scholarly journals Using Milk Urea Nitrogen to Evaluate Diet Formulation and Environmental Impact on Dairy Farms

2001 ◽  
Vol 1 ◽  
pp. 852-859 ◽  
Author(s):  
J.S. Jonker ◽  
R.A. Kohn
Keyword(s):  
Environmental Impact ◽  
Dairy Cattle ◽  
Dairy Cows ◽  
Chesapeake Bay ◽  
Dairy Farms ◽  
Utilization Efficiency ◽  
Urea Nitrogen ◽  
Lactating Dairy Cows ◽  
Milk Urea ◽  
Lactating Dairy Cattle

Reducing nitrogen (N) excretion by dairy cattle is the most effective means to reduce N losses (runoff, volatilization, and leaching) from dairy farms. The objectives of this review are to examine the use of milk urea nitrogen (MUN) to measure N excretion and utilization efficiency in lactating dairy cows and to examine impacts of overfeeding N to dairy cows in the Chesapeake Bay drainage basin. A mathematical model was developed and evaluated with an independent literature data set to integrate MUN and milk composition to predict urinary and fecal excretion, intake, and utilization efficiency for N in lactating dairy cows. This model was subsequently used to develop target MUN concentrations for lactating dairy cattle fed according to National Research Council (NRC) recommendations. Target values calculated in this manner were 8 to 14 mg/dl for a typical lactation and were most sensitive to change in milk production and crude protein intake. Routine use of MUN to monitor dairy cattle diets was introduced to dairy farms (n = 1156) in the Chesapeake Bay watershed. Participating farmers (n = 454) were provided with the results of their MUN analyses and interpretive information monthly for a period of 6 months. The average MUN across all farms in the study increased in the spring, but the increase was 0.52 mg/dl lower for farmers receiving MUN results compared to those who did not participate in the program. This change indicated that participating farmers reduced N feeding compared to nonparticipants. Average efficiency of feed N utilization (N in milk / N in feed x 100) was 24.5% (SD = 4.5). On average, farmers fed 6.6% more N than recommended by the NRC, resulting in a 16% increase in urinary N and a 2.7% increase in fecal N compared to feeding to requirement. N loading to the Chesapeake Bay from overfeeding protein to lactating dairy cattle was estimated to be 7.6 million kg/year. MUN is a useful tool to measure diet adequacy and environmental impact from dairy farms.

scholarly journals Corn supplementation on milk urea nitrogen content of dairy cows grazing on temperate annual pasture

2020 ◽  
Vol 50 (2) ◽  
Author(s):  
Aline Cristina Dall-Orsoletta ◽  
João Gabriel Rossini Almeida ◽  
Márcia Maria Oziemblowski ◽  
Henrique Mendonça Nunes Ribeiro-Filho
Keyword(s):  
Dairy Cows ◽  
Protein Production ◽  
Milk Protein ◽  
Live Weight ◽  
Corn Silage ◽  
Utilization Efficiency ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Lactation Stage ◽  
Milk Urea

ABSTRACT: The excretion of urinary nitrogen (N), one of the most important environmental contaminants from livestock systems, is highly correlated with milk urea N content. The objective of this research was to evaluate the use of different types of corn supplementation on milk urea N in grazing dairy cows. Twelve Holstein × Jersey lactating dairy cows were divided into six uniform groups according to milk production, lactation stage and live weight. Treatments were compared according to a 3 × 3 replicated Latin square experimental design, with three periods of seventeen days (twelve days to adaptation and five to measurements). The experimental treatments were exclusively grazing (G); grazing + supplementation with 4.2 kg DM of corn silage (CS) and grazing + supplementation with 3.2 kg DM of ground corn (GC). The pasture used was annual ryegrass (Lolium multiflorum L.) and white oats (Avena sativa L.). The milk protein production increased 65 g/day in the GC treatment group compared to the G and CS groups. The supplemented dairy cows showed lower milk urea N (-2.8 mg/dL) than unsupplemented cows, but the N utilization efficiency (g N output in milk/ g N intake) did not change between treatments (average = 0.26). Additionally, there was a relationship between milk and plasma urea nitrogen concentrations (R2 = 0.64). In conclusion, for dairy cows grazing annual temperate pastures, corn ground supplementation increased milk protein production and reduced the excretion of milk urea N, whereas corn silage reduced the excretion of milk urea N without affecting milk protein production.

scholarly journals Cow and herd variation in milk urea nitrogen concentrations in lactating dairy cattle

2012 ◽  
Vol 95 (12) ◽  
pp. 7261-7268 ◽  
Author(s):  
M. Aguilar ◽  
M.D. Hanigan ◽  
H.A. Tucker ◽  
B.L. Jones ◽  
S.K. Garbade ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Urea Nitrogen ◽  
Nitrogen Concentrations ◽  
Milk Urea ◽  
Lactating Dairy Cattle ◽  
Milk Urea Nitrogen

scholarly journals Feeding Behavior of Lactating Dairy Cattle Fed Sorghum-Based Diets and Increasing Levels of Tannic Acid

Agriculture ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 172
Author(s):  
José Danrley Cavalcante dos Santos ◽  
Edilson Paes Saraiva ◽  
Severino Gonzaga Neto ◽  
Carla Aparecida Soares Saraiva ◽  
Antônio da Costa Pinheiro ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Feeding Behavior ◽  
Dairy Cows ◽  
Tannic Acid ◽  
Production Efficiency ◽  
Condensed Tannin ◽  
Latin Square ◽  
Positive Effects ◽  
Lactating Dairy Cows ◽  
Lactating Dairy Cattle

Tannins have been used to trigger positive effects on ruminal metabolism and increase ruminant production efficiency, since they increase the supply of dietary protein in the small intestine. Increasing levels of tannic acid in a sorghum-based diet on the feeding behavior of five Holstein/Zebu crossbred lactating dairy cows was evaluated. They were subjected to a 5 × 5 Latin square experimental design, with fivelevels of tannin as dry matter (DM) in the diet (0.46, 1.30, 2.60, 3.90, and 5.20%). The levels of the tannic acid added were established based on the quantity of condensed tannin in high-tannin sorghum. Thus, diets 2, 3, 4 and 5 were supplemented with 1.5 g (13% DM), 79.5 g (2.6% DM), 157.5 g (3.9% DM), and 235.5 g (5.2% DM) of tannic acid, totaling 0.078, 0.156, 0.234, and 0.321 kg of tannin/day, respectively. Feeding behavior variables included the following states and events: feeding, drinking, rumination, and inactivity; the frequency of visiting the feed and water troughs; and the occurrence of urination and defecation. Water was provided ad libitum, and its intake was measured during periods of behavioral data collection. The use of two tannin sources (hydrolysable and condensed) corresponding to the total level of 5.20% (on a DM basis) in the diet of lactating dairy cattle does not affect the animals’ health. Tannic acid can be included in the diet of lactating dairy cattle at a level of 3.93% (on a DM basis) without inducing variation in the total time spent daily on feed intake. Dairy cows dilute the effects of dietary tannin (5.20%) through greater fragmentation of food consumption in the hours following its supply (180 min). The astringent effects caused by tannin intake in lactating dairy cows are mitigated by increasing the daily water intake as the amount of tannin in the diet increases, starting at a level of 3.90% tannin (on a DM basis).

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