The Effect of milk replacer with different levels of crude protein on dry matter intake and growth performance of Saanen suckling goat kids

The production of dairy goat breeds such as Saanen has become widespread in many countries and factors like the nutritional value of goat milk, high amounts of milk yield compared to body weight, and less methane gas production have played important role for the mentioned development. Previous studies have shown that reaching the insemination weight (35 kg) of replacement female goats is one of the most important points in the breeding of the dairy goat breeds. Subsequently, other studies have shown that improving growth and weight gain during suckling period reduces the time to reach the required weight and body size for insemination, the growth of mammary glands and increases milk production, and it is economically important. Protein is one of the factors which play important role in growth and body frame development of goats especially at life's early stages. Therefore, the aim of the present study was to investigate the effects of different levels of crude protein in milk replacer on performance of Saanen suckling kids. Sixteen Saanen female kids with 10 days of age and 4.678± 0.57 kg of BW were randomly assigned to two experimental treatments, including milk replacer with 22% crude protein (22CP; milk replacer contain 22% crude protein) and milk replacer with 28% crude protein (28CP; milk replacer contain 22% crude protein plus 10 gram of whey protein concentrate per liter of milk replacer). The experimental kids were weaned at 64 days of age and during this time milk replacer, starter, and alfalfa hay intake of kids was recorded daily, and the weight of the goats was measured weekly. The results showed that average daily weight gain of kids fed with 28CP treatment was significantly higher (P < 0.05) compared to the 22CP treatment during the first month, the second month and whole experimental period. Also, the kids body weight at the end of second month for 28CP treatment was significantly higher (P = 0.05) compared to the 22CP treatment (16.14 vs. 14.21 kg).  The amount of total dry matter intake (DMI) during the entire experimental period was higher (P < 0.05) for the 28CP treatment compared to the 22CP treatment (509.65 vs. 459.68 grams per day). There were no significant differences among the experimental treatments for the feed conversion ratio (FCR) during the first month, the second month and the entire experimental period. In fact, although the 28 CP treatment had a higher daily weight gain compared to the CP22 treatment, due to higher DMI, but it had a similar FCR compared to the CP22 treatment. Results showed that feeding milk replacer containing high levels of crude protein (28%) can results to the higher average daily gain and subsequently heavier weaning weight in Saanen goat kids.