Influence of Dietary Protein on Reproductive Performance of Dairy Cows

Abstract

From 10 +/- 3.5 d after parturition to 149 +/- 3.5 d of lactation, 146 cows (109 Holstein and 37 Ayrshires) were fed either a 15 or 20% crude protein diet of 45% sorghum silage and 55% concentrate. Milk production was enhanced by the 20% protein diet, but percentage of milk fat and protein were unchanged. Average daily intake of DM was unaffected by diet. Actual decreases in body weight and condition were small, although cows on 15% protein lost more condition. Concentration of plasma urea nitrogen increased rapidly during the first 4 wk of the experiment with cows on the 20% protein diet maintaining a 10 mg/dl advantage after the 4th wk on experiment. Diet did not affect the postpartum interval to first normal corpus luteum and standing estrus. Cows were inseminated artificially between 55 and 145 d post-calving with one freeze batch of semen from one bull of each appropriate breed mainly by one inseminator. Overall, days open, services per conception, and percentage cows pregnant on experiment were 80, 1.40, and 85, respectively. Concentration of protein in the diet did not affect these reproductive traits. There was no conflict between the amount of dietary protein provided for lactation and reproduction in this experiment.

Impacts of the Source and Amount of Crude Protein on the Intestinal Supply of Nitrogen Fractions and Performance of Dairy Cows

“…Mean and median values were similar for all variables in this data set. A significant curvilinear relationship (R 2 = 0.19) was found between milk yield and the concentration of CP All data were taken or calculated from experiments reported in 112 independent studies (Barney et al, 1981;Mielke and Schingoethe, 1981;van Dijk et al, 1983;Henderson et al, 1985;Polan et al, 1985Polan et al, , 1997Van Horn et al, 1985;Broderick, 1986Broderick, , 1992Broderick, , 2003Lundquist et al, 1986;Annexstad et al, 1987;Garnsworthy and Jones, 1987;Howard et al, 1987;Jaquette et al, 1987;Kaim et al, 1987;Bowman et al, 1988;Hadsell and Sommerfeldt, 1988;Jones and Garnsworthy, 1988;Léonard and Block, 1988;Manson and Leaver, 1988;Robinson and Kennelly, 1988;Schingoethe et al, 1988;Sloan and Rowlinson, 1988;Voss et al, 1988;Bruckental et al, 1989Bruckental et al, , 2000De Gracia et al, 1989;Garnsworthy, 1989;Herrera-Saldana and Huber, 1989;Higginbotham et al, 1989;Mä ntysaari et al, 1989;Blauwiekel et al, 1990;Broderick et al, 1990Broderick et al, , 1993Canfield et al, 1990;Casper et al, 1990Casper et al, , 1999…”

Influence of rumen protein degradability on productive and reproductive performance in buffalo cows

“…Overfeeding proteins has been associated with a decline in fertility in most [6][7][8][9], but not all [10] studies. Jordan et al [11] found an increase in urea-nitrogen (N) concentration in the uterine secretions and plasma of cows fed 23% crude protein (CP).…”

Uso da uréia como suplemento protéico na dieta de doadoras e receptoras de embriões bovinos

“…Corroborando este argumento, Howard et al (1987) demonstraram que o livre acesso a uma dieta completamente misturada é um dos fatores responsáveis pela ausência de efeitos deletérios do excesso de proteína sobre a reprodução, como foi o caso do fornecimento da dieta no presente experimento.…”

“…A forma da suplementação do nitrogênio não protéico e ou da proteína verdadeira, bem como a Tabela 7 -Análise bromatológica da pastagem das receptoras de embriões relação energia:proteína do suplemento e dieta total, deve ser aspecto fundamental para que não haja transtornos reprodutivos também para as vacas recptoras mantidas em pasto, conforme considerações importantes apontadas neste sentido por Erb et al (1976) e Howard et al (1987). Todas as receptoras que participaram do experimento e não confirmaram prenhez foram colocadas em estação de monta de novembro de 1999 a março de 2000.…”