Influence of undegraded intake protein supplementation on milk production, weight gain, and reproductive performance in postpartum Brahman cows

Abstract

Eighty first-calf Brahman heifers and 51 mature Brahman cows were allotted to one of three diets based on parity, sex of calf, and breed of calf sire (Angus, Brahman, or Tuli) to evaluate rumen undegraded intake protein's (UIP) influence on production characteristics and reproductive performance. Supplements contained either 38.1% (low), 56.3% (medium), or 75.6% (high) UIP. Supplements were given from d 7 to 119 after calving to dams grazing rye-ryegrass overseeded Coastal bermudagrass pastures and with access to Coastal bermudagrass hay. Dam and calf BW and dam body condition score were recorded on d 7, 35, 63, 91, and 119 after calving. Four-hour milk production was recorded on the above days for low (n = 18), medium (n = 19), and high (n = 18) UIP animals and on d 7 and 35 for the entire group. Blood for progesterone RIA was drawn weekly and on d 6, 8, 10, and 12 after an observed estrus. Medium UIP heifers produced more (P < .02) milk (1.18 +/- .07 kg/4 h) than high UIP heifers (.94 +/- .07 kg/4 h), but milk production in mature cows was not influenced by diet. Low UIP dams had lower (P < .04) first-service conception rates (29.2%) than medium (57.6%) and tended (P < .10) to have lower rates than high UIP dams (54.6%). Overall pregnancy rates tended (P < .10) to be higher in medium (61.5%) and high (56.4%) UIP groups than in the low (43.2%) UIP group. Supplementing UIP at the medium rate improved first-service conception rates and tended to improve pregnancy rates.

Efeito da suplementação protéica a pasto sobre consumo de forragens, ganho de peso e condição corporal, em vacas Nelore

“…Este ganho foi 0,353; 0,532; e 0618 kg para os animais dos tratamentos T0, T1 e T2, respectivamente, sendo o ganho das vacas do T0 inferior (P<0,05) ao das vacas do T1 e T2, que não diferiram entre si (P>0,05). A variação no ganho, em função da suplementação protéica, também foi observada em vacas Brahman adultas por TRIPLETT et al (1995).…”

“…Os pesos dos bezerros foram avaliados ao final do Tabela 2 -Médias e coeficiente de variação (CV) para escore da condição corporal ao parto (ESCP), escore ao final do experimento (ESCF), peso inicial (PESI), peso final (PESF), média de ganho diário (GMD) e peso do bezerro final (PEBF) Tabela 3 -Média das análises dos teores de proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA) e fibra detergente ácido indigestível (FDA-i), expressos na matéria seca, do suplemento protéico e do pasto período experimental, não sendo diferentes entre os tratamentos (P>0,05), sugerindo que a suplementação não influenciou a produção de leite, o que também foi observado por TRIPLETT et al (1995). Avaliações do escore da condição corporal dos animais foram realizadas de 14 em 14 dias, com intuito de verificar possíveis modificações dentro de cada tratamento, no período pós-parto.…”

Influence of post-calving supplemental protein on calf performance and reproductive efficiency for beef cows fed silage

“…The effect of supplemental protein for beef cows has mostly been examined in cows fed basal diets containing considerably less CP than in our trials (De Gracia and Ward 1991;Rusche et al 1993;Triplett et al 1995). In our trials protein intake from silage alone was at least 20% in excess of NRC (1996) requirements; therefore, a response to protein should not have been observed for any level of supplementation.…”

“…This suggested that the response by cows was from the UIP, rather than from the overall increase in CP concentration. Other research has also shown responses to UIP supply up to a certain level (Blasi et al 1991;De Gracia and Ward 1991;Rusche et al 1993;Triplett et al 1995). On silage-based diets, this can be attributed to low metabolizable protein supply, possibly due to a highly degradable protein source combined with a lack of energy available to rumen microbes for microbial protein synthesis (AFRC 1990).…”

“…Blasi et al (1991) found the same response pattern in cows supplemented with incremental amounts of UIP. Triplett et al (1995) fed up to 480 g d -1 supplemental UIP to grazing Brahman cows but observed a response only up to 370 g d -1 . In our study, a decline in performance was not observed until predicted UIP values were somewhat higher, but our data are based on total, not supplemental, UIP.…”