Study about Holsteins vs. Jerseys

[Guest guest]

With the discussion lately about the different breeds of cows, I thought

some of you might be interested in reading this article that I had filed

on my computer. I can't remember if I got to this one time because of

someone in our group here, or if I just found it by myself.

Bonnie in NC

http://www.lib.ncsu.edu/etd/public/etd-15171027310041171/etd-title.html

Investigation of Pasture and Confinement Dairy Feeding Systems Using

Jersey and Holstein Cattle.

by

Sharon White

Master's Thesis submitted to the Faculty of the North Carolina State

University in partial fulfillment of the requirements for the degree of

MS in Animal Science

Approved

Dr. P. Washburn, Chair

Dr. T. Green, Jr.

Dr. Geoffrey A. Benson

Dr. Vivek Fellner

March 30, 2000

Raleigh, North Carolina

Abstract

Today, dairy farmers in the U.S. are faced with the challenge of reducing

the cost of producing milk. Milk prices have risen very little in the

past decade, while the cost of producing milk has risen steadily. In

North Carolina alone, dairy farm numbers have dropped more than 30% in

the last ten years, and the trend is expected to continue. Dairy farmers

have been forced to increase their profitability to stay in business. In

addition, farmers have been forced to comply with stricter environmental

regulations. Over the past few years, interest has been shown in

intensive management rotational grazing systems. This four-year

comparison trial was designed to compare the milk production, herd

health, reproductive performance, and environmental impacts of

pasture-based and confinement feeding systems using Holstein and Jersey

cattle for the Mid-Atlantic region. The project had both Spring and Fall

calving herds with breeding via artificial insemination in 75-day

periods. Each seasonal herd replicate had 36 cows on pasture and 36 cows

in the confinement group. Similar numbers of Holsteins and Jerseys were

included in each year. Paddocks grazed comprised 29 ha of cool and warm

season pasture species in 37 paddocks for year-round grazing. Pasture-fed

cows received variable amounts of grain and baled silage as needed

depending upon pasture availability. Confinement cows were housed in a

covered freestall barn with access to an exercise lot and received a

total mixed ration with corn silage as the primary forage. Confinement

cows produced significantly more milk than pasture-fed cows, both for

total lactation and average daily production. Reproductive performance of

the two treatments did not differ with an overall 75-day pregnancy rate

of 68%. Jerseys in both systems did have higher percentages of cows

inseminated (96.5%), conception rate (59.6%), and 75-day pregnancy rate

(78%) compared to Holsteins (86%, 49%, 57.9% respectively). The

percentage of cows infected with at least one case of clinical mastitis

was higher in the confinement herd than the pasture-fed herd (43% vs.

24%) with Holsteins higher than Jerseys (41% vs. 26%). Interactions of

breed and feeding system and average somatic cell count scores were not

significantly different. Pasture-fed cows had lower average body

condition scores than confinement cows, ranging from 0.2 to 0.6 points

lower on a 5-point scale. In a short-term trial, intake measurements were

taken from pasture-fed Holsteins and Jerseys consuming a grain

supplement. This supplement was similar to those that were fed to the

pasture-fed cows during the four-year trial. It was determined that

Jerseys could consume as much as Holsteins at three different feeding

levels (6.8, 4.5, and 2.3 kg/cow per feeding). This experiment showed

that in certain time frames, Jersey cattle can consume equal amounts of

supplements compared to Holsteins. Therefore in mixed groups Jerseys can

consume relatively more supplemental energy relative to body size and

milk production compared the Holsteins. In another short-term trial using

cows from a spring season replicate, milk samples were obtained from

pasture-fed and confinement-fed cattle and analyzed for fatty acid

composition. The pasture grazed was a warm-season pasture, while the

confinement-fed cattle consumed a corn-silage based TMR. The major fatty

acid of interest was conjugated linoleic acid (CLA), which has been shown

to be a potent anticarcinogen. Concentrations of CLA were 80% higher in

pasture-fed cattle compared to the confinement-fed cattle. In addition

concentrations of CLA were higher in Holsteins compared to Jerseys. To

study the distribution of manure in a pasture-based system, pastured cows

were observed for several 24-h periods. Data included: (1) times and

location of all feces and urine events from eight cows, observed while in

the pasture, feed area, milking parlor or in transit; and (2) all urine

and feces events on pasture for all 36 cows each grazing period. The

locations of urine and feces events were surveyed, mapped and analyzed.

Percentages of the manure events in each area were highly correlated with

time spent in each area (r= .99). Feces and urine (estimated at .12 m2

and .36 m2, respectively) from six observational periods covered 10% of

the total paddock. Within 30 m2 of the portable waterer and gate,

concentrations of feces and urine from the warm season observations were

significantly greater than concentrations during the cool season

observations. Manure on pasture was relatively evenly distributed over

multiple grazing periods with the exception of the area around the water

tank during summer grazings. These experiments showed that when compared

to confinement-fed cattle, pasture-fed cattle produced less milk,

produced more conjugated linoleic acid, had less mastitis and had lower

body condition scores, while reproductive performance did not differ

between the two groups. Jerseys had less mastitis, produced less

conjugated linoleic acid, and performed better reproductively when

compared to Holstein cattle. In addition, pasture-fed Jersey cattle can

consume as much supplemental grain in certain time frames as pasture-fed

Holstein cattle. Manure distribution on a pasture-based system is highly

correlated with time spent in an area and is fairly evenly distributed

over the paddock area over multiple grazing periods except for the area

around the water tank during heat stress temperatures.

Full text (PDF) 817,541 Bytes

The author grants to North Carolina State University or its agents the

right to archive and display their thesis or dissertation in whole or in

part in the University Libraries in all forms of media, now or hereafter

known. The author retains all proprietary rights, such as patent rights.

The author also retains the right to use in future works (such as

articles or books) all or part of this thesis or dissertation.

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