Find Your Family- Cattle Genetics

Target Grade Level / Age Range:

                1st and 3rd grade

Estimated Time:

                30 minutes

Purpose:

Students will explore heredity as they use their observation skills to sort cattle into their breeds. Through this activity students will gain a deeper understanding of genetics and offspring are similar to, but not exactly like their parents.

Materials:

  •  String (optional for making cards into necklaces)

Essential Files (maps, charts, pictures, or documents)

Vocabulary  

  • Heredity – the passing on of physical or mental characteristics genetically from one generation to another.
  • Phenotype – physical features of an organism
  • Trait – a characteristic 
  • Bull – cattle that are male and capable of breeding
  • Heifer – cattle that are female and have not had a calf
  • Cow – cattle that are female and have had a calf
  • Calf – cattle aged 3-12 months

 

Background – Agricultural Connections

The study of genetics and heredity are incredibly important to agriculturalists. For centuries, farmers and ranchers have selected plant varieties and livestock for specific beneficial traits. Livestock producers select for animals with increased milk production, ample muscle mass or structural correctness, among other things. Selecting these traits allows farmers to produce a higher quality and more abundant food supply.

Most plants and animals have two (or more) of every kind of gene. One comes from the female, and one comes from the male. There are different forms of genes that are referred to as alleles. Alleles are forms of the same gene with small differences in their DNA sequence. These small differences contribute to each organism’s unique physical features, which are called “phenotypes.”

Alleles can be either dominant or recessive. Dominant alleles overpower recessive alleles and are always expressed in offspring. Recessive alleles are only expressed if a recessive allele is inherited from both parents. For example, the allele in cattle that causes horns to grow is recessive. The hornless, or polled, allele is dominant, however, the gene for polled is also linked to other traits. This makes it difficult for farmers to breed for polled cattle while still having cattle with phenotypes they need (e.g., high milk production, structural correctness, docile behavior, etc.). Dominant alleles are denoted by an uppercase letter, and recessive alleles are denoted by a lower-case letter. When both dominant and recessive genes are present (one parent contributed a dominant gene and one contributed a recessive gene), the condition is called “heterozygous.” This would look like an “Aa.” When both genes are either dominant or recessive, the condition is called “homozygous.” This would look like “aa” or “AA.”

Understanding genetics is crucial for farmers. Beef producers try to breed for good characteristics, such as good marbling (intramuscular fat that contributes tenderness, juiciness and flavor), abundant muscle mass, and structural correctness. Beef producers try not to breed cattle to have horns, because they can be dangerous, small bodied, or have bad temperament. Breeders also have to pay attention to any genetic diseases that may be passed on from dams and sires to offspring.

There are several beef breeds that have distinguishing characteristics that are transferable to their offspring. Angus cattle are generally smaller bodied, less muscular cattle with good marbling and poor disposition. They are polled and either all red or all black. Hereford cattle are reddish brown, with a white face and underbelly. They are larger framed with abundant muscle but have less marbling than Angus cattle. Herefords can be either polled or horned and have calm dispositions. Angus and Hereford cattle are often bred together to get the best of both worlds: a large bodied, heavily muscled animal with good meat characteristics. A Black Angus-Hereford cross can be identified by a white face and all black body, usually with no horns, which is usually called a Black Baldy. This makes the calves look similar to, but not exactly like their parents. We can even see this pattern in purebred cattle. For example, Holstein spot patterns or coat color in Highland cattle.

Interest Approach – Engagement

Show students the Cattle Phenomena PowerPoint. Let them know that Hereford and Black Angus are breeds, or types of cattle. Ask students what they notice is different between these two cows. Let students know that what they listed are called phenotypes, or traits of animals. Then let students know that farmers will often breed, or mate, these two breeds together to get traits they want. Ask students what traits a farmer may want in their cattle.

Advance the PowerPoint slide so that the calf image shows. Let students know that this is an image of a calf from the two parents. Pause and ask students what a calf is (young cow). Ask students what they notice that is similar between the calf and the Hereford parent, repeat for the Black Angus. Let students know that today they are going to investigate this further.

Modification: If you don’t have access to a projector, start this activity at the Explore section

Procedures

  1. Explore

    • Place students into groups of 3-4. Double check that you have enough cattle cards so that each student can have one and there are still groups of 3 where each calf has parents.
      1. Modification: if you need to remove a card, remove a Holstein calf as this grouping has twin calves. If you need to add one card, consider adding a calf card. Then use this as a way to foster a conversation of how some farmers will have a cow adopt a calf.
    • Pass out the Cattle Breed Images. **Make sure that each person in the group has a different breed. ** Discuss with students if they are a Cow, Bull, Heifer Calf, or Bull calf. Remind students that a calf is a young cow, a cow is a female that’s had a calf, a bull is a male that is not castrated, and a heifer is a female that has not had a calf.
    • Have students explore their card and the cards of their group members. Students should observe the different traits the cattle have and how they are similar or different.

  2. Explain

    • Students share what they noticed about their cattle traits. Keep track of what students say on the board. Encourage students to share what they mean by a trait. For example, if a student says color, have them expand and describe what colors or patterns they see.

  3. Elaborate

    • Remind students that at the beginning they explored how two parents and their offspring. Let students know that each of them is part of a breed group made up of two parents (cow, bull) and an offspring (calf).  
    • Students then work as a whole group to sort the cattle breeds into their appropriate breed groups with two parents and a calf.

  4. Evaluate

    • Have students sit in their cattle breed groups. Ask students to look for differences between their cattle card and their group member's card.
      1. For example, the Angus group may notice that the bull has a lot of muscle while the female has less, and the calf has thicker hair.
        • Optional Extension: pass out the Cattle Breed cards and have students learn more about their breed.
    • Show students the statement: Calves look like their parents, but not exactly like their parents.
    • Individually or in their groups, students write a response to the statement with either agreeing or disagreeing. Students should use evidence from their activity to back up their answer.



Did you know? (Ag facts)

  • Cows eat mostly corn, and no state grows more corn than Iowa!
  • Cows are raised in all 99 counties in Iowa!
  • There are over 70 breeds of cattle, but two of the most popular in Iowa are Black Angus and Hereford!
  • As of 2023, Iowa was the 7th highest beef cattle producing state!

Extension Activities

  • Explore what beef cattle can be used for in the activity Beef Basics 
  • Explore more about dairy cattle with the activity All About Milk!
  • Create cattle related sentences using the Beef Book Word Blocks, which can be requested from the IALF lending library

Suggested Companion Resources

Sources/Credits

Author(s)

Cathryn Carney, Jamie Champion, Alyson McCarty, Alexandra Osborn

Organization Affiliation

Iowa Agriculture Literacy Foundation

Dallas County Farm Bureau

Agriculture Literacy Outcomes

  • T4.3-5.c. Identify examples of how the knowledge of inherited traits is applied to farmed plants and animals in order to meet specific objectives (i.e., increased yields, better nutrition, etc.)

Iowa Core Standards

  • Science
    1. 1-LS3-1. Make observations to construct an evidence-based account that young plants and animals are like, but not exactly like, their parents.
    2. 3-LS3-1. Analyze and interpret data to provide evidence that plants and animals have traits inherited from parents and that variation of these traits exists in a group of similar organisms.  
  • English Language Arts
    1. (W.1.1) (DOK 2) Write opinion pieces in which they introduce the topic or name the book they are writing about, state an opinion, supply a reason for the opinion, and provide some sense of closure.
    2. (W.1.2) (DOK 2) Write informative/explanatory texts in which they name a topic, supply some facts about the topic, and provide some sense of closure.
    3. (W.3.1) (DOK 3,4) Write opinion pieces on topics or texts, supporting a point of view with reasons.
      • Introduce the topic or text they are writing about, state an opinion, and create an organizational structure that lists reasons.
      • Provide reasons that support the opinion.
      • Use linking words and phrases (e.g., because, therefore, since, for example) to connect opinion and reasons.
      • Provide a concluding statement or section.
    4. (W.3.2) (DOK 3,4) Write informative/explanatory texts to examine a topic and convey ideas and information clearly.
      • Introduce a topic and group related information together; include illustrations when useful to aiding comprehension.
      • Develop the topic with facts, definitions, and details.
      • Use linking words and phrases (e.g., also, another, and, more, but) to connect ideas within categories of information.
      • Provide a concluding statement or section.