Flushing

Fact Sheet Series on Meat Goat Herd Management Practices

#3 – Flushing

By tatiana Stanton, Nancy & Samuel Weber

This fact sheet is about flushing as an on-farm management tool forNew Yorkmeat goat

farms.Flushingis the herd management practice of feeding diets with high nutrient

concentrations to female animals shortly before breeding in an attempt to increase ovulation rates

at breeding and, potentially, litter size. Obviously, if a doe develops only one egg or ova during

the first heat the buck is exposed to her, only one egg is available to be fertilized and her litter

size is limited to one, except in the unlikely event that she fails to conceive during that first heat.

In contrast, if the doe develops multiple eggs in the first heat after the buck is put in the herd, her

litter size can be as large as the number of eggs she developed, assuming all eggs are fertilized

and all fetuses come to term. Please note that “flushing” as discussed in this article does not

refer to the very specialized practice of “flushing” embryos from donor does for embryo transfer.

Instead, “flushing” as referenced here is a low technology tool available to any goat farmer.

Flushingis usually practiced by increasing the nutrients available to a doe herd about 3

weeks prior to breeding and continuing the improved nutrition for at least 2 weeks after the

breeding buck has been brought into the herd. Commonly, the does have been on an all forage

diet, and a supplemental high energy concentrate feed is added to their ration at the rate of about

0.5 to 1 pounds each daily. However, flushing can also be practiced by switching does from low

quality pastures to pastures with extremely good levels of total digestible nutrients (TDN) or by

increasing the amount of concentrate fed to does that have been receiving some concentrated

feed previously. Previous studies on various livestock species have indicated that the body

condition of the female animals can influence the effectiveness of flushing. Lean females are

FlushingPage 2

most likely to increase their ovulation rates as a response to flushing while flushing appears to

have less effect on the ovulation rates of females that are in excessive body condition (fat).

In 2005, the Cornell Animal Science Department in cooperation with theEmpireState

Meat Goat Producer’s Association was awarded a grant from the Northeast Sustainable

Agriculture Research and Education Program (NE SARE) to observe the effectiveness of various

herd practices including flushing on NY meat goat farms. In the fall of 2006, a NY meat goat

farm agreed to split their doe herd three weeks prior to breeding so that half the herd was fed

extra concentrate while the other half was not. The does were scored for body condition at the

same time the ration was increased and their age, breed, and the service sire they had been

assigned to was recorded. Each of these factors can affect litter size. For example, does that are

kidding for the first time tend to have smaller litter sizes than does that are on their 2nd to 5th

kidding while all bucks and breeds are not equally fertile. Does were randomly assigned to

flushing or not after making sure that similar distributions of age, body condition, genetics and

service sire were represented in each group.

Does were removed from pasture and dewormed at the beginning of the 3-week study.

Each treatment group was fed grass hay and offered some ear corn daily with the restriction that

the same amount of ear corn was to be offered to each group and that the daily amount (including

ears and cobs) was not to exceed ½ lb per doe per day. In addition, the does in the “flushed”

group were fed 1 pound each of a 16% crude protein (CP), high energy, pelleted feed. At the

end of three weeks, the two groups were combined with one of two service sires and all does

were fed 1 pound of the 16% CP pelleted feed on a daily basis during the breeding period. The

bucks joined their breeding groups on December 1, 2006 and all does kidded within

FlushingPage 3

approximately 150 to 169 days later. Thus, it appeared that all the does were bred and conceived

upon their first heat after exposure to the breeding bucks.

Table 1 summarizes the make up of each treatment group and the results. With the

exception of one Nubian doe, all does were high percentage Boers. The majority of the does

were relatively lean with body condition scores (Body CS) of 2.0 (13does), 2.5 (6 does) and 3.0

(1 doe) on a scale of 1 (dangerously lean) to 5 (dangerously obese). All but one doe in each

treatment was assigned to and bred by the first service sire. However, one doe in each treatment

was a daughter of this first service sire and was bred instead to the second service sire. Each

treatment consisted of two 2 yr old does that had never kidded before, five 2 yr old does that had

kidded previously as yearlings, and three 3 to 4 yr old does that had kidded twice previously.

Table 1. Breakdown of breed, age class, service sire, and body condition and results for each treatment

Flushed Group Not Flushed Group

ID# Body

CS

Age1 Breed Service

Sire

Litter

Size

ID# Body

CS

Age1 Breed Service

Sire

Litter

Size

1 2.0 3 Boer 1 Twins 4 2.0 3 Boer 1 single

3 2.0 3 Boer 1 Twins Nub 2.0 3 Nubian 1 twins

7 2.0 2 Boer 2 Twins 5 2.0 2 Boer 2 twins

18 2.0 3 Boer 1 Twins 15 2.5 3 Boer 1 twins

4093 2.5 1 Boer 1 Twins 4106 2.0 2 Boer 1 single

4114 2.5 2 Boer 1 Single 4107 2.5 2 Boer 1 single

4116 2.5 1 Boer 1 Twins 4118 2.0 1 Boer 1 single

4119 2.0 2 Boer 1 Triplet

s

4120 2.0 2 Boer 1 single

4124 2.0 2 Boer 1 Twins 4133 3.0 1 Boer 1 single

4138 2.5 2 Boer 1 Twins 4139 2.0 2 Boer 1 twins

Total number of kids 20 Total number of kids 14

Average litter size 2.0 Average litter size 1.4

1 Age classes are as follows, 1 = 2 yr old doe never kidded before, 2= 2 yr old doe, kidded as

yearling, 3 = 3 to 4 yr old doe, kidded twice previously.

The data were evaluated statistically using an analysis of variance method to determine if

any of the differences in litter size among experimental factors were not due to chance. The

FlushingPage 4

Nubian doe was removed from the analysis because she was the only representative for her

breed. The statistical model was:

Y = μ + BCS + Age + SS + ε

where Y = Litter Size, μ = herd constant, BCS = the fixed effect of body condition score, Age =

the fixed effect of age and parity (the number of times the goat has already kidded), SS = the

fixed effect of the buck the doe was bred to and ε = the residual variance including the random

effect of the doe herself.

A data set with only 19 does is a very small data set. Therefore, differences had to be

extreme to detect significant differences in litter size. For example, even though does in Age

Class 3 tended toward larger litters than did does in Age Classes 1 and 2, the differences were

not noticeable enough in this small data set to render them statistically significant. Possible

differences in litter size due to either service sire or body condition score were also too small in

this data set to conclude that they had an influence on litter size. In contrast, differences in litter

size due to flushing were significant statistically (P < 0.05) with does that were flushed

averaging 2.0 kids and does that were not flushed averaging only 1.4 (± 0.33) kids. In this meat

goat herd under the environmental and genetic conditions for the year studied, flushing appeared

to increase kidding rate from 140% to 200% or about 6 more kids for every 10 breeding does.

Even with rising prices for concentrate feeds, flushing 3 weeks prior to the breeding period

appeared to be a sound financial decision for meat goat herds with BoerX does in relatively lean

body condition. Keep in mind, that only one of the does observed in this on-farm study had a

body condition score of 3 or greater. Thus, the results of this study may not indicate the

effectiveness of flushing in does carrying extra weight at breeding.

FlushingPage 5

There are two additional factors to point out from this study. All does, regardless of

whether they were in the “flushed” group or not, were fed some ear corn on a daily basis for 3

weeks prior to breeding. However, litter size was much improved in the group of does that

additionally received 1 pound of a 16% CP high energy pelleted feed per day. The small amount

of ear corn fed appears to have been insufficient to cause a “flushing effect” in the does. In

contrast, the additional pound of 16% CP pellets did “flush” the does. Would we have had the

same response if we had substituted the pelleted feed with 1 pound of shell corn or with a high

quality pasture? This study does not answer that question. However, one reason we had put the

does on a relatively high protein pellet was because the extension educator involved (tLS) had

anecdotally observed in her own herd that litter size was disappointing in the years she flushed

with shell corn versus in the years she flushed with a mixture of shell corn and grain byproducts

adjusted to raise the protein level to 14 to 16 % CP. This study indicates that flushing can be

achieved by feeding a 16% CP high energy pellet for three weeks prior to breeding and for 2 to 3

weeks into the breeding period. Further observations are warranted to see what other methods of

flushing are effective and whether flushing requires increased nutrients in terms of protein,

minerals and vitamins, as well as energy, to be effective.

A second factor to stress is that all of the does (flushed or control) were fed 1 lb of the

16% CP concentrate on a daily basis as soon as they were put in with the buck. However, these

additional nutrients appeared to have come too late to improve ovulation rate and, thus, litter

size. The results of this study help to emphasize that flushing is unlikely to be effective if

delayed until the buck is actually in the breeding group because most does will be bred during

the first following heat.Flushingneeds to be started about 3 weeks before introduction of the

bucks.

FlushingPage 6

Share on Facebook