly not a sheep or a goat.

Sefardim, Ashkenazim and buffalos

Is kisuy hadam required on a buffalo? This is a dispute between the Shulchan Aruch and the Rema, the Shulchan Aruch (Yoreh Deah 28:4) concluding that there is no requirement to perform kisuy hadam, whereas the Rema rules that one should do so without a brocha since we are uncertain whether it is considered a chayah. The Aruch Hashulchan (Yoreh Deah 297:8) notes that this dispute between the Shulchan Aruch and the Rema will also affect whether one is permitted to crossbreed buffalo with ordinary cattle, since the Shulchan Aruch, by concluding that it is a beheimah, must hold that they are halachically considered to be the same species. On the other hand, since the Rema is concerned that buffalo might be a variety of chayah, one would not be permitted to crossbreed it with cattle.

Halachic conclusion: According to the Aruch Hashulchan, a Sefardi would be permitted to crossbreed buffalo with cattle, and an Ashkenazi would not.