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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #239257
Title: IMPLICATIONS OF GOING AGAINST THE DOGMA OF FEED THEM TO BREED THEM

Author
item Roberts, Andrew
item GRINGS, ELAINE - International Livestock Research Institute (ILRI) - The Netherlands
item Macneil, Michael
item Waterman, Richard
item Alexander, Leeson
item Geary, Thomas

Submitted to: Western Section of Animal Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/10/2009
Publication Date: 6/15/2009
Citation: Roberts, A.J., Grings, E.E., MacNeil, M.D., Waterman, R.C., Alexander, L.J., Geary, T.W. 2009. Implications OF Going Against the Dogma OF Feed Them To Breed Them. Western Section of Animal Science Proceedings 60:85-88.

Interpretive Summary: Effects of providing differing levels of harvested feed during postweaning development and subsequent winters on reproduction, weight, body condition and weight of calf were evaluated in heifers produced over a 7-yr period from dams fed levels of harvested feed from Dec to March that were expected to be marginal (MARG) or adequate (ADEQ), based on average quality and availability of winter forage. Heifers were either fed to appetite (CON) or restricted fed at 80 % of that consumed by CON on common weight basis (REST) for 140-d period from about 2 mo after weaning to 1 mo before breeding. Heifers were managed together through breeding until Dec when they were separated so CON could be fed adequate harvested feed and REST could be fed marginal levels of harvested feed until 2 to 3 wk before start of calving in March. Cows remained in their treatment through subsequent winters until removed for failure to reproduce or wean a calf. Percent of heifers becoming pregnant and remaining at start of 2nd breeding season was not influenced by dam or heifer treatments. However, proportion of heifers staying in the herd until start of 3rd breeding was less for REST (58 %) than CON (69 %) heifers. Retention to 4th and 5th breeding was dependant on how the cow was treated as well as how its dam was treated. The lowest retention was for REST cows that were from ADEQ dams (46 % and 39 % at start of 4th and 5th breeding). In contrast, REST cows from MARG dams had the highest retention out to start of 5th breeding (66 %), with retention of CON cows from MARG (50%) or ADEQ dams (51 %) being intermediate. At the beginning of each breeding season, cows from the REST group were ~ 10 kg lighter weight and 0.10 less body condition score than CON cows. The way a cow’s dam was treated also affected how much she weighed at start of 3rd, 4th and 5th breeding; cows from MARG dams were 15 to 24 kg heavier than cows from ADEQ dams. Calves from REST cows and MARG granddams were lighter at birth and weaning by 1.0 and 6.9 kg, respectively, than calves from the other groups. These results demonstrate that retention, weight, condition and productivity of cows managed on 2 levels of harvested feed inputs were influenced by the level of harvested feed that had been provided to their dams. Retention was maximized by the lowest level of feed input rather than the greatest level of feed input, and appeared to be accompanied by a modest decrease in calf weight at birth and weaning.

Technical Abstract: Effects of providing differing levels of harvested feed during postweaning development and subsequent winters on reproduction, BW, BCS, and calf BW were evaluated in heifers produced over a 7-yr period from dams fed levels of harvested feed from Dec to March that were expected to be marginal (MARG) or adequate (ADEQ), based on average quality and availability of winter forage. Heifers were either fed to appetite (CON) or restricted fed at 80 % of that consumed by CON on common BW basis (REST) for 140-d period from about 2 mo after weaning to 1 mo before breeding. Heifers were managed together through breeding until Dec when they were separated so CON could be fed adequate harvested feed and REST could be fed marginal levels of harvested feed until 2 to 3 wk before start of calving in March. Cows remained in their treatment through subsequent winters until removed for failure to reproduce or wean a calf. Percent of heifers becoming pregnant and remaining at start of 2nd breeding season was not influenced by dam or heifer treatments (P > 0.23; total df = 631). Retention to start of 3rd breeding was less (P = 0.01) in REST (58 %) than CON (69 %). Interaction of dam and cow treatments (P < 0.07) influenced retention to 4th and 5th breeding. Retention to 4th breeding was less (P < 0.1) for REST cows from ADEQ dams (46 %) than the other dam by cow treatment groups (57 to 62 %). Retention to 5th breeding was less for REST cows from ADEQ dams (39 %; P < 0.01) than REST cows from MARG dams (66 %); with CON cows from MARG (50%) or ADEQ dams (51 %) being intermediate. Weight and BCS at start of each breeding was 10 kg and 0.10 BCS less (P < 0.01) for REST than CON cows. At start of 3rd, 4th and 5th breeding, cows from MARG dams were 15 to 24 kg heavier (P < 0.01) than cows from ADEQ dams. Calves from REST cows and MARG granddams were lighter (P < 0.01) at birth and weaning by 1.0 and 6.9 kg, respectively, than calves from the other groups (interaction P <0.06). Productivity of cows managed on 2 levels of harvested feed inputs was influenced by the level of harvested feed provided to their dams; greatest feed input did not maximize long term retention.