<?php

$arr = [
		7100 => [
					'qtdadulto' =>  0,
      				'qtdpintoumdia' => 0,
      				'qtdovosferteis' =>0
      			],
  		7108 => [
  					'qtdadulto' => 0,
      				'qtdpintoumdia' =>0,
      				'qtdovosferteis' => 0
      			],
  		7110 => [
  					'qtdadulto' => 0,
		        	'qtdpintoumdia' => 0,
      				'qtdovosferteis' =>  0
      				]
];

$arr2 = [7100 => 1, 7108 => 200, 7110 => 500, 800 => 99];


foreach($arr as $k => $v){
	if(isset($arr2[$k])){
		$arr[$k]['nome'] = $arr2[$k];
	}
}

print_r($arr);